{"collection":"philosophy-ethics","full_text_available":true,"graph_url":"https://unchartedknowledge.5gfusion.net/v2/api/page/gutenberg_54462/graph","html_url":"https://unchartedknowledge.5gfusion.net/v2/page/gutenberg_54462","id":"gutenberg_54462","license":"Public Domain (US)","rights_basis":"gutenberg_metadata_copyright_false","source":"gutenberg","source_url":"https://www.gutenberg.org/ebooks/54462","summary":null,"tags":["Animal behavior","Animal intelligence","Category: Philosophy & Ethics","Category: Psychiatry/Psychology","Category: Science - Biology"],"text":"ANIMAL BEHAVIOUR\n\n BY\n C. LLOYD MORGAN, F.R.S.\n\n AUTHOR OF \u201cTHE SPRINGS OF CONDUCT,\u201d \u201cHABIT AND INSTINCT,\u201d\n \u201cPSYCHOLOGY FOR TEACHERS,\u201d ETC. ETC.\n\n _ILLUSTRATED_\n\n SECOND EDITION\n THIRD IMPRESSION\n\n LONDON\n EDWARD ARNOLD\n 1920\n (_All rights reserved_)\n\n\n\n\nPREFACE TO THE FIRST EDITION\n\n\nMy book on \u201cAnimal Life and Intelligence\u201d being out of print, I\nundertook to revise it for a new Edition. As the work of revision\nproceeded, however, it appeared that the amended treatment would not\nfall conveniently under the previous scheme of arrangement. I therefore\ndecided to write a new book under the title of \u201cAnimal Behaviour.\u201d A\nfew passages from the older work have been introduced, and some of the\nobservations and conclusions already published in greater detail in\n\u201cHabit and Instinct\u201d have been summarized. But it will be found that\nthese occupy a relatively small space in the following pages.\n\n C. LL. M.\n\n UNIVERSITY COLLEGE, BRISTOL,\n OCTOBER 1_st_, 1900.\n\n\n\n\nCONTENTS\n\n\n CHAPTER I\n\n _ORGANIC BEHAVIOUR_\n\n PAGE\n\n I. BEHAVIOUR IN GENERAL 1\n II. BEHAVIOUR OF CELLS 3\n III. CORPORATE BEHAVIOUR 14\n IV. THE BEHAVIOUR OF PLANTS 24\n V. REFLEX ACTION 31\n VI. THE EVOLUTION OF ORGANIC BEHAVIOUR 35\n\n\n CHAPTER II\n\n _CONSCIOUSNESS_\n\n I. THE CONSCIOUS ACCOMPANIMENTS OF CERTAIN ORGANIC CHANGES 42\n II. THE EARLY STAGES OF MENTAL DEVELOPMENT 48\n III. LATER PHASES IN MENTAL DEVELOPMENT 56\n IV. THE EVOLUTION OF CONSCIOUSNESS 61\n\n\n CHAPTER III\n\n _INSTINCTIVE BEHAVIOUR_\n\n I. DEFINITION OF INSTINCTIVE BEHAVIOUR 63\n II. INSTINCTIVE BEHAVIOUR IN INSECTS 71\n III. THE INSTINCTIVE BEHAVIOUR OF YOUNG BIRDS 84\n IV. THE CONSCIOUS ASPECT OF INSTINCTIVE BEHAVIOUR 98\n V. THE EVOLUTION OF INSTINCTIVE BEHAVIOUR 106\n\n\n CHAPTER IV\n\n _INTELLIGENT BEHAVIOUR_\n\n I. THE NATURE OF INTELLIGENT BEHAVIOUR 117\n II. INTELLIGENT BEHAVIOUR IN INSECTS 123\n III. SOME RESULTS OF EXPERIMENT 134\n IV. THE EVOLUTION OF INTELLIGENT BEHAVIOUR 155\n V. THE INFLUENCE OF INTELLIGENCE ON INSTINCT 168\n\n\n CHAPTER V\n\n _SOCIAL BEHAVIOUR_\n\n I. IMITATION 179\n II. INTERCOMMUNICATION 193\n III. SOCIAL COMMUNITIES OF BEES AND ANTS 205\n IV. ANIMAL TRADITION 220\n V. THE EVOLUTION OF SOCIAL BEHAVIOUR 225\n\n\n CHAPTER VI\n\n _THE FEELINGS AND EMOTIONS_\n\n I. IMPULSE, INTEREST, AND EMOTION 235\n II. PLAY 248\n III. COURTSHIP 258\n IV. ANIMAL \u201c\u00c6STHETICS\u201d AND \u201cETHICS\u201d 270\n V. THE EVOLUTION OF FEELING AND EMOTION 282\n\n\n CHAPTER VII\n\n _THE EVOLUTION OF ANIMAL BEHAVIOUR_\n\n I. THE PHYSIOLOGICAL ASPECT 295\n II. THE BIOLOGICAL ASPECT 305\n III. THE PSYCHOLOGICAL ASPECT 315\n IV. CONTINUITY IN EVOLUTION 324\n\n INDEX 338\n\n\n\n\nILLUSTRATIONS\n\n\n FIG. PAGE\n\n 1. _Paramecium_. (From \u201cAnimal Biology.\u201d Longmans) 4\n\n 2. Behaviour of Paramecia. (After Jennings, _American Journal of\n Psychology_) 8\n\n 3. Cell-division. (From \u201cAnimal Biology.\u201d Longmans) 13\n\n 4. Wapiti with antlers in velvet. (Drawing by Mr. Charles Whymper,\n after photograph by Miss Reynolds) 16\n\n 5. Wapiti with velvet shredding off. (Drawing by Mr. Charles Whymper,\n after photograph by Miss Reynolds) 17\n\n 6. Sun-dew leaf and tentacles. (From Darwin\u2019s \u201cInsectivorous Plants.\u201d\n Murray. By kind permission of Mr. Francis Darwin, F.R.S.) 26\n\n 7. Venus\u2019s Fly-trap. (From Darwin\u2019s \u201cInsectivorous Plants.\u201d Murray. By\n kind permission of Mr. Francis Darwin, F.R.S.) 27\n\n 8. Flower of _Valisneria_ 28\n\n 9. Flower of _Catasetum_ 30\n\n 10. Flower of _Catasetum_ dissected. (From Darwin\u2019s \u201cFertilization\n of Orchids.\u201d Murray. By kind permission of Mr. Francis\n Darwin, F.R.S.) 31\n\n 11. Solitary Wasp stinging Caterpillar. (After Plate III. in Dr. and\n Mrs. Peckham\u2019s \u201cSolitary Wasps\u201d) 75\n\n 12. Solitary Wasp dragging a Caterpillar to its Nest. (After Plate IV.\n in Dr. Peckham\u2019s \u201cSolitary Wasps\u201d) 76\n\n 13. Insect Larv\u00e6: _Sitaris_, _Argyrom\u0153ba_, and _Leucopsis_. (After\n Fabre \u201cSouvenirs\u201d) 80\n\n 14. Yucca Flower and Moth 83\n\n 15. Newly-hatched Chick swimming. (Drawn by Mr. Charles Whymper, after\n instantaneous photographs and a sketch by the author) 85\n\n 16. Nestling Megapode. (From Dr. R. Bowdler Sharpe\u2019s \u201cWonders of the\n Bird World.\u201d Wells Gardner) 87\n\n 17. Cuckoo ejecting Meadow Pipit. (From Mrs. Hugh Blackburn\u2019s sketch\n in \u201cBirds from Moidart.\u201d David Douglas) 91\n\n 18. Leaf-case of Birch-weevil 121\n\n 19. Solitary Wasp using a stone as a tool. (After Plate V. in Dr.\n Peckham\u2019s \u201cSolitary Wasps\u201d) 127\n\n 20. Spiders placed by Solitary Wasps in crotches of branching stems.\n (After Plate X. in Dr. Peckham\u2019s \u201cSolitary Wasps\u201d) 133\n\n 21. Fox-terrier lifting the latch of a gate. (Drawn by Mr. Charles\n Whymper, after a photograph by Miss Alice Worsley) 145\n\n 22. Cage used by Dr. Thorndike. (After figure in \u201cAnimal\n Intelligence,\u201d _Psychological Review_, 1898) 148\n\n 23. Diagram illustrating Dr. Thorndike\u2019s Experiments. (Based on\n data given in his monograph on \u201cAnimal Intelligence\u201d) 150\n\n 24. Wood ant. (From Shipley\u2019s \u201cInvertebrates.\u201d A. & C. Black) 207\n\n 25. Beetle soliciting food from Ant. (After Wasmann. Enlarged) 213\n\n 26. Honey-pot Ant. (Enlarged) 215\n\n\n\n\nANIMAL BEHAVIOUR\n\n\n\n\nCHAPTER I\n\n_ORGANIC BEHAVIOUR_\n\n\nI.--BEHAVIOUR IN GENERAL\n\nWe commonly use the word \u201cbehaviour\u201d with a wide range of meaning. We\nspeak of the behaviour of troops in the field, of the prisoner at the\nbar, of a dandy in the ball-room. But the chemist and the physicist\noften speak of the behaviour of atoms and molecules, or that of a gas\nunder changing conditions of temperature and pressure. The geologist\ntells us that a glacier behaves in many respects like a river, and\ndiscusses how the crust of the earth behaves under the stresses to\nwhich it is subjected. Weather-wise people comment on the behaviour\nof the mercury in a barometer as a storm approaches. Instances of\na similar usage need not be multiplied. Frequently employed with a\nmoral significance, the word is at least occasionally used in a wider\nand more comprehensive sense. When Mary, the nurse, returns with the\nlittle Miss Smiths from Master Brown\u2019s birthday party, she is narrowly\nquestioned as to their behaviour; but meanwhile their father, the\nprofessor, has been discoursing to his students on the behaviour\nof iron filings in the magnetic field; and his son Jack, of H.M.S.\n_Blunderer_, entertains his elder sisters with a graphic description of\nthe behaviour of a first-class battle-ship in a heavy sea.\n\nThe word will be employed in the following pages in a wide and\ncomprehensive sense. We shall have to consider, not only the kind\nof animal behaviour which implies intelligence, sometimes of a high\norder; not only such behaviour as animal play and courtship, which\nsuggests emotional attributes; but also forms of behaviour which, if\nnot unconscious, seem to lack conscious guidance and control. We shall\ndeal mainly with the behaviour of the animal as a whole, but also\nincidentally with that of its constituent particles, or cells; and we\nshall not hesitate to cite (in a parenthetic section) some episodes of\nplant life as examples of organic behaviour.\n\nThus broadly used, the term in all cases indicates and draws attention\nto the reaction of that which we speak of as behaving, in response\nto certain surrounding conditions or circumstances which evoke the\nbehaviour. The middy would not talk of the behaviour of his ship as\nshe lay at anchor in Portland harbour; the word is only applicable\nwhen there is action and reaction as the vessel ploughs through a\nheavy sea, or when she answers to the helm. Apart from gravitation the\nglacier and the river would not \u201cbehave in a similar manner.\u201d Only\nunder the conditions comprised under the term \u201cmagnetic field\u201d do iron\nfilings exhibit certain peculiarities of behaviour. And so, also, in\nother cases. The behaviour of cells is evoked under given organic or\nexternal conditions; instinctive, intelligent, and emotional behaviour\nare called forth in response to those circumstances which exercise a\nconstraining influence at the moment of action.\n\nIt is therefore necessary, in a discussion of animal behaviour, that we\nshould endeavour to realize, as far as possible, in every case, first,\nthe nature of the animal under consideration; secondly, the conditions\nunder which it is placed; thirdly, the manner in which the response is\ncalled forth by the circumstances, and fourthly, how far the behaviour\nadequately meets the essential conditions of the situation.\n\n\nII.--BEHAVIOUR OF CELLS\n\nFrom what has already been said it may be inferred that our use of\nthe term \u201cbehaviour\u201d neither implies nor excludes the presence of\nconsciousness. Few are prepared to contend that the iron filings in a\nmagnetic field consciously group themselves in definite and symmetrical\npatterns, or that sand grains on a vibrating plate assemble along\ncertain nodal lines because they are conscious of the effects of the\nbow by which the plate is set in sounding vibration. But where organic\nresponse falls under our observation, no matter how simple and direct\nthat response may be, there is a natural tendency to suppose that the\nbehaviour is conscious; and where the response is less simple and\nmore indirect, this tendency is so strengthened as to give rise to a\nstate of mind bordering on, or actually reaching, conviction. Nor is\nthis surprising: for, in the first place, organic responses, even the\nsimplest, are less obviously and directly related to the interplay of\nsurrounding circumstances; and, in the second place, they are more\nobviously in relation to some purpose in the sense that they directly\nor indirectly contribute to the maintenance of life or the furtherance\nof well-being. Now where behaviour is complex and subserves an end\nwhich we can note and name, there arises the supposition that it may\nwell be of the same nature as our own complex and conscious behaviour.\n\nTake for example the behaviour of the Slipper-animalcule, Paramecium,\none of the minute creatures known to zoologists as Protozoa. The\nwhole animal is constituted by a single cell, somewhat less than\none-hundredth of an inch in length, the form and behaviour of which\nmay be readily studied under the microscope. Thousands may be obtained\nfrom water in which some hay has been allowed to rot. The surface of\nthe Paramecium is covered with waving hair-like cilia, by which it is\npropelled through the water, while stiffer hairs may be shot out from\nthe surface at any point where there is a local source of irritation,\nas indicated at the top of the accompanying figure. Two little sacs\nexpand and contract, and serve to drain off water and waste products\nfrom the substance of the cell. Food is taken in at the end of the\nfunnel, shown in the lower part of the figure. The cilia here work\nin such manner as to drive the particles into and down the tube, and\non reaching its inner end these particles burst through into the\nsemi-fluid substance, and circulate therein. Just above the funnel\nthere are two bean-like bodies, the larger of which is known as the\nmacronucleus, the smaller as the micronucleus.\n\n[Illustration: FIG. 1.--Paramecium.]\n\nThe process of multiplication is by \u201cfission,\u201d or the division of each\nParamecium into two similar animalcules. Not infrequently, however,\ntwo Paramecia may be seen to approach each other and come together,\nfunnel to funnel; and in each the nuclei undergo curious changes. The\nmacronucleus breaks up, and is scattered. The micronucleus in each\ndivides into four portions, of which three break up and disappear;\nwhile the fourth again divides into two parts, one to be retained and\nthe other to be exchanged for the similar micronuclear product of the\nother Paramecium. The retained portion and that received in exchange\nthen unite to form a new micronucleus. M. Maupas concludes from his\ncareful observations that, in the absence of such \u201cconjugation\u201d in\nthe mid-period of life, Paramecia pass into a state of senility which\nends in decrepitude and death. If this be so, conjugation is in them\nnecessary for the continuance of a healthy race.\n\nHere we have what a zoologist would describe as a specialized mode of\nbehaviour of the nuclei; and we have also the behaviour of the minute\ncreatures (which contain the nuclei) as they approach each other and\ncome together in conjugation. Can one wonder that the latter, at any\nrate, has been regarded as an example of conscious procedure? In\ntruth we do not know in what manner and by what subtle influences the\nParamecia are drawn together in conjugation. But it is scarcely logical\nto base on such ignorance any positive assertion as to conscious\nattraction. It is better to confess that here is a piece of organic\nbehaviour, the exact conditions of which are at present unexplained.\n\nWe may take from the writings[1] of Dr. H. S. Jennings, of Harvard,\nsome account of other modes of behaviour among Paramecia. They largely\nfeed upon clotted masses of bacteria. If a number are placed upon a\nglass slip, together with a small bacterial clot, they will be seen to\ncongregate around the clot and to feed upon it. All apparently press in\nso as to reach it, or get as near it as possible. And if a number be\nplaced on another slide without any clot, they soon collect in groups\nin one or more regions, as in Fig. 2, III. It appears as if they were\nactuated by some social impulse leading them to crowd together and shun\nisolated positions. Nay, more; it seems as if, after thus collecting\nand crowding in to some centre of interest, the attractive influence\ngradually waned; the group spreads, and the Paramecia are less densely\npacked; the assembly scatters more and more, but still seems to be\nretained by an invisible boundary beyond which the little creatures do\nnot pass.\n\n[Illustration: FIG. 2.--Behaviour of Paramecia (after Jennings).]\n\nFurthermore, if kept in a jar, the Paramecia crowd up towards the\nsurface where the bacteria clots are floating; and if, beneath the\ncover glass of a slip on which they are under microscopic examination,\na drop of liquid be introduced through a very fine tube, they will seem\neither to be attracted to it, as in Fig. 2, I., or repelled from it,\nas in Fig. 2, II., according to its nature. From alkaline liquids they\nare repelled; to slightly acid drops they are attracted, unless the\nacidity be too pungent. Heat and cold are alike repellent, and even a\ndrop of pure distilled water forms an area into which the Paramecia do\nnot enter.\n\nWith such facts before him, the incautious observer may be led to\nthe conclusion that Paramecia are not only conscious, but endowed\nwith intelligence and volition. Even M. Binet,[2] who occupies a\nposition which should lead him to exercise more caution, tells us\nthat there is not a single infusorian which cannot be frightened,\nand does not manifest its fear by rapid flight; he speaks of some\nof these unicellular animals as \u201cendowed with memory and volition,\u201d\nand possessed of \u201cinstinct of great precision;\u201d and he describes the\nfollowing stages:--\n\n\u201c(1) The perception of an external object;\n\n\u201c(2) The choice made between a number of objects;\n\n\u201c(3) The perception of their position in space;\n\n\u201c(4) Movements calculated either to approach the body and seize it, or\nto flee from it.\u201d\n\nBut when we seem to have grasped his point of view, when we have\ncatalogued the memory, fear, instinct, perception, choice and\nvolition, the whole intelligent edifice crumbles; for we are told that\n\u201cwe are not in a position to determine whether these various acts\nare accompanied by consciousness, or whether they follow as simple\nphysiological processes.\u201d To most of us fear, memory, choice, volition,\nimply something more than simple physiological processes; they imply\nnot only consciousness, but highly elaborated consciousness.\n\nDr. Jennings\u2019s researches show that no such implication can be accepted\nunless we are prepared to cast aside the trammels of reasonable\ncaution. In the first place, the whole matter of feeding appears to\nbe referable to simple organic behaviour not necessarily involving\nconsciousness. The cilia in the mouth-groove and funnel constantly\nwave in such a manner as to drive a current of water, together with\nany particles which float therein, towards the interior; and the\nparticles are then engulphed, no matter what their composition may be.\nDigestible or indigestible, in they go. There is no selection of the\none or rejection of the other. But, as we have seen, the Paramecia\ncollect around a bacterial clot and feed upon it. Surely here there\nis selection of the nutritious! Apparently not. They collect in just\nthe same way towards a piece of blotting-paper, cotton-wool, cloth,\nsponge, or other fibrous body, and remain assembled round such an\ninnutritious centre just as long as round a bacterial clot. There seems\nto be no choice in the matter; contact with any substance gives rise,\nas an organic response, to the lessening or cessation of the regular\nmovements in all the cilia except those of the mouth-groove and funnel.\nAs the Paramecia swim hither and thither, first one, then another,\nthen more, chance to come in contact with the bacterial clot, the\nblotting-paper, or other substance, and since the lashing of the cilia\nis then automatically lessened, there they stay; others find their way\nto the same spot in the course of their random movements, and they,\ntoo, stay; thus many soon collect.\n\nBut this does not account for the seemingly social assemblages of\nParamecia where there is no such substance to arrest their progress.\nDr. Jennings attributes this to the fact that a dilute solution of\ncarbon-dioxide has, what we may call for the present, an attractive\ninfluence. If a bubble of air and a bubble of carbon dioxide be\nintroduced into the water in which Paramecia are swimming beneath a\ncover-glass, the animalcules collect around the carbonic dioxide, but\nnot around the air bubble. At first they press up close to the bubble\nof carbon dioxide, but gradually form a ring farther and farther from\nits limiting boundary. This is held to be due to the fact that it\nis only the dilute solution of carbonic acid that has the peculiar\n\u201cattraction\u201d--a stronger solution has a different effect. And, as the\ngas dissolves, the Paramecia collect in a ring just where the solution\nis sufficiently dilute.\n\nNow carbon dioxide is a product of the organic waste of living\nsubstance; it is given off by active Paramecia. Where therefore many\nare collected together they form a centre of the production of this\nsubstance; and when other Paramecia come, in the course of their random\nmovements, into such a centre they remain there and help to swell the\nnumbers in the cluster. If Paramecia be placed in water to which a\ndistinctly reddish tinge is given by mixing it with a small quantity\nof rosol--a substance which is decolourized by carbon dioxide, and is\nnot injurious to Paramecia--it will be seen that, where the groups\nare collected, the reddish tinge fades and disappears. As the groups\nexpand, and are less densely packed, the colourless area expands too:\nand the limits within which the group is circumscribed are also the\nlimits of decolourization. Dr. Jennings considers it beyond question\nthat the assembling of Paramecia is due to the presence in such\nassemblages of carbonic acid produced by the animals themselves. The\nfirst beginning of the crowd may be some small fragment of bacterial\nclot or other substance.\n\nIt would seem, then, that Paramecia are attracted by faintly acid\nsolutions; and here at least there is, it may be urged, an element of\nchoice. But even here, according to Dr. Jennings, there is not only\nno real choice, but not even any real attraction. What takes place,\naccording to his observations, is briefly as follows. Suppose a faintly\nacid drop be inserted beneath the cover-glass. Paramecia may almost\ngraze its boundary without being in any way affected by its presence.\nBut in their random movements some, and eventually many, perhaps most,\nof the little animals chance to enter the faintly acid region; but\nthere is no sign of reaction or response; they swim on across the\ndrop until they reach its further margin. Here a reaction does take\nplace. Instead of proceeding onwards, slowly revolving on its long\naxis, a Paramecium thus situated jerks backwards by a reversal of\nall the cilia, at the same time revolving on its axis in a direction\nopposite to that in which it was before turning. But the cilia of\nthe mouth-groove resume their normal mode of working sooner than the\nothers, and this causes the Paramecium to turn aside. It then goes\nahead until it again reaches the boundary at another point, when the\nsame behaviour is seen. The course of such a Paramecium is shown in\nFig. 2, IV.\n\nIf, instead of a faintly acid drop, a little alkaline liquid be\nintroduced beneath the cover-glass, the Paramecium similarly jerks\nbackward and turns aside on reaching its outer boundary. The turning\nmay carry it away from the alkali, as shown in Fig. 2, V.; but it just\nas often brings it again towards the drop, especially a large one. It\nseems to be a matter of chance which result follows. But eventually\nthe little creature sails off, since each time it comes within the\ninfluence of the alkaline fluid it jerks back and turns. It appears,\nthen, that when it is swimming in a normal solution a faintly acid\nliquid does not much modify its behaviour, but an alkaline fluid\nevokes a reversal of the cilia; and that when it is a slightly acid\nsolution, not only does stronger acid cause reversal, but normal fluid\nproduces a similar result. A reaction of essentially the same kind is\nin fact called forth by such different stimuli as chemical substances,\nwater heated above the normal temperature, or cooled considerably\nbelow it, and fluids which cause changes of internal pressure within\nthe substance of the cell. Nor does it matter where the stimulus is\napplied. If it be applied at the hinder end the infusorian still jerks\nbackward, though this may drive it into a destructive solution and thus\ncause death. There is, however, some evidence of different behaviour in\nsome infusorians according as the stimulus is here or there. In other\nwords, the behaviour is to some extent related to the position of the\npart stimulated.\n\nFurthermore, it may be gathered from Dr. Jennings\u2019s account that there\nis nothing to lead us to suppose that such free living cells show\nany indication of what may be regarded as the keynote of intelligent\nbehaviour. They do not profit by experience. They exhibit organic\nreactions which may be accompanied by some dim form of consciousness,\nbut which do not seem to be under the guidance of such consciousness,\nif it exist.\n\nOne of the first lessons which the study of animal behaviour, in its\norganic aspect, should impress upon our minds is, that living cells\nmay react to stimuli in a manner which we perceive to be subservient\nto a biological end, and yet react without conscious purpose--that is\nto say, automatically. The living cell assimilates food and absorbs\noxygen, it grows and subdivides, it elaborates secretions, produces\na skeletal framework or covering, rids itself of waste products,\nresponds to stimuli in a definite fashion, moves hither and thither at\nrandom, its functional activities being stimulated or checked by many\ninfluences; and yet this varied life may give no evidence of a guiding\nconsciousness: if purpose there be, it lies deeper than its protoplasm,\ndeeper than the dim sentience which may be present or may be absent--we\ncannot tell which.\n\nAnd when the cells are incorporated in the body of one of the higher\nanimals, instead of each preserving a free and nomad existence; when\nthey become the multitudinous constituents of an organic republic with\nunity of plan and unity of biological end, then the behaviour of each\nis limited in range but perfected within that range, in subservience to\nthe requirements of the more complex unity. The muscle cell contracts,\nthe gland-cell secretes, the rods and cones of the retina respond to\nthe waves of light, and all the normal responses of the special cells\ngo on with such orderly regularity that the term behaviour seems\nscarcely applicable to reactions so stereotyped. But the physiologist\nand the physician know well that such uniformity of response is\ndependent on uniformity of conditions. A little dose of some drug\nwill profoundly modify and render abnormal the procedure which was\nbefore so mechanical in its exactitude; and we are thus led to see how\ndependent the orderly behaviour really is on the maintenance of certain\nsurrounding conditions.\n\nMoreover, the existence of every cell in the body corporate is the\noutcome of a process of division involving a special mode of behaviour\nin the nucleus, of which we are only beginning to guess the meaning\nand significance, and of which we seek in vain to find an explanation\nin mechanical terms. And when we trace these divisions back to their\nprimary source in the fertilized ovum, we find changes and evolutions\nin the nuclear matter of which it can only be said that the more they\nare studied the more complex and varied do they appear.\n\nThe egg, or ovum, is a single cell produced by the female, and varying\nmuch in size, according to the amount of food-yolk with which it is\nsupplied. Like other cells, it has a nucleus, and this undergoes\nchanges which are definitely related to the fertilization of the ovum,\nwhich we describe as the biological end. Such preparatory changes\nfor a future contingency are especially characteristic of organic\nbehaviour. There is nothing like it in the mineral kingdom. The nucleus\ndivides into two parts, one of which passes out of the ovum and is\nlost. The nucleus again divides, and again one part passes out and is\nlost. Thus only one quarter of the original amount of nuclear matter\nremains. Now, division of the nucleus occurs whenever an animal cell\ndivides; but in this case (apart from details which would here be out\nof place) there is this difference. During the ordinary division of\ncells there are found in the nucleus a definite number of curved rods,\nand this number is constant for any given species; but in the nucleus\nwhich remains in the ovum after three parts of its substance are lost,\nthe number of rods has been reduced to half that which is common to the\nspecies. The egg is now ready for fertilization. A minute active cell,\nwhich is produced by the male, and which also has only half the normal\nnumber of rods, enters the ovum. The two nuclei approach each other,\nand give rise to the single nucleus of the fertilized ovum, which thus\nhas the full number of rods--half of them derived from one parent, half\nfrom the other parent. The sperm cell of the male adds little to the\nstore of protoplasm in the ovum; but it introduces a minute body, which\nseems to initiate subsequent divisions of the cell. The nature of these\ndivisions may be seen in the accompanying diagrammatic figure. In A\nthe cell is just preparing to divide. Above the nucleus is the minute\nbody (centrosome) just spoken of, which has already divided. In the\nnucleus the matter of which the rods will be constituted is net-like.\nIn B this net-work has taken on the new form of a coiled thread, while\nthe divided body above is associated with a spindle of delicate fibres.\nIn C the membrane round the nucleus has disappeared, and the coiled\nthread has broken up into curved rods (chromosomes), four of which are\nshown. The two halves of the minute body form the centres of radiating\nstars. In D each curved rod has split along its length, and the two\nparts are being drawn asunder towards the centres of the two stars;\nthe cell itself is beginning to divide. In E the process is carried a\nstep further, while in F the cell has completely divided into two: the\nrods have disappeared as such, and are replaced by a net-work; a new\nnuclear membrane has been formed, and the minute body has again divided\npreparatory to the further division of the cell.\n\n[Illustration: FIG. 3.--Cell-division.]\n\nSuch, stripped as far as possible of technicalities, are some of the\nfacts concerning the behaviour of cells and their nuclei during the\nprocess of cell-multiplication. No good purpose would be subserved by\npretending that we fully understand them. The splitting of the rods\ndoes indeed seem an efficient means to the end of securing a fair\ndivision of the nuclear substance, which, according to many biologists,\nis the organic bearer of hereditary qualities in the cells. But that\nis nearly all that we can say. Is the process accompanied by some form\nof sentience? We do not know. That it is controlled and guided by any\nconsciousness in the cell is most improbable. But if it be a purely\norganic and unconscious process it should at least impress on our\nminds the fact that such organic behaviour may reach a high degree of\ndelicacy and complexity.\n\n\nIII. CORPORATE BEHAVIOUR\n\nThe word \u201ccorporate\u201d is here applied to the organic behaviour of\ncells when they are not independent and free, but are incorporated\nin the animal body, and act in relation to each other. If the\nbehaviour of the individual cell during division impresses us with the\nsubtle intricacy of organic processes, the behaviour of the growing\ncell-republic during the early stages of organic development must\nimpress us no less forcibly. We place the fertilized egg of a hen in\nan incubator, and supply the requisite conditions of warmth, moisture,\nand fresh air. Before the egg is laid cell-division has begun. A\nsmall patch of closely similar cells has formed on the surface of\nthe yolk. Further subdivision is then arrested until the warmth of\nincubation quickens again the patch into life. But when once thus\nquickened no subsequent temporary arrest is possible--life will not\nagain lie dormant. If arrest there be it is that of death. And from\nthat little patch of cells, which spreads further and further over\nthe yolk, a chick is developed. Into the intricate technicalities\nof embryology this is not the place to enter. But it is a matter of\ncommon knowledge that, whereas we have to-day an egg such as we eat\nfor breakfast, three weeks hence we shall have a bright active bird,\na cunningly wrought piece of mechanism, and, more than that, a going\nmachine. During this wonderful process the cellular constituents take\non new forms and perform new functions, all in relationship to each\nother, all as part of one organic whole. Here bones are developed\nto form a skeletal framework, there muscles are constituted which\nshall render orderly movements possible; feathers, beak, and claws\ntake shape as products of the skin; gut and glands prepare for future\nmodes of nutrition; heart and blood-vessels undergo many changes,\nsome reminiscent of bygone and ancestral gill-respiration, some in\nrelation to the provisional respiration of the embryo by means of a\ntemporary organ that spreads out beneath the shell, some preparatory to\nthe future use of the lungs,--some, again, related to the absorption\nof food from the yolk, others to subsequent means of digestion;\nnerve, brain, and sense-organs differentiate. A going machine in the\negg, the chick is hatched, and forthwith enters on a wider field of\nbehaviour. Few would think of attributing to the consciousness of the\nembryo chick any guiding influence on the development of its bodily\nstructure, any control over the subtle changes and dispositions of its\nconstituent cells. But no sooner does the chick, when it is hatched,\nbegin to show wider modes of instinctive behaviour, than we invoke\nconscious intelligence for their explanation, seemingly forgetful of\nthe fact that there is no logical ground for affirming that, while the\nmarvellous delicacies of structure are of unconscious organic origin,\nthe early modes of instinctive behaviour are due to the guidance of\nconsciousness. Such modes of behaviour will, however, be considered in\nanother chapter. Here we have to notice that the unquestionably organic\nbehaviour of the incorporated republic of cells may attain to a high\ndegree of complexity, and may serve a distinctly biological end.\n\n[Illustration: FIG. 4.--Wapiti with antlers in velvet.]\n\nThere is, perhaps, no more striking instance of rapid and vigorous\ngrowth than is afforded by the antlers of deer,[3] which are shed\nand renewed every year. In the early summer, when growing, they are\ncovered over with a dark hairy skin, and are said to be \u201cin velvet.\u201d\nIf you lay your hand on the growing antler, you will feel that it is\nhot with the nutrient blood that is coursing beneath it. It is, too,\nexceedingly sensitive and tender. An army of tens of thousands of busy\nliving cells is at work beneath that velvet surface, building the bony\nantlers, preparing for the battles of autumn. Each minute cell, working\nfor the general good, takes up from the nutrient blood the special\nmaterials it requires; elaborates the crude bone-stuff, at first soft\nas wax, but ere long to become hard as stone; and then, having done\nits work, having added its special morsel to the fabric of the antler,\nremains embedded and immured, buried beneath the bone-products of its\nsuccessors or descendants. No hive of bees is busier or more replete\nwith active life than the antler of a stag as it grows beneath the\nsoft, warm velvet. And thus are built up in the course of a few weeks\nthose splendid \u201cbeams,\u201d with their \u201ctynes\u201d and \u201csnags,\u201d which, in the\ncase of the wapiti, even in the confinement of our Zoological Gardens,\nmay reach a weight of thirty-two pounds, and which, in the freedom of\nthe Rocky Mountains, may reach such a size that a man may walk, without\nstooping, beneath the archway made by setting up upon their points the\nshed antlers. When the antler has reached its full size, a circular\nridge makes its appearance at a short distance from the base. This\nis the \u201cburr,\u201d which divides the antler into a short \u201cpedicel\u201d next\nthe skull, and the \u201cbeam\u201d with its branches above. The circulation in\nthe blood-vessels of the beam now begins to languish, and the velvet\ndies and peels off, leaving the hard, bony substance exposed. Then is\nthe time for fighting, when the stags challenge each other to single\ncombat, while the hinds stand timidly by. But when the period of battle\nis over, and the wars and loves of the year are past, the bone beneath\nthe burr begins to be eaten away, through the activity of certain large\nbone-absorbing cells, and, the base of attachment being thus weakened,\nthe antlers are shed; the scarred surface skins over and heals, and\nonly the hair-covered pedicel of the antler is left.\n\n[Illustration: FIG. 5.--Wapiti with velvet shredding off.]\n\nWe have no reason to suppose that this corporate cellular behaviour,\ninvolving the nicely adjusted co-operation of so vast an army of\norganic units, is under the conscious guidance of the stag. And yet\nhow orderly the procedure! how admirable the result! Nor is there an\norgan or structural part of the stag or any other animal that does not\ntell the same tale. This is but one paragraph of the volume in which\nis inscribed the varied and wonderful history of organic behaviour in\nits corporate aspect. Is it a matter for wonder that the cause of such\nphenomena has been regarded as \u201ca mystery transcending naturalistic\nconception; as an alien influx into nature, baffling scientific\ninterpretation\u201d? And yet, though not surprising, this attitude of\nmind, in face of organic phenomena, is illogical, and is due partly\nto a misconception of the function of scientific interpretation,\npartly to influences arising from the course pursued by the historical\ndevelopment of scientific knowledge. The function of biological science\nis to formulate and to express in generalized terms the related\nantecedences and sequences which are observed to occur in animals and\nplants. This can already be done with some approach to precision. But\nthe underlying cause of the observed phenomena does not fall within\nthe purview of natural science; it involves metaphysical conceptions.\nIt is no more (and no less) a \u201cmystery\u201d than all causation in its last\nresort--as the _raison d\u2019\u00eatre_ of observed phenomena--is a mystery.\nGravitation, chemical affinity, crystalline force,--these are all\n\u201cmysteries.\u201d\n\nIf the mystery of life, lying beneath and behind organic behaviour, be\nsaid to baffle scientific interpretation, this is because it suggests\nultimate problems with which science as such should not attempt to\ndeal. The final causes of vital phenomena (as of other phenomena) lie\ndeeper than the probe of science can reach. But why is this sense\nof mystery especially evoked in some minds by the contemplation of\norganic behaviour, by the study of life? Partly, no doubt, because\nthe scientific interpretation of organic processes is but recent, and\nin many respects incomplete. People have grown so accustomed to the\nmetaphysical assumptions employed by physicists and chemists when they\nspeak of the play of crystalline forces and the selective affinities\nof atoms, they have been wont for so long to accept the \u201cmysteries\u201d\nof crystallization and of chemical union, that these assumptions have\ncoalesced with the descriptions and explanations of science; and\nthe joint products are now, through custom, cheerfully accepted as\nnatural. Where the phenomena of organic behaviour are in question, this\ncoalescence has not yet taken place; the metaphysical element is on\nthe one hand proclaimed as inexplicable by natural science, and on the\nother hand denied even by those who talk glibly of physical forces as\nthe final cause of the phenomena of the inorganic world.\n\nSo much reference to the problems which underlie the problems of\nscience seems necessary. It is here assumed that the phenomena of\norganic behaviour are susceptible of scientific discussion and\nelucidation. But even assuming that an adequate explanation in terms\nof antecedence and sequence shall be thus attained by the science of\nthe future, this will not then satisfy, any more than our inadequate\nexplanations now satisfy, those who seek to know the ultimate meaning\nand reason of it all: What makes organic matter behave as we see it\nbehave? what drives the wheels of life, as it drives the planets\nin their courses? what impels the egg to go through its series of\ndevelopmental changes? what guides the cells along the divergent course\nof their life-history? These are questions the ultimate answers to\nwhich lie beyond the sphere of science--questions which man (who is a\nmetaphysical being) always does and always will ask, even if he rests\ncontent with the answer of agnosticism; but questions to which natural\nscience never will be able, and should never so much as attempt, to\ngive an answer.\n\nEnough has now been said to show that organic behaviour is a thing _sui\ngeneris_, carrying its own peculiar marks of distinction: and further,\nthat, for science, this is just part of the constitution of nature,\nneither more nor less mysterious than, let us say, crystallization or\nchemical combination. But associated and closely interwoven with all\nthat is distinctively organic there is much which can to some extent be\ninterpreted in terms of physics and chemistry.\n\nThe animal[4] has sometimes been likened to a steam-engine, in which\nthe food is the fuel which enters into combustion with the oxygen taken\nin through the lungs. It may be worth while to modify and modernize\nthis analogy--always remembering, however, that such an analogy must\nnot be pushed too far.\n\nIn the ordinary steam-engine the fuel is placed in the fire-box, to\nwhich the oxygen of the air gains access; the heat produced by the\ncombustion converts the water in the boiler into steam, which is made\nto act upon the piston, and thus set the machinery in motion. But\nthere is another kind of engine, now extensively used, which works on\na different principle. In the gas-engine the fuel is gaseous, and it\ncan thus be introduced in a state of intimate mixture with the oxygen\nwith which it is to unite in combustion. This is a great advantage. The\ntwo can unite rapidly and explosively. In gunpowder the same end is\neffected by mixing the carbon and sulphur with nitre, which contains\nthe oxygen necessary for their explosive combustion. And this is\ncarried still further in dynamite and gun-cotton, where the elements\nnecessary for explosive combustion are not merely mechanically mixed,\nbut are chemically combined in a highly unstable compound.\n\nBut in the gas-engine, not only are the fuel and the oxygen thus\nintimately mixed, but the controlled explosions are caused to act\ndirectly on the piston, and not through the intervention of water in a\nboiler. Whereas, therefore, in the steam-engine the combustion is to\nsome extent external to the working of the machine, in the gas-engine\nit is to a large extent internal and direct.\n\nNow, instead of likening the animal as a whole to a steam-engine, it\nis more satisfactory to liken each cell to an automatic gas-engine\nwhich manufactures its own explosive. During the period of repose\nwhich intervenes between periods of activity, its protoplasm is busy\nin construction, taking from the blood-discs oxygen, and from the\nblood-fluid carbonaceous and nitrogenous materials, and knitting these\ntogether into relatively unstable explosive compounds, which play the\npart of the mixed air and gas of the gas-engine. A resting muscle may\nbe likened to a complex and well-organized battery of gas-engines. On\nthe stimulus supplied through a nerve-channel a series of co-ordinated\nexplosions takes place: the gas-engines are set to work; the muscular\nfibres contract; the products of the silent explosions are taken up\nand hurried away by the blood-stream; and the protoplasm prepares a\nfresh supply of explosive material. Long before the invention of the\ngas-engine, long before gun-cotton or dynamite were dreamt of, long\nbefore some Chinese or other inventor first mixed the ingredients of\ngunpowder, organic nature had utilized the principle of controlled\nexplosions in the protoplasmic cell, and thus rendered animal behaviour\npossible.\n\nCertain cells are, however, more delicately explosive than others.\nThose, for example, on or near the external surface of the body--those,\nthat is to say, which constitute the end-organs of the special\nsenses--contain explosive material which may be fired by a touch, a\nsound, an odour, the contact with a sapid fluid or a ray of light.\nThe effects of the explosions in these delicate cells, reinforced in\ncertain neighbouring nerve-batteries, are transmitted down the nerves\nas waves of subtle chemical or electrolytic change, and thus reach\nthat wonderful aggregation of organized and co-ordinated explosive\ncells, the brain. Here it is again reinforced and directed (who, at\npresent, can say how?) along fresh nerve-channels to muscles, or\nglands, or other organized groups of explosives. And in the brain,\nsomehow associated with the explosion of its cells, consciousness,\nthe mind-element, emerges; of which we need only notice here that\nit belongs to a _wholly different order of being_ from the physical\nactivities and products with which we are at present concerned.\n\nWe must not press the explosion analogy too far. The essential thing\nseems to be that the protoplasm of the cell has the power of building\nup complex and unstable chemical compounds, which are perhaps stored\nin its spongy substance; and that these unstable compounds, under\nthe influence of a stimulus (or, possibly, sometimes spontaneously),\nbreak down into simpler and more stable compounds. In the case of\nmuscle-cells, this latter change is accompanied by an alteration\nin length of the fibres, and consequent movements in the animal,\nthe products of the disruptive change being useless or harmful, and\nbeing, therefore, removed as soon as possible. But very frequently\nthe products of explosive activity are made use of. In the case of\nbone-cells, one of the products of disruption is of permanent use to\nthe organism, and constitutes the solid framework of the skeleton. In\nthe case of the secreting cells in the salivary and other digestive\nglands, some of the disruptive products are of temporary value for the\npreparation of the food. It is probable that these useful products\nof disruption, permanent or temporary, took their origin in waste\nproducts for which natural selection has found a use, and which have\nbeen gradually rendered more and more efficacious in modes of organic\nbehaviour increasingly complex.\n\nIn the busy hive of cells which constitutes what we call the animal\nbody, there is thus ceaseless activity. During periods of apparent\nrest the protoplasm is engaged in constructive work, building up fresh\nsupplies of unstable materials, which, during periods of apparent\nactivity, break up into simpler and more stable substances, some of\nwhich are useful to the organism, while others must be got rid of as\nsoon as possible. From another point of view, the cells during apparent\nrest are storing up energy to be utilized by the animal during its\nperiods of activity. The storing up of available energy may be likened\nto the winding up of a watch or clock; it is when an organ is at rest\nthat the cells are winding themselves up; and thus we have the apparent\nparadox that the cell is most active and doing most work when the organ\nof which it forms a part is at rest. During the repose of an organ, in\nfact, the cells are busily working in preparation for the manifestation\nof energetic action that is to follow. Just as the brilliant display\nof intellectual activity in a great orator is the result of the silent\nwork of a lifetime, so is the physical manifestation of muscular power\nthe result of the silent preparatory work of the muscle-cells.\n\nIt may, perhaps, seem strange that the products of cellular life should\nbe reached by the roundabout process of first producing unstable\ncompounds, from which are then formed more stable substances, useful\nfor permanent purposes as in bone, or temporary purposes as in the\ndigestive fluids. It seems a waste of power to build up substances\nunnecessarily complex and stored with an unnecessarily abundant supply\nof energy. But only thus could the organs be enabled to act under the\ninfluence of stimuli, and afford examples of corporate behaviour. They\nare like charged batteries ready to discharge under the influence of\nthe slightest organic touch. In this way, too, is afforded a means\nby which the organ is not dependent only upon the products of the\nimmediate activity of the protoplasm at the time of action, but can\nutilize the store laid up during preceding periods of rest.\n\nSufficient has now been said to illustrate the nature of some of the\nphysical processes which accompany organic behaviour in its corporate\naspect. The fact that should stand out clearly is that the animal body\nis stored with large quantities of available energy resident in highly\ncomplex and unstable chemical compounds, elaborated by the constituent\ncells. These unstable compounds, eminently explosive according to\nour analogy, are built up of materials derived from two different\nsources--from the nutritive matter (containing carbon, hydrogen, and\nnitrogen) absorbed during digestion, and from oxygen taken up from the\nair during respiration. The cells thus become charged with energy that\ncan be set free on the application of the appropriate stimulus, which\nmay be likened to the spark that fires the explosive.\n\nLet us note, in conclusion, that it is through the blood-system,\nramifying to all parts of the body, and the nerve-system, the\nramifications of which are not less perfect, that one of the larger\nand higher animals is knit together into an organic whole. The former\ncarries to the cell the raw materials for the elaboration of its\nexplosive products, and, after the explosions, carries off the waste\nproducts which result therefrom. The nerve-fibres carry the stimuli\nby which the explosive is fired, while the central nervous system\norganizes, co-ordinates, and controls the explosions, and initiates the\nelaboration of the explosive compounds. Blood and nerves co-operate to\nrender corporate behaviour possible.\n\n\nIV.--THE BEHAVIOUR OF PLANTS\n\nA short parenthetic section on the behaviour of plants may serve\nfurther to illustrate the nature of organic behaviour. We have seen\nthat Paramecium is apparently attracted by faintly acid solutions,\nand have briefly considered Dr. Jennings\u2019s interpretation of the\nfacts disclosed by careful observation. In the ferns the female\nelement, or ovum, is contained in a minute flask-shaped structure\n(archegonium), in the neck and mouth of which mucilaginous matter, with\na slightly acid reaction, is developed; and this is said to exercise\nan attractive influence on the freely swimming ciliated male elements,\nor spermatozoids, which are necessary for fertilization. \u201cNow, it\nhas been shown by experiment that the spermatozoids of ferns are\nattracted by certain chemical substances, and especially by malic acid.\nIf artificial archegonia are prepared (consisting of tiny capillary\nglass-tubes) and filled with mucilage to which a small quantity of this\nacid has been added, they are found, when placed in water containing\nfern-spermatozoids, to exercise the same attraction upon them which\nthe real archegonia exercise in nature. The malic acid gradually\ndiffuses out into the water, and the spermatozoids are influenced by\nit, so that they move in the direction in which the substance is more\nconcentrated, _i.e._ towards the tube. Although it cannot be proved\nthat the archegonia themselves contain malic acid, as they are too\nsmall for a recognizable quantity to be obtained from them, yet there\ncan be little doubt that the natural archegonia owe their attractive\ninfluence to the same chemical agent which has proved efficacious\nin experiment.\u201d[5] In the light of Dr. Jennings\u2019s observations, it\nis perhaps not improbable that this so-called attractive influence\nis similar to that seen in Paramecium; and that the spermatozoids\nenter the organic acid in the course of their random movements, and\nthere remain. Be that as it may, the male elements collect in the\nmucilaginous mass, and pass down the neck of the flask until one\nreaches and coalesces with the female element, or ovum, and effects its\nfertilization. Here we have organic behaviour unmistakably directed to\na biological end--behaviour which may indeed be accompanied by some dim\nform of consciousness, but which is due to a purely organic reaction.\nIt is scarcely satisfactory to say that the spermatozoids \u201cpossess a\ncertain power of perception, by which their movements are guided.\u201d[6]\nIf consciousness be present, it is probably merely an accompaniment\nof the response, and has no directive influence on its nature and\ncharacter.\n\nIn the higher plants, as in the higher animals, the differentiation\nand the orderly marshalling of the cell-progeny arising from the\ncoalescent male and female elements, afford, during development,\nexamples of corporate organic behaviour which can be more readily\ndescribed than explained, but which not less clearly subserve definite\nbiological ends, and in many cases, such as the direction of growth\nin radicles and roots, the curling of tendrils, and the reaction to\nthe influence of light and warmth, are related to and evoked by the\nenvironing conditions. More closely resembling familiar modes of\nbehaviour in animals are such movements as are seen in the \u201ctentacles\u201d\nwhich project from the upper surface and margin of the Sun-dew leaf.\nTheir knobbed ends secrete a sticky matter, which glistens in the\nsun, and to which small foreign bodies readily adhere. If particles\nof limestone, sand, or clay, such as may be blown by the wind, touch\nand stick to these knobs, there follows an exudation of acid liquid,\nbut no marked and continuous change occurs in the position of the\ntentacles. But should an insect alight on the leaf, or a small piece\nof meat be placed upon the tentacles, not only is there a discharge\nof acid juice, but a ferment is also produced, which has a digestive\naction on the nitrogenous matter. Slowly the tentacle curves inwards\nand downwards, as one\u2019s finger may bend towards the palm of one\u2019s\nhand; neighbouring tentacles also turn towards and incline on to the\nstimulating substance; then others, further off, behave in a similar\nway, until all the tentacles, some two hundred in number, are inflected\nand converge upon the nitrogenous particle. Nay, more: \u201cWhen two little\nbits of meat are placed simultaneously on the right and left halves\nof the same Sun-dew leaf, the two hundred tentacles divide into two\ngroups, and each one of the groups directs its aim to one of the bits\nof meat.\u201d[7]\n\n[Illustration: FIG. 6.--Sun-dew (_Drosera_). Leaf (enlarged) with the\ntentacles on one side inflected over a bit of meat placed on the disc.\n(From Darwin\u2019s \u201cInsectivorous Plants.\u201d)]\n\nThe movements, though slow, are orderly, methodical, and effective,\nthe secretions of many glands being brought to bear on just those\nsubstances which are capable of digestion and absorption by the\nplant. The seemingly concerted action is moreover due to an organic\ntransmission of impulses from cell to cell--a transmission accompanied\nby visible changes in a purple substance contained within the cells. In\nthe Sun-dew any tentacle may form the starting-point of the spreading\nwave of impulse. But in the Venus\u2019s Fly-trap there are six delicate\nspines, the slightest touch on any one of which causes the two halves\nof the specially modified leaf-end to fold inwards on the midrib as a\nhinge. The transmission of impulse is more rapid, the trap closing in a\nfew seconds; and electric currents have been observed to accompany the\nchange. Tooth-like spines at the edge of the trap interlock, and serve\nto prevent the escape of small insects, while short-stalked purple\nglands secrete an acid digestive juice. Division of labour has been\ncarried further; and organic behaviour, not less purposive, is carried\nout in a manner even more effective.\n\n[Illustration: FIG. 7.--Venus\u2019s Fly-trap (_Dion\u00e6a_). Leaf viewed\nlaterally in its expanded state. (From Darwin\u2019s \u201cInsectivorous\nPlants.\u201d)]\n\nIn other plants adaptive movements are well known. \u201cFew phenomena\nhave such a peculiar appearance as the movements which occur in the\nsensitive Oxalis when rain comes on. Not only do the leaflets on which\nthe finest rain-drops fall fold together in a downward direction, but\nall the neighbouring ones perform the same movement, although they have\nnot themselves been shaken by the impact of the falling drops. The\nmovement is continued to the common leaf-stalk bearing the numerous\nleaflets. This also bends down towards the ground. The rain-drops now\nslide over the bent leaf-stalk and down over the depressed leaflets,\nand not a drop remains behind on their delicate surfaces.\u201d[8] The\nwaves of impulse are said to be transmitted along definite lines, and\nto cause the expulsion of water from certain cells at the point of\ninsertion of the leaflets or leaf-stalks, rendering them flaccid.\n\n[Illustration: FIG. 8.--Flower of _Valisneria_.]\n\nAppealing even more strongly to the popular imagination, though\nprobably not of deeper biological significance, is the behaviour of\nplants in relation to the essential process of fertilization. Only two\nexamples can here be cited. _Valisneria spiralis_ is an aquatic plant,\nwith long submerged strap-like leaves, which grows in still water in\nSouthern Europe. The female flower is enclosed in two translucent\nbracts, which form a protective bladder so long as the flower is\nbeneath the surface of the water; but the flower-stalk continues to\ngrow until the flower reaches the surface, when it becomes freely\nexposed by the splitting of the bracts. There are three boat-shaped\nsepals, which act as floats; three quite minute petals; and three large\nfringed stigmas, which project over the abortive petals in the space\nbetween the boat-like sepals. The flower is now ready for fertilization.\n\nThe male flowers, which are developed on different individuals from\nthose which produce the female flowers, grow in bunches beneath an\ninvesting bladder. The stalk does not elongate, so that the bladder\nnever rises far above the bottom, and remains completely submerged.\nHere the bladder bursts, and the male flowers, with short stalks, are\ndetached. Each has three sepals, which enclose and protect the stamens.\nThe separated flower now ascends to the surface, the sepals open and\nform three hollow boats, by means of which the flower floats freely,\nwhile the two functional stamens project upwards and somewhat obliquely\ninto the air, exposing the large sticky pollen-cells. Blown hither\nand thither by the wind, these little flower-boats \u201caccumulate in the\nneighbourhood of fixed bodies, especially in their recesses, where\nthey rest like ships in harbour. When the little craft happen to get\nstranded in the recesses of a female Valisneria flower, they adhere to\nthe tri-lobed stigma, and some of the pollen-cells are sure to be left\nsticking to the fringes on the margins of the stigmatic surface.\u201d[9]\n\nThis is a good example of purely organic behaviour admirably adapted to\nsecure a definite and important biological end. Few will be likely to\ncontend that it is even accompanied by, still less under the guidance\nof, any conscious foresight on the part of the plant. And the lesson it\nshould teach is that, in the study of organic behaviour, adaptation to\nthe conditions of existence is not necessarily the outcome of conscious\nguidance.\n\nIt is well known that the orchids exhibit, in their mode of\nfertilization, remarkable adaptations by which the visits of insects\nare rendered subservient to the needs of the plant. In the Catasetums,\nfor example, the male flower may be described as consisting of two\nparts--a lower part, the cup-like labellum (Fig. 9, _l_), which\nconstitutes a landing-stage on which insects may alight; and an upper\npart, the column (Fig. 9, _c_), surrounded by the upper sepal and\npetals. In the upper part of the column the pollen-masses are borne at\none end of an elastic pedicel, at the other end of which is an adhesive\ndisc, and the rod is bent over a pad so as to be in a state of strain.\nThe disc is retained in position by a membrane with which two long\ntubular horns (Figs. 9, _h_; 10, _an_) are continuous. These project\nover the labellum, where insects alight to gnaw its sweet fleshy walls,\nand if they be touched, even very lightly, they convey some stimulus to\nthe membrane which surrounds and connects the disc with the adjoining\nsurface, causing it instantly to rupture; and as soon as this happens,\nthe disc is suddenly set free. The highly elastic pedicel then flirts\nthe disc out of its chamber with such force that the whole is ejected,\nsometimes to a distance of two or three feet, bringing away with it the\ntwo pollen-masses. \u201cThe utility of so forcible an ejection is to drive\nthe soft and viscid cushion of the disc against the hairy thorax of\nthe large hymenopterous insects which frequent the flowers. When once\nattached to an insect, assuredly no force which the insect could exert\nwould remove the disc and pedicel, but the caudicles [by which the\npollen-masses are attached] are ruptured without much difficulty, and\nthus the balls of pollen might readily be left on the adhesive stigma\nof the female flower.\u201d[10]\n\n[Illustration: FIG. 9.--Flower of _Catasetum_; _c_, column; _h_, horns;\n_l_, labellum.]\n\nHere again we have adaptive behaviour of exquisite nicety, and we\nhave the transmission of an impulse very rapidly along the cells of\nthe irritable horns, followed by the sudden rupture of a membrane.\nBeautiful, however, as is the adaptation, effective as it is to a\ndefinite biological end, the organic behaviour does not afford any\nindication of the guidance of consciousness. Among plants we have many\ninteresting and admirable examples of organic behaviour; but nowhere so\nmuch as a hint of that profiting by individual experience which is the\ncriterion of the effective presence of conscious guidance and control.\n\n[Illustration: FIG. 10.--_Catasetum_; C, diagram of column; _a_, anther;\n_an_, horn; _d_, adhesive disc; _f_, filament of anther; _g_, ovarium;\n_ped_, pedicel; D and E, pollinium; _p_, pollen-mass. (From Darwin\u2019s\n\u201cOrchids.\u201d)]\n\n\nV.--REFLEX ACTION\n\nIt is sometimes said that the tentacles of the Sun-dew leaf indicate\na primitive kind of reflex action in plants, and that they afford\nevidence of discrimination. \u201cIt is,\u201d says Romanes, \u201cthe stimulus\nsupplied by continuous _pressure_ that is so delicately perceived,\nwhile the stimulus supplied by _impact_ is disregarded.\u201d[11] And,\ncomparing this with what is observed in the Venus\u2019s Fly Trap, he\nsays: \u201cIn these two plants the power of discriminating between these\ntwo kinds of stimuli has been developed to an equally astonishing\nextent, but in opposite directions.\u201d[12] It is well, however, to\navoid terms which carry with them so distinctively a conscious\nimplication as \u201cdiscrimination\u201d and \u201cperception\u201d do for most of us.\nJust as the photographer\u2019s film reacts differently according to the\nquality of light-rays, violet or red, which reach it, so do many\norganic substances react differently to stimuli of different quality,\nirrespective of their intensity. The \u201cdiscrimination\u201d of plants and of\nsome of the lower animals is of this kind, and it is better to speak of\nit simply as differential reaction. There can then be no chance of its\nbeing confused with conscious choice.\n\nNor should the movements of the Sun-dew tentacles or of those of the\nSea-anemone be termed in strictness reflex action. As originally\nemployed by Marshall Hall, and, since that time, by common consent,\n_reflex action_ involves a differentiated nervous system. There is,\nfirst, an afferent impulse from the point of stimulation passing\ninwards to a nerve-centre; secondly, certain little-understood changes\nwithin this centre; and thirdly, an efferent impulse from the centre\nto some organ or group of cells which are thus affected. In plants\nthere is no indication of anything analogous to this specialized mode\nof response. The impulse passes directly from the point of stimulation\nto the part affected without the intervention of anything like a\nnerve-centre. In the sensitive Oxalis the impulse passes directly to\nthe point of insertion of the leaflet or leaf-stalk; in Catasetum, from\nthe horn to the retaining membrane; in the Sun-dew, from the affected\ntentacle to those in its neighbourhood. Even in the Sea-anemone, though\nthere is a loosely diffused nervous system, the passage of the impulse\nfrom one part of the circlet of tentacles to other parts, seems to\nfollow a direct rather than a reflex course, and there do not appear to\nbe any specialized centres by which the impulses are received and then\nredistributed.\n\nIn all animals in which well-differentiated nervous systems are found,\nin which there are distinct nerve-fibres and nerve-centres, reflex\nactions, simple or more complicated, occur. They form the initial\nsteps leading up to the highest types of organic behaviour. So long\nas the nervous arcs--afferent fibres, nerve-centre, and efferent\nfibres--remain intact reflex acts may be carried out with great\nprecision and delicacy, even when the higher centres, which we believe\nto be those of conscious guidance and control, have been destroyed.\nWhen, for example, the whole of the brain of a frog has been extirpated\nand the animal is hung up by the lower jaw, if the left side be touched\nwith a drop of acid the left leg is drawn up and begins to scratch\nat the irritated spot, and when this leg is held, the other hind leg\nis, with seemingly greater difficulty, brought to bear on the same\nspot. \u201cThis,\u201d says Sir Michael Foster, \u201cat first sight looks like\nan intelligent choice.... But a frog deprived of its brain so that\nthe spinal cord only is left, makes no spontaneous movements at all.\nSuch an entire absence of spontaneity is wholly inconsistent with\nthe possession of intelligence.... We are therefore led to conclude\nthat the phenomena must be explained in some other way than by being\nreferred to the working of an intelligence.\u201d[13] But if we concede that\nintelligence is absent, may there not at least be some consciousness?\nSir Michael Foster\u2019s reply to such a question goes as far as we have\nany justification for going, even when we give free rein to conjecture.\n\u201cWe may distinguish,\u201d he says, \u201cbetween an active continuous\nconsciousness, such as we usually understand by the term, and a passing\nor momentary condition, which we may speak of as consciousness, but\nwhich is wholly discontinuous from an antecedent or from a subsequent\nsimilar momentary condition; and indeed we may suppose that the\ncomplete consciousness of ourselves, and the similarly complete\nconsciousness which we infer to exist in many animals, has been\nevolved out of such a rudimentary consciousness. We may, on this view,\nsuppose that every nervous action of a certain intensity or character\nis accompanied by some amount of consciousness which we may, in a\nway, compare to the light emitted when a combustion previously giving\nrise to invisible heat waxes fiercer. We may thus infer that when the\nbrainless frog is stirred by some stimulus to a reflex act, the spinal\ncord is lit up by a momentary flash of consciousness coming out of\nthe darkness and dying away into darkness again; and we may perhaps\ninfer that such a passing consciousness is the better developed the\nlarger the portion of the cord involved in the reflex act and the more\ncomplex the movement. But such a momentary flash, even if we admit its\nexistence, is something very different from consciousness as ordinarily\nunderstood, is far removed from intelligence, and cannot be appealed to\nas explaining the \u2018choice\u2019 spoken of above.\u201d[14]\n\nThese sentences indicate with sufficient clearness the distinction,\nmore than once hinted at in the foregoing pages, between consciousness\nas an accompaniment, and consciousness as a guiding influence. We\nshall have more to say in this connection in subsequent chapters. The\nexperiment with the frog shows, at any rate, that reflex actions, of\na distinctly purposive nature, may be carried out when the centres,\nwhich are believed to exercise conscious control and guidance have\nbeen destroyed. It is said that in man, when, owing to injuries of\nthe spine, the connection between the brain and the lower part of the\nspinal cord have been severed, tickling of the foot causes withdrawal\nof the limb without directly affecting the consciousness of the\npatient. But in all such cases we are dealing with a maimed creature.\nThe living frog or man, healthy and intact, is, presumably in the one\ncase, certainly in the other, conscious of these reflex actions, and\ncan exercise some amount of guidance and control over them. In man this\nis unquestionably the case. But granting that the brain is the organ\nof conscious control, granting that it can receive impulses from and\ntransmit impulses to the reflex centres, no more is here implied, and\nno more can be legitimately inferred, than that the kind of organic\nbehaviour we call \u201creflex action\u201d is in the higher animals in touch\nwith the guiding centres. We have no ground for assuming that in\nreflex action there is any power of intelligent guidance independent\nof that which is exercised by the brain or analogous organ. In brief,\nreflex acts, in animals endowed with intelligence, may be regarded as\nspecialized modes of organic behaviour; which are in themselves often\ncharacterized by much complexity; which subserve definite biological\nends; which are effected by subordinate centres capable of transmitting\nimpulses to, and receiving impulses from, the centres of intelligent\nguidance; and which, as responses confined to certain organs or parts\nof the body, form elements in the wider behaviour of the animal as a\nwhole.\n\n\nVI.--THE EVOLUTION OF ORGANIC BEHAVIOUR\n\nThe interpretation of organic behaviour in terms of evolution mainly\ndepends on the answer we give to the question: Are acquired modes\nof behaviour inherited? A negative answer to this question is here\nprovisionally accepted. But the premisses from which this conclusion is\ndrawn are too technical for discussion in these pages. It must suffice\nto state as briefly as possible what this conclusion amounts to, and to\nindicate some of the consequences which follow from its acceptance.\n\nThe fertilized egg gives origin, as we have seen, to the multitude\nof cells which build up the body of one of the higher animals. There\nare, on the one hand, muscle-cells, gland-cells, nerve-cells, and\nother constituents of the various tissues; and there are, on the\nother hand, the reproductive cells--ova or sperms, as the case may\nbe. Now, every cell in the developed animal is a direct descendant of\nthe fertilized egg. But of all the varied host only the reproductive\ncells take any direct share in the continuity of the race. Hereditary\ntransmission is therefore restricted to the germinal substance of\nthese reproductive cells. Trace the ancestry of any cell in the adult\nbody, say a nerve-cell, and you reach the fertilized ovum. Trace back\nthe ancestral line yet further, and you follow a long sequence of\nreproductive cells, or, at least, of cells which have undergone but\nlittle differentiation; but never again will you find, in the course of\na genealogy of bewildering length, a nerve-cell. Such a tissue-element\nis a descendant, but cannot become an ancestor; it dies without direct\nheirs.\n\nIt is universally admitted that the bodily structures are subject\nto what is termed _modification_ under the stress of environing\ncircumstances. The muscles may acquire unusual strength by use and\nexercise; the nerve-centres may learn certain tricks of behaviour\nin the course of individual life; and other structures may be\nsimilarly _accommodated_ to the conditions which affect them. To such\nmodifications of structure or function in the organs or parts the term\n_acquired_ is primarily applied. The tissues have thus a certain amount\nof organic plasticity, through which they are adjusted to a range of\ncircumstances varying in extent. They are able to acquire new modes of\nbehaviour. But the cells of which they are composed are off the line\nof racial descent. They leave no direct heirs. When the body dies the\nmodifications of behaviour acquired by its parts perish with it. Only\nif in some way they exercise what we may term a hom\u0153opathic influence\non the germinal substance can the accommodation they have learnt be\ntransmitted in inheritance. By a _hom\u0153opathic_ influence is here\nmeant one that is of such a nature as to communicate to the germinal\nsubstance, the seeds of similar changes of structure or function.\nAnd of the occurrence of any such hom\u0153opathic influence there is no\nconvincing evidence.\n\nLogically contrasted with the modifications of the tissues, dependent\non organic plasticity, are the _variations_ which arise from the\nnature and constitution of the reproductive cells. How they arise\ncannot here be discussed. But they are, it is believed, subject to\nthe influence of natural selection, which has guided them, throughout\nthe ages of organic evolution, in the directions they have taken;\ndisadvantageous variations having been eliminated, and favourable\nvariations surviving in the struggle for existence. Such modes of\nbehaviour as are congenital and are due to hereditary transmission are\ntherefore the outcome of variations which have been selected generation\nafter generation. And the fit adjustment of this congenital behaviour\nto the needs of life is termed _adaptation_. It is here assumed that\nmodifications of behaviour in one generation are not inherited, and\ntherefore contribute nothing to the store of adaptive behaviour in the\nnext generation.\n\nIt must not, however, be supposed that the provisional acceptance of\nthis conclusion involves the denial of all connection of any sort\nbetween accommodation and adaptation. When we remember that plastic\nmodification and germinal variation have been working together,\nin close association, all along the line of organic evolution to\nreach the common goal of adjustment to the circumstances of life,\nit is difficult to believe that they have been throughout the whole\nprocess altogether independent of each other. Granted that acquired\nmodifications, as such, are not directly inherited, they may none the\nless afford the conditions under which _coincident variations_ escape\nelimination. By coincident variations I mean those the direction of\nwhich coincides with that taken by modification. The survival of an\nanimal depends on its adjustment to the circumstances of its life, no\nmatter how this adjustment is secured. And this survival would in the\nlong run be better secured, we may suppose, where the two methods of\nadjustment were coincident and not conflicting;[15] just as a man who\nnot only acquires by his own exertions a fortune but also inherits\none, is better off than his neighbour, of equal business capacity,\nwho is entirely dependent on his own exertions. The inheritance of a\nsmall capital may, indeed, make just the difference between success\nand failure. Even with it, if he had no power of acquiring more, he\nmight remain a poor man. Inheritance and acquisition combined may\nbest lead to survival in competition. Thus modification may supply\nthe conditions under which coincident variations are favoured, and,\ngiven time, to reach step by step, through natural selection, a fully\nadaptive level. If this be so we may accept many of the facts adduced\nby the transmissionist in favour of the direct inheritance of acquired\ncharacters, and at the same time interpret them on selectionist\nprinciples.\n\nIf, however, acquired characters are not hereditary the method of\nnatural selection in racial progress is curiously indirect. Apart from\nthe preservation of their fecundity, the cells on which the continuity\nof life, in all the higher animals, depends, have themselves taken\nlittle part in the struggle for existence. Just as in the forest tree,\nthe firmly implanted roots, the sturdy stem, and the strong branches\nhave to bear the stress of the winter storm, that the flowers of\nspring may ripen the seeds which contain the potentiality of all this\nstrength; so do muscle, sinew, and brain secure the survival of the\nanimal, that his descendants may carry on the struggle. One may liken\nthe cellular constituents of the animal to a hive of bees with fertile\ndrones and queen, and sterile workers. It is on the exertions of the\nlatter that, in the struggle for existence, the continued existence\nof the swarm depends, while it is by the pairing of the fertile drone\nand queen that the continuity of the race is secured. No worker can\ntransmit the qualities which are so essential to the well-being of\nthe community. But in the eggs of their sister the queen-mother these\nqualities lie dormant. And since the race is one race, the workers\nby their exertions contribute indirectly to the maintenance of those\nhereditary aptitudes to which they are unable to contribute directly.\nFor it is essential to bear in mind that they not only work for their\nown generation, but they determine the course of heredity. Picture two\nsuch communities set in an environment which intensifies the struggle\nfor existence. The one is strong, healthy, and vigorous; the other in\nall respects the reverse. The incidence of the battle of life falls\nmainly on the workers. If they succumb in the one group their fertile\nqueen either perishes, or gives rise to a poor stock, certain in the\nlong run to be eliminated. But the vigorous workers in the other group\nsurvive and secure, too, the survival of their queen, who, since she is\nalso their sister, bears, in her ovaries, the good seed from which a\nnew generation of vigorous workers shall be developed. Thus though the\nsterile bees contribute nothing directly to the heredity of the race,\nthey indirectly determine the direction which that heredity shall take.\nSo, too, in the higher animals, the reproductive cells are the fertile\nsisters of a host of sterile body cells, on which the main incidence\nof the struggle for existence falls. Their sterility precludes their\ndirectly contributing to the success of future cell-generations; but\nin protecting their fertile sisters, the reproductive cells, they are\nreally determining the lines along which the evolution of the race\nshall continue.\n\nAcquired characters may thus be regarded as the results of those\naccidents, fortunate or the reverse as the case may be, which happen\nto the body, and more or less modify its outward form or hidden\nstructure, and its modes of organic behaviour; but which, as such, have\nno direct effects for better or worse on the germinal substance. All\nthat the plant or animal can be is due to heredity; all that it _is_,\nto heredity and circumstance. Even the ability to yield to circumstance\nis part of heredity\u2019s dower. Fortunate, then, the plant or animal\nthat inherits such definiteness of structure and behaviour as may fit\nit to its station, together with such plasticity as may enable it to\naccommodate itself to those changes of environing conditions which may\nfall to its lot.\n\nOne more point must be noticed in connection with this difficult and\npuzzling subject. The acceptance of the conclusion that acquired modes\nof behaviour are not hereditary nowise commits us to the belief that\nheredity has nothing whatever to do with them. Though what is acquired\nmay not be transmitted, what one may term the acquisitiveness is\nunquestionably inherited. Though this, that, or the other acquired mode\nof behaviour may have no direct descendants, the power of acquiring\nany one of them under the appropriate circumstances is handed on as an\ninvaluable legacy. Just as the mirror which has reflected a fleeting\nscene retains no lasting image of the bygone events, so heredity may\nretain no impress of acquired characters; but just as the mirror\nkeeps its power of reflecting such scenes, so does heredity transmit\nthe power of acquiring such characters. As the leaves of the oak are\nrenewed each successive spring, so may acquired modes of behaviour be\nrepeated in each successive generation if only the requisite conditions\nrecur in due season.\n\nFrom what has preceded it may, therefore, be inferred that organic\nbehaviour may arise either through modifications occurring in the\nplastic tissues, or through variations having their origin in the\ngerminal substance. Broadly speaking, however, we may regard as\npredominantly due to adaptation those congenital modes of behaviour and\nthose organic responses which on their first occurrence are relatively\ndefinite in character, and which are directed to a biological end, for\nwhose attainment the tissues have had no preparatory training; and we\nmay regard as predominantly due to accommodation those responses which\nare, so to speak, learnt by the tissues in the course of individual\nlife. Both are dependent on heredity, but in different ways. What the\nanimal owes to heredity may, indeed, as I have elsewhere said,[16] be\nclassified under two heads. Under the first will fall those relatively\ndefinite modes of behaviour which fit the animal to deal at once, on\ntheir first occurrence, with certain essential or frequently recurring\nconditions of the environment. Under the second head will fall the\npower of dealing with special circumstances as they arise in the\ncourse of a varied life. The former may be likened to the inheritance\nof specific drafts for definite needs which are sure to arise in the\nconduct of life; the latter to the inheritance of a legacy which may\nbe drawn upon for any purpose as occasion may demand. If the need\nbecomes habitual the animal may, so to speak, instruct his banker to\nset aside a specific sum to meet it as it arises. But this arrangement\nis a purely individual matter, dictated by experience, and in no wise\nenjoined by the original terms of the bequest. And both types are\nfostered by natural selection which develops (_a_) such congenital\ndefiniteness of response, and (_b_) such innate plasticity, as are\nadvantageous under the conditions of existence; uniform conditions\ntending to emphasize the former, variable conditions the latter.\n\nDifficult as it may be to earmark the items of the organic bequest--to\nsay that, of the sum of energy expended in any given case of organic\nbehaviour, so much is due to a specific draft definitely assigned in\nheredity for this particular purpose, and so much is contributed from\nthe general legacy of innate plasticity,--it none the less conduces\nto clear thinking to emphasize the logical distinction between them,\nso long as it is steadily borne in mind that logical distinction does\nnot imply biological separation. The animal, with all its varied modes\nof behaviour, is an organic whole, and as an organic whole it has\nbeen developed from the fertilized egg. The very same tissues which\nexhibit congenital modes of behaviour are capable also of acquiring new\nresponses and playing their part in accommodation. We have not one set\nof organs which are the products of variation and another set which\nresult from modification. Our study would no doubt be simplified if\nthis were the case; but it is not so. And we must take the animal as we\nfind it, presenting varied behaviour of complex origin. Even the reflex\nnervous centres, which are concerned in responses so automatic as to\nsuggest a stereotyped structure of distinctively germinal origin, are\nalso, as we saw at the close of the last section, in close touch with\nthose centres of control which are associated with the supreme power of\naccommodation arising from the possession of consciousness.\n\n\n\n\nCHAPTER II\n\n_CONSCIOUSNESS_\n\n\nI.--THE CONSCIOUS ACCOMPANIMENTS OF CERTAIN ORGANIC CHANGES\n\nIt is possible that all organic behaviour is accompanied by\nconsciousness. But there is no direct means of ascertaining whether\nit is so or not. This is, and must remain, a matter of more or less\nplausible conjecture. We have, indeed, no direct knowledge of any\nconsciousness save our own. Undue stress should not, however, be laid\non this fundamental isolation of the individual mind. We confidently\ninfer that our fellow-men are conscious, because they are in all\nessential respects like us, and because they behave just as we do when\nwe act under its guiding influence. And on similar grounds we believe\nnot less confidently that many animals are also conscious. But how far\nwe are justified in extending this inference it is difficult to say.\nProbably our safest criterion is afforded by circumstantial evidence\nthat the animal in question profits by experience. If, as we watch\nany given creature during its life-history, we see at first a number\nof congenital or acquired modes of behaviour, we may not be able to\nsay whether they are accompanied by consciousness or not; but if we\nfind that some of these are subsequently carried out more vigorously\nwhile others are checked, we seem justified in the inference that\npleasurable consciousness was associated with the results of the\nformer, and disagreeable consciousness with those of the latter. When\nwe see that a chick, for example, pecks at first at any small object,\nit is difficult to say, on these grounds, whether it is a sentient\nanimal or only an unconscious automaton; and if it continued to behave\nin a similar fashion throughout life, our difficulty would still\nremain. But when we see that some objects are rejected while others are\nselected, we infer that consciousness in some way guides its behaviour.\nThe chick has profited by experience. But even this is clearly only a\ncriterion of what we may term _effective_ consciousness. There may be\nsentience which is merely an accompaniment of organic action without\nany guiding influence on subsequent modes of behaviour. In that case it\nis not effective; and whether it is present or not we have no means of\nascertaining.\n\nWe seem also to be led to the conclusion, both from _a priori_\nconsiderations and from the results of observation, that effective\nconsciousness is associated with a nervous system. Its fundamental\ncharacteristic is control over the actions, so that some kinds of\nbehaviour may be carried out with increased vigour, and others checked.\nAnd it is difficult to see how this can take place unless the centres\nof control are different from those over which they exercise this\ninfluence. If we are to understand anything definite by the guidance\nof consciousness, we must conceive it as standing apart from and\nexercising an overruling influence over that which it guides. This\nis unquestionably an essential characteristic of consciousness, as\ngenerally understood by those who take the trouble to consider its\nrelation to behaviour; and though some would seek to persuade us\nthat a mere accompaniment of consciousness can somehow determine the\ncontinuance or discontinuance of organic behaviour, it is difficult\nto see how this can be the case. The accompaniment of air-tremors\ncan no more influence the vibrations of a sounding string than an\naccompaniment of consciousness can affect the nature of the organic\nchanges in the tentacles of the Sun-dew leaf.\n\nAnd if, instead of trusting to such general _a priori_ considerations,\nwe study with attention the conditions under which an animal so behaves\nas to lead us to infer that it profits by experience, we find that it\nis not the consciousness that accompanies the behaviour which leads to\nfuture guidance, but the consciousness that arises from the results of\nthe behaviour. Let us willingly grant that the newly hatched, and as\nyet inexperienced chick, when it pecks at a small object is conscious\nof a visual impression, and is conscious also of movements of its\nneck and beak. These do not constitute the experience by which it\nprofits. This is provided by the results of the pecking, according as\nthe morsel seized is nice or nasty. We may say, in popular language,\nthat the little bird remembers when it sees a similar object that the\nformer results were pleasant or distasteful, as the case may be; and\nthat it is through this remembrance that future guidance is rendered\npossible. But all the evidence that we possess goes to show that the\nsensory centres, stimulated by what we will assume to be the taste\nof the morsel, are different from those which are affected by sight,\nand the movements concerned in pecking. So that the consciousness\nwhich is effective in guiding future action is an accompaniment of the\nstimulation of centres that are different from those concerned in the\nbehaviour over which guidance is exercised. And if this interpretation\nof the observed facts be correct, it supports the conclusions reached\nfrom _a priori_ considerations. It seems further to show that, not\nonly is a nervous system necessary for the occurrence of controlled\nbehaviour, but that no little complexity in its intercommunications is\nessential.\n\nIt may be urged that the chick\u2019s behaviour which has been selected\nfor purposes of illustration, and the interpretation we have put upon\nit, throws too much stress on remembrance, so called, and further\ngives the false impression that all experience must be for _future_\nguidance. There are surely numberless cases, it will be said, in which\nnothing of the nature of distinct memory is involved, and in which the\nguidance of consciousness is exercised at once over present behaviour,\nwithout any postponement to the future. Even omitting for the present\nthe former point, the formula implied--that present experience is\nfor future guidance--cannot be accepted in view of the familiar fact\nthat present experience is constantly influencing present behaviour.\nPractically speaking, this is perfectly true: because, practically,\nunder the term present we include quite an appreciable period of\ntime--say, a few seconds, or even minutes. If we narrow our conception\nof the present, as is commonly done in philosophical discussions, to\nthe boundary line between past and future, then it will be seen that\neven the guidance of what in popular speech is called present behaviour\nis really exercised on the _subsequent_ phases of that behaviour. At\nthe risk of some technicality our position must be explained a little\nmore fully. It is assumed that the data of consciousness are afforded\nby afferent impulses coursing inwards from the organs of special sense,\nor those concerned in responsive movements. This conclusion rests on\nsuch a wide body of psychological inference that it may be accepted\nwithout discussion, at any rate for our immediate purpose. The efferent\nimpulses, those which effect the orderly contraction of the muscles,\nare unconscious; but when the movement is produced afferent impulses\ncourse inwards from the parts concerned in the behaviour, and these may\nthen contribute data to consciousness.\n\nNow let us suppose that a chick, which has been hatched in an\nincubator, be removed some twelve hours after birth, held in the hands\nfor a few minutes until its eyes have grown accustomed to the light,\nand placed on a table near some small pieces of hard-boiled egg.\nLet us watch its behaviour and endeavour to interpret it. We shall\nhave occasion to consider hereafter whether the conscious experience\nof parents and ancestors is inherited as such; for the present we\nwill assume that it is not. The chick has to acquire for itself its\nown experience. A piece of egg catches the eye of the little bird,\nwhich then pecks at it, and just fails to seize it. Here is a piece\nof congenital organic behaviour. Taken by itself one might find it\ndifficult to say whether it is accompanied by consciousness or not,\njust as one finds it difficult to say whether the closure of the\nVenus\u2019s Fly-trap is conscious. But the subsequent behaviour of the\nchick leads us to infer that it is a sentient animal; and we may,\ntherefore, fairly assume that it is sentient from the first. Dividing\nthe course of the observed behaviour into stages, we may say that the\nfirst stage is that in which the chick receives a visual stimulus\naccompanied by a sensation of sight. Upon this there rapidly follows\nthe second stage, when the bird pecks, and its experience is widened\nby new data of consciousness derived from a group of motor sensations;\nand upon this, again, there follows the third stage, when sensations\ncome in from the morsel of egg which the chick touched but just failed\nto seize. After a pause the chick strikes again. But we have not a mere\nrepetition of the former sequence of stages. The visual stimulus at\nfirst fell upon the eye of a wholly inexperienced bird; now it falls\nupon the eye of one that has gained experience of pecking and tasting.\nWhat we may call the _conscious situation_ has completely changed, at\nall events if we assume that the items of consciousness, including\nas essential the consciousness of behaviour, do not remain separate\nand isolated, but have coalesced into a group through association.\nAnd in this group the consciousness of behaving is perhaps the most\nimportant element in the situation, making it of practical value.\nWhat psychologists term the _presentative_ visual stimulus, now calls\nup _re-presentative_ elements, motor and gustatory; and these place\nthe situation in a wholly new aspect. They give it what Dr. Stout\nterms \u201cmeaning.\u201d On the second or third attempt the chick seizes and\nswallows the morsel of egg. Its experience is yet further widened; and\nthereafter the situation has other new elements. Later it pecks at\nsome nasty grub; shakes its head, and wipes its bill on the ground.\nThe conscious situation has for the future become more complex, and\nthe behaviour is henceforth differentiated into that of acceptance and\nthat of rejection, in each case determined by the acquired meaning\nin the coalescent conscious situation: the sight of a nice piece of\negg being one situation, that of a nasty caterpillar another, each\nassociated with its specific behaviour-consciousness. We need not\ncarry the illustration further on these lines: the essential feature\nis that experience grows by the coalescence of successive increments,\nand that each increment modifies the situation which takes effect on\nthe _succeeding_ phases of behaviour, even if they succeed within the\nfraction of a second. That is what is meant by saying that present\nexperience is for future guidance. The future need not be remote, but\nmay be so immediate that in popular speech we may say that it is not\nfuture but present guidance which is rendered possible.\n\nWe may now turn for a moment to the criticism that there are\nnumberless cases in which nothing of the nature of distinct memory\nis involved. We may now substitute for the word remembrance, which\nwas used above, the more technical term _re-presentation_. Profiting\nby experience, regarded as a criterion of the presence of effective\nconsciousness, involves re-presentative elements in the conscious\nsituation which carry with them meaning. Let us for the moment assume\nan ultra-sceptical attitude with regard to any conscious accompaniment.\nThe chick when it pecks, let us say, is an unconscious automaton. It\nseizes a piece of egg; this affords an unconscious stimulus, which sets\nagoing unconscious acts of swallowing; or it seizes a piece of meal\nsoaked in quinine, which sets agoing unconscious acts of rejection and\ntouches the hidden springs which make the automaton wipe its bill.\nSo far we find no great difficulty. It is when we have to consider\nsubsequent behaviour that a severe strain is felt on this method of\ninterpretation. One can understand an automatic action repeated again\nand again as often as the stimulus is repeated. But the chick may shake\nits head and wipe its bill on the mere sight of the quinine-soaked\nmeal, which, on the hypothesis of conscious experience, has already\nproved distasteful. So that if we accept the unconscious automaton\ntheory we must assume an organic association which closely simulates\nthe conscious association to which our own experience testifies. But\nthe associations which take part in the guidance of behaviour in the\nchick are so varied and delicate, so closely resemble those which in\nourselves imply conscious guidance, that a sceptical attitude throws\nmore strain upon our credulity than the acceptance of the current\nbelief in conscious control. We shall therefore assume that evidence\nfor such coalescent association is also evidence of the presence of\neffective consciousness.\n\nIt may still be said, however, that in selecting an example from so\nhighly organized an animal as a bird, we are taking for granted that a\ncomplex case of controlled behaviour may fairly be accepted as a type\nof more simple cases. Unfortunately the only being with whose power\nof conscious control we have any first-hand acquaintance is possessed\nof a nervous system even more complex than that of the chick. Our\npsychological interpretations are inevitably anthropomorphic. All\nwe can hope to do is to reduce our anthropomorphic conclusions to\ntheir simplest expression. The irreducible residuum seems to be that\nwherever an animal, no matter how lowly its station in the scale of\nlife, profits by experience, and gives evidence of association, it must\nhave some dim remembrance, or, let us now say, some re-presentation,\nof the results of previous behaviour which enters into and remodels\nthe conscious situation; that through the re-presentative elements\nbehaviour is somehow guided; and, further, that the centre of conscious\ncontrol is different from the centre of response over which the control\nis exercised.\n\n\nII.--THE EARLY STAGES OF MENTAL DEVELOPMENT\n\nWe use the phrase \u201cmental development\u201d in its broadest acceptation as\ninclusive of, and applicable to, all phases of effective consciousness.\nWe shall assume that throughout this development there is a concomitant\ndevelopment of nerve-centres and of their organic connections. And we\nshall further assume that experience, as such, is not inherited.\n\nThe nature of the grounds on which the latter assumption is based must\nfirst be briefly indicated. It is commonly asserted that fear of man,\nthe inveterate hunter and sportsman, is inherited by many animals, as\nis also that of other natural enemies. This is, however, questioned,\nor even denied, by many careful observers. Mr. W. H. Hudson has an\nexcellent chapter on \u201cFear in Birds\u201d in his \u201cNaturalist in La Plata,\u201d\nand concludes that fear of particular enemies is, in nearly all\ncases, the result of experience individually acquired. I have found\nthat pheasants, partridges, plovers, domestic chicks, and other young\nbirds, hatched in an incubator, show no signs of fear in the presence\nof dog or cat, so long as the animal is not aggressive. It should be\nmentioned, however, that Miss M. Hunt[17] asserts that chicks do show\ninherited fear of the cat. Dr. Thorndike\u2019s[18] observations, on the\nother hand, support my own, which I have since repeated with the same\nresults. Neither birds nor small mammals show any signs of fear of\nstealthily moving snakes. My fox terrier smelt, nose to nose, a young\nlamb which was lying alone in a field. I was close at hand, and could\ndetect no indication of alarm on the part of the lamb till the mother\ncame running up in great excitement. Then the lamb ran off to her dam.\nWhenever opportunity has arisen, I have introduced young kittens to my\nfox terrier, and have never seen any sign of inherited fear. He was a\ngreat hunter of strange cats, but was trained to behave politely to all\nbirds and beasts within the precincts of my study. It is true that he\nwas on good terms, or at least terms of permissive neutrality, with the\nkittens\u2019 mother. And it may be said that this was inherited; but such\nan argument cannot apply in the case of pheasant or lamb.\n\nHere, as throughout our study of animal behaviour in its conscious\naspect, we have not only to conduct observations with due care, but\nto draw inferences with due caution. Douglas Spalding described how\nnewly hatched turkeys showed signs of alarm at the cry of a hawk; and\nhe inferred that, since this sound was quite new to their individual\nexperience, the alarm was due to the inheritance of ancestral\nexperience of hawks. But since young birds show signs of alarm at any\nsudden and unaccustomed sound--a sneeze, the noise of a toy horn, a\nloud violin note, and so forth--the safer inference seems to be that\nthey may be frightened by strange sounds of many kinds. But this\ndoes not imply the inheritance of experience, which is essentially a\ndiscriminating process. There is no sufficient evidence that a peculiar\ncry suggests the hawk, of which the progenitors have acquired bitter\nexperience; nothing to justify the belief that the sound carries\nwith it inherited meaning. And as with hearing, so with sight. Young\nbirds may be frightened by many strange objects. I have seen a group\nof several species, filled with apparent alarm at a large white jug\nsuddenly placed among them, at balls of paper tossed towards them, at a\nhandkerchief dropped in their midst. It is, in fact, their inexperience\nwhich is often the condition of such fear. As Mr. Hudson says:[19] \u201cA\npiece of newspaper carried accidentally by the wind is as great an\nobject of terror to an inexperienced young bird as a buzzard sweeping\ndown with death in its talons.\u201d\n\nUntil recently it was commonly asserted that birds avoid gaudy but\nnauseous or harmful insects through the inheritance of experience\ngained by their ancestors through many generations. But here again\nthe inference seems to have been incautiously drawn. Of the hundreds\nof young birds I have had under observation, not one has avoided the\npeculiarly distasteful cinnabar caterpillar, until it had gained for\nitself experience of its nauseous character. So too of wasps and bees.\nOnly through experience are these avoided. It is true that chicks may\nshrink from them if they buzz or even walk rapidly towards them. But a\nlarge harmless fly will inspire just as much timidity. As the result of\ncareful observations, Mr. Frank Finn[20] concludes \u201cthat each bird has\nto separately acquire its experience, and well remembers what it has\nlearnt.\u201d And with this conclusion my own observations are entirely in\naccord.\n\nSuch is some of the observational evidence on which is based the\nprovisional hypothesis that experience, as such, is not inherited.\nWhat, then, is inherited? Clearly the organic conditions under which\nexperience can be acquired. Since a young bird inherits a tendency\nto peck at small objects, especially, in the case of some birds such\nas plovers or partridges, at small moving objects, opportunities\nare afforded for discrimination in accordance with the results of\nexperience. Since its inherited timidity leads the chick to shrink\nfrom many things seen or heard, a wide range of conscious data is\nsupplied. Inheritance provides the raw material of organic behaviour\nfor effective consciousness to deal with in accordance with the results\nwhich are its data.\n\nHaving thus cleared the ground and laid bare some at least of the\nassumptions which we accept as foundations on which to build, we may\nnow follow up the line of treatment which was suggested in the first\nsection of this chapter. Remembering that our aim is to understand the\ninfluence of consciousness on behaviour--or, in more accurate, if more\ncumbrous phraseology, the influence of certain nerve-centres which have\nfor their concomitant what we have termed effective consciousness--the\nquestions which present themselves in any given case are: What is the\nconscious situation which is effective in guidance? what elements\nenter into the situation, whence are they derived, and how were they\nintroduced? how do they take effect in behaviour?\n\nIf it be true that, in many of the lower forms of life, consciousness\nor sentience, though presumably present in some dim form, is merely\nan accompaniment of organic behaviour without reaching the level of\nrecognizable effectiveness; and if, during the development of one\nof the higher animals from the fertilized ovum, the early stages of\norganic behaviour are in like manner merely sentient; it follows\nthat, when effective consciousness enters upon the scene (who can say\nat what exact stage of evolution?), it finds itself a partner in a\ngoing concern. Much organic business is being transacted with orderly\nregularity; preparations have been made for more extensive operations;\nand energies lying dormant, or expending themselves aimlessly in starts\nand twitches, await the guidance which shall direct them to higher and\nwider biological ends. Or, to vary the analogy, consciousness is the\nheir to a wide estate, over which he has no control until he comes of\nage. Up to that time the estate is managed in strict accordance with\nthe dictates of the hereditary bequest. He may be aware of what is\ngoing on, but merely as a spectator without power of interference. And\nwhen he comes into possession his first business is to gather up the\nthreads. He must learn bit by bit how the estate is being managed, that\nhe may have data for the guidance of his own management within the wise\nlimits of the hereditary entail.\n\nNow, when a mammal is born, a bird is hatched, an insect emerges from\nthe chrysalis, we have, if not the beginning, at any rate a great and\nsudden extension of the range of effective consciousness. In the case\nof the mammal and bird the experience gained in the womb or within the\negg-shell is presumably of little value for the wider life upon which\nan entrance is made. It is true that an insect has passed through a\nprevious stage of active and no doubt consciously guided existence as\na caterpillar. But we do not know whether the experience thus acquired\nis effectual for use in the later imago stage. And we may perhaps\ninfer from the extensive remodelling of the nervous system, which\noccurs during the chrysalis sleep, that this itself serves to break\nthe continuity of experience. In any case the newly hatched chick, if\nit inherit no experience, and can have gained little of guiding value\nin the egg, enters upon a situation which from the number and variety\nof the data supplied may well seem to us bewildering. If we picture\nourselves in such a position, with sights, sounds, motor sensations,\ntouches, and pressures raining in upon a virgin experience, we wonder\nhow we should make a beginning; how we could possibly decide on\nthe first step towards reducing this multiplicity and diversity to\nsomething like unity and order. And perhaps we wonder how we ourselves\nmade a beginning when we were pink newly born babies.\n\nIf it may be said without paradox, we never did make a beginning. The\nbeginning was made for us. For we habitually associate ourselves with\nthe control centres, and regard our bodies, like our watches, as ours\nand not us. We wind the bodily watch, and set its hands from time to\ntime; but we did not make it, and it was already going when heredity\nhanded it to us over the counter of birth. The first step towards\nreducing the seeming chaos of sensory experience to something like\norder is not due to the selection by consciousness of this or that\nelement for prominence among the rest, but to the thrusting forward\nof certain modes of behaviour by the conditions of organic life. The\ndifferentiation of the field of vision in the chick is not effected\nby any conscious determination to fix the attention on that wriggling\nmaggot, but through the congenital response it calls forth. This serves\nnot only to make the grub stand out clearly amid its surroundings, but\nalso to emphasize a motor group, called into vigorous action in the\nmidst of other motor sensations, and, in rapid sequence, to lay stress\non a sensation of taste suddenly called into prominence.\n\nNor, as we have seen, do the organic effects cease here. The functional\naction of three sensory centres is thus called into play. But they are\nconstituent parts of one nervous system. The direct stimulation of each\nby nerve impulses from eye, motor organs, and beak, gives temporary\npredominance to certain sensory data which are termed presentative. But\nthe several centres are connected with each other. And thenceforward,\nin subsequent stages of experience, the direct stimulation of the\nvisual centre indirectly calls into play the other two, so that the\npresentation through sight evolves re-presentations of the motor group,\nand of taste. Hence sentience is not sufficient for guidance; there\nmust be _consentience_ involving the presence of several elements. But\nthese elements must not be regarded as separate save in our analysis;\nthey form constituent parts of the coalescent situation as a whole,\nof which alone the chick is presumably conscious, without analysis of\ndetail.\n\nIt is just because the chick is a going concern when consciousness\ncomes of age and begins to assume control--just because a wide range\nof congenital behaviour is part of the organic heritage--that the\nearly stages of the acquisition of experience proceed so rapidly and so\nsmoothly. The animal has not to make and fashion the early conscious\nsituations; it has only to accept them. It has not at first to\nenforce order on the multiplicity of sensory data raining in upon the\nconscious centres; it has only to take note of the existing order among\nthem. It has not painfully to learn how to co-ordinate the efferent\nimpulses proceeding to the many muscles concerned in some simple\nresponse; it has only to be sensitive to the response as a whole. It\nhas not to select the association of this, that, and the other group\nof data within a coalescent situation; organic behaviour provides it\nwith predetermined sequences ready made--sequences which have for\ngenerations received the emphatic sanction of natural selection.\nCongenital tendencies which it has inherited but not acquired determine\nall its earliest behaviour, determine what elements in the sensory\ncomplex shall be thrust into conscious prominence, determine in what\nmanner these data shall be associated; determine, in fact, what salient\npoints in the developing situations shall stand out clearly from the\nrest, and how these salient points shall be grouped and linked by the\nconnecting threads of association and shall coalesce into effective\nwholes.\n\nAnd if in the comparatively helpless human infant the congenital modes\nof response seem less organized than those of the chick, if there is a\nlarger percentage of random and apparently aimless movements, if the\norganic management of the bodily estate is less definitely ordered\nby the terms of the hereditary bequest, if there is more of maternal\nguidance and fosterage; still the data are provided in a substantially\nsimilar way. The situations are indeed destined to become more complex,\nthe distinctions which arise in consciousness are more numerous, the\ncoalescence and association include a wider range and succession of\nsalient points; a longer time is required to become acquainted with\nthe transactions of a business conducted in a far greater number\nof centres: but, at least in the early stages, the data are of the\nsame kind, and are emphasized in the same way. Presentation and\nre-presentation play a similar _r\u00f4le_; and the chief difference lies\nin the fact that less stereotyped congenital behaviour is supplemented\nby some guidance, probably far less than is generally supposed, from\nthose who lovingly minister to the course of infant development.\n\nNo attempt can here be made to trace even in outline (an outline\nwhich must in any case be imaginary and conjectural) the sequence of\nsituations which marks the course of mental development in its earlier\nstages. An example may, however, serve to show how the exercise of\ncongenital tendencies may give rise to a new situation, and lead to a\nfurther development of behaviour.\n\nI kept some young chicks in my study in an improvised pen floored\nwith newspaper, the edges of which were turned up and supported, to\nform frail but sufficient retaining walls. One of the little birds,\na week old, stood near the corner of the pen, pecking vigorously and\npersistently at something, which proved to be the number on the page\nof the turned-up newspaper. He then transferred his attention and his\nefforts to the corner of the paper just within his reach. Seizing this,\nhe pulled at it, bending the newspaper down, and thus making a breach\nin the wall of the pen. Through this he stepped forth into the wider\nworld of my study. I restored the paper as before, caught the bird, and\nreplaced him near the scene of his former efforts. He again pecked at\nthe corner of the paper, pulled it down, and escaped. I then put him\nback as far as possible from the spot. Presently he came round to the\nsame corner, repeated his previous behaviour, and again made his escape.\n\nNow, here the inherited tendency to peck at small objects led, through\nthe drawing down of the paper, to a new situation, of which advantage\nwas taken. The little drama consisted of two scenes, which may be\nsufficiently described as \u201cthe corner of the pen,\u201d and \u201cthe open way,\u201d\nthis being the sequence in experience. Subsequently the first scene\nwas again enacted in presentative terms, and there followed first\na re-presentation of scene ii., with its associated behaviour, and\nthen the presentative repetition of this scene. We may take this as\na sample of the nature of a conscious situation which is effective\nin guidance. We have seen the nature of the elements (sensory data,\nincluding as essential those supplied by the behaviour itself, with a\npleasurable or painful tone) which enter into such a situation; we have\nseen that they owe their primary origin to direct presentation, but\nthat they may be subsequently introduced indirectly in re-presentative\nform; we have seen that the situation as a whole results from the\ncoalescence of the data. There only remains the question how the\nfelt situation takes effect on behaviour. And to this question,\nunfortunately, we can give but a meagre and incomplete reply. All\nwe can say is, that connections seem to be in some way established\nbetween the centres of conscious control and the centres of congenital\nresponse; and that through these channels the responsive behaviour may\nbe either checked or augmented (as a whole or in part), according to\nthe tone, disagreeable or pleasant, that suffuses the situation. How\nthis is effected we do not fully know.\n\n\nIII.--LATER PHASES IN MENTAL DEVELOPMENT\n\nSome surprise may be felt that in our brief discussion of the early\nstages of mental development nothing has been said of percepts and\nconcepts, nothing of abstraction or generalization. The omission\nis not only due to a desire to avoid the subtle technicalities of\npsychological nomenclature. It is partly due to the wish not to\nforejudge a difficult question of interpretation. Spirited passages of\narms from time to time take place between psychologists in opposing\ncamps, as to whether animals are or are not capable of forming abstract\nand general ideas; and untrained camp followers hang on the skirts\nof the fray, making a good deal of noise with blank-cartridge. The\nquestion at issue turns partly on the definitions of technical terms;\npartly, when there is agreement on this point, on the interpretation\nto be put on certain modes of behaviour. Nothing seems at first sight\nmuch easier than to say what we mean by an abstract idea or by a\ngeneral idea. We are thinking about colour, which is both abstract\nand general--abstract, because in itself it is a special quality of\nvisible objects floated off, so to speak, from other qualities, such\nas hardness and weight, shape and size; general, because it includes\nmany different colours in one group. Looking up at the bookshelves, we\nsee a volume with a red back. We neglect the shape, the contents, the\nlettering; it is the colour with which we are immediately concerned,\nwhich forms an important feature in the present thought-situation;\nand this is, in virtue of that situation, abstracted from the rest.\nBut a chick a few days old may have acquired experience of several\nkinds of caterpillars much alike in shape and size; of which, one kind\nis ringed with orange and black. And while the others are eagerly\nseized, caterpillars of this kind are left untouched. It is not the\nsize or the shape which is an effective element in the situation; it\nis the peculiar coloration of the cinnabar caterpillars. Now, does the\neffectiveness of this quality in the stimulus justify the inference\nthat the chick forms an abstract idea of colour? That clearly depends\non our definition of abstract idea, and on our inferences concerning\nthe nature of the chick\u2019s mind.\n\nA dog lies dozing upon the mat, and hears a step in the porch without.\nHis behaviour at once shows that this enters into the conscious\nsituation. There is, moreover, a marked difference according as the\nstep has the familiar fall of the master\u2019s tread, the well-known\nshuffle of the irrepressible butcher\u2019s lad, or an unfamiliar sound.\nThese several situations are, without question, nicely distinguished.\nLet us suppose the situation of the moment is introduced by a strange\nfootfall. It seems to suggest man; but this cannot be any particular\nman, since he is as yet invisible and is a stranger. Does the dog,\nthen, frame a general idea of man? Does the chamois do so when,\nbounding across the snow field, he stops suddenly on scenting the\ndistant footprints of a mountaineer? Do you do so when you hear the\nbleating of an invisible lamb in the meadow behind yonder wall? Here,\nagain, the answers we give to these questions depend partly on the\nexact meaning of the term \u201cgeneral idea;\u201d partly on our interpretation\nof what passes through the mind of the being concerned. We have sought,\nso far, rather to avoid than to answer these questions. We seem to be\non safe ground so long as we content ourselves with saying that the\norange and black of the cinnabar caterpillar, the strange footfall,\nor the trail of the mountaineer, enter as effective elements into the\nimmediate conscious situation.\n\nBut when we pass to the higher phases of mental development we can\nno longer wholly ignore such questions. When we are dealing with\nintellectual human beings, there can be no doubt that they at least\nare capable of framing, with definite intention, and of set purpose,\nboth general and abstract conceptions. And how do they reach these\nconceptions? By reviewing a number of past situations, analyzing them,\nintentionally disentangling and isolating for the purposes of their\nthought certain elements which they contain, and classifying these\nabstracts under genera and species--that is to say, into broader and\nnarrower groups. The primary and proximate object of this process is to\nreach a scheme of thought by which the scheme of nature, as given in\nexperience, can be _explained_. And, no doubt, underlying this primary\nobject is the purpose of guiding future behaviour in accordance with\nthe rational scheme which is thus attained. Man is sometimes described\nas _par excellence_ the being who looks before and after. All his\ngreatest achievements are due to his powers of reflection and foresight.\n\nWhat share the symbolism of speech takes in the process briefly\nindicated in the last paragraph is the subject of much discussion.\nWithout going so far as to urge that the very beginnings of reflective\nthought are inexplicable without its aid, it may be accepted as\nobviously true that words are a great assistance. They may be regarded\nas intellectual pegs upon which we hang the results of abstraction\nand generalization. It may be said that we often think in pictures\nor images, and not in words, but the more abstract and general our\nthought, the more it is dependent on the symbolic elements.\n\nWe may say, then, that the higher phases of mental development are\ncharacterized by the fact that the situations contain the products of\nreflective thought, presumably absent in the earlier stages; they are\nfurther characterized by a new purpose or end of consciousness, namely,\nto explain the situations hitherto merely accepted as they are given\nin presentation or re-presentation; they require deliberate attention\nto the relationships which hold good among the several elements of\nsuccessive situations; and they involve, so far as behaviour is\nconcerned, the intentional application of an ideal scheme with the\nobject of rational guidance. We shall follow Dr. Stout in terming\nthis later stage of mental development the _ideational stage_; and in\nspeaking of the simpler situations considered in the preceding section\nas belonging to the _perceptual stage_.\n\nIt should be observed that we are not attempting to determine just\nwhere, in the scale of organic existence, the line between the\nperceptual and the ideational stages of mental development is to be\ndrawn. We are certainly very far from asserting that the one does not\ngive rise to the other in the course of an evolution which is orderly\nand progressive. We are merely contrasting the rational guidance\nof effective consciousness at its best with the earlier embryonic\ncondition out of which it has arisen by natural genesis. In doing this\nwe have been forced to make some reference to the difficulties of\ntechnical nomenclature. And some further reference is necessary lest\nour point of view be misunderstood.\n\nWe shall regard these abstract and general ideas as the products of\nan intentional purpose directed to the special end of isolating the\none and of classifying the other; we shall reserve the term _rational_\nfor the conduct which is guided in accordance with an ideal scheme or\ndeliberate plan of action; while for behaviour to the guidance of which\nno such reflection and deliberation seems to have contributed we shall\nreserve the term _intelligent_. If, for example, the rejection of a\ncinnabar caterpillar by the chick is the direct result of experience\nthrough the re-presentation in the new situation of certain elements\nintroduced during the development of a like situation, we shall call\nit an intelligent act. But if we have grounds for supposing that the\nsituation is reflectively considered by the chick in relation to an\nideal and more or less definitely conceived plan of action which is\n(perhaps dimly) taking form in its mind, we shall regard it as so\nfar rational. And so, too, in other cases of animal behaviour. Now,\nwith regard to the control through which consciousness is effective\nin the guidance of behaviour, it is necessary, in view of these\nconsiderations, to distinguish its intelligent from its rational\nexercise. And this is of importance since we generally speak of control\nin the latter sense in reference to human conduct. Intelligent control\n(on the perceptual plane) is due to the direct operation of the results\nof experience without the intervention of any generalized conception or\nideal. In rational control (on the ideational plane), such conceptions\nand ideals exert a controlling influence. If, to prevent a boy sucking\nhis thumb we administer bitter aloes, we trust to intelligent control\nthrough the immediate effects of experience; but if he be induced to\ngive up the habit because it is babyish, he so far exercises rational\ncontrol. What we call self-control is of this type. Only one more\ndistinction need be drawn. Intelligent behaviour, founded on direct\nassociation gained through previous experience, we shall attribute to\n_impulse_; but for rational conduct, the outcome of reflection and\ndeliberation, we seek to ascertain the _motive_. In human affairs our\nmotives are referred to certain categories each of which presupposes\nan ideal scheme, prudential, \u00e6sthetic, ethical, or other. To act from\nmotive and not from impulse is to act deliberately, because we judge\nthe action to be expedient, seemly, or right, as the case may be. If,\nthen, we contrast the lower perceptual stages of mental evolution with\nthe higher ideational phases, the former includes behaviour due to\nimpulse; but from it conduct due to motive is excluded.\n\n\nIV.--THE EVOLUTION OF CONSCIOUSNESS\n\nThe origin of consciousness, like that of matter or energy, appears\nto be beyond the pale of scientific discussion. The appearance of\neffective consciousness on the scene of life does indeed seem to\njustify the belief in the prior existence of sentience as the mere\naccompaniment of organic behaviour. _Ex nihilo nihil fit._ And\nsince effective consciousness must, on this principle, be developed\nfrom something, it is reasonable to assume that this something is\npre-existing sentience. Again, we may assume that this sentience is a\nconcomitant of _all_ life-processes, or only of some. But we have no\ncriterion by which we can hope to determine which of these alternatives\nis the more probable.\n\nWe appear, however, at all events to have evidence that when effective\nconsciousness does enter on the scene and play its part in the guidance\nof behaviour, its progress is, in technical phraseology, marked by\nthat differentiation of conscious elements, and that integration of\nthese differentiated items, which are seemingly the correlatives of\nthe differentiation and integration of nervous systems. There is thus,\npresumably, a progressive development of orderly complexity in the\nconscious situations of which controlled or guided behaviour is the\noutcome. And when this has reached a certain stage--what stage it is\nmost difficult to determine--the relationships, at first implicit in\nthe conscious situations, as they naturally arise in the course of\nexperience, begin to be rendered explicit with the dawn of reflection.\nIntentional abstraction and generalization to which data are afforded\nby the reiterated emphasis in experience of the salient features in\nsuccessive situations, supply new elements to the more highly developed\nsituations of rational life. Ideal schemes and plans of action, the\nproducts of reflection and foresight, take form in the mind and enter\ninto the conscious situation. And the intelligent animal, hitherto the\ncreature of impulse, guided only by the pleasurable or painful tone\nwhich gives colour to experience, becomes a rational being, capable of\njudging how far his own behaviour and that of others is conformable to\nan ideal.\n\nIf, then, we were asked to characterize in the briefest possible\nterms the stages of conscious evolution, we should say that in the\nfirst stage we have consciousness as accompaniment; in the second,\nconsciousness as guide; in the third, consciousness as judge. And if\nwe were pressed to apply distinctive terms to these three, we should\nadopt St. George Mivart\u2019s term _consentience_ for the mid-phase,\nand speak of mere sentience in the first stage; consentience in the\nsecond; and consciousness, with restricted signification, in the\nthird and highest stage. Such a distinction in terms is, however, a\ncounsel of perfection, and we shall not attempt to preserve it in the\nfollowing pages, in which the word \u201cconsciousness\u201d will be used in a\ncomprehensive sense.\n\nEver since the publication of Darwin\u2019s \u201cOrigin of Species,\u201d\nevolutionists have been divided into two sections where consciousness\nin the narrower sense is under discussion. The members of the one\nhave contended that, though the physical and perhaps the lower mental\nnature of man is the outcome of evolutionary process, his higher mental\nattributes are of other origin. The members of the second section have\nurged that the higher not less than the lower characteristics of the\nmind of man have been evolved. It is somewhat strange that naturalists\nwho accept the latter position are not infrequently impatient when\nany serious attempt is made to discuss it from the standpoint of\npsychology. It is, however, becoming more and more clearly evident that\nthe discussion of the relation of the animal to the human mind, if it\nis to be made a subject of scientific inquiry, must be conducted on\npsychological lines by those who have devoted years of study to the\nsubject. In this work such a discussion will be attempted, and animal\nbehaviour will be treated as the precursor of human conduct, and as\naffording evidence of the germs from which the distinctively human\nmental attributes may have been evolved.\n\n\n\n\nCHAPTER III\n\n_INSTINCTIVE BEHAVIOUR_\n\n\nI.--DEFINITION OF INSTINCTIVE BEHAVIOUR\n\nThere are probably few subjects which have afforded more material for\nwonder and pious admiration than the instinctive endowments of animals.\n\u201cI look upon instinct,\u201d wrote Addison in one of his graceful essays,\n\u201cas upon the principle of gravitation in bodies, which is not to be\nexplained by any known qualities inherent in the bodies themselves,\nnor from any laws of mechanism, but as an immediate impression from\nthe first Mover and the Divine Energy acting in the creatures.\u201d[21] In\nlike manner Spence said: \u201cWe may call the instincts of animals those\nfaculties implanted in them by the Creator, by which, independent of\ninstruction, observation or experience, and without a knowledge of\nthe end in view, they are all alike impelled to the performance of\ncertain actions tending to the well-being of the individual and the\npreservation of the species.\u201d[22] According to such views, instinct is\nan ultimate principle the natural genesis of which is beyond the pale\nof explanation. But similar views were, at the time these passages\nwere written, held to apply, not only to animal behaviour, but also\nto animal structure. The development of the stag\u2019s antler, or of the\ninsect\u2019s wing, was also regarded as \u201can immediate impression from\nthe first Mover and the Divine Energy acting in the creatures.\u201d This\nview, however, is, neither in the case of structure nor in the case\nof behaviour, that entertained by modern science. It is indeed an\nexpression of opinion concerning the metaphysics of instinct. Leaving\nthe question of ultimate origin precisely where it stood in the times\nof Addison and of Spence, modern science seeks to trace the natural\nantecedents of all natural phenomena, and regards structure and\nbehaviour alike as the products of evolution, endeavouring to explain\nthe manner of their genetic origin in terms of progressive heredity.\n\nOmitting, therefore, all reference to problems which, however\nimportant, are beyond the limits of scientific inquiry,[23] we may\ntake as a basis for further discussion Spence\u2019s definition, according\nto which the instincts of animals are those faculties by which,\nindependent of instruction, observation, or experience, and without\na knowledge of the end in view, they are all alike impelled to the\nperformance of certain actions tending to their own well-being and the\npreservation of the species.\n\nLet us first consider the reference of instinctive actions to\na _faculty_ by which animals are said to be impelled to their\nperformance. Paley also defined instinct as \u201ca _propensity_ prior to\nexperience.\u201d And unquestionably in the popular conception it is usual\nto attribute instinctive acts to some such conscious cause. But it\nwill be more convenient, for the present, to consider instinctive\nbehaviour from the objective point of view, as it is presented to\nour observation; we may then proceed to the further consideration of\nthe conscious concomitants which may be inferred. From the objective\npoint of view, therefore, we may agree with Professor Groos, who\nsays[24] that \u201cthe idea of consciousness must be rigidly excluded\nfrom any definition of instinct which is to be of practical utility,\u201d\nsince \u201cit is always hazardous in scientific investigation to allow an\nhypothesis which cannot be tested empirically.\u201d In this we have the\nsupport of Dr. and Mrs. Peckham, whose studies of the life-histories\nof spiders and wasps are models of careful and patient investigation.\n\u201cUnder the term Instinct,\u201d they say, \u201cwe place all complex acts which\nare performed previous to experience, and in a similar manner by all\nmembers of the same sex and race, leaving out as non-essential, at\nthis time, the question of whether they are or are not accompanied by\nconsciousness.\u201d[25]\n\nIt may be said, however, that some reference to the conscious aspect\nof instinctive behaviour is implied by saying that the acts are\nperformed without instruction or experience. But the reference at\npresent is wholly negative. We may say, as the result of observation,\nthat instinctive acts are performed under such circumstances as exclude\nthe possibility of guidance in the light of individual experience, and\nrender it in the highest degree improbable that there exists any idea\nof the end to be attained. But this is a very different position from\nthat of asserting the presence of a positive faculty or propensity\nwhich impels an animal to the performance of certain actions. This it\nis which, from the observational point of view, is unnecessary. For\nthe reference of a given type of observed behaviour to a \u201cpropensity\u201d\nso to behave or to a \u201cfaculty\u201d of thus behaving, is no more helpful\nthan the reference of the development of any given type of structure\nto a \u201cpotentiality\u201d so to develop. We may, therefore, without loss of\nprecision, simplify Spence\u2019s definition by stating that instinctive\nbehaviour is independent of instruction and experience, and tends to\nthe well-being of the individual and the preservation of the species.\n\nLet us next consider the clause which affirms that instinctive\nbehaviour is prior to experience. This is well in line with the\ndistinction now drawn by biologists between congenital and acquired\ncharacters. It refers them to the former category, and implies that\nthe organic mechanism by which they are rendered possible is of\ngerminal origin. This is not, however, universally admitted. Professor\nWundt, for example, approaching the subject from the point of view\nafforded by the study of man and the higher animals, gives to the\nterm a wider meaning, and so defines instinct as to include acquired\nhabits. \u201cMovements,\u201d he says,[26] \u201cwhich originally followed upon\nsimple or compound voluntary acts, but which have become wholly or\npartly mechanized in the course of individual life, or of generic\nevolution, we term _instinctive_ actions.\u201d In accordance with this\ndefinition, instincts fall into two groups. Those \u201cwhich, so far as we\ncan tell, have been developed during the life of the individual, and\nin the absence of definite individual influences might have remained\nwholly undeveloped, may be called _acquired_ instincts.\u201d They have\nbecome instinctive through repetition. \u201cTo be distinguished from these\nacquired human instincts are others which are _connate_.\u201d Now, there\ncan be no question that behaviour which has become habitual through\nfrequent repetition is frequently, in popular speech, described as\ninstinctive. We hear it said that the experienced cyclist guides his\nmachine instinctively. And the word is similarly used in many like\ncases. But we shall find it conducive to precision and clearness of\nthought to emphasize the distinction between what is acquired in\nthe course of life and what is congenital in the race. And to this\nend we shall regard behaviour which has \u201cbecome mechanized in the\ncourse of individual life\u201d as due to acquired habit, reserving the\nterm _instinctive_ for such behaviour as is independent of individual\nexperience. We shall, in short, so far accept Spence\u2019s definition.\n\nIn this definition, as in those of the majority of naturalists,\nit seems to be further implied that instinctive behaviour is of a\nrelatively definite kind, though it is no doubt subject to such\nvariation as is found in animal structure and organization. Mr.\nRutgers Marshall, however, in a recent work,[27] protests against any\nsuch implication, and urges that \u201cthis variableness is so wide that\ndefiniteness of reaction cannot for a moment be used as a differentia\nin relation to instinct without narrowing our conception of the bounds\nof instinct in a manner to be deplored.\u201d \u201cThe actions,\u201d he says,\n\u201cconnected with the preparation for self-defence, those connected with\nprotection of the young, with nest-building, with migration, etc.,\nthese actions are surely to be classed as instinctive; and yet they\nare exceedingly variable and unpredictable in detail; all that we can\npredict is the general trend of the varying actions which result from\nvarying stimuli under varying conditions, and which function to some\ndeterminate biological end.\u201d\n\nMr. Marshall then proceeds to argue that we are \u201cwarranted in speaking\nof the ethical instincts, of the patriotic instincts, of the benevolent\ninstincts, and of the artistic instincts;\u201d and thus leads up to the\nposition, to be further elaborated in his work, that there exists in\nman a religious instinct which has fulfilled a function of biological\nvalue in the development of our race. Now, here again there is much in\npopular usage of the words _instinct_ and _instinctive_ which lends\nsupport, for what it is worth, to Mr. Marshall\u2019s very broad conception\nof the range of instinct. Again and again we hear, in the pulpit and\nelsewhere, of the religious instinct; we hear, too, of the benevolent,\npatriotic, and artistic instincts, and more besides. But what we are\nendeavouring to define is a type of behaviour which, as such, is\nprior to instruction and experience. Can we affirm that patriotic and\nreligious behaviour conforms to such a type? Is it unquestionably\ncongenital and not acquired? If we are forced to give negative answers\nto these questions we must regard Mr. Marshall\u2019s conception of instinct\n(one inclusive of multifarious tendencies which have a biological\nvalue) as too broad and too vague to be of any service to us at this\nstage of our study of animal behaviour.\n\nWhat, then, shall we understand by Spence\u2019s phrase that instinct\ninvolves the performance of \u201ccertain actions\u201d? And how far shall\nwe accept it? We shall take it as implying so much definiteness of\nbehaviour as renders instinctive acts susceptible of scientific\ninvestigation, and in this sense shall accept it with some modification\nof phraseology. We shall freely admit, however, the existence of\nvariations of instinctive behaviour analogous to variations in animal\nstructure. It is the occurrence of such variations that renders the\nnatural selection of instinctive modes of behaviour conceivable.\nWe shall also admit some, nay much, variation in detail. Take, for\nexample, two of the cases which Mr. Marshall cites--nest-building\nand migration. Both involve, not merely a simple response to a given\nstimulus, but a complex sequence of actions. In detail there may be\nmuch variation even among members of the same species. And yet, can it\nbe questioned that the behaviour as a whole is in each case relatively\ndefinite? May we not even say that it is remarkably definite? May we\nnot even go further, and assert that only on the assumption that any\ngiven instinctive act is relatively definite, can we regard it as a\nsubject for scientific investigation, and can we hope to distinguish it\nfrom other modes of behaviour?\n\nThe next point for consideration in Spence\u2019s definition, which we\nhave taken as our text, is his characterization of instinctive acts\nas \u201ctending to the well-being of the individual and the preservation\nof the species.\u201d Here we have Mr. Marshall with us, for he too lays\nstress on the fact that instinctive behaviour has reference to a\ndefinite biological end. But in saying that the biological end is _the_\nobjective mark of an instinct,[28] he seems to be in error. Because,\nin the first place, there are other \u201cobjective marks,\u201d and because, in\nthe second place, this objective mark is not restricted to instinctive\nbehaviour. According to Spence, a further characteristic of instinctive\nacts is that they are independent of instruction or experience; and\nthis serves to differentiate them from other modes of behaviour which\nare also subservient to a biological end. Intelligent behaviour, not\nless than that which we term instinctive, has reference to a biological\nend. Many intelligent acts, for example, have for their object the\nwell-being of the individual; many subserve race preservation; these\nbear, every whit as much as instinctive acts, the \u201cobjective mark\u201d\nwhich Mr. Marshall regards as characteristic of instinct. And if we\nturn to his subjective criterion--the absence of any conception of\nthe biological end which the behaviour subserves--Mr. Marshall\u2019s\nposition is equally untenable. There are thousands of acquired modes of\nbehaviour, dependent on instruction or experience, in which there is,\non the subjective side, so far as we can judge, no conception of the\nbiological end to be attained. What can the animal in the early stages\nof intelligence know of biological ends? Mr. Marshall\u2019s subjective\ncriterion applies just as much to a wide range of intelligent behaviour\nas it does to instinctive actions.\n\nIn accepting, therefore, Spence\u2019s statement that when animals\nbehave instinctively they perform, without a knowledge of the end\nin view, certain actions tending to their own well-being and the\npreservation of the species, we must take it in connection with the\npreceding limitation, remembering that they are also performed without\ninstruction and experience.\n\nA further point for very brief consideration is suggested by the\nphrase in which Spence says that animals are _all alike_ impelled to\nthe performance of certain actions. As it stands it is too sweeping\nand general. Still, we do require some explicit statement of the\nfacts which he had in mind when he wrote the words \u201call alike.\u201d And\nwe find it with sufficient exactness in Dr. Peckham\u2019s definition,\nwhere he comprises under the category of instinctive behaviour \u201call\ncomplex acts which are performed previous to experience, and _in a\nsimilar manner by all members of the same sex and race_.\u201d This places\ncongenital behaviour in line with morphological structure as a subject\nfor comparative treatment.\n\nOne more question remains. What shall we understand by \u201ccomplex acts\u201d?\nIn the first place, it is well to restrict the term instinctive\nto _co-ordinated_ actions; and this implies the presence of\nnerve-centres by which the co-ordination is effected. We thus exclude\nthe organic behaviour of plants, since there is no evidence in the\nvegetable kingdom of co-ordinating centres. In the second place, the\nco-ordination is, as we have seen, congenital, and not acquired in the\ncourse of individual experience. Young water-birds, and indeed young\nchicks, as soon as they are born, and have recovered from the shock\nof birth, can swim with definite co-ordination of leg movements. Here\nthe definiteness is not only congenital, but _connate_, if we use the\nlatter term for an instinctive activity which is performed at or very\nshortly after birth. On the other hand, young swallows cannot fly at\nbirth; they are then too immature, and their wings are not sufficiently\ndeveloped. But when they are some three weeks old, and the wings have\nattained functional size and power, little swallows can fly with\nconsiderable if not perfect skill. The co-ordination is congenital,\nfor it is not acquired in the course of individual experience; but it\nis not connate, since it is not exhibited at or shortly after birth.\nThe term _deferred_ may be applied to such congenital activities as\nare thus carried out when the animal has undergone a certain amount of\nfurther development after birth.\n\nIn the third place, it is customary to distinguish between such reflex\nactions as have already been briefly exemplified,[29] and instinctive\nbehaviour. It is, however, by no means easy, if indeed it be possible,\nto draw any sharp and decisive line of demarcation. Instinct has indeed\nbeen well described by Mr. Herbert Spencer as compound reflex action;\nhence the distinction between instinctive and reflex behaviour turns in\nlarge degree on their relative complexity. It would seem, however, that\nwhereas a reflex act--such as the withdrawal of the foot of a sleeping\nchild when the sole is tickled--is a restricted and localized response,\ninvolving a particular organ or a definite group of muscles, and is\ninitiated by a more or less specialized external stimulus; instinctive\nbehaviour is a response of the animal as a whole, and involves the\nco-operation of several organs and of many groups of muscles. Partly\ninitiated by an external stimulus or group of stimuli, it is also,\nseemingly, determined in part, in a greater degree than reflex action,\nby internal factors which cause uneasiness or distress, more or less\nmarked, if they do not find their normal instinctive satisfaction. This\npoint, however, may be more profitably discussed in connection with\nthe conscious aspect of instinct. If, then, we say that reflex acts\nare local responses of the congenital type due to specialized stimuli,\nwhile instinctive activities are matters of more general behaviour,\nusually involving a larger measure of central (as opposed to local or\nganglionic) co-ordination, and due to the more widely-spread effects\nof stimuli in which both external and internal factors co-operate, we\nshall probably get as near as is possible to the distinction of which\nwe are in search. But it must be remembered that there are cases in\nwhich the distinction can hardly be maintained.\n\nWe are now in a position to define instinctive behaviour as comprising\nthose complex groups of co-ordinated acts which are, on their first\noccurrence, independent of experience; which tend to the well-being\nof the individual and the preservation of the race; which are due to\nthe co-operation of external and internal stimuli; which are similarly\nperformed by all the members of the same more or less restricted group\nof animals; but which are subject to variation, and to subsequent\nmodification under the guidance of experience.\n\n\nII.--INSTINCTIVE BEHAVIOUR IN INSECTS\n\nSince instinctive behaviour is, by definition, independent of\nexperience, and since the animals which act instinctively are also, in\nmany cases, able to act intelligently, it is clear that, apart from\nhereditary variations, we must expect to find acquired modifications\nof instinct. As Huber said of bees, their instinctive procedure often\nindicates \u201ca little dose of judgment.\u201d It is, indeed, exceedingly\ndifficult, as a matter of observation, to distinguish between\nhereditary variation and acquired modification. For the _r\u00f4le_ played\nby these two factors in any given behaviour can only be determined if\nthe whole life-history of the individual be known, and if there be\nopportunities for comparing it with the complete life-histories of\nother members of its race. And this is seldom possible.\n\nThese considerations must be borne in mind as we proceed to a brief\nstudy of some of the instinctive modes of behaviour in insects.\n\nDr. and Mrs. Peckham\u2019s investigations on the instincts and habits of\nthe solitary wasps have been described in a volume[30] worthy to be\nplaced by the side of Fabre\u2019s \u201cSouvenirs.\u201d Their descriptions seem to\nglow with the warm sunshine, and are redolent of the fresh air which\nafforded the conditions under which the observations were conducted. We\ncan but regret that, in extracting from their bright pages some of the\nsalient facts, the natural delicacy and grace of their treatment must\nbe lost. For we can only give the dry skeleton which they have clothed\nwith the flesh of lively detail. They enumerate the following primary\nmodes of instinctive behaviour:--\n\n1. Stinging.\n\n2. Taking a particular kind of food.\n\n3. Method of attacking and capturing prey.\n\n4. Method of carrying prey.\n\n5. Preparing nest, and then capturing prey, or the reverse.\n\n6. The mode of taking prey into the nest.\n\n7. The general style and locality of the nest.\n\n8. The spinning or not spinning of a cocoon, and its specific form when\none is made.\n\nWhen the young _Pelop\u0153us_ emerges from the pupa-case and gnaws its\nway out of the mud cell, with limp and flaccid wings, it responds\nto a touch by well-directed movements of the abdomen with thrusts\nof the sting, as perfect as those of the adult. There is clearly no\nopportunity here for either instruction or experience to afford any\nintelligent guidance. Stinging is an instinctive act. And it is an act\nof which great use is made in the capture of prey which shall serve for\nfood to the young--it has a biological end. But the wasps of different\nspecies do not have to learn by experience what prey to attack. It\nis by instinct, too, that they take their proper food-supply, one\ncaterpillars, another spiders, a third flies or beetles. So deeply\nseated, indeed, is the hereditary preference, that no fly-robber ever\ntakes spiders, nor will the capturer of spiders change to caterpillars\nor beetles. Some keep to a few species or genera, while _Philanthus\npunctatus_ preys chiefly or entirely on bees of the genus _Halictus_.\n\nRomanes[31] thought that the manner of stinging and paralyzing their\nprey might \u201cbe justly deemed the most remarkable instinct in the\nworld.\u201d Spiders, insects, and caterpillars are stung, he says, \u201cin\ntheir chief nerve-centres, in consequence of which the victims are not\nkilled outright, but rendered motionless; they are then conveyed to a\nburrow and, continuing to live in their paralyzed condition for several\nweeks, are then available as food for the larv\u00e6 when these are hatched.\nOf course the extraordinary fact which stands to be explained is that\nof the precise anatomical, not to say also physiological knowledge\nwhich appears to be displayed by the insect in stinging only the\nnerve-centres of its prey.\u201d Eimer[32] thought that it \u201cis absolutely\nimpossible that the animal has arrived at its habit otherwise than by\nreflection upon the facts of experience.\u201d \u201cAt the beginning,\u201d he says,\n\u201cshe probably killed larv\u00e6 by stinging them anywhere, and then placed\nthem in the cell. The bad results of this showed themselves; the larv\u00e6\nputrified before they could serve as food for the larval wasps. In the\nmean time the mother wasp discovered that those larv\u00e6 which she had\nstung in particular parts of the body were motionless but still alive,\nand then she concluded that larv\u00e6 stung in this particular way could be\nkept for a longer time unchanged as living motionless food.\u201d\n\nNow, since these wasps, when they have stored their nests and laid an\negg on one of the victims, close it up once and for all, and take no\nfurther interest in it or its contents, there seems no opportunity,\nat any rate in the existing state of matters, for the acquisition of\nthat experience on which Eimer relied. But both his explanation and\nRomanes\u2019s difficulty are based on the following assumptions: first,\nthat the victims are instinctively or habitually stung in the chief\nnerve-centres; secondly, that when thus stung they are not killed\nbut remain paralyzed for weeks; and thirdly, that the marvellously\ndefinite and delicate instinctive behaviour is in direct relation to\nthe uniform result of prolonged paralysis and consequent preservation\nof the food in the fresh state. But Dr. Peckham\u2019s careful observations\nand experiments show that, with the American wasps, the victims stored\nin the nests are quite as often dead as alive; that those which are\nonly paralyzed live for a varying number of days, some more, some\nless; that wasp larv\u00e6 thrive just as well on dead victims, sometimes\ndried-up, sometimes undergoing decomposition, as on living and\nparalyzed prey; that the nerve-centres are not stung with the supposed\nuniformity; and that in some cases paralysis, in others death, follows\nwhen the victims are stung in parts far removed from any nerve-centre.\n\u201cWe believe,\u201d he says, \u201cthat the primary purpose of the stinging is to\novercome resistance, and to prevent the escape of the victims, and that\nincidentally some of them are killed and others are paralyzed.\u201d\n\nIf, therefore, as will probably be shown to be the case, these\nconclusions are found to be generally true for this interesting group\nof insects, the mystery of \u201cthe precise anatomical, not to say also\nphysiological knowledge which appears to be displayed\u201d by these wasps\nturns out to be one of our own fabrication. It melts away in the light\nof fuller and more searching investigation.\n\n[Illustration: FIG. 11.--Solitary Wasp stinging Caterpillar (after\nPeckham).]\n\nIt must not be supposed, however, from what has been said, that the\nbehaviour in the act of stinging is altogether indefinite. On the\ncontrary, each species proceeds in a relatively definite manner with\nsome variation or modification of method. _Philanthus punctatus_, for\nexample, stings the bees, on which she preys, under the neck, and the\nthrust is at once fatal. Dr. Peckham further notes that he was only\nsuccessful in getting the wasps to sting when they were hunting; those\nthat had not yet begun to store the nests paid no attention to the\nbees. This is an example of that internal factor to which reference was\nmade in the last section. Marchal observed that _Cerceris ornata_ runs\nthe end of her abdomen along the under surface of the thorax of the\nbee, and delivers her thrust at the division of the segments--that is,\nwhere the sting can enter. The action does not imply any physiological\nknowledge. In general she begins at the neck. Spiders are usually, but\nnot always, stung on the ventral surface. To give but one more example,\nDr. Peckham observed in three cases the procedure of _Ammophila\nurnaria_ which preys on caterpillars, and often, after stinging, bites\nthe neck in several places, this process being termed malaxation. In\nthree observed captures, all the caterpillars being of the same species\nand alike in size, the thrusts were given on the ventral surface near\nthe middle line, between the segments. In the first, seven stings were\ngiven at the extremities (there being thirteen segments), the middle\nsegments being left untouched, and no malaxation was practised. In the\nsecond, seven stings were again given, but in the anterior and middle\nsegments, followed by slight malaxation. In both these cases the first\nthree thrusts were in definite order, behind the third, the second, and\nthe first segments successively. In the case of the third caterpillar,\nonly one thrust was given, between the third and fourth segments--that\nis to say, in the position of the first stab in the other cases,--and\nafter this one thrust there was prolonged malaxation. Of fifteen stored\ncaterpillars examined, some lived only three days, others a little\nlonger, while a few showed signs of life at the end of a fortnight. In\nmore than one instance the second of the two caterpillars stored in\neach nest died and became discoloured before the first one was entirely\neaten. The larva under such circumstances ate it with good appetite,\nand then spun its cocoon as if nothing unpleasant had occurred.\n\n[Illustration: FIG. 12.--Solitary Wasp dragging a Caterpillar to its\nNest (after Peckham).]\n\nThe mode of carrying their booty is in these wasps instinctive, and\nrelatively uniform. _Ammophila urnaria_ grasps the caterpillar, near\nthe anterior end, in her mandibles, and carries or drags it beneath her\nlegs, walking forwards. It is generally but not always with the ventral\nsurface uppermost. _Pompilus_ takes hold of her spider anywhere, but\nalways drags it over the ground, walking backwards. _Oxybelus_ clasps\nher fly with her hind legs; _Bembex_ with the second pair. Each works\nafter her own fashion in a way that is relatively uniform for each\nspecies.\n\nThe general style of the nest, its mode of construction, and its method\nof closure, are always performed, says Dr. Peckham, by each species\nin a similar manner, not indeed in circumstantial detail, but quite\nin the same way in a broad sense. Variation or modification is always\npresent, but the tendency to depart from a nest of a given type is not\nexcessive. Some dig in the ground curved tunnels, with or without one\nor more chambers. Others bore into decaying wood; others use straws,\nor make tunnels in bramble stems; while the mud-daubers build cells in\nwhich to store the food and lay the egg. This is sometimes deposited\non the first, sometimes on the last, sometimes on some intermediate\nvictim, but generally in much the same place and position. _Ammophila_,\nfor instance, lays it on the side of the sixth or seventh segment--that\nis to say, in about the mid position.\n\nSome species first capture their prey, and then make the nest in which\nit is to be entombed. Others first prepare the nest, and then carry\nor drag their prey to it--often from considerable distances--quite\nirrespective of what seems to us the more appropriate method of the\ntwo under the particular circumstances of the case. And the way in\nwhich the victim is dragged into the nest is similarly a matter of\ninheritance. Each way is characteristic of the species concerned, and\nwould be an important part of any definition of the animal based upon\nits modes of behaviour. For example, a _Sphex_ places her grasshopper\njust at the entrance of the nest, which she then enters herself before\ndragging in her prey by the antenn\u00e6. When the wasp was in the hole,\nFabre moved the victim a little way off; the wasp came out, brought\nthe grasshopper to the entrance as before, and went in a second time.\nThis was repeated about forty times, each time with the same result,\nuntil the patience of the naturalist was exhausted, and the persistent\nwasp took her booty in after her appropriate fashion. She must place\nthe grasshopper close to the opening; she must then descend and examine\nthe nest, and, after that, must drag it down. Nothing less than the\nperformance of these acts in a certain order satisfies her instinctive\nimpulse.\n\nIn a private letter, from which he kindly allows me to quote, Dr.\nPeckham says: \u201cWe have recently made some experiments on this wasp\n(_Sphex ichneumonea_). First we allow her to carry in her prey\nundisturbed, to see how far she was faithful to the traditions of her\nancestors, and to observe her normal methods. On the next day, when she\nhad placed her grasshopper just at the opening of the nest, and while\nshe was below, we drew it back to a little distance. She came out, and\nwe both repeated our operations four times--she running down into the\nnest, always after getting the grasshopper into position, and we as\nregularly drawing it away. The fifth time she changed her plan, seized\nit by the head and backed into the nest with it. The next day, at the\nfourth trial, she straddled it and walked head first into the nest with\nit; and on the fourth day, at the eighth trial, she backed in with it\nas on the second day.\u201d These interesting observations show that the\nwasp has sufficient intelligence to modify her procedure in accordance\nwith an unwonted situation. The \u201cconsecutive necessity,\u201d as it has been\ntermed, has a potent influence, but is not absolute.\n\nFabre notes a case of similar consecutive necessity in the case of the\nmason bee, _Chalicodoma_. If while a bee is provisioning its nest with\nhoney and pollen the structure be destroyed, she sometimes breaks open\na completed cell, and, having done so, goes on bringing more provision,\nthough the cell already contains a sufficient store of food; and only\nwhen she has completed the superfluous storing does she deposit her egg\nand seal up the cell. So, too, when the cell is removed in an early\nstage of construction, and another completed cell already partially\nstored is substituted, the bee, instead of simply adopting the new\ncell, goes on building until the cell is as much as one-third beyond\nthe usual height; then, and not till then, does she proceed in due\ncourse to the next stage of the instinctive procedure, the provisioning\nof the cell.\n\nFrom our general knowledge of animal nature, we should expect to\nfind parasitic forms ready to take advantage of the material stored\nby such insects as the solitary wasps and the mason bees. It is said\nthat _Chalicodoma_ provides nourishment to the larv\u00e6 of some sixteen\nunbidden guests. A parasitic bee (_Stelis nasuta_) breaks open a\nclosed cell, and, after depositing its eggs, seals it up again with\nmortar. Since her eggs and larv\u00e6 develop more rapidly than those of\nthe mason bee, they are first served with the store of provision,\nwhile the rightful owner is done out of its inheritance. By a curious\nact, of what appears to us like retributive justice, these parasitic\nlarv\u00e6 sometimes fall a prey to another parasite, also a hymenopterous\ninsect named _Monodontomerus_, the larv\u00e6 of which prey on the young\nof both bees. Another genus of the same family, _Leucopsis_ (Fig. 13,\nF), also succeeds in piercing with its ovipositor, at a suitable spot,\nthe walls of the _Chalicodoma_ cell, and suspends its curious hooked\negg (Fig. 13, G) on the delicate cocoon within which the chrysalis\nlies. Fabre found in some cases as many as five of these parasitic\neggs on a single cocoon. But he never found more than one larva in any\ncell that he examined. The following is an epitome of his conclusions\nand inferences. From the parasitic egg is hatched a minute arched\ngrub, with relatively large head and mandibles, and provided with\na number of bristles, which aid it in progression (Fig. 13, H). It\ndoes not, however, at once attack the bee larva, but makes a series\nof excursions, the object of which is to reach and destroy any other\nparasitic eggs. This was not actually observed, but the eggs were\nfound to have been destroyed, and there was seemingly no other means\nof destruction under the conditions maintained. The larva, this done,\nchanges its skin and takes on a new form, destitute of bristles, with a\nvery small head and minute mandibles (Fig. 13, I). In this new form it\nattacks the _Chalicodoma_ larva, making a very small incision, through\nwhich the juices of the host are transferred to the guest without\nfurther injury to the grub. It is interesting to note that, if the\nfacts are accurately described and the inferences are correct, there\nare associated with two types of instinctive behaviour two distinct\ntypes of structure. The creature can have no conscious control over its\nstructural development, and there is no ground for assuming that it has\nany control over its instinctive behaviour.\n\n[Illustration: FIG. 13.--Insect Larv\u00e6. A, B, of _Sitaris_; C, D, E, of\n_Argyrom\u0153ba_; G, H, I, of _Leucopsis_; F, imago of _Leucopsis_ (after\nFabre).]\n\nThe specialization of structure and of instinctive behaviour, in\naccordance with a definite sequence of life-conditions, is even more\nremarkable in another of the many parasites which _Chalicodoma_\nunwittingly labours to nourish. This time it is a fly (_Argyrom\u0153ba_),\nwhich lays a minute egg on the outside of the cell. From this egg is\nhatched a slender threadlike worm, barely one-twentieth of an inch in\nlength (Fig. 13, C). It has three pairs of longish bristles near the\nanterior end, and a single yet longer pair at the hinder extremity.\nThese aid it in creeping over the wall of the cell. Its small head\nis armed with short, stiff bristles. For many days it wanders over\nthe surface of the cell, inserting its bristly head into each minute\ncranny and crack. Throughout this long period it has never a bite nor\nsup. Probably many of them never succeed in finding a crevice by which\nthey can effect an entrance, but those that do manage to wriggle in\nundergo a change, lose their bristles, and develop a minute suctorial\nmouth, through which the contents of the larva are absorbed into their\nswelling bodies (Fig. 13, D). When fully grown they are quite helpless,\nand unable to get out from the cell in which they are now imprisoned.\nFor months they lie quiescent, but in the succeeding spring they pass\ninto a pupal condition very different from that of most flies. The\nrelatively large head is armed with strong spines; the middle region\nbears bristles directed backwards; the posterior end has short spines\n(Fig. 13, E). Fixing itself to the interior of the cell by the latter,\nit strikes with its armoured head repeated blows on the walls of its\nprison until a breach is at last made, and sufficiently enlarged to\nform a suitable exit. Then the pupa-skin bursts, and the imago insect\nemerges and flies off. At each stage of life there is the closest\nrelation between structure and behaviour, and each is equally adapted\nto a biological end of which the creature has never had an opportunity\nof gaining any experience.\n\nExceedingly multifarious are the ways in which insects thus provide\nfor the future of young they will never see. _Antherophagus_ lives\nin flowers, and is believed to seize with its mandibles humble bees,\nwhich then unwittingly bear the parasitic beetle to the nests in which\nalone the larv\u00e6 have been found. The larv\u00e6 of our common oil-beetle\n(_Melo\u00eb_) are parasitic on the bee, _Anthophora_. It deposits its ten\nthousand eggs without observable discrimination; but the active young\nlarva instinctively seizes and attaches itself to any hairy object.\nThousands must go astray. They have been found on hairy beetles, flies,\nand bees of the wrong genus. Some, however, become thus attached to\nthe one suitable species, and are conveyed by the _Anthophora_ to her\nnest, where they promptly eat the egg she lays. It is not difficult\nto picture to one\u2019s self how this incompletely evolved instinct might\nbe further perfected by natural selection, through the survival of\nthose females which laid their eggs in the haunts of the bee-host. And\nsuch an advance in instinctive behaviour is seen in another and rarer\nbeetle--_Sitaris_. Her eggs are laid in August near the entrance to a\nnest of the _Anthophora_. In September they hatch to form larv\u00e6, which\nhibernate in groups till the following spring. Then they become active\n(Fig. 13, A), and attach themselves to hairy objects. Being near the\n_Anthophora_ nest, there is an increased chance of their fastening upon\nthis bee. The chance is still far from good, for if this were so, we\nshould not find that the _Sitaris_ laid as many as two thousand eggs.\nStill, on these grounds, we may presume that its chance of survival is\nabout five times as good as that of _Melo\u00eb_, which lays ten thousand\neggs. The larva is said generally to attach itself to a male bee, which\nis hatched earlier than his mate, and to pass on to the female at the\nnuptial period; but in any case it eventually slips on to the egg that\nshe lays. This forms the food of the larva during the remainder of this\nstage of its existence. It then moults and assumes a new form, capable\nof feeding on the honey (Fig. 13, B); and, after further changes,\nbecomes a pupa, and then assumes the imago condition.\n\nIn these cases the advantage is wholly on the side of the parasite. But\nthere are cases of close relationship between insects and flowering\nplants where the instinctive behaviour gives rise to reciprocal\nbenefit. The Yucca is a genus of American Liliaceous plants, with large\npale sweet-smelling flowers; and these are dependent for fertilization\non the instinctive behaviour of a small straw-coloured moth of the\ngenus _Pronuba_. Just when the Yucca plant blossoms in the summer,\nthe moths emerge from their chrysalis cases. They mate; and the\nfemale then flies to a flower, collects a pellet of pollen from the\nanthers, proceeds to another flower, pierces the pistil with her sharp\novipositor, lays her eggs among the ovules, and finally darting to the\nstigma stuffs the pollen pellet into its funnel-shaped extremity (Fig.\n14). If the flower be not thus fertilized the ovules do not develop;\nand if the ovules do not develop the grubs which are hatched from the\nmoth\u2019s eggs die of starvation. There are enough ovules to supply food\nto the grubs, and leave a balance to continue the race of Yuccas.\n\n[Illustration: FIG. 14.--Yucca Flower and Moth.]\n\nWhether the female moth is attracted to the flower by sight or smell,\nwe do not know. And whether the male finds the female, in the case\nof the Yucca moth, through scent, we are not in a position to state\nwith certainty. It has, however, been shown that in certain moths[33]\nsome odour emitted by the female is the attractive stimulus, affecting\nsense-organs situated on the antenn\u00e6 of the male. To females confined\nin an opaque vessel over the mouth of which gauze was tied, the males\ncame in numbers; but when a clear glass vessel was inverted, and sand\nwas packed round the mouth, so as to prevent the escape of air from the\ninterior, no males came, though the imprisoned females were clearly\nvisible. If the antenn\u00e6 of the males were either removed or coated with\nshellac the moths failed to notice the females even when close to them.\nIn what way the intact male is made aware of the direction from which\nthe scent comes, we do not know--possibly by differential stimulation\nin the antenn\u00e6, the moth instinctively turning in the direction of\ngreater stimulation. It will be seen, therefore, that in the case of\nthe behaviour of the Yucca moth--behaviour which is essential to the\nbiological end of reproduction--there is much detail concerning which\nwe are ignorant. But for our present purpose the important point to\nnotice is that the procedure of the female cannot be due to imitation;\nnor can it be the outcome of individually acquired experience; for\nthe method of procedure is not gradually learnt, but is carried out\nwithout apparent hesitation the first and only time the appropriate\noccasion presents itself. Not only does the moth take no heed of her\ngrubs, but they are so placed that she could not in any case ascertain\nby observation that only if the ovules are fertilized do her offspring\nthrive. She cannot possibly know what effect the stuffing of the pollen\non to the stigma exercises, or indeed whether it have any effect at\nall. And yet generation after generation these moths collect the pollen\nfrom the anthers and bear it to the stigma. Spence\u2019s words \u201cwithout\nknowledge of the end in view\u201d are amply justified in this case, as in\nother cases of typically instinctive behaviour.\n\n\nIII.--THE INSTINCTIVE BEHAVIOUR OF YOUNG BIRDS\n\nSince it is easy to hatch birds of many species in an incubator, and\nto rear them under conditions which not only afford facilities for\nobservation but exclude parental influence, their study has special\nadvantages. One can with some approach to accuracy distinguish the\ninstinctive from the acquired factors in their behaviour.[34]\n\n[Illustration: FIG. 15.--Newly-hatched Chick swimming.]\n\nThe callow young of such birds as pigeons, jays, and thrushes are\nhatched in a helpless condition, and require constant and assiduous\nministration to their elementary organic needs. Most of their instincts\nare of the deferred type. But pheasants, plovers, moor-hens, domestic\nchicks, and ducklings, with many others, are active soon after birth,\nand exhibit powers of complex co-ordination, with little or no\npractice of the necessary limb-movements. They walk and balance the\nbody so soon and so well as to show us that this mode of procedure is\ncongenital, and has not to be gradually acquired through the guidance\nof experience. Young water-birds swim with neat and orderly strokes the\nvery first time they are gently placed in water. Even little chicks a\nday or two old can swim well. Dr. Thorndike, who draws attention to\nthis fact,[35] appears to accept the view, suggested by Dr. Bashford\nDean, that the movements are not those of swimming but only of running.\nI have carefully watched the action through the glass walls of a tank\nand compared it with that of a young moor-hen. In the two cases it\nis quite similar in type, and the type appears to be different from\nthat of running, though it is perhaps hard to distinguish the two.\nIn any case, the hand over hand action is well co-ordinated, and is\nvery different from a mere excited struggle. Chicks twenty-six hours\nold taken straight from the incubator drawer, before they had taken\nfood, made directly for the side of the tank and tried to scramble out.\nThey gradually sank deeper through the wetting of the down, but could\nkeep afloat for from two to three minutes. I have made observations on\nchicks of various ages from twenty-four hours to a month, and find in\nall cases similar results; but with the older birds the flapping of\nthe wings and more vigorous action cause them to get water-logged more\nrapidly. There is some apparent distress with cries; but less than one\nmight expect under the circumstances. For the purposes of the above\nillustration Mr. Charles Whymper had before him a sketch I made of the\nleg-action, and instantaneous photographs of the chicks swimming for\nwhich I am indebted to my colleague Mr. George Brebner. I have not\nobserved the behaviour of an adult hen when placed in the water. Dr.\nThorndike says, \u201cthere is no vigorous instinct to strike out toward the\nshore,\u201d she \u201cwill float about aimlessly for awhile and only very slowly\nreach the shore.\u201d But Mrs. Foster Wood informs me that she has seen a\nhen leap into a pond after her brood of ducklings and swim to the other\nside, a distance of twenty feet.\n\nDiving, in water-birds, is also an instinctive mode of behaviour; and\nthis is obviously a more difficult procedure than swimming, one further\nremoved from reflex action. And careful observations have placed beyond\nquestion the fact that flight is also instinctive. A swallow, for\nexample, taken from the nest under conditions which made it practically\ncertain that it had never yet taken wing, exhibited guided flight, and\nattempted to alight on a suitable ledge. Of course flight is generally\na deferred instinct, and is not performed until the wings have reached\na suitable state of development. An instinctive response, which may\nperhaps be regarded as one of its initial stages, is seen in quite\nyoung chicks. If placed in a basket, and rapidly lowered therein\nthrough a foot or two, the chick will extend its skinny and scarcely\nfeathered wings. But though, from the usual conditions of development,\nflight in birds is a deferred instinct, yet in exceptional cases it\nmay be connate. The mound-builders (_Megapodes_) of the Australian\nregion are hatched from large eggs in warm earth or sand, and are not\ntended by the parents. So well fledged are these birds that they can\nfly the day they emerge from the egg. Dr. Worcester, while digging in\none of their mounds, made an unsuccessful attempt to seize one which\nwas newly hatched; but it flew several rods into thick brush, and this\nnotwithstanding the fact that it had probably never before seen the\nlight of day.\n\n[Illustration: FIG. 16.--Nestling Megapode, to show the well-developed\nwings. (From Dr. R. Bowdler Sharpe\u2019s \u201cWonders of the Bird World.\u201d)]\n\nIt must not be supposed that, in adducing flight as an example of\ninstinctive behaviour in birds, we are contending that it is this and\nnothing more throughout life. The inference to be drawn from the facts\nof observation is rather that instinct provides a general ground plan\nof behaviour which intelligent acquisition, by enforcing here and\nchecking there, perfects and guides to finer issues. Few would contend\nthat the consummate skill evinced in fully developed flight at its\nbest, the hurtling swoop of the falcon, the hovering of the kestrel,\nthe wheeling of swifts in the summer air, the rapid dart and sudden\npoise of the humming bird, the easy sweep of the sea-gull, the downward\nglide of the stork--that these are, in all their exquisite perfection,\ninstinctive. A rough but sufficient outline of action is hereditary;\nbut the manifold graces and delicacies of perfected flight are due to\nintelligent skill begotten of practice and experience.\n\nThere are many little idiosyncracies and special traits of flight\nwhich are probably instinctive--such as enable an ornithologist or a\nsportsman to recognize a flying bird from a distance. And the same is\ntrue of other modes of behaviour. The observer of young birds cannot\nfail to note and to be impressed by many of these. The way in which a\nlittle moor-hen uses its wings in scrambling up any rough surface is\nvery characteristic; so, too, is the manner in which a guinea-chick\nruns backwards and then sideways at a right angle when one attempts to\ncatch him. If suddenly startled, moor-hens and chicks scatter and hide;\nplovers drop and crouch with their chins on the ground; pheasants stand\nmotionless and silent. Knowledge of the ways of birds enables one to\npredict with tolerable accuracy how each kind will behave under given\ncircumstances. That the actions are always precisely alike cannot be\nsaid with truth; but that the behaviour is so relatively definite as to\nbe readily recognizable can be confidently asserted. That a moor-hen\nwill flick its tail, that a chick will dust itself in the sand, that\npheasants and partridges will scratch the ground, that a jay will go\nthrough certain actions in the bath, that the preening of the down will\nbe carried out in particular ways--moor-hens, for example, wringing out\nthe water in a peculiar manner,--and that all these, and many other\nmodes of behaviour, will be presented in relatively definite ways: all\nthese are, to borrow a phrase of Dr. Peckham\u2019s, so characteristic of\nthe several groups of birds, that they would be an important part of\nany definition based upon behaviour. And there can be no question that\nthey are instinctive. They may indeed seem trivial and commonplace,\nscarcely worthy of special note; but they serve to show in how many\ndetails organic heredity lays the foundation for future behaviour, and\naffords groups of data for effective consciousness to utilize.\n\nTo show the instinctive nature of such behaviour, the following\nexamples will suffice. One of a batch of moor-hen chicks showed once,\nand once only, when a week old, an incipient tendency to bathe in the\nshallow tin of water which was placed in their run, but soon desisted;\nnor was the action repeated, though he and the others enjoyed standing\nin the water. Five weeks later one of the batch was taken to a beck.\nHe walked quietly through the comparatively still water near the edge;\nbut when he reached the part of the stream where it ran swiftly and\nbroke over the pebbles, he stopped, ducked, and took an elaborate bath,\ndipping his head well under, flicking the water over his back, ruffling\nhis feathers, and behaving in a most characteristic manner. Each day\nthereafter he did the same, with a vigour that increased up to the\nthird morning, and then remained constant. The same bird some weeks\nlater was swimming in a narrow part of the stream, with steep banks\non either side, when he was frightened by a rough-haired pup. Down he\ndived, for the first time in his life; and after a few seconds his head\nwas seen to appear, just peeping above the water beneath the bank.\n\nTen days after receiving two nestling jays I placed in their cage a\nshallow tin of water. They took no notice of it, having never seen\nwater before; for they were fed chiefly on sopped food. Presently one\nof them hopped into it, whether attracted by the water or by accident\nit is difficult to say, squatted in it bending his legs, and at once\nfluttered his feathers, as such birds do when they bathe, though his\nbreast scarcely touched the water. The other seized the tin in his\nbill, and then pecked at the water, thus wetting his beak. He, too,\nfluttered his feathers in a similar fashion, though he was outside the\ntin and not in the water at all. A little later the first again entered\nthe tin, and dipped his breast well into the water; this was followed\nby much fluttering and splashing. The bird took a good bath, as did the\nother shortly afterwards, and then spent half an hour in a thorough\ngrooming, with much fluttering of the wings, the crest feathers being\nconstantly raised and lowered, expressive of an emotional state.\n\nNow, in these cases it would be impossible to say whether the behaviour\nwas carried out in the manner characteristic of the species, prior to\nexperience and independent of imitation, on the basis of mere casual\nand chance observation. But in these cases the whole life-history\nof the individuals concerned was known; and it can be asserted with\nconfidence that the behaviour was hereditary, and not acquired by any\ngradual process of learning. Moreover, in each case there seemed to\nbe such evidence as observation can afford, that internal emotional\nfactors co-operated with the direct external stimuli in determining\nthe nature of the behaviour. Whether such actions so far contribute\nto the well-being of the individual as to be of decisive advantage it\nis difficult to say. Some would contend that bathing is practised by\nbirds merely for the pleasure it seemingly affords; others would urge\nthat it is a means of getting rid of troublesome and presumably hurtful\nparasites, to the attacks of which birds are peculiarly subject.\n\n[Illustration: FIG. 17.--Young Cuckoo ejecting nestling Meadow Pipit.\n(From Mrs. Hugh Blackburn\u2019s sketch in \u201cBirds from Moidart.\u201d)]\n\nOne of the most remarkable instincts of young birds is that of\nthe cuckoo, which ejects eggs and nestlings from the home of its\nfoster-parent. Mrs. Hugh Blackburn found a nest which contained two\nmeadow-pipits\u2019 eggs, besides that of a cuckoo. On a later visit \u201cthe\npipits were found to be hatched, but not the cuckoo. At the next visit,\nwhich was after an interval of forty-eight hours, we found the young\ncuckoo alone in the nest, and both the young pipits lying down the\nbank, about ten inches from the margin of the nest, but quite lively\nafter being warmed in the hand. They were replaced in the nest beside\nthe cuckoo, which struggled about until it got its back under one of\nthem, when it climbed backwards directly up the open side of the nest,\nand hitched the pipit from its back on to the edge. It then stood quite\nupright on its legs, which were straddled wide apart, with the claws\nfirmly fixed halfway down the inside of the nest, among the interlacing\nfibres of which the nest was woven, and, stretching its wings apart and\nbackwards, it elbowed the pipit fairly over the margin, so far that\nits struggles took it down the bank instead of back into the nest. As\nit was getting late, and the cuckoo did not immediately set to work\non the other nestling, I replaced the ejected one and went home. On\nreturning next day, both nestlings were found dead and cold, out of\nthe nest.\u201d[36] Here we have a definite account by an eye-witness, who\nsketched the young cuckoo, which was naked, blind, and could scarcely\nhold up its head. And her account, itself confirmatory of that given\nby Jenner in 1778, is confirmed by that of Dr. John Hancock,[37] who\nwitnessed the ejection of a fledgling hedge-sparrow, which \u201cwas put\nover the edge of the nest exactly as illustrated by Mrs. Blackburn.\u201d\nThe procedure is unquestionably instinctive.\n\nThe sounds uttered by young birds are sufficiently definite to be\nreadily recognized and are susceptible of classification. In domestic\nchicks at least six notes may be distinguished. First the gentle\n\u201cpeeping\u201d note, expressive of contentment. A further low note, a double\nsound, seems to indicate extreme satisfaction and pleasure. Very\ncharacteristic and distinct is the danger-note--a sound difficult to\ndescribe, but readily recognized. If a humble-bee, a black-beetle, a\nbig worm, a lump of sugar--anything strange and largish--be thrown to\nthe chicks, this danger-note is at once heard; and it serves to place\nothers on the alert, though this is perhaps the outcome of experience.\nThen there is the cheeping sound, expressive apparently of a state of\nmild dissatisfaction with the present state of affairs. It generally\nceases when one throws some grain, or even stands near them. Extreme\ndissatisfaction is marked by a sharper, shriller squeak, when one\nseizes them against their inclination. Lastly, there is the shrill\ncry of greater distress, when, for example, their swimming powers are\nsubjected to critical examination. With pheasants a gentle, \u201cpeeping\u201d\nnote of contentment, a shriller cry of distress, and a danger-note,\ngenerically like, but specifically distinct from, that of the chick,\nare early differentiated. The complaining note of the partridge is\nuttered six or seven times in quick succession, followed by a pause.\nThe note of the plover is high-pitched, and much like the familiar\ncry of the adult bird, to which it owes its popular name of \u201cpeewit.\u201d\nSo, too, the guinea-fowl in down utters from the first notes quite\ncharacteristic of its kind, while its danger-note is not unlike that\nof the chick or pheasant. The piping of ducklings is comparatively\nmonotonous, and there does not seem to be a definite danger-note. With\nmoor-hen chicks, even on the first day, two notes are well-marked--a\ncall-note, lower in pitch than that of the chick, and rather harsh and\nraucous, and a \u201ctweet, tweet\u201d of pleasure, something like the contented\nnote of a canary. Later, five or six notes are differentiated, the most\ncharacteristic of which is the harsh \u201ccrek, crek,\u201d when the little bird\nis from any cause excited. It is uttered in a crouching attitude, with\nhead thrown back and wings held outwards and forwards, waving to and\nfro in a very characteristic manner. That this has suggestive value for\nother moor-hen chicks is shown by its distinctly infectious effect; if\none bird has cause to utter the note and strike the attitude others\nfollow suit. While clearly instinctive in their mode of occurrence,\nwhile they seem to show well the co-operation of an internal emotional\nfactor, their biological value seems to lie in their suggestive effect\non other members of the brood. They form an elementary but sufficient\nsocial bond.\n\nIf these notes afford evidence of an incipient social factor, the\ninstinct of pecking is distinctively individualistic. Chicks peck\nwith considerable but not complete accuracy of aim at practically\nanything of suitable size at suitable distance; but it is through\nexperience that they learn what to select for food and what to reject\nor leave untouched. Moving objects, however, are more readily pecked\nat than those which are still; and the instinctive response seems to\nbe stimulated if one tap on the ground near the object, or move it\nwith a pencil, thus simulating the action of the hen. And this is even\nmore marked with pheasants and partridges. Plovers seize small worms\nwith an avidity which looks like an inherited response to the sight\nof natural food. Pheasants and partridges also appear to be specially\naffected by worms, and when one of them seizes a worm for the first\ntime, he shakes it and dashes it against the ground. Chicks, a week or\nten days old, also seize a largish fly or bee with a dash, and maul it\non the ground, throwing it on one side before again approaching it.\nAnd such birds seem to show an instinctive tendency to bolt with such\ntreasures as caterpillars or small worms. Moor-hens cannot at first be\ninduced to take food from the ground. It has to be held above them,\nwhereupon they crouch down, with head and neck held back, opening\ntheir beaks more like the callow young of nursling birds; but they\nalso strike upwards at the object--these modes of behaviour being, no\ndoubt, correlated with the manner in which the mother moor-hen normally\nfeeds her young from her beak during the early days of life. Callow\nfledglings, such as young jays, simply open their mouths, gaping widely\nto be fed. And many will respond in this way to such a note as a low\nwhistle, as may readily be seen with swallows. But at a later age such\nbirds show instinctive modes of reaction of a more complex type. A jay,\nfor example, was offered a summer chafer or June bug, seized it at once\nin his bill, and tried to place his foot on it. Then he hopped down on\nto the floor of his cage, dropped the beetle, seized it again as it\ncrawled off, and after two or three attempts swallowed it, tossing it\nback from the point of his bill into the throat. This was the first\ntime he took food from the ground or swallowed it in this manner.\n\nOn the whole, there seems to be much inherited definiteness of\nco-ordination, and some tendency to respond in a definite manner to\nspecific stimuli. That there should not be more differentiation in\nthis respect than observation discloses is probably due to the fact\nthat the parent birds afford, under natural conditions, much guidance\nin the selection of food. Since the solitary wasp unerringly seizes\nits appropriate food, since it responds instinctively to specific\nstimuli, there would seem no reason why birds should not show similar\ninstinctive differentiation. But one must remember that in the\ncase of the wasp there is no parental guidance; the insect is more\ncompletely dependent on instinct than is the bird to whose needs the\nhen assiduously ministers.\n\nIt is at first sight surprising that such birds as chicks and pheasants\ndo not peck instinctively at still water. When a shallow vessel\ncontaining water was placed among some little chicks, several of them\nran repeatedly through the water, but took no heed of it. Then, after\nabout an hour, one of them standing in the vessel pecked at his toes,\nand at once lifted his head and drank freely with characteristic\naction. Another subsequently pecked at a bubble near the edge, and\nthen he too drank. In fact, the best way of inducing them to drink is\nto scatter some grains of food in the tin; they peck at the grains,\nwhich catch their eye, and incidentally find the water, and the touch\nof water in the bill at once leads to the characteristic response and\ncongenitally definite behaviour. That the sight of a still surface does\nnot itself suffice to evoke this behaviour is probably again due to the\nfact that under nature the hen guides them and pecks at the water, when\nthey follow her lead.\n\nOne fact which must be constantly borne in mind is that what is\ninherited is instinctive co-ordination, often related to a definite\nstimulus, not instinctive knowledge. A chick pecks at a grain when it\nis at a suitable distance, not because instinct provides him with the\nknowledge that this is something to be seized and tested, but because\nhe cannot help doing so. He is so organized that this stimulus produces\nthat result through an organic co-ordination that is independent of\nconscious knowledge or experience. How definite is the inherited\nco-ordination is shown by many observations. A young pheasant, only a\nfew hours old, was taken from the incubator drawer, and held snugly\nwhile a piece of egg-yolk was moved before his eyes with the aid of\nfine forceps. He did not peck at it, but followed with movements of\nhis head every motion of the object in a narrow circle. Simple as\nthis action seems, it presents a striking example of co-ordinated\nmovements accurately related to movements in the visual field, the\nwhole performed without any opportunity for learning or practice, and\nless than half an hour after the bird was taken from the drawer of the\nincubator and first saw daylight. Psychologists sometimes puzzle their\nheads over the question how and by what steps the field of vision and\nthe field of movement are brought into relation with each other; but in\nsuch a case as this, the problem ceases to be primarily psychological.\nThe relation is purely organic; the conscious data are grouped from the\noutset. With young jays there was no such co-ordination at first; and\nwhen they began after a few days (about twelve or fourteen) to follow\nan object with the head and eye, the movements were at first jerky. But\na week later, when I swept the food through a circle a foot in diameter\nin front of their cage, it was followed smoothly and evenly. Here a\ncertain amount of learning and practice, absent in the case of the\npheasant, was required. And it is difficult to say what proportion of\nthe final result was acquired, what proportion hereditary; but probably\nthe behaviour is in the main instinctive, though somewhat deferred.\n\nOne more example, perhaps even more trivial in the eyes of some\npeople, may be given. A duckling a few hours old will scratch the side\nof his head. It is true he may topple over in the process, through\ninsufficient powers of balance, for the simultaneous performance of\npoising on one leg and having a good scratch with the other is no easy\nmatter. But let not either our familiarity with such behaviour, nor\nsome observed and laughable failure on the part of the duckling, blind\nus to the fact that this is a congenital activity, and one of no little\ncomplexity, indicating a definite organic nexus. A local irritation\nsets agoing movements of the hind limb of that side through which\njust that particular spot is scratched in the absence of any previous\npractice, any learning to localize the spot. There can be no question\nthat such inherited co-ordinations, whether perfect from the first,\nor with deferred perfection and some aid from acquisition, afford\nready-made data to consciousness, which are of the utmost service in\nthe guidance of subsequent behaviour. The two-days-old chick, with\nthe aid of this instinctive co-ordination, performs well a number of\nactions, which, had she to consciously learn them all, would probably\nbe still but half mastered when she was a skinny old hen.\n\nOur whole treatment of instinctive behaviour has been based on the\nassumption, already to some extent justified, that experience is\nnot inherited. If it be hereditary, how comes it that chicks show\nno recognition of still water, which must have been familiar to the\nexperience of generation after generation of birds? How comes it that\nthey do not even seem to recognize their natural parent and protector,\nthe hen? Two chicks ten days old were taken to the yard whence were\nderived the eggs from which they were hatched, and were placed about\ntwo yards from a hen which was clucking to her brood. They were not in\na frightened condition, for they stood on my hand and ate grain from\nit, scratching at the palm. But of the clucking of the hen they took\nno notice whatever. The same results were obtained with other chicks\nthirteen days old. Was this due, as Spalding suggested, to loss of\nthe instinctive response which was perhaps present at an earlier age?\nSeemingly not. For a chick was taken at the age of two and a half days\nto its own mother, which had three chicks. These followed her about,\nand ran at once to her when she clucked and pecked on the ground. The\nlittle stranger, however, took no notice, nor did he show any tendency\neither to go to the hen or to follow the three chicks, having been\npurposely brought up alone. When the hen took her little brood under\nher wing, the stranger was placed close to her. She clucked, and seemed\nanxious to entice and welcome the little fellow, seizing an oat-husk\nand dropping it before him; but he remained indifferent, walking away\nand standing in the sunshine. After about forty minutes he seemed more\ninclined to go with the other chicks, but still ignored the existence\nof the hen. The natural instinctive tendency seems to be from the first\nto nestle under anything; and there is the hen provided by nature for\nthe purpose. By experience the chicks grow accustomed to her fussy\nways, as they grow accustomed to the ways of such a foster-parent\nas the writer of these pages. Still, though there is, apparently,\nno instinctive knowledge of the hen as their natural protector, and\nthough I have seen no observable response to the clucking sound, this\nmust not be taken as necessarily implying that there is no instinctive\nresponse to any of her modes of behaviour. There is such a response\nto her pecking on the ground; there is probably such a response to\nher danger-note; and there may be many other such instinctive modes\nof behaviour related to her actions. How far they extend can only be\nascertained by patient observation; and such responsive behaviour need\nnot imply any instinctive knowledge begotten of inherited experience.\n\nWe may now summarize some of the general conclusions which may be drawn\nfrom observations of instinctive behaviour in young birds.\n\n1. That which is inherited is essentially a motor response or train\nof such responses. Mr. Herbert Spencer\u2019s description of instinct as\ncompound reflex action is thus justified.\n\n2. These often show very accurate and nicely-adjusted hereditary\nco-ordinations.\n\n3. They are evoked by stimuli, the general type of which is fairly\ndefinite, and may in some cases be in response to particular objects.\n\n4. They are also generally shown under conditions which lead us to\ninfer the presence of an internal factor, emotional or other.\n\n5. There does not seem to be any evidence of inherited knowledge or\nexperience.\n\n\nIV.--THE CONSCIOUS ASPECT OF INSTINCTIVE BEHAVIOUR\n\nIn our definition of instinctive behaviour all positive reference to\nthe presence of conscious states was omitted. By some writers, however,\nthe fact that it is accompanied by consciousness is regarded as a\ndistinguishing feature of instinct. Romanes introduced his definition\nwith the words:[38] \u201cInstinct is reflex action into which there is\nimported the element of consciousness.\u201d And he emphasized the conscious\naspect when he said: \u201cThe term comprises all those _faculties of mind_\nwhich are concerned with conscious and adaptive action, antecedent to\nindividual experience.\u201d Professor Wundt also lays some stress on the\nconscious accompaniments of instinctive activities which, he says,[39]\n\u201cdiffer from the reflexes proper in this, that they are accompanied\nby emotions in the mind, and that their performance is regulated by\nthese emotions.\u201d The definitions of other writers express or imply the\npresence of consciousness in differing modes and degrees, culminating\nin the hypothesis of inherited knowledge. Douglas Spalding, for\nexample, said[40] that \u201canimals can forget the instinctive knowledge\nwhich they never learned!\u201d\n\nNow, the exclusion from our definition of direct reference to the\nconscious aspect must not be taken to imply that instinctive behaviour\nis a mere matter of unconscious automatism; nor even that it is\nunprofitable to discuss how much consciousness there may be, of what\nsort, and how distributed. All that it does imply is, that the amount,\nnature, and distribution of consciousness cannot well be introduced\ninto a definition the object of which is to help us to distinguish\ncertain observable types of behaviour from others. In a word, the\ndefinition given is biological and objective, and is to be accepted\nor rejected without prejudice to such psychological considerations as\nthose upon which we have now briefly to enter.\n\nThe first thing we have to decide is how much we are to include,\nfrom the psychological standpoint, under instinct. For we may take\neither a broader or a narrower view of the matter; and which of these\nwe adopt will make much difference in our conclusions. Let us first\ndeal with the narrower. We have said above that what is hereditary in\ninstinctive behaviour is the co-ordination. Now, such co-ordination of\nmovements into a finished and appropriate act is due to a nicely graded\ndistribution of efferent nerve-waves to the several muscles concerned,\nso that these muscles may be caused to contract in due order, and each\nto just the right extent. But efferent nerve-waves as such, and their\nmode of distribution by the nerve-centres, are in all probability\nunconscious, while the contraction of the muscles is a purely organic\nmatter. If, therefore, we narrow our conception of instinct so as to\ninclude only the co-ordinated act by itself, excluding all reference\nboth to the stimuli which are its antecedents, and to the effects in\nconsciousness which its performance may produce; and if the data for\nconsciousness are in all cases supplied through afferent channels;\nthen there seems to be no escape from the conclusion that instinctive\nbehaviour as such may be, and probably is, altogether outside the\nindividual consciousness. It should be noted, however, that on this\nview only the instinctive co-ordination in itself can be fairly\nregarded as independent of the stream of experience.\n\nNow, in the first place it is convenient so far to broaden our\nconception as to include under the head of instinctive behaviour,\nin its conscious aspect, not only the co-ordinated act but the data\nwhich its performance affords to consciousness. It may indeed seem\nthat we are here trying to draw a distinction where no real difference\nexists. The physiological distinction is, however, not only clear and\nundeniable, but quite easily understood. For the sake of illustration\nlet us take the case of an intentional action, such as glancing up from\nthe words we are reading to the clock. Efferent waves course along\nseveral motor nerves to the six muscles by which each eye is moved,\nand to the muscles of accommodation within the eye. These muscles\nare called into duly co-ordinated activity, by which our vision is\nfocussed upon the clock-face. This is one part of the physiological\nprocedure--that by which the intended result is attained. But there\nis a second part readily distinguishable from the former. As the\neyes move, afferent messages course inwards from the muscles or the\neye-sockets and their neighbourhood; and it is these incoming waves\nwhich afford data to consciousness, telling us that the movements are\nin progress or have been effected. The nerves involved in the latter\npart are quite different from those concerned in the former part, and\nthey proceed to areas of the brain differently situated from those\nwhence the efferent waves issued. Thus it is in all cases of movement;\nthe efferent nerves call the muscles into play; the afferent nerves\nbring information that the movements are carried out. It is through the\nlatter that data are unquestionably afforded to consciousness.\n\nBut in the case of any complex action--and, as we have seen,\ninstinctive behaviour is often remarkably complex--the information\nthat the action has begun comes in before the behaviour is completed.\nPractically we may say that any given stage of performance and the\nconsciousness it evokes are simultaneous; for though in strictness\nthe one lags just a little behind the other, yet they are so nearly\ncoincident in time that we may disregard the interval between them.\nSuch being the case, therefore, we may fairly regard the felt\nperformance of the instinctive act as capable of introducing important\nelements into the conscious situation.\n\nBut not only does instinctive behaviour thus introduce important\nelements into the conscious situation, it is also called forth by\nstimuli which themselves afford not less important elements. To exclude\nthese from any consideration of instinct, in its conscious aspect,\nwould render the treatment of the problem so incomplete as to be wholly\nunsatisfactory from a psychological point of view. Can we believe that\nwhen the moor-hen dived, as it never had dived before, at the sight\nof the rough-haired pup, the vivid experience of that strange and\ndisquieting intruder did not enter into, and form a prominent feature\nin, the conscious situation? If we are to consider the conscious aspect\nat all, we must try and grasp the situation as a whole. And on these\ngrounds we may yet further broaden our conception so as to include,\nfrom the psychological point of view, not only the behaviour itself,\nand its effects in consciousness, but also the stimulating conditions\nunder which it is called into play. If, then, we accept this position,\nand agree to use the term \u201cinstinct\u201d for our present purpose in a\ncomprehensive sense, we may now proceed to consider very briefly the\nnature of the elements which enter into the instinctive situation.\n\nFirst, there are the external stimuli affecting one or more of the\nsense organs, and thus evoking consciousness; and secondly, there are\ninternal factors, having their source in the condition of the body, or\nits parts and organs. It is convenient to take these two together, so\nthat we may see what relationship they bear to each other. Both seem to\nbe present, and to co-operate in a great number of instinctive acts. In\nthe behaviour connected with feeding, for example, an internal element\nof hunger co-operates with the external presentation of the appropriate\nfood or prey. So, too, with the instincts concerned in the propagation\nof the race. Looking at the matter generally, we may regard the\ninternal factors of the kind with which we are now dealing, as giving\nrise to a want or need, passing in some cases into a state of craving.\nIn themselves such conscious states are in their inception exceedingly\nindefinite; for a want can only be rendered definite in experience by\nits appropriate satisfaction. In many cases of instinctive behaviour\nthe indefinite want and the particular and duly related stimulus seem\nto lead, without prevision and by a blind impulse, to the performance\nof those acts which will afford the unforeseen satisfaction. And when\nonce this satisfaction has been attained, subsequent wants or needs of\nlike character will no longer be indefinite; nor will future behaviour\nof the same kind be thereafter wholly instinctive, for it can never\nagain be prior to, or independent of, experience.\n\nGranted, however, that a felt need of some kind, indefinite at\nfirst but none the less real, is present in many cases as a spur to\ninstinctive behaviour; is it in all cases a necessary factor? May we\nsay that this distinguishes instinctive from merely reflex action? The\nquestion is, from the nature of the case, exceedingly difficult to\nanswer. But without going so far as to say that reflex action may be\nunerringly distinguished from instinctive behaviour by the absence of\nany such internal factors, we may perhaps, at any rate, go so far as\nto give provisional acceptance to the view that in instinct these wants\nand felt needs enter into the conscious situation in a manner and to\na degree that are so far distinctive--which seems to be the position\nadopted by Professor Wundt.\n\nThere is, however, a further relation between the external stimulus and\nthese internal factors which is presumably of no little importance.\nThe stimulus intensifies the want, or may in some cases call it into\nexistence. Just as a whiff from the kitchen may lead us to realize\nthat we need the satisfaction that will erelong be presented at table,\nso may the sight of his mate in the spring evoke in the breast of\nthe yearling sparrow a need, having its source in morphological and\nphysiological changes, that spurs him on to the courtship that shall\nlead to its due satisfaction. Popular attention has, indeed, been so\nnaturally drawn to the internal needs or wants with which we are now\ndealing, as to give them an almost exclusive monopoly of the term\n\u201cinstinct,\u201d which thus often comes to be regarded as a connecting link\nbetween the stimulus and the act. The sight of a mouse, for example, is\nsaid to call forth the instinct of the cat, which is satisfied by her\npouncing upon it. And so it comes about that, while the biologist fixes\nupon the instinctive act as the essential feature, the psychologist\nis apt to regard the impulse[41] which prompts to action as the more\ncentral and characteristic element. We are here endeavouring to combine\nboth these points of view.\n\nTo come to closer quarters with the relationship which holds good\nbetween the external and internal elements, it appears that, when the\nstimulus evokes or intensifies the want or need, this is probably\neffected by efferent waves which call the organs or parts into tonic\naction, of which the animal becomes conscious through the afferent\nmessages which come in from them to the sensory centres; in much the\nsame way as the whiff from the kitchen takes effect on the salivary\nand other glands, and throws the organs of digestion into a felt\npreparedness for the fulfilment of their functions. But it may have\nother and more indirect consequences. When the moor-hen dived to escape\nfrom the obtrusive puppy, his heart-beat was probably affected; he\nhad, perhaps, an uncomfortable sinking in his gizzard; his breathing\nwas short and laboured; and he experienced creepy sensations in the\nskin and around the feather-roots. Such we may suppose were the\naccompaniments or sources of the emotional state of fear or alarm. And\nthey presumably entered with no little vividness into the conscious\nsituation at the moment of instinctive action. In all those cases in\nwhich the behaviour is associated with such an emotional state as anger\nor fear, the external stimulus seems to produce widely-spread effects\non the glands, respiratory organs, heart and blood-vessels, skin and\nother parts, as well as the more direct response in productive action.\nAnd all this must enter into the conscious situation, contributing\nlargely, as we shall hereafter see, to the emotions in their\ninstinctive origin.\n\nEnough has now been said to indicate with sufficient clearness the\nkind of co-operation and mutual relationship which subsists between\nthe external and the internal factors in the conscious situation which\nleads to instinctive behaviour. We have seen that, not improbably, some\norganic prompting is always present in greater or less degree. But the\nquestion still remains whether anything like a definite and particular\nexternal stimulus is in all cases a necessary factor.\n\nWhen the predaceous larva of the water-beetle, _Dytiscus_, ceases to\nfeed, and, creeping into the moist earth near the pond\u2019s edge, makes\na hollow cell in which to enter upon its pupal sleep, there does not\nseem to be any well-defined stimulus from the outer world which can be\nsaid to initiate the behaviour of whose purport the larva can have no\nidea. Some inner need seems to impel the creature to this necessary\nbut as yet unknown course of action; and this appears to constitute,\nif not the sole, at least the preponderant element in the conscious\nsituation. In healthy young birds and other animals there is after the\nrest of sleep a certain exhilaration and exuberance of spirits which\nseemingly leads to characteristic action; dancing, flapping of the\nwings, running hither and thither in short quick spurts, and so forth.\nNo doubt in such cases external stimuli are present, and contribute\nin some degree to the effects produced; but they do not seem to be\nparticularized so that one can say that just this or that well-defined\nstimulus is necessary to give rise to the observed behaviour. In the\ncase of migration, too, an internal factor--the nature of which we do\nnot know--is probably as strong as if not stronger than any influence\nfrom without. While, therefore, we may say that some external factors\nare frequently, not improbably always, contributory, we must add that\nobservation does not enable us in all cases to define them with any\napproach to accuracy; and, further, that promptings from within seem\nin some instinctive acts to be the most important elements in the\nconscious situation.\n\nIt now only remains to draw attention to the fact that the effects of\nthe behaviour, as the animal becomes conscious of the performance of\nthe acts concerned, serve to complete and render definite the conscious\nsituation. Consciousness, however, probably receives information of the\nnet results of the progress of behaviour, and not of the minute and\nseparate details of muscular contraction. These net results, having\nthus entered presentatively into the situation, are subsequently\nsusceptible of re-presentative recall, when the recurrence of certain\nsalient elements serve to reproduce the essential features of the\nsituation of which experience has been gained on a former occasion.\nHence, as has already been noted, it is only the _first_ performance of\nan instinctive action which can be described as prior to experience.\nThe second time the deed is done it is done by an animal which has\nhad opportunity of gaining experience on the foregoing occasion. And\nthen it may be done with a difference, with some acquired modification\nof performance. By the repetition of the slightly modified behaviour\nthe effects of habit are introduced, and thus acquired peculiarities\nof action are established as individual traits. We must not forget\nthat, in a large number of cases, so-called instinctive behaviour, as\npresented to observation, has lost through modified repetition its\noriginal purity of type. The acts we see are often the joint products\nof heredity and individual acquisition, the inherited co-ordination\nhaving been supplemented or otherwise altered through experience.\n\nEven in the case of the very first exhibition of such a deferred\ninstinct as the moor-hen\u2019s dive, although that organized sequence\nof acts which constituted the behaviour as a whole had never before\noccurred, although there was no gradual learning how to dip beneath\nthe surface, and to swim under water, still many of the constituent\nacts had been often repeated; experience had already been gained of\nmuch of the detail then for the first time combined in an instinctive\nsequence. So that if we distinguish between instinct as congenital and\nhabit as acquired, we must not lose sight of the fact that there is\ncontinual interaction, in a great number of cases, between instinct\nand habit, and that the first performance of a deferred instinct may\nbe carried out in close and inextricable association with the habits\nwhich, at the period of life in question, have already been acquired.\nInstinct supplies an outline sketch of behaviour, to which experience\nadds colour and shading. Which predominates in the finished picture\ndepends on the status of the animal. In the lower and less intelligent\ntypes the outline stands out clearly, there being but little shading to\ndivert our attention from the clear firm lines inscribed by heredity;\nbut in the higher and more intelligent animals, the deft pencil of\nexperience has added so much detail and has interwoven with the fainter\noutline so many new and skilfully introduced touches, that the original\nsketch is scarcely distinguishable unless we have carefully watched\nfrom the beginning the gradual development of the picture.\n\n\nV.--THE EVOLUTION OF INSTINCTIVE BEHAVIOUR\n\nIt may be assumed that the fact of evolution is generally admitted.\nThe question of its method is, however, still open to discussion. It\nis possible that, as some biologists contend, there is an inherent\ntendency in organic beings to evolve in certain definite directions\nindependently of their relation to the environment. But it is scarcely\nprobable that instinctive behaviour is mainly due to any such inherent\ntendency--of the nature of which in any case we know but little.\nSetting this on one side, therefore, we have two hypotheses: first,\nthat instincts are the result of natural selection; secondly, that they\nare due to the inheritance of acquired habits. These two views we will\nnow proceed to consider.\n\nWe have seen that Professor Wundt distinguishes two classes of\ninstinctive acts: first, those which are _acquired_ or have become\nwholly or partly mechanized in the course of individual life; secondly,\nthose which are _connate_ or have been mechanized in the course of\ngeneric evolution. \u201cThe laws of practice,\u201d he says,[42] \u201csuffice for\nthe explanation of the acquired instincts. The occurrence of connate\ninstincts renders a subsidiary hypothesis necessary. We must suppose\nthat the physical changes which the nervous elements undergo can be\ntransmitted from father to son.... The assumption of the inheritance of\nacquired dispositions or tendencies is inevitable if there is to be any\ncontinuity of evolution at all. We may be in doubt as to the extent of\nthis inheritance; we cannot question the fact itself.\u201d\n\nNow, the application of the term \u201cinstinct,\u201d both to acquired and to\nconnate behaviour, seems to prejudge the question of their genetic\nconnection. And since we have the well-recognized term _habits_ for\nactions the performance of which becomes automatic through frequency\nof repetition, we may substitute this term, or the phrase _habitual\nacts_, for the \u201cacquired instincts\u201d of Professor Wundt. Modifying,\ntherefore, his statement in accordance with this usage, the fact which,\nhe says, we cannot question is that acquired habits are inherited as\ncongenital instincts. This opinion has long been held: G. H. Lewes\nregarded instinctive actions as transmitted habits from which the\nintelligence, through which they were originally acquired, had lapsed.\nDarwin believed that such inheritance was a factor in the evolution\nof instinctive behaviour. Romanes distinguished instincts due to\nthis mode of origin as \u201csecondary;\u201d reserving the term \u201cprimary\u201d for\nthose attributable to natural selection, and describing those in which\nboth factors co-operate as \u201cinstincts of blended origin.\u201d The late\nProfessor Eimer, of T\u00fcbingen, going further than either Darwin or\nRomanes, reverted almost entirely to what we may term the Lamarckian\ninterpretation. \u201cI describe as automatic actions,\u201d he says,[43]\n\u201cthose which, originally performed consciously and voluntarily, in\nconsequence of frequent practice come to be performed unconsciously and\ninvoluntarily.... Such acquired automatic actions can be inherited.\nInstinct is inherited faculty, especially is inherited habit.\u201d In his\ndiscussion of the subject Eimer makes no express allusion to primary\ninstincts; but he attributes to lapsed intelligence some of those\nwhich were classed by Romanes as primary, and his tendency is to\nrefer all instincts to the same source. \u201cEvery bird,\u201d he says, \u201cmust,\nfrom the first time it hatches its eggs, draw the conclusion that\nyoung will also be produced from the eggs which it lays afterwards,\nand this experience must have been inherited as instinct.\u201d Why, in\nthe first instance, it must draw the conclusion from observation if\nit inherit instinctive knowledge, is not made clear. But our present\npurpose is to indicate, not to criticize, Eimer\u2019s position. He claims\nthat \u201cthe original progenitors of the cuckoo, when they began to\nlay their eggs in other nests, acted by reflection and design.\u201d Of\nthe behaviour of mason wasps and their allies, which provide their\nyoung with paralyzed but living prey, he exclaims, \u201cWhat a wonderful\ncontrivance! What calculation on the part of the animal must have been\nnecessary to discover it!\u201d Of the instincts of neuter bees he remarks,\n\u201cSelection cannot here have had much influence, since the workers do\nnot reproduce. In order to make these favourable conditions constant,\ninsight and reflection on the part of the animals, and the inheritance\nof these faculties were necessary.\u201d And he concludes, \u201cThus, according\nto the preceding considerations, automatic action may be described as\nhabitual voluntary action; instinct, as inherited habitual voluntary\naction, or the capacity for such action.\u201d\n\nTurning now to the opposite end of the scale of opinion, we find\nthat Professor Weismann, commenting on the supposed inheritance\nof acquired habit, says,[44] \u201cI believe that this is an entirely\nerroneous view, and I hold that all instinct is entirely due to the\noperation of natural selection, and has its foundation, not upon\ninherited experiences, but upon variation of the germ.\u201d Ziegler and\nGroos in Germany, Whitman and Baldwin in America, Poulton and Wallace\nin England, either deny the existence of secondary instincts, due\nto the inheritance of acquired habits, or question the sufficiency\nof the evidence adduced in support of such transmission. In their\nexplanation of the manner in which that inherited co-ordination,\nwhich is biologically the central fact in instinctive behaviour, has\nbeen evolved they rely mainly or entirely on the principle of natural\nselection.\n\nWhat, then, were the facts which appeared to Romanes sufficient to\njustify a belief in the existence of a class of instincts dependent\non inherited habit for their origin? He tells us that he only gives a\nfew examples \u201camongst almost any number\u201d that he could quote. It is\ncertainly unfortunate that, out of more than one hundred and fifty\npages devoted to instinct in his work on \u201cMental Evolution in Animals,\u201d\nonly three[45] are assigned to secondary instincts; or six, if we\ninclude one dealing with inherited peculiarities of hand-writing in\nman, and two showing the force of heredity in the domain of instinct,\n\u201cwhether of the primary or secondary class.\u201d It is true that many pages\nare devoted to instincts of blended origin, but the co-operation of\nthe Lamarckian factor is here rather assumed than proved. We must,\nhowever, be content to take the few examples that are actually given.\nThey are four in number. First, that ponies in Norway are used without\nbridles, and are trained to obey the voice; and that, as a consequence,\na race-peculiarity has been established, for Andrew Knight says that\nit is impossible to give them what is called \u201ca mouth.\u201d No details are\ngiven, and Romanes does not further discuss the evidence. Secondly,\nMr. Lawson Tait had a cat which was taught to beg for food like a\nterrier. All her kittens adopted the same habit under circumstances\nwhich precluded the possibility of imitation. Supposing the facts to\nbe correctly reported, and granting that the owners of the kittens,\npresumably aware of the maternal propensity, did not take some pains to\nteach the offspring of such a parent to beg (and this does not present\nmuch difficulty), one can hardly found a scientific conclusion on so\nslight an anecdotal basis. Thirdly, instinctive fear is said to be an\ninherited acquisition; which, fourthly, is lost by disuse. But, as\nwe have already seen, modern investigation has placed this matter of\nso-called hereditary fear of natural enemies on a different footing.\nPheasants, partridges, moor-hens, and wild duck show no fear of a quiet\ndog. If approached gently, in the absence of their parents, callow\nwild birds in their nest exhibit little alarm at the slow and gentle\napproach of man. Mr. Hudson\u2019s opinion has already been quoted, but\nwill bear repetition; it is, \u201cthat fear of particular enemies is in\nnearly all cases the result of experience.\u201d And there is no evidence to\nshow that, in those cases in which it is truly instinctive and not the\nresult of experience, the instinctive behaviour is necessarily due to\ninherited habit and not to natural selection.\n\nIt cannot be said that the evidence for the supposed mode of origin\nof secondary instincts is sufficiently varied and cogent to carry\nconviction. On the other hand, there does seem some evidence which\npoints to a different conclusion. When instinctive behaviour follows\non a sensory impression, not only is the co-ordination hereditary,\nbut there is an inherited linkage of stimulus and response. Thus in\nthe solitary wasps the sight of the natural prey is followed by the\nappropriate modes of attack. The _Melo\u00eb_ larva springs upon anything\nhairy. In chicks the sight of a small object at a certain distance\ninitiates the act of pecking. In moor-hens and ducklings the stimulus\nof water produces the movements concerned in swimming. And so, too,\nin many other examples of instinctive behaviour, we infer from the\nobserved facts that stimulus and response have an organic connection\nfounded on hereditary links in the nervous system. Now, if such\nconnection were due to inherited habit, we should expect them to be\nestablished wherever the experience to which they are related has\nbeen constant through many generations. How comes it, then, that the\nchick does not instinctively respond by appropriate behaviour to the\nsight of water? How comes it that young birds do not instinctively\navoid bees, and wasps, and nauseous caterpillars? If the effects of\nancestral experience be hereditary, one would surely expect that in\nthese cases the connection between stimulus and response--a connection\nwhich passes into acquired habit--would have become congenital; that\nthe habitual behaviour would have long ago become instinctive. But this\ndoes not appear to be the case. And with regard to disuse causing the\nloss of instinct, how comes it that young chicks swim with well-ordered\nleg-movements, though swimming is not an act that is habitually\nperformed by the members of their race?\n\nWhat, then, has the alternative hypothesis of natural selection to\nadvance in explanation of these facts? On this hypothesis instinctive\nacts have biological value in such degree that they have become\ncongenital through the preservation of adaptive variations. But if this\nbe so, why does not the chick respond instinctively to the sight of\nthat which is so essential to its existence as water to drink? In reply\nto this question it may be suggested that, under natural conditions,\nthe hen teaches all her chickens to peck at the water, and thus shields\nthem from the eliminating influence which gives rise to natural\nselection, in the absence of which the habit of drinking in response\nto the sight of water, though acquired by each succeeding generation\nof birds, has not become instinctive and congenital. Or, to put the\nmatter from a slightly different point of view, the maternal instincts\nof the hen protect her chicks from any elimination in this respect; and\nin the absence of such elimination the habit has not been inherited as\ninstinct. But though the hen can lead her young to peck at the water,\nshe cannot teach them how to perform the complex movements of the\nmouth, throat, and head in actual drinking. In this matter, therefore,\nher own instinctive procedure does not shield them from the incidence\nof that elimination which leads to survival under natural selection.\nThose chicks would be eliminated which, on pecking the water, failed to\nrespond to the stimulus by the complex behaviour involved in drinking,\nleaving those to survive in which the response had been congenitally\nestablished. Thus it would seem that, when natural selection is\nexcluded, the habit has not become congenitally linked with a visual\nstimulus; but when natural selection is in operation, the response has\nbeen thus linked with the stimulus of water in the bill. Whence we may\ninfer that the co-operation of natural selection is an essential factor\nin the evolution of instinctive behaviour.\n\nThere are, however, cases of instinctive behaviour which may seem too\ntrivial and unimportant to be subject to the sway of natural selection.\nThere are numberless little idiosyncracies of behaviour which seem to\nbe truly instinctive, which are readily recognizable as distinctive\ntraits, but which can hardly be regarded as of sufficient biological\nvalue to determine whether the creatures in which they are developed\nshould survive or be eliminated in the struggle for existence. In many\ncases, however, these serve rather to distinguish the detailed manner\nof behaviour than its biological end or purpose. In different species\nnatural selection may determine the survival of those whose instinctive\nbehaviour meets a biological need. The relatively unimportant details,\ndiffering slightly in each species, are mere adjuncts; and since\nnatural selection deals with each species or inter-generating group\nseparately, the essential behaviour may in each case carry with it\nthe associated differences of manner. We must remember, too, that, as\nin the matter of structure so in that of behaviour, it is the animal\nas a whole that is selected for survival; and so long as the whole\nis adapted to the circumstances of life, the associated differences\nof form or manner may share in, without doing much to determine,\nsurvival. In any case these little instinctive traits, if they are so\ntrivial as to seem of small value from the biological point of view,\nappear to be too unimportant to have been intelligently acquired as\nhabits.\n\nLet us now consider one or two cases of instinctive behaviour which\nwould fall under Romanes\u2019s category of instincts of blended origin\npartly due to natural selection, partly to the inheritance of acquired\nhabit. It is the custom of the house martin to build beneath the eaves.\nForsaking the ancestral rocky haunts, it has been led to utilize\nthe houses that man has built. This has all the appearance of being\ndue to an intelligent modification of the ancestral instinct; but\nhow far the modification has become through heredity a congenital\nvariation, we do not know. The intelligence which is said to have\nenabled the martin of the past to adopt this method of nidification is\nstill operative. The nestlings brought up under the eaves would have\nopportunities for acquiring experience which might lead them to build\nunder similar circumstances. Nest and eaves would be associated in\nthe conscious situation. Nor would the effects of natural selection\nbe necessarily excluded. One may suppose that in the open country,\nfar from rock-shelters, those martins in which there was a congenital\ntendency to build in house-shelters would bring up their broods and\ntransmit this tendency; while those in which it was absent would either\ngo elsewhere or fail to bring up broods at all. In the absence of\nfuller knowledge as to the truly instinctive nature of the behaviour,\nand as to its mode of genesis, we are in large degree at the mercy\nof conjecture. But in any case the incidence of elimination is not\nnecessarily excluded, and there are, therefore, no grounds for denying\nthat natural selection has been a co-operating factor in the evolution\nof the instinctive behaviour, if such it be.\n\nIt is well known that the lapwing will apparently simulate the\nactions of a wounded bird, with the object, as it seems, of drawing\nintruders away from her nest. And such tactics are not restricted\nto this bird, nor even to one or two species. They are common,\nno doubt with diversities of detail, to such different birds as\ngrouse, pigeons, plovers, rails, avocets, ducks, pipits, buntings,\nand warblers. Granting that the behaviour is truly instinctive, it\nforms a very pretty subject for transmissionists and their critics to\nquarrel over. \u201cIf we seek, as an example,\u201d the transmissionist may\nexclaim, \u201can instinct which bears the marks of its intelligent, and\ntherefore acquired origin, this of feigning wounded provides all that\nwe can possibly demand.\u201d \u201cWhat mode of instinctive behaviour,\u201d the\nselectionist may ask, \u201ccan be adduced which is more obviously useful\nto the species? Is not this just the kind of procedure which natural\nselection, if it be a factor at all, must fix upon and perpetuate\nthrough the elimination of failures? Those birds which, through\ncongenital variation of behaviour, acted in this way would certainly\nenable their offspring to escape destruction by enemies, and these\nwould survive to perpetuate the instinct.\u201d\n\nLet us expand the transmissionist position a little further. An\nextremist, of the type presented by Eimer, would perhaps urge that the\nlapwing reasons thus: \u201cIf I pretend to be wounded, trail my wing, and\nflutter along the ground, instead of flying off, I shall draw upon\nmyself the intruder\u2019s attention, and lead him to suppose that I shall\nbe easily caught; and if I thus entice him away, my little ones will be\nsaved, and my end gained.\u201d Thus, it may be said, might the bird argue,\nand then give practical effect to its reasoning. But are we not here\nattributing to the lapwing powers of ratiocination beyond the capacity\nof the most intelligent of birds? Are we not assuming a histrionic\npower, and a realization of the effects on others of its display, which\nmany a human actor might well covet?\n\n\u201cBut may not the bird,\u201d it may be urged in reply, \u201chave found by\nexperience, without any elaborate process of abstract reasoning, that\nthe trick is effectual?\u201d In any case it would be experience perilously\nacquired. Granting that the bird has the wit to try the trick, a\nlittle over-acting, a little too much lameness of wing, and she is\nherself seized and killed; a little under-acting, and the trick\nfails--her brood is found and destroyed. Does it not seem probable\nthat such experience would be dearly bought, that failure would mean\neither death to the parent or death to the offspring? And is it not\nclear that natural selection is thus introduced in any case? And may\nnot the selectionist pertinently ask: \u201cIf natural selection is thus\nintroduced as a factor, why halt midway between two hypotheses? Why\nnot take the further step--one by which all the difficulties attending\nthe intelligent acquisition and the biological transmission are alike\navoided--of allowing that natural selection exercises, throughout, its\ninfluence on congenital variations, and not on acquired modifications\nof behaviour?\u201d\n\nThere is, however, a way in which, when natural selection is operative,\nintelligence may serve to foster congenital variations of the required\nnature and direction. We must remember that acquired habits on the one\nhand, and congenital variations of instinctive behaviour on the other\nhand, are both working, in their different spheres, towards the same\nend, that of adjustment to the conditions of life. If, then, acquired\naccommodation and congenital adaptation reach this end by different\nmethods, survival may be best secured by their co-operation. And the\nmore thorough-going the co-operation the better the chance of survival.\nThere would be a distinct advantage in the struggle for existence when\ninherited tendencies of independent origin coincided in direction with\nacquired modifications of behaviour; a distinct disadvantage when such\ninherited tendencies were of such a character as to thwart or divert\nthe action of intelligence. Thus any hereditary variations which\ncoincide in direction with modifications of behaviour due to acquired\nhabit would be favoured and fostered; while such variations as occurred\non other and divergent lines would tend to be weeded out. Professor\nMark Baldwin,[46] who has independently suggested such relation\nbetween modification and variation, has applied to the process the\nterm \u201cOrganic Selection;\u201d but it may also be described as the natural\nselection of coincident variations.\n\nIt may be urged, therefore, that if natural selection be accepted as\na potent factor in organic evolution, and unless good cases can be\nadduced in which natural selection can play no part and yet habit has\nbecome instinctive, we may adopt some such view as the foregoing.\nWhile still believing that there is some connection between habit and\ninstinct, we may regard the connection as indirect and permissive\nrather than direct and transmissive. We may look upon some habits as\nthe acquired modifications which foster those variations which are\ncoincident in direction, and which go to the making of instinct.\n\nThe net result of a study of instinctive behaviour is to lead us to\nthe conclusion that its evolution runs parallel with the evolution\nof animal structure. This is perhaps best seen in the case of those\ninsects in which typical instinctive acts are performed by larv\u00e6 of\nwholly different form and structure, though they are stages in the\ndevelopment of the same species. This is exemplified in the cases\nof _Sitaris_, _Argyrom\u0153ba_, and _Leucopsis_ which have been briefly\ndescribed. It is probable that in all cases of instinctive action\nnatural selection has been a co-operating factor. Without going so far\nas to assert with Professor Weismann the \u201call-sufficiency of natural\nselection,\u201d we may echo the words of Professor Groos,[47] and say:\n\u201cNevertheless, we know no principle except that of selection, and\nwe must go as far as that will take us. Absolute knowledge of such\nphenomena is unattainable.\u201d And in this conclusion we have the support\nof Dr. Peckham, who says,[48] \u201cWe have found them [the instinctive\nacts of solitary wasps] in all stages of their development, and are\nconvinced that they have passed through many degrees from the simple\nto the complex, by the action of natural selection. Indeed, we find in\nthem beautiful examples of the survival of the fittest.\u201d\n\n\n\n\nCHAPTER IV\n\n_INTELLIGENT BEHAVIOUR_\n\n\nI.--THE NATURE OF INTELLIGENT BEHAVIOUR\n\nSuch an animal as a newly hatched bird or an insect just set free\nfrom the chrysalis is a going concern, a living creature. It is the\nbearer of wonderfully complex automatic machinery, capable, under the\ninitiating influence of stimuli, of performing instinctive acts. But\nif this were all we should have no more than a cunningly wrought and\nself-developing automatic machine. What the creature does instinctively\nat first it would do always, perhaps a little more smoothly as the\norganic mechanism settled down to its work--just as a steam-engine goes\nmore smoothly when it has been running for a while; but otherwise the\naction would continue unchanged. Instinctive behaviour would remain\nunmodified throughout life. The chick, however, or the imago insect is\nsomething more than this. It affords evidence of the accommodation of\nbehaviour to varying circumstances. It so acts as to lead us to infer\nthat there are centres of intelligent control through the action of\nwhich the automatic behaviour can be modified in accordance with the\nresults of experience. When, for example, a young chick walks towards\nand pecks at a ladybird, the like of which he has never before seen,\nthe behaviour may be purely instinctive; and so, too, when he similarly\nseizes a wasp-larva. Even when he rejects the ladybird or swallows the\nlarva, this may be directly due to unpleasant stimulation in the one\ncase, and pleasant in the other. But when, after a few trials, the\nchick leaves ladybirds unmolested while he seizes wasp-larv\u00e6 with\nincreased energy, he affords evidence of selection based on individual\nexperience. And such selection implies intelligence in almost its\nsimplest expression. We may say, therefore, that, whereas instinctive\nbehaviour is prior to individual experience, intelligent behaviour\nis the outcome and product of such experience. This distinction is\npresumably clear enough; and it is one that is based on the facts\nof observation. But we must not fail to notice that, though the\nlogical distinction is quite clear, the acquired modifications of\nbehaviour, which we speak of as intelligent, presuppose congenital\nmodes of response which are guided to finer issues. We may say,\nthen, that where these congenital modes of response take the form of\ninstinctive behaviour, there is supplied a general plan of action\nwhich intelligence particularizes in such a manner as to produce\naccommodation to the conditions of existence.\n\nWe have already frankly admitted that, in the present state of our\nknowledge, we do not know with any definiteness how intelligent\nmodification of behaviour is effected. But it seems probable that from\nall parts of the automatically working organic machine messages come\nin to the centres of conscious control, and that in accordance with\nthe net result of all these messages, and the past experience which\nthey recall, other messages go out to the automatic centres, and, by\nchecking their action here and enforcing it there, give new direction\nto the resulting behaviour. If this be so, the consciousness associated\nwith the control-centres is like the person who sits in a central\noffice and guides the working of some organized system in accordance\nwith the information he is constantly receiving; who sends messages to\ncheck activity in certain directions and to render it more efficient\nand vigorous in others.\n\nIt may be said, however, that intelligent guidance is, at any rate\nin such simple cases as the selection of a palatable grub and the\nrejection of a nauseous ladybird, itself determined by instinctive\nlikes and dislikes. All young chicks apparently find wasp-larv\u00e6\npalatable and ladybirds the reverse; and this is just as much\nthe outcome of heredity as the instinctive act of pecking. Since,\ntherefore, heredity determines what shall be selected and what\nrejected--since the likes and dislikes are themselves instinctive--any\nessential difference between congenital and acquired behaviour seems to\nbe evanescent.\n\nNow, if we apply to the affective qualities of mental states--the\npleasurable tone or its opposite which characterize such states--the\nterm \u201cinstinctive,\u201d we do so in reference to the broader psychological\nconception of instinct, rather than in accordance with the narrower\nbiological acceptation of the term. For the likes and dislikes\nconstitute part of the conditions under which the behaviour occurs,\nand not elements in the co-ordinated response as such. Hence it is\npreferable to apply to these hereditary qualities the term _innate_,\nrather than the term _instinctive_. But, waiving this distinction,\nit is true that such pleasant or unpleasant qualities of the sensory\nresults of stimuli are part of the animal\u2019s hereditary outfit, and\nare not acquired in the course of individual experience. What, then,\nis acquired? What part does experience play in the development of\nintelligent behaviour? Let us consider the case of the chick and the\nladybird, and see whether it helps us to answer these questions. The\nchick is stimulated to the instinctive pecking response by a small\nmoving object. That is the first scene of the little drama. In the\nsecond scene the ladybird is seized, sensory centres are unpleasantly\nstimulated, and the insect is dropped or thrown on one side with signs\nof disgust. Let us grant that this aversion with its characteristic\nresponse is also instinctive. _There is no hereditary connection\nbetween scene 1 and scene 2._ After an interval the curtain rises\non act ii. The characters are the same as in the first scene of the\nprevious act. But the action of the drama is different. The chick does\nnot seize the ladybird. Why? Because _there is an acquired connection\nbetween scenes 1 and 2 of the previous act_. The chick has gained\nexperience of the nauseous character of the insect, and this experience\ninfluences and modifies his behaviour. The essentially new feature,\ntherefore, is the establishment of a connection which is not provided\nthrough inheritance. To put the distinction in a brief form, we may\nsay that instinct depends on how the nervous system is built through\nheredity; while intelligence depends upon how the nervous system is\ndeveloped through use.\n\nAssuming that an animal is capable of gaining experience and of\nacquiring new nervous connections in the course of individual\nexperience, it follows that, as has already been indicated,\ninstinctive behaviour in its logical purity is only presented in\nthe first performance of any given co-ordinated act. For after this\nthe animal has gained experience of its performance; and this can\nno longer conform to a definition of instinct, according to which\nit is characterized as \u201cprior to experience.\u201d On the other hand,\nintelligent behaviour cannot be presented on the first occurrence of\nany action, since there is no prior experience thereof in the light\nof which it may be guided. This logical distinction may be expressed\nby saying that instinctive behaviour is always prior to experience,\nwhile intelligent behaviour is always subsequent to experience. When,\nhowever, instinctive procedure continues throughout life practically\nunmodified or but little modified, we may still class it under\ninstinct, since the hereditary connections are still the predominant\nfactors. And where the latter part of an instinctive sequence is\nmodified by the experience gained in the former part, we may still term\nthe modification intelligent, however small may be the time-interval\nimplied in the word \u201csubsequent.\u201d Sharp as the logical distinction is,\nthe behaviour of animals is in the main a joint-product, and whether we\nterm it instinctive or intelligent depends upon whether the hereditary\nor the acquired factor predominates.\n\nPassing on now to consider some further characteristics of intelligent\nbehaviour, we may first notice what Dr. Charles Mercier, in his\nwork on \u201cThe Nervous System and the Mind,\u201d terms the four criteria\nof intelligence. Intelligence is manifested, he says, first in the\nnovelty of the adjustments to external circumstances; secondly, in the\ncomplexity; thirdly in the precision; and fourthly, in dealing with\nthe circumstances in such a way as to extract from them the maximum of\nbenefit.\n\n[Illustration: FIG. 18.--Leaf-case of Birch-weevil.]\n\nIf, however, we are to regard these severally as criteria of\nintelligence, each should serve to differentiate intelligent from\ninstinctive behaviour. But this is not the case. The precision of the\nadjustment cannot be regarded as a criterion of intelligence, for many\ninstinctive acts are remarkably precise. No grocer\u2019s assistant rolls a\npaper funnel with more precision than is displayed by the birch-weevil\n(_Rhynchites betul\u00e6_) in constructing the leaf-case in which her eggs\nare laid. Curved incisions of constant form are made on either side of\nthe midrib, and are \u201cof just the right shape to make the overlaps in\nthe rolling, and to retain them rolled up with the least tendency to\nspring back,\u201d[49] while the tip of the leaf is rolled into a second\nsmaller funnel, which is tucked in to close the opening of the first,\nafter the eggs have been deposited. \u201cThe eggs hatch in their dark\nplace, each giving rise to an eyeless maggot, which ultimately leaves\nthe funnel for the earth.... Hence the beetle cannot be considered\nto have ever seen a funnel, and certainly has never witnessed the\nconstruction of one, though, when disclosed, it almost immediately\nsets to work to make funnels on the complex and perfect system\u201d\ncharacteristic of the species. This is but one example of instinctive\nprecision out of the many which could be cited. We may say, then,\nthat though, when an act is otherwise shown to be intelligent, the\nprecision is a criterion of the level attained by the intelligence,\nstill it cannot be said to be a criterion which serves to distinguish\nintelligent from instinctive behaviour.\n\nNor can we regard apparent prevision (which is sometimes advanced as\na criterion of intelligence) as specially distinctive of intelligent\nacts regarded objectively in the study of animal behaviour. For, as we\nhave had occasion to show, there are many instincts which display an\nastonishing amount of what may be termed \u201cblind prevision\u201d--instance\nthe instinctive regard for the welfare of unborn offspring which the\nmother will never see, and the instinctive preparation for an unknown\nfuture existence in the case of insect larv\u00e6.\n\nNor, again, is the complexity of the adjustment distinctive of\nintelligence as contrasted with instinct. We have cited examples\nwhich afford evidence of much complexity in instinctive behaviour.\nThe construction and storage of the nest among solitary wasps, and\ntheir methods of capturing and conveying the insects or spiders on\nwhich they prey, are sufficiently complex. So, too, is the behaviour\nof the Sitaris larva which attaches itself to the male bee, passes to\nthe female, and then slips on to the eggs she lays; and so, again,\nis that of the Yucca moth, which collects pollen from the anthers,\nconveys it to the stigma, and then lays her eggs among the ovules.\nThese cases show, too, that the circumstances may be dealt with in\nsuch a way as to extract from them the maximum of benefit. It would be\ndifficult intelligently to improve upon the manner of dealing with the\ncircumstances displayed in many familiar modes of instinctive procedure.\n\nThere remain the novelty of the adjustment and the individuality\ndisplayed. And here we seem to have valid criteria of intelligent\nbehaviour. The ability to perform acts in special adaptation to\nnew circumstances, and the individuality manifested in dealing with\nthe complex conditions of a variable environment,--these seem to be\ndistinctive features of intelligence. On the other hand, in instinctive\nbehaviour there seems to be no choice; the animal is impelled to their\nstereotyped performance through impulse, as by a stern necessity; they\nare so far from novel that they are performed by every like individual\nof the species, and have been so performed by their ancestors for\ngenerations; and in performing the instinctive act, the animal seems to\nhave no more individuality or originality than a piece of adequately\nwound clockwork.\n\nGranting, then, that behaviour is shown to be intelligent by the fact\nthat there is evidence of profiting by experience, we may say that\nthe level attained by the intelligence is indicated by the complexity\nof the adjustment, its precision, the individuality shown, the amount\nof prevision disclosed, and in its being such as to extract from the\ncircumstances the maximum of benefit. Many of these points, however,\nserve equally well to mark the level of instinctive procedure.\n\n\nII.--INTELLIGENT BEHAVIOUR IN INSECTS\n\nIt is, as we have seen, among the higher invertebrates, especially in\ninsects, that some of the most remarkable and complex instincts may be\nfound. There is,[50] however, a tendency to ascribe the behaviour of\ninsects entirely to instinct, without sufficient evidence that neither\nimitation, instruction, nor intelligent learning play any part. This\nis, perhaps, a survival of the old-fashioned view that all the acts\nof the lower animals are performed from instinct, whereas those of\nhuman beings are to be regarded as rational or intelligent. In popular\nwritings and lectures, for example, we frequently find some or all of\nthe following activities of ant-life ascribed to instinct: recognition\nof members of the same nest; powers of communication; keeping aphides\nfor the sake of their sweet secretion; collection of aphid eggs in\nOctober, hatching them out in the nest, and taking them in the spring\nto the daisies, on which they feed, for pasture; slave-making and\nslave-keeping, which, in some cases, is so ancient a habit that the\nenslavers are unable even to feed themselves; keeping insects as beasts\nof burden, _e.g._ a kind of plant-bug to carry leaves; keeping beetles,\netc., as domestic pets; habits of personal cleanliness, one ant giving\nanother a brush-up, and being brushed-up in return; habits of play\nand recreation; habits of burying the dead; the storage of grain and\nnipping the budding rootlet to prevent further germination; the habits\ndescribed by Dr. Lincecum, and to a large extent confirmed by Dr.\nMcCook, that Texan ants prepare a clearing around their nest, and six\nmonths later harvest the ant-rice, a kind of grass of which they are\nparticularly fond, even, according to Lincecum, seeking and sowing the\ngrain which shall yield this harvest; the collection by other ants of\ngrass to manure the soil on which there subsequently grows a species of\nfungus upon which they feed; the military organization of the ecitons\nof Central America; and so forth. Now, the description of the habits\nof ants forms one of the most interesting chapters in natural history.\nBut to class them all as illustrations of instinct is a survival of an\nold-fashioned method of treatment.\n\nTo put the matter in another way. Suppose that an intelligent ant\nwere to make observations on human behaviour as displayed in one of\nour great cities or in an agricultural district. Seeing so great an\namount of routine work going on around him, might he not be in danger\nof regarding all this as evidence of hereditary instinct? Might he not\nfind it difficult to obtain satisfactory evidence of the establishment\nof our habits, of the fact that this routine work has to some extent\nto be learnt? Might he not say (perhaps not wholly without truth), \u201cI\ncan see nothing whatever in the training of the children of these men\nto fit them for their life-work. The training of their children has no\nmore apparent bearing upon the activities of their after-life than\nthe feeding of our grubs has on the duties of ant-life. And although\nwe must remember,\u201d he might continue, \u201cthat these large animals do not\nhave the advantage which we possess of awaking suddenly, as by a new\nbirth, to their full faculties, still, as they grow older, now one and\nnow another of their deferred instincts is unfolded and manifested.\nThey fall into the routine of life with little or no training as\nthe period proper to the various instincts arrives. If learning\nthereof there be, it has at present escaped our observation. And such\nintelligence as their activities evince (and many of them do show\nremarkable adaptation to uniform conditions of life) would seem to be\nrather ancestral than of the present time; as is shown by the fact that\nmany of the adaptations are directed rather to past conditions of life\nthan to those which now hold good. In the presence of new emergencies\nto which their instincts have not fitted them, these poor men are often\ncompletely at a loss. We cannot but conclude, therefore, that, although\nshown under somewhat different and less favourable conditions, instinct\noccupies fully as large a space in the psychology of man as it does in\nthat of the ant, while their intelligence is far less unerring and,\ntherefore, markedly inferior to our own.\u201d\n\nOf course, the views here attributed to the ant are very absurd. But\nare they much more absurd than the views of those who, on the evidence\nwhich we at present possess, attribute all the varied activities of\nant-life to instinct? Take the case of the ecitons, or military ants,\nor the harvesting ants, or the ants that are said to keep draught-bugs\nas beasts of burden: have we sufficient evidence to enable us to\naffirm that these modes of behaviour are purely instinctive and not\nintelligent; that all the varied man\u0153uvres of the military ants, for\nexample, are displayed to the full without any learning or imitation,\nwithout teaching and without intelligence on the part of every\nindividual in the army.\n\nThat in some cases there is something very like a training or education\nof the ant when it emerges from the pupa condition is rendered probable\nby the observations of M. Forel. As Romanes says,[51] \u201cThe young\nant does not appear to come into the world with a full instinctive\nknowledge of all its duties as a member of a social community. It is\nled about the nest and \u2018trained to a knowledge of domestic duties,\nespecially in the case of larv\u00e6.\u2019 Later on, the young ants are taught\nto distinguish between friends and foes.\u201d\n\nWe have only to weigh the evidence brought forward by such observers\nas Fabre and Dr. Peckham to see that among the solitary wasps and\nmason bees the behaviour, though founded on instinct, is in large\ndegree modified by intelligence. The care with which a site for the\ntunnelled nest in the ground is selected, betokens something more\nthan instinct. The following is a slightly condensed statement of Dr.\nand Mrs. Peckham\u2019s observations on one of the solitary wasps (_Aporus\nfasciatus_).[52] \u201cWe were working one day in the melon-field when we\nsaw one of these little wasps going backwards and dragging a spider.\nShe twice left it on the ground while she circled about for a moment,\nbut soon carried it up on to one of the large melon leaves, and left\nit there while she made a long and careful study of the locality,\nskimming close to the ground in and out among the vines; at length she\nwent under a leaf close to the ground, and began to dig. After her head\nwas well down in the ground we broke off the leaf that we might see\nher method of work. She went on for ten minutes without noticing the\nchange, and then, without any circling, flew off to visit her spider.\nWhen she tried to return to her hole it was evident that some landmark\nwas missing. Again and again she zig-zagged from the spider to the\nnesting-place, going by a sort of path among the vines from leaf to\nleaf, and from blossom to blossom, but when she reached the spot she\ndid not recognize it. At last we laid the leaf back in its place over\nthe opening, when she at once went in and resumed her work, keeping\nat it steadily for ten minutes longer. At this point she suddenly\nreversed her operations, and began to fill in the hole that she had\nmade. She then glanced at the spider, selected a new place, and began\nto dig again. This hole was also filled in; she looked once more at\nthe spider, and started a nest in a new place. This, in turn, was soon\nabandoned, as was a fourth. The fifth beginning was made under a leaf\nthat lay close to the ground, but after twenty minutes\u2019 work this place\nalso was abandoned and a sixth started. This, however, was the final\nchoice, and after forty-five minutes spent in digging it was completed.\u201d\n\n[Illustration: FIG. 19.--Solitary Wasp using a stone to beat down the\nearth over its nest (after Peckham).]\n\nThis description shows an amount of apparent fastidiousness which\nis quite irreconcilable with the hypothesis that the behaviour\nis merely instinctive. Not less fastidious are some wasps in the\ntemporary closure of the hole with a stone or pellet of earth,\nthe operation being repeated several times with different covers\nbefore the insect seems to be satisfied; while in other cases the\nhole is hidden by bringing earth in such quantity as to render the\nplace indistinguishable from the rest of the field. But in one case\nobserved by Dr. Peckham, intelligent procedure was carried so far as\napparently to involve the use of a tool, the same behaviour having been\nindependently observed in the same genus (_Ammophila_) by Dr. S. W.\nWilliston of Kansas University. \u201cJust here,\u201d writes Dr. Peckham,[53]\n\u201cmust be told the story of one little wasp whose individuality stands\nout in our minds more distinctly than that of any of the others. In\nfilling up her nest she put her head down into it and bit away the\nloose earth from the sides, letting it fall to the bottom of the\nburrow, and then, after a quantity had accumulated, jammed it down with\nher head. Earth was then brought from the outside and pressed in, and\nthen more was bitten from the sides. When, at last, the filling was\nlevel with the ground, she brought a quantity of fine grains of dirt\nto the spot, and, picking up a small pebble in her mandibles, used\nit as a hammer in pounding them down with rapid strokes, thus making\nthis spot as hard and firm as the surrounding surface. Before we could\nrecover from our astonishment at this performance she had dropped her\nstone and was bringing more earth, and in a moment we saw her pick up\nthe pebble and again pound the earth into place with it. Once more the\nwhole process was repeated, and then the little creature flew away.\u201d\n\nHere we have intelligent behaviour rising to a level to which some\nwould apply the term rational. For the act may be held to afford\nevidence of the perception of the relation of the means employed to\nan end to be attained, and some general conception of purpose. In\nthis section, which deals with description of behaviour based on\nobservation, the psychological explanation cannot be discussed. Similar\nindications of deliberate action may be held to be afforded by the\nsometimes elaborate \u201clocality studies\u201d which these insects seem to\nmake,--by the \u201ccare that is taken by wasps to acquaint themselves with\nthe surroundings of their nests.\u201d A _Sphex_, for example, which had\npartially made and then abandoned several nests, left them without any\nlocality study; but when she had completed a nest in a suitable spot\nshe made \u201ca most thorough and systematic study of the surroundings.\nShe flew in and out among the plants, first in narrow circles near\nthe surface of the ground, and then in wider and wider ones as she\nrose higher in the air, until at last she took a straight line and\ndisappeared in the distance.\u201d Another species (_Cerceris deserta_) \u201chas\nthe habit of making a number of half circles in front of the nest, and\nthen, after rising a little higher, of flying several times completely\nround it.\u201d The method of procedure is, it seems, so normal to the\nspecies that it is probably founded on an instinctive basis. Dr. and\nMrs. Peckham, in commenting on their observations, say:[54] \u201cIf the\nexamination of the objects about the nest makes no impression upon the\nwasp, or if it is not remembered, she ought not to be inconvenienced\nnor thrown off her track when weeds and stones are removed and\nthe surface of the ground is smoothed over; but this is just what\nhappens.\u201d For convenience of observation they \u201csometimes gently moved\nintercepting objects to one side, but even such a slight change threw\nthe wasp out of her bearings, and made it difficult for her to recover\nher treasure.\u201d Where wasps form a number of nests in a small plot of\nground, as in the case of _Bembex_, each knows and returns to its own\nhole, as was proved by Dr. Peckham, who marked the insects and their\nnests with paint.\n\nSo, too, with regard to prey. In the course of his observations on\n_Pompilus_, Fabre removed the spider which the wasp had deposited on\na tuft of vegetation before she made her nest. As she was at work\nbeneath the surface she could not see what went on above ground or\nwhere the spider had been redeposited some twenty inches from its\nformer position. On emerging from the nest the wasp went straight to\nthe original spot, searched round it for some time, then made further\nexcursions, and discovered the spider. After slightly altering its\nposition, and placing it on another tuft of vegetation, she returned to\nher subterranean labours, giving the observer an opportunity of again\nmoving the spider. Five times did Fabre repeat the operation, and every\ntime the wasp returned to the spot where she had last deposited her\nprey.\n\nThe same observer records some interesting experiments with the mason\nbee, _Chalicodoma_. The mud nests of the species investigated were\naffixed to stones on the banks of the Rhone. When a nest was partially\nconstructed, the bee having flown off for more material, Fabre moved\nthe stone to a new position, near at hand and easily visible from the\noriginal site. The bee went straight to the place where the nest had\nbeen, searched the immediate neighbourhood, flew off, and returned\nto the same spot to continue the search. If she came across her own\nnest in its new position she did not recognize it as hers, but left it\nafter examination. But if a stone with the nest of another bee in about\nthe same stage of construction was placed in the position occupied\nby her own, she adopted it. And when two nests near together, both\nhalf built, were transposed, each bee unhesitatingly adopted the nest\nwhich occupied the position where its own nest had been. It may well\nseem strange that, the general locality-memory being so well marked,\nthe recognition of the particular stone and nest should be deficient.\nThis may be due to the fact that the so-called compound eyes are\nthe organs concerned in locality vision, while the ocelli deal with\ndetails at very close range, and that the former alone afford the\nrequisite data for recognition; by their instrumentality alone arises\nthe conscious situation which affords guidance in behaviour. And in\nthat situation slight changes which for us make it \u201cstill the same but\nwith a difference\u201d render it no longer the same for a being of more\nlimited intelligence--one probably incapable of analyzing the situation\nand seeing that the sameness preponderates over the difference. Be\nthis as it may, the failure of a bee to recognize its own nest under\ncircumstances so foreign to its experience as removal to a new spot may\nbe paralleled with what I have observed in the case of sticklebacks.\nA nest had been built in a round glass bell jar which stood near a\nwindow. Some aquatic vegetation grew in the tank, and the nest was\nbuilt on the window side. An experiment was made by turning the large\nbell jar through a right angle. The male stickleback searched for its\nnest in the old direction on the window side--that is to say, the\nsame position in reference to the incidence of the light. The search\nwas, of course, fruitless, and a new nest was begun in this position.\nPresently the old nest was discovered, and was then vigorously\ndestroyed in just the same way as the nest of a rival is pulled to\npieces and scattered. Here a new incidence of light and new direction\nof shadows seemed to have completely transformed the visual situation.\n\nTo return to insects, it is probable that the homing faculty is not\nthe result of an inborn mysterious instinct dependent on some sense of\ndirection of which we have no knowledge, but is based upon experience\ngained during their flight hither and thither--that, in a word, it is\nintelligent and not instinctive. Experiments of Fabre at first seemed\nto suggest some magnetic influence to which bees were sensitive; for\nwhen a minute magnet was fixed to a bee as it started on its return\njourney, the insect was at fault; but as a check experiment he affixed\na piece of straw instead of a magnet, with similar results. Some of\nFabre\u2019s observations and those of Dr. Bethe[55] are difficult to\nreconcile with the hypothesis that, in the homing, guidance is due to\nacquired acquaintance with the locality. But, on the other hand, the\nexperiments of Lord Avebury and of Romanes seem to favour this view.\nRomanes found that when bees were taken inland from their hive near\nthe seaboard, and then liberated, they returned from considerable\ndistances, the whole locality being familiar; but taken to the\nseashore, where the objects around them were unfamiliar (since the\nseashore is not the place where flowers and nectar are to be found),\nthe bees, though not far distant from the hive, were nonplussed and\nlost their way. Dr. and Mrs. Peckham, as the result of their extremely\ncareful observations, seem to have no doubt that the homing of solitary\nwasps is due to locality-experience; and of the social wasp, _Polistes\nfusca_, they say:[56] \u201cWe have seen the young workers make repeated\nlocality studies when they first began to venture away from home, but\nas they occupy the same nest all summer they, of course, grow more and\nmore familiar with their surroundings, until they become so thoroughly\nacquainted with them that they can find their way without the least\ndifficulty. We have no doubt that with them, as with the solitary\nwasps, the faculty is not instinctive, but is the direct outcome of\nindividual experience.\u201d\n\nIn the interesting pages of the works in which Dr. and Mrs. Peckham\ndescribe their investigations, there are many observations which show\nthat wasps are capable of intelligently profiting by the experience\nwhich their instinctive behaviour places them in a position to acquire.\nThe inherited tendencies and aptitudes pave the way for acquired\nmodification and accommodation of behaviour. To catch and paralyze\nspiders, to dig and prepare a tunnelled nest, and to carry the prey\nto the nest, all this affords the instinctive basis; but when the\nobservers tell us that they \u201chave several times seen wasps enlarge\ntheir holes when a trial had demonstrated that a spider would not go\nin,\u201d and even on one occasion without trial when an unusually bulky\nspider was brought, there is something beyond instinct; there is\nintelligent adjustment to special circumstances given in experience.\nPresumably intelligent is the habit frequently observed in one species\nof _Pompilus_, and occasionally in another, of hanging the paralyzed\nspider in a crotch of a branching stem, usually of bean or sorrel,\nwhere it will be safe from the depredation of ants. On one occasion\nDr. Peckham, desirous of seeing the exact manner in which the victim\nwas stung, substituted an unhurt spider for that which the wasp had\nparalyzed.[57] \u201cAccording to the habit of its species when danger\nthreatens, it kept perfectly quiet, and when the wasp returned it was\nhanging there as motionless as a piece of dead matter; but she would\nnot touch it; she hunted all over that plant and then over several\nothers near to it, returning continually to look again at the right\nspot. After five minutes she flew off in the direction of the woods\nto catch another spider. Why did she go to the woods? Why did she\nnot take the one that hung there in plain view? It could not have\nbeen due to the fact that we had handled the spider, since when, on\nother occasions, we took one that had been paralyzed, examined it, and\nthen returned it to the wasp, she accepted it without hesitation....\nIn forty minutes she came back with another spider, but, instead of\ntaking it into the nest, she hung it upon a bean plant near by, and\nthen proceeded to dig a new hole a few inches distant from the first.\nFoolish little wasp, what a waste of labour! Truly, if you are endowed\nwith energy beyond your fellows, you are but meagrely furnished with\nreason.\u201d\n\n[Illustration: FIG. 20.--Spiders placed by Solitary Wasps in the\ncrotches of branching stems (after Peckham).]\n\nHere we have the routine of instinct--the normal mode of hunting and\ncapturing prey, the normal procedure of bringing the spider, and\nthen making the nest, predominating over any tendency to initiate\nintelligent improvements. This, however, should not surprise us, in\nwhom the force of habit is often so strong. Nor should we feel surprise\nat the apparently stupid tolerance some of these wasps display in\npresence of parasites. _Bembex_, which does not store and close its\ncell, but brings continual supplies of food to its larv\u00e6, is not\ndisturbed by the presence in the cell of the grubs of the parasitic\nfly _Miltogramma_. She could, we think, easily free her nest of these\nintruders, but she continues to bring supplies, though the parasites\nmay absorb it all and leave her own larv\u00e6 to perish. She adapts her\nprocedure to the new conditions, being incapable of knowing that she is\nfeeding the enemies of her race.\n\nEnough has now been said to show the extent and the limitations of the\nintelligence of such insects as the solitary wasps. It will be noticed\nthat the acquired modifications of behaviour occur in close connection\nwith the inherited ground-plan of instinctive procedure. We shall\nhave occasion to note the same connection in our discussion of social\nbehaviour in the next chapter. And we shall consider the influence of\nintelligence on instinct before we bring this chapter to a close.\n\n\nIII.--SOME RESULTS OF EXPERIMENT\n\nIt is unnecessary to give a _resum\u00e9_ of entertaining anecdotes\nillustrative of intelligent behaviour in the higher animals. Such\nanecdotes are too often the outcome of casual observations by untrained\nobservers; and the interpretation put upon the facts frequently shows\na want of psychological discrimination. Such is not the material of\nwhich science is constituted. What is needed is systematic observation\nconducted, so far as possible, under controlled conditions. Two\nthings are necessary: first, to distinguish instinctive behaviour,\ninherited as such, from the acquired modifications or new departures\ndue to intelligence; and secondly, to determine the method and range\nof intelligent procedure. These problems can only be solved in their\nentirety by a complete knowledge of the life-history of the animal\nconcerned. But they may be attacked in detail by a systematic study\nof particular modes of behaviour, and by an investigation into\ntheir manner of origin. That this may be done with some approach\nto accuracy, resort must be had to experiment, which permits of\nobservation under controlled conditions.\n\nTo ascertain, for example, how far nest-building is instinctive in\nbirds, Mr. John S. Budgett hatched a hen greenfinch under a canary. In\nthe following autumn he bought a caged bird, a cock, probably of the\nsame year, and in the succeeding spring turned the pair into a large\naviary, supplying such material as twigs, rootlets, dried grass, moss,\nfeathers, sheep\u2019s wool and horsehair. The hen soon began to build, the\ncock bird taking no share in the work, and finished her nest in a few\ndays. On careful comparison it was found to resemble that of a wild\ngreenfinch in every particular, being made of wool, roots, and moss,\nlined with horsehair. A second nest the aviary greenfinch built was\nalso quite normal.\n\nIn the case of a bullfinch which Mr. Budgett reared, having obtained it\nwhen a few weeks\u2019 old, the first nest was composed of dried grass with\na little wool and hair, but without either rootlets or twigs. A second\nwhich she built was, however, quite typical, made of fine twigs and\nroots, and lined with horsehair; as was also a third nest.\n\nIt is just possible, though most improbable, that the bullfinch\nutilized its three weeks\u2019 experience gained in the nest from which it\nwas taken. But Mr. Jenner Weir describes[58] observations on canaries\nin which this source of experience is excluded. \u201cIt is usual,\u201d he\nsays, \u201cwith canary fanciers to take out the nest constructed by the\nparent birds, and to place a felt nest in its place, and when her young\nare hatched, and old enough to be handled, to place a second clean\nnest, also of felt, in the box, removing the other. But I never knew\nthat canaries so reared failed to make a nest when the breeding time\narrived. I have, on the other hand, marvelled to see how like a wild\nbird\u2019s the nests are constructed. It is customary to supply them with\na small set of materials, such as moss and hair. They use the moss for\nthe foundation, and line with the finer materials, just as a wild\ngoldfinch would do.\u201d\n\nExperiment seems, therefore, to show in a way, and with a clearness\nimpossible of attainment by observation under natural uncontrolled\nconditions, that nest-building in birds is instinctive. That the manner\nand method of procedure is often modified in accordance with special\nconditions--that the instinctive outline of nidification receives\nits final touches through individual experience--is sometimes seen\nunder nature, and more often under the semi-experimental conditions\nof domestication. Thus three pairs of pigeons in the Wilson Tower\nof Clifton College made their nests in 1898, as I am informed by\nMr. H. C. Playne, of galvanized iron wire, pieces of which were\nleft in a corner at the top of the tower, thus affording a parallel\nto the behaviour of the unconventional crow of Calcutta, mentioned\nby Mr. F. W. Headley,[59] which made its nest of soda-water bottle\nwires, which it picked up in a back yard. But even in this matter\nexperiment serves to bring out clearly the selective influence which\nis exercised by intelligence. Bolton,[60] in 1792, observed a pair of\ngoldfinches beginning to build their nest in his garden. They formed\nthe ground-work of moss, grass, etc., as usual; but on his scattering\nsmall parcels of wool in different parts of the garden they, in great\nmeasure, left off the use of their own stuff and used the wool.\nAfterwards he gave them cotton, and they then used this instead of the\nwool; then he supplied fine down, and they finished their work with\nthis, leaving the wool and cotton.\n\nIn studying the behaviour of wild animals under natural conditions, it\nmust always be difficult to distinguish the congenital basis from the\nacquired elements; for both tend to bring about a working adjustment\nto the conditions of life, and we can seldom have opportunities of\ntracing the interplay of the factors which produce the instinct-habits\nof adult life. But under domestication we seek to bring about a new\nworking adjustment to conditions imposed by man. The skilful trainer\nutilizes the natural instinctive tendencies as a basis; and, by a\nsystem of rewards and punishments, leads the intelligent modifications\nof behaviour along lines directed by his deliberate purpose. The\nconditions are largely those of experiment, and they bring out the\nplay and range of intelligence in a way which would otherwise elude\nour observation. The training of falcons for the chase affords a good\nillustration, since they cannot be bred in confinement, and the effects\nof training cannot therefore be hereditary. The falconer\u2019s object is\nto modify the congenital instinctive behaviour of a bird of prey for\nthe purposes of sport. She is trained to the lure at first at short\ndistances, and step by step through longer flights; she is taught by\nsnatching away the lure to stoop at it repeatedly as often as it is\njerked aside; and then she is trained on living quarry, at first under\neasy conditions, till eventually she can be flown at a wild bird. And\nas a result a well-trained falcon will follow her master from field\nto field, regulating her flight by his movements, always ready for a\nstoop when the quarry is sprung. The fact that she can be thus educated\nfor her work shows that her behaviour is plastic, and can be moulded\nby intelligence. Experimental conditions reveal the fact; but under\nnature the moulding influence of intelligence is presumably not less\nimportant, though it is more directly in line with the congenital\ninstinctive tendencies.\n\nThat much of the behaviour of the higher animals is guided by\nexperience similar to that which plays so large a part in their\ntraining under the experimental conditions of domestication is\ngenerally admitted. But what are the range and limits of animal\nintelligence, and whether it attains the level of rational conduct,\nin the restricted sense of the term \u201crational,\u201d are questions open to\ndiscussion, to which answers are more likely to be obtained through\nexperiment than by chance observations.\n\nBefore giving some of the results of such experiment it will be well\nto revert to the distinction, which was drawn in the second chapter,\nbetween the lower or intelligent stage of mental development and the\nhigher or rational stage. It will be remembered that rational processes\nwere characterized by the fact that the situations contain the products\nof reflective thought, presumably absent in the earlier stages of\ndevelopment; that they were further characterized by a new purpose or\nend of consciousness, namely, to explain the situations which at an\nearlier stage are merely accepted as they are given in presentation or\nre-presentation; they require deliberate attention to the relationships\nwhich hold good among the several elements of successive situations;\nand they involve, so far as behaviour is concerned, the intentional\napplication of an ideal scheme with the object of rational guidance.\n\nOn the other hand, the animal at the stage of intelligent behaviour\ndeals with the circumstances of his comparatively simple life by\nmaking use of the particular situations which have been presented to\nconsciousness in the course of his practical experience. If such an\nanimal be placed in the midst of new circumstances he has to find out\nby a process of trial and error how they are to be met. After a longer\nor shorter period of trial, guided only by particular experiences,\nhe chances to hit upon a mode of procedure which is successful. The\nsuccessful act is then incorporated in a new situation; at first,\nperhaps, only incompletely. The association is eventually established\nby repetition, through which is acquired the habit of doing the right\nthing in the appropriate manner. Why he does this and not something\nelse, in so far as he is intelligent and not rational, he probably\nneither knows nor has the wit to consider. The satisfaction of success\nsuffices for intelligence as such. If the circumstances be so modified\nas to render the particular mode of meeting them ineffectual, after\ntrying again and again in the old way, he will sometimes stumble upon\nthe proper mode of overcoming the difficulty, and after doing so two\nor three times a new conscious situation involving the requisite\nassociations will be established, and the appropriate behaviour will\nbecome habitual. But why this new mode of procedure rather than any\nother is adopted, intelligence as such does not know, because it does\nnot analyze the situation and disentangle the essential relationships.\nThe satisfaction of success again suffices. In a word, such an animal\nin the perceptual stage of mental development seems wanting in the\npower of reflection. He does not appear to show evidence of framing\nanything like a general scheme of knowledge which he can apply to the\nsolution of particular problems, of a practical nature, involving\ndifficulties and obstacles.\n\nThe method of intelligence--in the sense in which we are using this\nterm--the method of varied trial and error with the utilization of\nchance success, is a lengthy and somewhat clumsy process; but it\nsuffices. Now contrast it with the procedure of a rational animal, such\nas man is or may be. When he is confronted by a difficulty he is not\ncontent to meet it by trying this way, and that way, and another way,\nanyhow, and trusting to chance to bring success, but he considers the\nproblem in all its relations with a view to ascertaining the essential\nnature of the difficulty. For each attempted mode of meeting the case\nhe has a definite reason. He knows why he does this and not that. He\nhas a plan or scheme which he puts into execution. And if it fail,\nhe is not content till he finds out wherein the failure lay. This\nenables him to plan a better scheme. He sees why it is better; and if\nat last he be successful by a happy hit, as in the chance procedure\nof intelligence, he looks for the reason of it. And seeing why this\nfortunate attempt, unlike his previous efforts, just meets the case,\nhe repeats it because he perceives that herein lies the essential\nsolution of the difficulty. Both in the case of intelligence and in\nthat of reason, as here distinguished, present procedure is based upon\npast experience; but reason has built upon the foundations thus laid an\norderly scheme, and knows its whys and wherefores, while intelligence\nis at the mercy of chance associations. The reason for success it has\nnot the wit to assign.\n\nThe essential difference between the two cases may be put in another\nway by saying that the intelligent being forms sensory impressions and\nsensory images linked together by bonds of association, combining and\ncoalescing to constitute a conscious situation effective in behaviour\nunder the guiding influence of pleasure and pain; while the rational\nbeing not only does all this, but goes further. He fixes his attention\non the way in which the elements in the situation are connected and\nrelated; he builds an ideal framework on which the sensory impressions\nare set or move in an orderly manner. And it is this scheme, fashioned\nby reason and transforming the situation, which he utilizes in dealing\nwith difficulties.\n\nYet another way of putting the same essential distinction is to say\nthat intelligence deals with pictures, either directly presented to\nthe senses or called up in re-presentation. If we state the matter\nthus, however, we must remember that the \u201cpictures\u201d may be painted in\ncolours supplied by any of the senses; and that smells, tastes, sounds,\ntouches, pressures, limb-movements, and so forth, are elements in the\npictured product. Bearing this in mind, we may say that intelligence\ndeals with sensory impressions and their revived images in concrete\nand particular situations; while reason analyzes the pictures, and\nextracts from them general notions in terms of which the pictures may\nbe explained. For example, we picture a stone falling to the earth;\nbut we explain it by the general notion of gravitative attraction. The\nconception forms part of our ideal scheme of knowledge, which is not\nitself picturable, though this or that example of its action may be\npresented or re-presented in sensory imagery.\n\nOnce more we may say--and this way of looking at the question arises\nnaturally out of what has gone before--that intelligence deals with\nconcrete examples, and does not rise to the abstract and general\nrule. The ideal scheme of reason is the result of abstraction and\ngeneralization. It is a framework of conceptions which can be applied\nto the particular facts which fall under observation to see whether\nit fits and meets the case. Intelligence has to deal with the facts\nas they present themselves, without the aid of an organized system of\nknowledge built up into an ideal scheme.\n\nEnough has now been said to indicate the distinction between the\nmethod of intelligence and that of reason. It may, no doubt, be said\nthat the terminology used is open to criticism; for, on the one hand,\nthe words \u201cintelligence\u201d and \u201cintelligent\u201d are frequently used as\nsynonymous with \u201creason\u201d and \u201crational;\u201d and, on the other hand, acts\nrequiring neither abstraction, generalization, nor the application\nof any scheme of knowledge are frequently spoken of as \u201crational.\u201d\nHence there is, it may be urged, some danger of misunderstanding. This\nmay be granted. And unless some such restriction of meaning under\nsuitable terms be accepted by psychologists, misunderstanding will\ncontinue. More essential, however, than the distinctive terms we are\nto use is the distinction of method which underlies them. That, I\ntrust, is sound. Dr. Lindley, in an interesting paper on \u201cA Study of\nPuzzles,\u201d[61] has utilized the distinction in his investigation of the\nmental development of children, and has found that the procedure of\nyoung children is predominantly of the \u201csense-trial and error\u201d order\nwhich has above been termed intelligent; and he expresses the opinion\nthat \u201cmost of the adaptations of animals are on this sense-trial and\nerror level.\u201d\n\nSuch certainly seems to be the conclusion to be drawn from my own\nexperimental observations on dogs. It has frequently been asserted\nthat the behaviour of a dog with a stick in his mouth, when he comes\nto a narrow gap, shows that he at once perceives the nature of\nthe difficulty, and meets it in a rational manner by adopting the\nappropriate plan of action. He pulls the stick through by one end. But\nexperiments, which I have elsewhere described,[62] showed that a fox\nterrier, fourteen months old, seemed to be incapable of perceiving\nthe nature of the difficulty which vertical iron railings presented\nto his passage with a stick in his mouth, and only imperfectly learnt\nto overcome it after many ineffectual trials and many failures. The\nresults obtained on the first afternoon may be quoted to indicate the\nnature of the evidence. The dog was sent after a short stick into a\nfield, and had to pass through vertical rails about six inches apart.\nOn his return the stick caught at the ends. I whistled and turned as\nif to leave; and the dog pushed and struggled vigorously. He then\nretired into the field, lay down, and began gnawing the stick, but,\nwhen called, came slowly up to the railings and stuck again. After some\nefforts he put his head on one side, and brought the stick, a short\none, through. After patting and encouraging him, I sent him after it\nagain. On his return he came up to the railings with more confidence,\nbut, holding the stick by the middle, found his passage barred. After\nsome struggles he dropped it and came through without it. Sent after it\nagain, he put his head through the railings, seized the stick by the\nmiddle, and then pulled with all his might, dancing up and down in his\nendeavours to effect a passage. Turning his head in his efforts, he\nat last brought the stick through. A third time he was again foiled;\nagain dropped the stick; and again seizing it by the middle tried to\npull it through. I then placed the stick so that he could easily seize\nit by one end and draw it through the opening between the rails. But\nwhen I sent him after it, he went through into the field, picked up the\nstick by the middle, and tried to push his way between the railings,\nsucceeding, after many abortive attempts, by holding his head on one\nside.\n\nSubsequent trials on many occasions yielded similar results. But the\nfollowing summer, when I resumed the experiments, I was able with some\nguidance to teach him to bring a long stick to the railings, drop\nit, and then draw the stick through by one end; though even then,\nif he had dropped it so that one end just caught a rail, he often\nfailed, shaking his head vigorously, dropping the stick and seizing\nit again, and repeating this behaviour until it chanced to fall in\na more favourable position. He did not apparently perceive that by\ngently moving the stick a little one way or other the difficulty\ncould be simply overcome with little effort. Nor when given a crooked\nstick, which caught in a rail, did he show any sign of perceiving that\nby pushing the stick and freeing the crook he could pull the stick\nthrough. Each time the crook caught he pulled with all his strength,\nseizing the stick now at the end, now in the middle, and now near the\ncrook. At length he seized the crook itself, and with a wrench broke\nit off. A man who was passing, and who had paused for a couple of\nminutes to watch the proceedings, said, \u201cClever dog that, sir; he knows\nwhere the hitch do lie.\u201d The remark was the characteristic outcome of\ntwo minutes\u2019 chance observation. During the half hour or more during\nwhich I had watched the dog he had tried nearly every possible way of\nholding and tugging at the stick. Such is the mode of behaviour based\non intelligence--continued trial and failure, until a happy effect is\nreached, not by methodically planning, but by chance.\n\nTwo of my friends criticized these results, and said that they only\nshowed how stupid _my_ dog was. _Their_ dogs would have acted very\ndifferently. I suggested that the question could easily be put to the\ntest of experiment. The behaviour of the dog was in each case--the\none a very intelligent Yorkshire terrier, the other an English\nterrier--similar to that above described. The owner of the latter was\nsomewhat annoyed, used forcible language, and told the dog that he\ncould do it perfectly well if he tried.\n\nIn experimenting with my fox terrier on the method adopted in seizing\nand carrying differently balanced objects, I used (1) a straight\nstick, the centre of gravity of which was at the middle; (2) a Kaffir\nknob-kerrie, the centre of gravity of which was about six inches from\nthe knob; (3) a light geological hammer; and (4) a heavier hammer. In\nthe last, the centre of balance was close to the hammer head. The net\nresult of the observations was that the best place for seizing and\nholding the object was hit upon in each case after indefinite trials;\nthat after three or four days\u2019 continuous experience with one (say the\nknob-kerrie), another (say the stick) was at first seized nearer one\nend, showing the influence of the more recent association; and that\nthere was little indication of the dog\u2019s seizing any one of the four\nat once in the right place, that is to say, the point of seizure was\nnot clearly differentiated in accordance with the look of the object. I\ntied a piece of string, in later trials, round the centre of balance,\nbut this, at the time of the dog\u2019s death, had not served as a sure\nguide to his experience.\n\nThe way in which my dog learnt to lift the latch of the garden gate,\nand thus let himself out, affords a good example of intelligent\nbehaviour. The iron gate outside my house is held to by a latch, but\nswings open by its own weight if the latch be lifted. Whenever he\nwanted to go out the fox terrier raised the latch with the back of his\nhead, and thus released the gate, which swung open. Now the question in\nany such case is: How did he learn the trick? In this particular case\nthe question can be answered, because he was carefully watched. When\nhe was put outside the door, he naturally wanted to get out into the\nroad, where there was much to tempt him--the chance of a run, other\ndogs to sniff at, possibly cats to be worried. He gazed eagerly out\nthrough the railings on the low parapet wall shown in the illustration;\nand in due time chanced to gaze out under the latch, lifting it\nwith his head. He withdrew his head and looked out elsewhere; but\nthe gate had swung open. Here was the fortunate occurrence arising\nout of natural tendencies in a dog. But the association between\nlooking out just there and the open gate with a free passage into the\nroad is somewhat indirect. The coalescence of the presentative and\nre-presentative elements into a conscious situation effective for the\nguidance of behaviour was not effected at once. After some ten or\ntwelve experiences, in each of which the exit was more rapidly effected\nwith less gazing out at wrong places, the fox terrier had learnt to\ngo straight and without hesitation to the right spot. In this case\nthe lifting of the latch was unquestionably hit on by accident, and\nthe trick was only rendered habitual by repeated association in the\nsame situation of the chance act and the happy escape. Once firmly\nestablished, however, the behaviour remained constant throughout the\nremainder of the dog\u2019s life, some five or six years.\n\n[Illustration: FIG. 21.--Fox-terrier lifting the latch of a gate.]\n\nMr. E. J. Shellard observed[63] an act of similar import in a Scotch\nstaghound, which \u201cappeared at first to be the result of thought,\u201d\nbut which, on closer observation, was clearly seen to be the result\nof intelligence in the restricted sense of the term. The dog released\nthe lever-latch of a yard door. \u201cAt first he raised his paws to the\ndoor and scratched violently, manifesting various signs of impatience.\nHis scratches, which extended from the top of the door downwards, and\nover the whole area, would thus inevitably at some time or other reach\nthe handle of the latch, which was thus struck forcibly downwards, the\nlatch itself rising upwards. The door would then open from the weight\nof the dog pushing against it. The dog always opened the door in this\nmanner from the time when the incident was first noticed until he left,\na period of about three years. The door was opened with no greater\nease at the expiration of that period than at the commencement. His\npaws would strike various parts of the door, and he never appeared to\nexercise any degree of judgment in the localization of his strokes, the\nfact of his paws striking the handle of the latch being a necessary\nresult, providing the dog had sufficient patience and strength to\ncontinue.\u201d\n\nOne or two more experiments with my fox terrier may be briefly\ndescribed. I watched his behaviour when a solid indiarubber ball was\nthrown towards a wall standing at right angles to its course. At first\nhe followed it right up to the wall and then back as it rebounded. So\nlong as it travelled with such velocity as to be only just ahead of\nhim he pursued the same course. But when it was thrown more violently,\nso as to meet him on the rebound as he ran towards the wall, he\nlearnt that he was thus able to seize it as it came towards him. And,\nprofiting by the incidental experience thus gained, he acquired the\nhabit--though for long with some uncertainty of reaction--of slowing\noff when the object of his pursuit reached the wall so as to await its\nrebound. Again, when the ball was thrown so as to glance at a wide\nangle from a surface, at first--when the velocity was such as to keep\nit just ahead of him--he followed its course. But when the velocity\nwas increased he learnt to take a short cut along the third side of a\ntriangle, so as to catch the object at some distance from the wall. A\nthird series of experiments were made where a right angle was formed\nby the meeting of two surfaces. One side of the angle, the left, was\ndealt with for a day or two. At first the ball was directly followed.\nThen a short cut was taken to meet its deflected course. On the fourth\nday this method was well established. On the fifth, the ball was thrown\nso as to strike the other or right side of the angle, and thus be\ndeflected in the opposite direction. The dog followed the old course\n(the short cut to the left) and was completely non-plussed, searching\nthat side, then more widely, and not finding the ball for eleven\nminutes. On repeating the experiment thrice, similar results were that\nday obtained. On the following day the ball was thrown just ahead of\nhim, so as to strike to the right of the angle, and was followed and\ncaught. This course was pursued for three days, and he then learnt\nto take a short cut to the right. On the next day the ball was sent,\nas at first, to the left, and the dog was again non-plussed. I did\nnot succeed in getting him to associate a given difference of initial\ndirection with a resultant difference of deflection.\n\nI may here mention that, whenever searching for a ball of which he had\nlost sight in the road, he would run along the gutter first on one\nside and then on the other. A friend who was walking with me one day\nregarded this as a clear case of rational inference. \u201cThe dog knows,\u201d\nhe said, \u201cthe effects of the convex curvature of the road as well as we\ndo.\u201d I am convinced, however (having watched his ways from a puppy),\nthat this method of search was gradually established on a basis of\npractical experience. No logical inference on his part is necessary for\nthe interpretation of the facts; and we should not assume its presence\nunless the evidence compels us to do so.\n\nDr. E. L. Thorndike, in a monograph on \u201cAnimal Intelligence\u201d published\nas a supplement to the _Psychological Review_ (June, 1898), has fully\ndescribed and carefully discussed a number of interesting experiments.\nThe subjects (one might, alas! almost say victims) of some of these\nwere thirteen kittens or cats from three to eighteen months old. His\nmethod of investigation shall be stated in his own words.\n\n \u201cAfter considerable preliminary observation of animals\u2019 behaviour\n under various conditions, I chose for my general method one which,\n simple as it is, possesses several other marked advantages besides\n those which accompany experiment of any sort. It was merely to put\n animals when hungry in enclosures from which they could escape by\n some simple act, such as pulling at a loop of cord, pressing a lever,\n or stepping on a platform. The animal was put in the enclosure,\n food was left outside in sight, and his actions observed. Besides\n recording his general behaviour, special notice was taken of how he\n succeeded in doing the necessary act (in case he did succeed), and a\n record was kept of the time that he was in the box before performing\n the successful pull, or clawing, or bite. This was repeated until the\n animal had formed a perfect association between the sense-impression\n of the interior of that box and the impulse leading to the successful\n movement. When the association was thus perfect, the time taken to\n escape was, of course, practically constant and very short.\n\n \u201cIf, on the other hand, after a certain time the animal did not\n succeed, he was taken out, but _not fed_. If, after a sufficient\n number of trials, he failed to get out, the case was recorded as one\n of complete failure. Enough different sorts of methods of escape\n were tried to make it fairly sure that association in general, not\n association of a particular sort of impulse, was being studied.\n Enough animals were taken with each box or pen to make it sure that\n the results were not due to individual peculiarities. None of the\n animals used had any previous acquaintance with any of the mechanical\n contrivances by which the doors were opened. So far as possible the\n animals were kept in a uniform state of hunger, which was practically\n utter hunger.\u201d\n\n[Illustration: FIG 22.--Cage used in Professor Thorndike\u2019s\nexperiments.]\n\nTo Dr. Thorndike\u2019s monograph we must refer those who desire detailed\ninformation as to apparatus and procedure. It must here suffice to\nstate that the box-cages employed were rudely constructed of wooden\nlaths, and formed cramped prisons about twenty inches long by fifteen\nbroad and twelve high. Nine contained such simple mechanisms as Dr.\nThorndike describes in the passage above quoted. When a loop or cord\nwas pulled, a button turned, or a lever depressed, the door fell open.\nIn another, pressure on the door as well as depression of a thumb-latch\nwas required. In one cage two simple acts on the part of the kitten\nwere necessary, pulling a cord and pushing aside a piece of board; and\nin yet others three acts were requisite. In those boxes from which\nescape was more difficult a few of the cats failed to get out. The\ntimes occupied in thoroughly learning the trick of the box by those\nwho were successful are plotted in a series of curves, the essential\nfeature of which is the graphic expression of a gradual diminution\nin the time interval between imprisonment and escape in successive\ntrials. This is shown in Fig. 23, which is constructed from some of Dr.\nThorndike\u2019s data. In some cases the cats were set free from a box when\nthey (1) licked themselves or (2) scratched themselves.\n\n[Illustration: FIG. 23.--Diagram showing times taken by a kitten to\nescape from the cage in twenty-four successive experiments.]\n\nDr. Thorndike comments on the results of his experiments as follows:--\n\n \u201cWhen put into the box the cat would show evident signs of discomfort\n and of an impulse to escape from confinement. It tries to squeeze\n through any opening; it claws and bites at the bars or wire; it\n thrusts its paws out through any opening, and claws at everything\n it reaches; it continues its efforts when it strikes anything loose\n and shaky: it may claw at things within the box. It does not pay\n very much attention to the food outside, but seems simply to strive\n instinctively to escape from confinement. The vigour with which it\n struggles is extraordinary. For eight or ten minutes it will claw,\n and bite, and squeeze incessantly.... The cat that is clawing all\n over the box in her impulsive struggle will probably claw the string,\n or loop, or button so as to open the door. And gradually all the\n other non-successful impulses will be stamped out, and the particular\n impulse leading to the successful act will be stamped in by the\n resulting pleasure, until, after many trials, the cat will, when put\n in the box, immediately claw the button or loop in a definite way....\n Starting, then, with its store of instinctive impulses, the cat hits\n upon the successful movement, and gradually associates it with the\n sense-impression of the interior of the box until the connection is\n perfect, so that it performs the act as soon as confronted with\n the sense-impression.... Previous experience makes a difference\n in the quickness with which the cat forms the associations. After\n getting out of six or eight boxes by different sorts of acts, the\n cat\u2019s general tendency to claw at loose objects within the box is\n strengthened and its tendency to squeeze through holes and bite\n bars is weakened; accordingly it will learn associations along the\n general line of the old more quickly. Associations between licking\n or scratching and escape are similarly established, and there was\n a noticeable tendency to diminish the act until it becomes a mere\n vestige of a lick or scratch. After the cat gets so that it performs\n the act soon after being put in, it begins to do it less and less\n vigorously. The licking degenerates into a mere quick turn of the\n head with one or two motions up and down with tongue extended.\n Instead of a hearty scratch, the cat waves its paw up and down\n rapidly for an instant.\u201d\n\nSuch experiments carried out on a different method give results in line\nwith my own. The conditions are, however, somewhat unnatural, which\nI regard as in some respects a disadvantage. But we need experiments\non different methods--the more the better,--and if the results they\nfurnish are in accord, their correctness will be rendered the more\nprobable. It is to be hoped that Dr. Thorndike will devise further\nexperiments in which (1) the conditions shall be somewhat less strained\nand straitened, while the subjects are in a more normal state of\nequanimity (cannot \u201cutter hunger\u201d be avoided?), and (2) there shall\nbe more opportunity for the exercise of rational judgment, supposing\nthe faculty to exist. To establish the absence of foresight in the\nprocedure of the cats, it is surely necessary so to arrange matters\nthat the connections are clearly open--nay, even obvious--to the eye of\nreason. It appears that this consideration has not weighed sufficiently\nwith Dr. Thorndike.\n\nA series of experiments were made to ascertain whether instruction\n(in the form of putting the animal through the procedure requisite\nfor a given act) was in any degree helpful. The conclusion is that\nsuch instruction has no influence. Those who have had experience in\nteaching animals to perform tricks will probably agree here--though\nsome trainers give expression to a different opinion. It is, however,\nessential to distinguish carefully between showing an animal how a\ntrick is done, and either stimulating its attention or furnishing\naccessory guidance (such as the occasional taps of the trainer\u2019s whip\nwhen he wants a performing horse to kneel), or affording suitable\nconditions the results of which temporarily enter into the association\ncomplex. If the latter be eliminated the practice of trainers, I\nbelieve, bears out the general result of the experiments. Dr. Thorndike\nnever succeeded in getting an animal to change its way of doing a thing\nfor his. Nor was I, after repeated trials, able to modify the way in\nwhich my dog lifted the latch of the gate. He did it with the back\nof his head. I could not get him to do it (more gracefully) with his\nmuzzle.\n\nIt may be said that the remarkable feats of performing animals imply\nthe existence of faculties of a higher order than Dr. Thorndike and\nI are prepared to admit on the basis of our experiments. Mr. P. G.\nHamerton many years ago described[64] how, in his own house, a cleverly\ntrained dog would fetch in their right order the letters which spelt\nthe English or German equivalents of common French words, and do other\nwonderful things. But the owner of the dog (M. du Rouil) admitted that\nthere was a means of rapport between them which he was not prepared to\ndivulge. It is just because the trainer has to lead up to and utilize\nchance experiences that such prolonged patience and care are required.\nThe animal is but the instrument on which his clever trainer plays;\nan instrument of wonderful intelligence, but lacking in the higher\nrational faculty. The organized scheme is the master\u2019s, not that of his\nwilling slave. A rational being might not do more wonderful things; but\nhe would learn them more rapidly and by a less wearisome method. As it\nis, the clever performing dog originates little or nothing, and repeats\nagain and again the same stereotyped behaviour, which--if one witnesses\nthe performance often--touches one with a profound sense of its lack of\nrational spontaneity.\n\nAs at present advised, therefore, I see no reason for withdrawing\nfrom the position provisionally taken up. The utilization of chance\nexperience, without the framing and application of an organized\nscheme of knowledge, appears to be the predominant method of animal\nintelligence.\n\nOn this view, then, we may see in instinctive behaviour, and the\nmultifarious automatic acts of animals, a means of providing\nexperience of the right kind and on profitable lines. We may see in\nthe play-instincts of the young a training ground for the more serious\nbusiness of animal life--a theme developed by Professor Groos. We\nmay see in the imitative tendency--the innate proclivity to follow\na lead blindly and at first unintelligently--a further means of\nproviding those useful items of experience which intelligence finds so\nserviceable. And we may see in the intelligence which can profit by\nchance occurrences that arise in these several ways all that suffices\nfor the simple needs of animal existence.\n\nWith some differences of opinion Dr. Thorndike and I have much in\ncommon in the conclusions to which we have been independently led\nas to the method and limits of animal intelligence. We seem to be\nin essential agreement in the belief that the method of animal\nintelligence is to profit by chance experience without rational\nforesight, and that unless such experience be individually acquired,\nthe data essential for intelligent progress are absent. While in our\nattempts to realize the general nature of animal consciousness there\nis a close similarity of treatment. In my \u201cIntroduction to Comparative\nPsychology\u201d a good deal of space is devoted to an analysis of the\npsychology of skill \u201cin order that we may infer what takes place in\nthe minds of animals;\u201d and I said:--\u201cWhen I am playing a hard game of\ntennis, or when I am sailing a yacht close to the wind in a choppy\nsea, self does not at all tend to become focal. Hence, though I am a\nself-conscious being I am not always self-conscious. And presumably\nwhen I am least self-conscious, I am nearest the condition of the\nanimal at the stage of mere sense experience. I am exhilarated with the\nsense of pleasurable existence, my whole being tingles with sentient\nlife. I sense, or am aware of, my own life and consciousness, in an\nunusually subtle manner. Experience is vivid and continuous. Such I\ntake it to be the condition of the conscious but not yet self-conscious\nanimal.\u201d\n\nI can therefore cordially endorse Dr. Thorndike\u2019s conclusions as\nexpressed in the following passages:--\n\n\u201cOne who has watched the life of a cat or dog for a month or more under\ntest conditions, gets, or fancies he gets, a fairly definite idea of\nwhat the intellectual [intelligent] life of a cat or dog feels like. It\nis most like what we feel when consciousness contains little thought\nabout anything, when we feel the sense-impressions in their first\nintention, so to speak, when we feel our own body, and the impulses\nwe give to it. Sometimes one gets this animal consciousness while in\nswimming, for example. One feels the water, the sky, the birds above,\nbut with no thoughts about them or memories of how they looked at other\ntimes, or \u00e6sthetic judgments about their beauty; one feels no ideas\nabout what movements he will make, but feels himself make them, feels\nhis body throughout. Self-consciousness dies away. Social consciousness\ndies away. The meanings, and values, and connections of things die\naway. One feels sense-impressions, has impulses, feels the movements he\nmakes; that is all.\u201d\n\nAnd after an illustration from such a game as tennis, Dr. Thorndike\nadds: \u201cFinally the elements of the associations are not isolated.\nNo tennis-player\u2019s stream of thought is filled with free-floating\nrepresentations of any of the tens of thousands of sense-impressions\nor movements he has seen and made on the tennis-court. Yet there\nis consciousness enough at the time, keen consciousness of the\nsense-impressions, impulses, feelings of one\u2019s bodily acts. So with the\nanimals. There is consciousness enough, but of this kind.\u201d\n\nIt may be said that between the method of intelligence and that of\nfully developed rational procedure there is a wide gap which must\nhave been bridged in the course of mental evolution. Unquestionably.\nAnd in contending that the methods of the animal are predominantly\nintelligent, I am far from wishing to assert dogmatically that in no\nanimals are there even the beginnings of a rational scheme. Indications\nthereof do not indeed at present appear to have been clearly disclosed\nby experiment. But the experimental development of the subject is still\nin its infancy. We shall probably have to await the further results\nwhich must be the outcome of patient and well-directed child-study.\nThe human child does pass in the course of his individual development\nfrom intelligent to rational procedure. Here there is a bridge which\nis crossed by every child. When we know more about the stadia of this\ndevelopment we shall be in a position to apply the results obtained in\nchild-study in the analogous field of animal-study. Till then we must\npossess our souls in patience, and base our provisional conclusions on\nthe results of systematic investigation, rather than on those of casual\nobservation and anecdote.\n\n\nIV.--THE EVOLUTION OF INTELLIGENT BEHAVIOUR\n\nNo attempt can be made in this section to trace the successive stages\nof the evolutionary progress of intelligence from its lower to its\nhigher developments. It is indeed questionable whether comparative\npsychology has, as yet, accumulated a sufficient body of data to render\nsuch a task profitable or even possible. And the lower the level of\nintelligence with which we have to deal, the less reliable are the\nscanty psychological data which we can obtain. To interpret the mental\nprocesses which accompany the acts of even the higher animals is a\nhard task, requiring careful psychological analysis. Still harder is\nthe task to infer the psychological basis of the actions of the lower\nanimals.\n\nIt is difficult to say where, in the hierarchy of animal progress, the\nbeginnings of intelligence can first be traced. In the articulated\nanimals, such as the insects, spiders, and crustacea, there is abundant\nevidence of intelligence of a relatively high grade. But even in their\ncase, how hard it is to realize the nature of their experience--to\nget any adequate notion of their mental processes! We are inevitably\nforced to describe their psychology in the most general terms. So, too,\nwith forms still lower in the scale of intelligence. Many molluscs\nunquestionably profit by experience. But can we clearly picture to\nourselves the nature and manner of acquisition of this experience? The\nway in which limpets return to the scars on the rock which form their\nhomes seems to show that they have acquired a practically adequate\nexperience of their near surroundings. Romanes cites[65] some of the\nearlier observations which have been extended by Professor Ainsworth\nDavis.[66] I looked into the matter myself some years ago, at Mewps Bay\nnear Lulworth in Dorsetshire. The method adopted[67] was to remove the\nlimpets from the rock, and affix them at various distances from their\nscars. This can be done without difficulty or injury to the mollusc if\none catches them as they are moving. But one must make sure that they\nare just leaving or returning to their proper homes, and are not taken\nin the midst of a more extended peregrination, as in that case their\nspecial scars cannot be noted. Failure to be careful in this matter\nvitiated my earlier observations, which are therefore excluded in the\nfollowing table:--\n\n ---------+------------+------------------------------------+\n Number | Distance | Number returned. |\n removed. | in inches. +-------------+-------------+--------+\n | | In 2 tides. | In 4 tides. | Later. |\n ---------+------------+-------------+-------------+--------+\n 25 | 6 | 21 | -- | -- |\n 21 | 12 | 13 | 5 | -- |\n 21 | 18 | 10 | 6 | 2 |\n 36 | 24 | 1 | 1 | 3 |\n ---------+------------+-------------+-------------+--------+\n\nFrom the nature of the rock surfaces the removal of a limpet to a\ndistance of two feet almost invariably involved placing them on the\nfurther side of an angle. And though some returned over such an angle,\nthe majority did not.\n\nIn most cases the individuals which failed to return to their\nrespective scars took up new positions; and in several instances, when\nthey were subsequently removed to a distance of a few inches from this\nnew position, they returned to it. Their return to the scar was watched\nin many cases, and the course was fairly, but not quite direct. One\nlimpet covered a distance of ten inches, over a somewhat curved course,\nin a little under twenty minutes. In another case the limpet on its\nreturn journey had to pass between two others, which necessitated the\nlifting of the shell to some height so as to clear one of them. On\nreaching the scar they twist and turn about so as to fit down in the\nnormal position which is constant. When they come up the wrong way\nround they rotate pretty rapidly through the 180 degrees to get into\nposition. One was observed to make a short excursion from and return to\nits scar under stillish water. But as a rule they seem to remain fixed\nwhen they are submerged, moving for the most part when the tide has\njust receded.\n\nThe greatest distance I have watched a limpet reach from its home was\ntwenty-two inches. But I have found them at a distance of three feet\nfrom their scars--that is to say, from those to which they fitted\nperfectly. This was on a large flat surface.\n\nWhen they move, the tentacles are projected out beyond the shell, and\nkeep on touching and slightly adhering to the rock. On reaching the\nscar they carefully feel round it with the tentacles. By excision\nof these feelers Professor Davis was led to conclude that it is not\nthrough their instrumentality that the limpet finds its way back to its\nparticular scar. But I am inclined to question these results. At any\nrate, further observations and experiments are needed to settle the\npoint.\n\nSnails will also return to special dark hollows or crannies in the\nwall after their foraging excursions. Such behaviour in molluscs\naffords evidence of something more than instinct. In popular speech,\nwe should say that there is memory of the locality. And in any case\nit is difficult to interpret the facts without the assumption that\nthe animals are conscious, and that re-presentative states are\nevoked through the mediation of presentative sense-impressions. But\nhow difficult, if not impossible, it is to form anything like a\nsatisfactory conception of the rudimentary mental processes of a limpet!\n\nThe most highly developed molluscs are the cephalopods. They have\nlong sensitive mobile arms with which they feel for and capture their\nprey. \u201cNow Schneider observed,\u201d writes Dr. Stout,[68] \u201ca very young\noctopus seize a hermit-crab. The hermit-crab covers the shell in which\nit takes up its abode with stinging zoophytes. Stung by these, the\noctopus immediately recoiled and let its prey escape. Subsequently it\nwas observed to avoid hermit-crabs. Older animals of the same species\nmanaged cleverly to pull the crab out of its house without being\nstung.\u201d Such cases afford evidence of profiting by experience through\nthe exercise of intelligence.\n\nDarwin\u2019s careful observations on the manner in which earthworms\ndrag leaves into their burrows seem to show that these annelids act\nintelligently, and deal with leaves of different shapes in different\nways. The leaves of Pine trees, consisting of two needles arising\nfrom a common base, were almost invariably drawn down by seizing this\nbasal point of junction; while the leaves of the Lime were, in 79\nper cent. of the cases examined, drawn down by the apex; in only 4\nper cent. by the base; and in the remaining 17 per cent. by seizing\nsome intermediate portion. On the other hand, the leaves of the\nRhododendron, in which the basal part of the blade is often narrower\nthan the apical part, were in 66 per cent. of the observations drawn\ndown by the narrower base. Triangles of paper were in the majority of\ncases seized by the apex. Commenting upon his observations, carried\nout with great care under experimental conditions, Darwin says,[69]\n\u201cAs worms are not guided by special instincts in each particular case,\nthough possessing a general instinct to plug up their burrows, and as\nchance is excluded, the next most probable conclusion seems to be that\nthey try in different ways to draw in objects, and at last succeed\nin some one way;\u201d that is to say, they profit by experience based on\nthe method of trial and failure. But Darwin adds that the evidence he\nobtained shows \u201cthat worms do not habitually try to draw objects into\ntheir burrows in many different ways.\u201d And he seems to attribute to\nthem an almost rational power of dealing with the circumstances in the\nlight of general conceptions. \u201cIf worms,\u201d he says, \u201care able to judge,\neither before drawing or after having drawn an object close to the\nmouths of their burrows, how best to drag it in, they must acquire some\nnotion of its general shape. This they probably acquire by touching it\nin many places with the anterior extremity of their bodies, which acts\nas a tactual organ. It may be well to remember how perfect the sense of\ntouch becomes in a man when born blind and deaf, as are worms. If worms\nhave the power of acquiring some notion, however rude, of the shape of\nan object and of their burrows, as seems to be the case, they deserve\nto be called intelligent; for they then act in nearly the same manner\nas would a man under similar circumstances.\u201d\n\nSuch power of perceiving the relation of the shape of a leaf or other\nobject to the form of the burrow is presumably beyond the reach of\nan earthworm. It may be regarded as more probable that the earthworm\ninherits an instinctive tendency to draw down objects in special\nways, and that this is subject to some modification under the play\nof experience, without the formation of anything so psychologically\ncomplex as a general notion, however rude. In any case the behaviour\nof earthworms in closing their burrows seems to afford indications\nof something more than instinct--of that profiting by the results of\nexperience which characterizes intelligent procedure. More than this we\ncannot say.\n\nProfessor Whitman[70] has made some interesting observations on\nthe leech _Clepsine_. \u201cPlace the animal,\u201d he says, \u201cin a shallow,\nflat-bottomed dish, and leave it for a few hours or a day, in order\nto give it time to get accustomed to the place, and come to rest\non the bottom. Then, taking the utmost care not to jar the dish or\nbreathe upon the surface of the water, look at the _Clepsine_ through\na low magnifying lens, and see what happens when the surface of the\nwater is touched with the point of a needle held vertically above the\nanimal\u2019s back. If the experiment is properly carried out, it will be\nseen that the respiratory undulations (if such movements happen to be\ngoing on) suddenly cease, and that the animal slightly expands its body\nand hugs the glass. Wait a few moments until the animal, recovering\nits normal composure, again resumes its respiratory movements. Then\nlet the needle descend through the water until the point rests on the\nbottom of the dish at a little distance from the edge of the body.\nAgain the movements will cease, and the animal will hug the glass with\nits body somewhat expanded. Now push the needle slowly along towards\nthe leech, and notice as the needle comes almost in contact with the\nthin margin of the body, that the part nearest the needle begins to\nretreat slowly before it. This behaviour shows a surprising keenness of\ntactile sensibility, the least touch of the water with a needle-point\nbeing felt at once.... If its back were rubbed with a brush or the\nhandle of a dissecting needle, in order to test its sensitiveness to\ntouch, the appearance would probably be that of insensibility and\nindifference to the treatment. Closer examination, however, would\nshow that the flesh of the animal was more rigid than usual, and that\nthe surface was covered with numerous stiff, conical elevations, the\ndermal papill\u00e6 or warts, which are so low and blunt in the normal\nstate of rest as to be scarcely visible. It would be seen that the\nanimal, although motionless, was in a state of active resistance to\nattack.... _Clepsine_ has another and entirely different method of\nkeeping quiet. The animal rolls itself up (head first and ventral side\ninnermost) into a hard ball, outwardly passive, free to roll or fall\nwhithersoever gravity or currents of water may direct it.... If by\nchance the animal has eggs, it will not desert them to escape in this\nway.... This species, then, has two quite distinct and peculiar ways\nof keeping quiet, and thus avoiding its enemies. If the animal has no\neggs, or if it has young, it may adopt either mode of escape, while\nif it has eggs it has no choice but to remain quiet over them.... The\nact of rolling up into a passive ball may be performed (_a_) _under\ncompulsion_, as when it is her last resort in self-defence; (_b_)\n_under a milder provocation_, as _one_ of three courses of behaviour,\nas when the resting-place is turned up to light, and the choice is\noffered between remaining quiet in place, creeping away at leisure,\nor rolling into a ball and dropping to the bottom; (_c_) or finally,\n_under no special external stimulus_, but rather _from internal_\nmotive, the normal demand for rest and shady seclusion, presumably very\nstrong in _Clepsine_ after gorging itself with the blood of its turtle\nhost.\u201d\n\nProfessor Whitman rightly regards the act of rolling into a ball as\ninstinctive, and due to natural selection. But he does not undertake\nto discuss the question as to how much intelligence, if any,\n_Clepsine_ may have. Nor, indeed, is it an easy matter to determine.\nThe differential reaction according as the animal has eggs or not\nsuggests intelligence; but it may be instinct varying according to\nthe conditions of stimulation external and internal. The different\nbehaviour which may be seen in different cases when a stone is turned\nto the light again suggests intelligence, but again may be determined\ndirectly by the conditions of stimulation. Prompted by Dr. Whitman\u2019s\nobservations, I endeavoured to determine whether a leech would grow\naccustomed to frequent gentle stimulation with a camel\u2019s-hair brush,\nand cease to react under circumstances which were followed by no ill\neffects. But though I incline to think that this is the case, the\nobservations were not such as to be satisfying and convincing. If\nintelligence be present we seem to find it in an early and rudimentary\nstate.\n\nObservation, we must confess, seems to afford little indication of the\nconditions under which intelligence first makes its appearance in the\nanimal kingdom. And if we turn to general considerations, which at the\nbest afford uncertain guidance, little light is thrown on the subject.\nIf we accept the view already indicated,[71] that the nerve-centres\nwhich are concerned in the conscious control begotten of experience\nare independent of those primarily concerned in normal reflex action,\nwe may perhaps believe that the simplest nervous system, worthy of\nthe name, contains both these elements, and that in the course of the\nevolution of nervous systems in higher and higher grades, there go on\n_pari passu_ the further differentiation of these elements, and the\nprogressive integration of reflex and control centres into a closely\nconnected and effective whole. Not that any expression of the facts, if\nsuch they be, in terms of an evolution formula, adds anything to our\nknowledge of the organic _modus operandi_. We know but little of the\nintimate nerve physiology of even the highest invertebrates. We see\nample evidence of the control of behaviour in the light of individual\nexperience. Of any detailed knowledge concerning the manner in which\nthis control is effected we do not seem to possess more than the rude\ninitial phases.\n\nWhen we compare, however, the several grades of intelligence which\nobservation suggests, and when we watch the conscious development of\nthe more intelligent animals, we seem to find evidence of the growth\nof a system of experience, at first in very close touch with inherited\nmodes of procedure, but gradually acquiring more of independence and\nfreedom. Increase of the range and complexity of behaviour brings\nwith it, not only increase in the range and complexity of experience,\nbut also--what is, perhaps, even more essential to effective\nprogress--greater unity and closer connection into a well-knit whole.\nAnd with this greater unity and closer connection there goes what one\nmay term a condensation of experience by an elimination of detail and\nthe survival of essential features repeatedly emphasized. This is\nanalogous in the development of intelligence to the generalization\nand abstraction which play so important a part in the development of\nreason. It affords, in fact, the data which reflection utilizes in the\npurposive and intentional condensation and concentration of knowledge\nat a higher stage of mental development.\n\nThe omission of detail and the survival of the salient features is well\nknown to us in the familiar facts of memory. We have seen thousands\nof sheep and oxen, no two of which are probably alike in all their\nexternal details as presented to vision. But we remember what a sheep\nor an ox looks like, and many of us can form a visualized image of\neither of these animals. This, however, is not the re-presentative\nimage of any particular sheep or ox. It is what psychologists term a\ngeneric image. It is like a composite photograph made by superimposing\non the same plate a number of individual images so that the salient\nfeatures which all possess in common stand out clearly by their\ncoincidence on the plate, while the distinctive details are but\ndimly presented. Thus does memory preserve the essentials common\nto many impressions while the distinguishing details are lost and\nfade, eliminated by forgetfulness. And thus in the experience which\nintelligence practically utilizes are the net results of a thousand\nparticular impressions condensed in one effective image.\n\nCondensation of experience is also effected by the elimination, under\nthe guidance of consciousness, of those modes of behaviour which are\nnot efficacious--a process to which Professor Mark Baldwin applies\nthe phrase Functional Selection. There is a tendency at first to the\noverproduction of relatively useless actions. The multifarious random\nmovements of the human infant, though their inexactness renders the\nchild terribly helpless, afford a wide store of plastic material which\nintelligence can guide to its appropriate use. And the prolonged period\nof pupilage in the child is correlated with an unsurpassed range of\ncombination and recombination of the abundant plastic material. The\nhereditary legacy, though it contains fewer drafts for definite and\nspecific purposes than are placed to the credit of an animal rich in\ninstinctive endowment, affords a far larger general fund on which\nintelligence may draw for the varied purposes of the freer financial\nexistence of a rational being.\n\nThe relatively helpless young of many of the higher mammalia exhibit\nalso much overproduction of seemingly aimless movements. But from\nthese intelligence selects those which are of value for the purposes\nof life--those which experience proves to be effective. These--the\nrelatively few--afford the motor impressions which by repetition stand\nout in experience, while the rest lapse from memory and are eliminated\nfrom experience as they are eliminated from practical performance. This\nis a great gain. Motor experience is rendered generic; the composite\nimage that is retained is the net result of effective behaviour; and\nall that is valuable in the acquisitions of early life is condensed\nwithin manageable limits.\n\nThis process of rendering generic the particular items of a widening\nexperience has a marked effect in the development of the conscious\nsituations in the light of which behaviour is intelligently guided.\nIt is not the master holding this whip or that ball which suggests\nto the dog a hiding or a scamper; it is a generic situation with\ninterchangeable details. It is not this, that, or the other previously\nunseen cat that at once determines the situation for the fox terrier;\nthe particular animal has never entered into his past experience: it is\nthe fulfilment of the essential conditions of the generic image that\nis operative in behaviour. The experience of animals must inevitably\nbecome in large degree generic by the elimination of the unessential\nand survival in re-presentative consciousness of the salient elements\nin many slightly diverse situations.\n\nStated in terms of this conception, the familiar phenomena of mimicry\nare due to the fact that the mimicking form accords sufficiently well\nwith the generic image to carry the same suggested meaning. As is\nwell known, the model has been proved in many cases to be unpalatable\nor hurtful, while the mimic is in itself neither the one nor the\nother. The drone-fly, _Eristalis_, mimics the drone. And it has been\nurged that this cannot be a true case of mimicry, since the drone\nis harmless, though the female and \u201cneuter\u201d bees are possessed of\nstings. But I have satisfied myself by experiments with young birds,\nthat (1) after experience with bees drones are avoided, and (2) that\nafter similar experience drone-flies are also left untouched. Hence it\nseems that all three fall within the same generic image, the points of\nresemblance outweighing the differences in detail--as they do, indeed,\nwith many men and women.\n\nSuch examples of mimicry belong to what is known as the \u201cBatesian\ntype\u201d--so called after H. W. Bates, who, in 1861, discussed its\noccurrence among Amazonian insects in the light of the theory of\nnatural selection. There are, however, certain groups of insects\nwhich, although themselves \u201cprotected,\u201d possess common warning\ncolours, causing them to resemble each other. These are sometimes\nclassed under the head of \u201cM\u00fcllerian mimicry\u201d--so called after Fritz\nM\u00fcller, who, in 1879, first offered an explanation of the facts\nbased on the theory of natural selection. He suggested that such\nmutual resemblance is advantageous to both protected forms, since it\nlessens the number of those which are killed by young birds and other\nanimals while they are learning by experience what to eat and what\nto leave. For, as the result of careful observation, Mr. Frank Finn\nconcludes \u201cthat each bird has to separately acquire its experience,\nand well remembers what it has learnt,\u201d--a conclusion with which, as\nalready stated, my own observations are entirely in accord. There is\ntherefore a certain amount of destruction of even well-protected forms\nby young and inexperienced birds. If, then, two such forms resemble\neach other, the acquisition of experience is thereby facilitated and\nthe amount of destruction reduced, on the assumption that the two\nfall within the same generic image. Upholders of natural selection\nare not, indeed, at one in accepting this explanation, and further\nobservation is unquestionably needed. It is not improbable, however,\nthat common protective coloration, such as the banding of yellow and\nblack, seen in such different forms as the caterpillar of the cinnabar\nmoth and the imago of the wasp, is of mutual utility. The following\nexperiment was made with young chicks. Strips of orange and black paper\nwere pasted beneath glass slips, and on them meal moistened with\nquinine was placed. On other plain slips meal moistened with water\nwas provided. The young birds soon learnt to avoid the bitter meal,\nand then would not touch plain meal if it were offered on the banded\nslip. And these birds, save in two instances, refused to touch cinnabar\ncaterpillars, which were new to their experience. They did not, like\nother birds, have to learn by particular trials that these caterpillars\nare unpleasant. Their experience had already been gained through the\nbanded glass slips; or so it seemed. I have also found that young birds\nwho had learnt to avoid cinnabar caterpillars left wasps untouched.\nSuch observations must be repeated and extended. But they seem to show\nthat one aspect of the M\u00fcllerian theory is not without some facts in\nsupport of it; and, so far as they go, they afford evidence that black\nand orange banding, irrespective of particular form, may constitute a\nguiding generic feature in the conscious situation.\n\nIt may be said that the generic condensation of experience here\nindicated implies the formation of general and abstract ideas, and\nthat we cannot in face of the evidence accept Locke\u2019s dictum that\nabstraction is \u201can excellency which the faculties of brutes do by no\nmeans attain to.\u201d Romanes contended[72] that \u201call the higher animals\nhave general ideas of \u2018good-for-eating\u2019 and \u2018not-good-for-eating\u2019 quite\napart from any particular objects of which either of these qualities\nhappens to be characteristic,\u201d and he quoted with approval Leroy\u2019s\nstatement,[73] that a fox \u201cwill see snares when there are none; his\nimagination, distorted by fear, will produce deceptive shapes, to\nwhich he will attach an abstract notion of danger.\u201d According to such\nviews animals form concepts; and concepts belong to the sphere of\nrational thought. It is not my intention to enter at length into the\nrefinements of psychological distinction. Many psychologists, however,\nseek to distinguish between, on the one hand, the predominance by\nnatural emphasis, of certain qualities, such as that of being suitable\nfor food, and, on the other hand, the intentional isolation of these\nqualities for the purposes of thought and rational explanation.\nAbstraction they regard as a deliberate process applied with rational\nintent to the material afforded by experience and reflection.\nGeneralization, too, they regard as deliberate, and carried out with\nlike intent. The result is not merely a composite or generic product,\nbut something more subtle and less dependent on sense. \u201cAll trees\nhitherto seen by me,\u201d said Noir\u00e9, \u201cleave in my imagination a mixed\nimage, a kind of ideal presentation of a tree. Quite different is my\nconcept, which is never an image.\u201d The concept \u201ctree\u201d is a deliberate\nsynthesis of abstract qualities intentionally isolated, and recombined\nin accordance with the general relationships which subsist between them.\n\nIf we accept this distinction, if we regard abstraction and\ngeneralization as intentional mental processes carried out with the\nrational intent of discovering the relationships of phenomena with the\nobject of explaining them and recombining their essential features in\nan ideal scheme of thought, we shall probably admit, with John Locke,\nthat these are excellencies which the faculties of brutes do by no\nmeans attain to. But we shall none the less see that the predominance\nof certain salient features in experience by reiterated emphasis in\nassociation with natural needs, and the development of generic in place\nof merely particular re-presentations will afford the appropriate\nmaterial for abstraction on the one hand, and generalization on the\nother. Intelligence supplies the embryonic mental structures from\nwhich, under the quickening influence of a rational purpose, abstract\nand general ideas may be evolved.\n\nThe essential features of the evolution of intelligence seem, then,\nto be, first, the development of controlling nerve-centres, by which\nthe responsive action of reflex automatic or instinctive centres\nmay be checked, augmented, or modified; secondly, the increased\ndifferentiation and integration of these control centres with extension\nof the range and complexity of experience in close touch with practical\nneeds; thirdly, the condensation and concentration of experience by\nthe formation of generic products through the reiterated emphasis\nbegotten of recurrent situations having certain salient features\nin common, though differing in details; and fourthly, an increased\nplasticity of behaviour, especially in early life, enabling an animal\nto deal effectually with an environment far less simple than that\nto which the more stereotyped instinctive behaviour is fitted by\ninheritance to respond. And this evolution of intelligent behaviour is\nworking its way up to, though as such it cannot reach, the succeeding\nphase of mental evolution in which the data, supplied by intelligence,\nare treated with a new purpose for higher ends in the rational thought\nwhich seeks to explain the phenomena, and frame an ideal scheme of\ntheir relations and interconnections.\n\nTwo further points may be noticed. First, that it is during the early\nand plastic days or months of life that intelligence is setting\nits seal on animal behaviour, and stamping it with its distinctive\ncharacter. Adult life is very much what youth has made it; and old\nage is stereotyped through habit. In times of progress, the character\nof the race is determined by plastic possibilities of the young.\nAmong them it is that the incidence of elimination makes itself felt,\nresulting in the survival of those whose intelligence can mould\nbehaviour in accordance with the new circumstances of a wider life.\n\nSecondly, this selection of the intelligent involves the survival\nof those in whose higher brain-centres there is room for a greater\nrange and variety of interconnection by means of associating fibres.\nIt involves a selective survival of the larger and more finely\norganized brains. It is probable, as Professor Ray Lankester has\nrecently indicated, that the ridiculously small-brained mammals and\nreptiles of the past were creatures of instinct with little capacity\nfor intelligent control. Their lives were simple, and their enemies\nand competitors no better provided with higher brain-centres than\nthemselves. Stereotyped instinctive behaviour sufficed to enable them\nto hold their own, and meet the requirements of a life of dull and\nunprogressive monotony. Strength without cunning made these big-framed\nanimals for a while masters of the situation. But among those existing\nanimals whose skeletons indicate an analogous zoological position,\nthere is none which exhibits a cerebral development so poor. And we\nmay fairly conclude that the fact that these huge creatures have left\nno lineal descendants may be taken as evidence of the importance and\nvalue, in evolution, of that cerebral tissue which is the organic basis\nof intelligence. The higher brain contains the potentiality of that\nexperience without which the evolution of intelligent behaviour in any\nrace of vertebrate animals is impossible.\n\n\nV.--THE INFLUENCE OF INTELLIGENCE ON INSTINCT\n\nWe have seen that the relation of instinct to intelligence is\nessentially that of congenital to acquired behaviour. We have seen,\ntoo, that in the Lamarckian interpretation what is acquired in the\ncourse of life may be transmitted through inheritance, and thus the\nintelligent behaviour of one generation may become instinctive and\ncongenital in the next. But serious biological difficulties stand in\nthe way of the acceptance of this interpretation; there is, moreover,\nlittle or no evidence of the assumed transmission to offspring of any\nacquired modifications of structure or behaviour. We have, therefore,\nbeen led to infer that instinctive behaviour has been evolved through\nthe selection of adaptive variations of germinal origin, the influence\nof intelligence being restricted to the fosterage of co-incident\nvariations, that is to say, of those congenital variations which\ncoincide in direction with the acquired modifications of behaviour due\nto intelligence. It is clear that on this interpretation the influence\nof intelligence on instinct is more indirect and less simple than that\nimplied by the Lamarckian hypothesis. Intelligence and instinct are\nin large degree independent, though there is continual interaction\nbetween them. We have now to consider the nature of this interaction,\nand to this end we must indicate the relation of acquired modifications\nto the hereditary groundwork of the animal constitution.\n\nThe basal fact is, that the bodily tissues are subject to a certain\namount of structural change during the course of individual life in\naccordance with the amount of functional strain put upon them. The\nlabourer\u2019s thickened skin, the enlarged and strengthened muscles of\nthe athlete, the juggler\u2019s acquired suppleness are familiar cases.\nLess familiar instances are afforded under abnormal conditions.\nShould one kidney from any cause be slowly destroyed, the other will\nslowly enlarge to carry on the increased work of elimination of waste\nproducts; when the larger shin bone of a dog has been removed after\ninjury, the smaller bone becomes thickened to bear the added strain;\nnew joint surfaces are sometimes formed where bones have been broken\nand the natural joints injured.\n\nOne may say that the normal development of any structure depends upon\na due amount of use. But, since in the course of strenuous life any\norgan is from time to time subject to an abnormal amount of strain, it\nmust be fitted to respond to a super-normal call on its strength and\nfunctional activity. Were the heart and the lungs, for example, unable\nto meet the greatly added drain on their energies, due to unwonted\nand severe exertion, collapse, perhaps death, would ensue if such\nexertion were imperatively demanded under special circumstances. And\nit is clear that many wild animals must be not infrequently placed in\nsuch circumstances as will subject their muscular structures and the\nfunctional activity of their organs of circulation and respiration to a\nstrain nearly up to their extreme limits of endurance. The carnivorous\nhunter would often fail to secure his prey if his organization were\nunequal to a hard and prolonged chase; the hunted prey would not\nsurvive to procreate his kind if he fell a victim to the first pursuer\nthrough inability to stand the exertion necessary to enable him to\nmake good his escape. It is thus, we may believe, through natural\nselection that a sufficiently high standard of strength and functional\nendurance is maintained. The failures in these respects are steadily\neliminated. It is difficult to realize the great strain put upon a\nbird\u2019s organization by the migration flight. Some ten times as many\nbirds leave our shores in the autumn as return to them in the following\nspring. What proportion of these is weeded out in the act of migration\nwe do not know; but we may be sure that only those fitted to stand a\nsevere test of physical endurance return to rear broods which shall\ninherit in large degree similar vigour of constitution.\n\nTwo factors, then, determine the limits of efficiency in the bodily\norgans--heredity and use. And these two co-operate in such a way\nthat we may say, either that due use is the essential condition of\nthe effective development of the hereditary powers, or that heredity\nserves to condition their effective development through use. But though\nclosely related, so that each may be regarded as conditional on the\nother, they are, if we accept the view that acquired characters are not\ntransmitted as such, so far independent in that use adds nothing to,\ndisuse subtracts nothing from, the hereditary store. It is, indeed,\ndifficult to conceive how, on any view, the absence of the conditioning\nfactor of normal use can be the efficient cause of a positive\ndiminution of the balance at the bank of heredity. And Lamarckian\nthinkers have not succeeded in placing their conception of the matter\nin the clear light of a working hypothesis.\n\nThe amount of what we may term \u201cmodifiability\u201d by use differs a good\ndeal in the several organs and tissues. The teeth of carnivora and the\nantlers of deer may be cited as structures in which the conditioning\neffects of use form a relatively unimportant factor. On the other\nhand, the nervous system, with which we are here primarily concerned,\nis of all animal structures that in which what is acquired may attain\nthe greatest importance in the successful conduct of life; the nature\nand the range of behaviour affording an index of the amount of\nmodifiability in this respect.\n\nWe have already seen that instinctive behaviour is primarily a matter\nof the first occasion on which any given action is performed, and that\nmany instinctive acts are subject to subsequent modification in the\nlight of the experience gained during the early performances. The range\nof such modification varies both in different animals and also with\nrespect to different modes of behaviour in the same animal. The more\nfixed and deeply rooted an instinct the less readily does intelligence\nobtain a hold on it, so as to direct the behaviour into new channels\nof better accommodation to the circumstances. M. Fabre describes how\na _Sphex_, one of the solitary wasps, instinctively draws its prey, a\ngrasshopper, into the burrow by its antenn\u00e6. When these were cut off\nthe wasp pulled the grasshopper in by the jaw appendages; but when\nthese were removed she seemed incapable of further accommodation to the\nunusual circumstances. It would seem an easy and obvious application\nof intelligence to seize the prey by one of the forelegs. But this\nwas not done; and the grasshopper was then left. Intelligence did\nnot seem equal to meeting the altered conditions presented by the\nmaimed grasshopper. Still, there was some modification of the normal\ninstinctive behaviour; and, as Dr. Peckham has shown, there may be more\nthan Fabre noted. Let us assume the existence of an animal whose every\nact is instinctive, whose whole behaviour is marked out in strictly\nhereditary lines, no new departures being acquired in the course of\nindividual life. This extreme case would afford an example of what we\nmay term completely stereotyped behaviour. On the other hand, let us\nassume the existence of an animal with no hereditary definiteness of\nreaction, whose every act is intelligent, whose whole behaviour is the\nresult of individual acquisition. This antithetical extreme case would\nafford an example of what we may term completely plastic behaviour.\nIt is questionable, however, whether either of these extreme types\noccur in nature. What we find in our study of animal behaviour is\nsome intermediate condition in which both factors co-operate, with a\npredominance either of stereotyped instinctive response on the one\nhand, or of plastic intelligent acquisition on the other hand. And in\nthe latter case, as such behaviour approaches its ideal limits, we have\nmodifiability under the circumstances of individual life at its maximum.\n\nThe evolution of intelligence as such runs parallel with the evolution\nof plastic behaviour; and this plasticity is necessitated by the\nvariety and the complexity of the conditions of life--a variety and a\ncomplexity requiring many subtle modifications of response to enable\nthe behaviour to reach accommodation to the changeful exigencies of\ndiverse circumstances. To meet constant and relatively fixed conditions\nstereotyped instinctive responses suffice; and the elimination under\nnatural selection of those individuals which fail to respond in fixed\nways by specially adaptive behaviour tends to render definite the\nhereditary channels of nervous intercommunication. An inherited system\nof no little complexity may thus be evolved; of which we have seen\nexamples in our study of instinctive behaviour. But the essential\ncondition of the successful working of such a system is constancy\nin the environment to which the instinctive behaviour is adapted.\nCompletely stereotyped behaviour, in its theoretical perfection, is\nin exact adaptation to the circumstances. Where instincts are only\nrelatively perfect, further adaptation is secured through congenital\nvariation and the survival of the individuals in which the behaviour\nis better adapted to the comparatively invariable circumstances.\nThis is one line of evolution. But the evolution of intelligence is\nalong independent lines of progress. Both, however, result from the\nfunctional activity of the same nervous system, they jointly determine\nthe behaviour, they interact not only in the course of individual life\nbut in the process of evolution, and they are both subject to the\nincidence of natural selection, which can determine whether the one\nline or the other shall preponderate--whether instinct or intelligence\nshall dominate behaviour.\n\nIf an answer must be given to the question whether instinct or\nintelligence has priority in the course of the evolution of behaviour,\nit may be urged that, on theoretical grounds, the claims of instinct\nare the stronger. Taking animals as we actually find them, however,\nthey afford numberless examples of behaviour at first instinctive but\nsubsequently modified, in greater or less degree, in accordance with\nthe teachings of experience. Let us, first, assume that the environment\nis slowly changing, or has changed, in some definite manner. Such\nchange would, of course, be relative, and might be due, either to new\nconditions brought to bear on the animal, or to the animal being itself\nbrought, in the expansion of its life, within their influence. The\nold instinct is no longer quite adapted to the changed circumstances.\nIf the change were sufficient in amount, and occurred somewhat\nsuddenly, variations of instinct might not occur soon enough to enable\nthe animal to reach adaptation by the gradual process of natural\nselection. If dependent on instinct alone the animal would, under\nthese circumstances, be eliminated. But if intelligence were able to\nmodify the behaviour to meet the new conditions this elimination would\nbe prevented. In successive generations intelligence would constantly\nmodify behaviour in the same manner and in a definite direction.\nMeanwhile congenital variations in different directions would occur.\nThose which were in directions antagonistic to that dictated by\nintelligence would tend to thwart accommodation and render it less\neffectual; but those which were coincident in direction would conspire\nwith accommodation and render it more effectual. The individuals in\nwhich variations of instinct tended to thwart intelligence would be\neliminated; while those in which coincident variations assisted and\naided intelligent modification would survive. Thus intelligence would\nlead the way along lines which congenital variations would follow. And\nin the course of a number of generations the new instinct would reach\nthe fully adaptive level, and further modification by intelligence\nwould become unnecessary unless the environment continued to change yet\nmore. Individual accommodation of behaviour would in this way determine\nthe direction of instinctive variation; and yet throughout the process\nthere would be, strictly speaking, no transmission of the intelligently\nacquired characters of the behaviour.\n\nBut though under constant and uniform changes in the environment the\nnet result would be only a guided variation of the original instinct,\nunder more variable and indefinitely changing circumstances the\nresult would be different. The higher animals exhibit an intelligent\nplasticity which enables them to meet the requirements of the\nmore complex environment into which their wider life has risen;\nfor evolution lifts the animal from narrower into progressively\nwider spheres of activity and behaviour, so that its environment\nbecomes relatively more complex. Here stereotyped behaviour would be\nrather a hindrance than an advantage. The winning animal in life\u2019s\nstruggle would be the one in which behaviour was most rapidly and\nmost surely modified to meet particular needs--the one in which the\nteachings of experience were most promptly utilized in effective\naction. The inevitable tendency of the evolution of intelligence\nmust be disintegration of the stereotyped modes of behaviour and the\ndissolution of instinct. Natural selection, which under a uniform and\nconstant environment leads to the survival of relatively fixed and\ndefinite modes of response, under an environment presenting a wide\nrange of possibilities leads to the survival of plastic accommodation\nthrough intelligence. It is not that intelligence has any direct\ninfluence tending to undermine the hereditary foundations of instinct,\nfor acquired plasticity is not inherited as such; it is rather that\nwhen the stereotyped and the plastic are pitted against each other in\nthe struggle for existence in the wider, freer, and more varied life of\nthe higher animals the plastic survives and the stereotyped succumbs.\n\nImperfect as is our present knowledge of the manner in which the\nnervous connections implied in psychological associations are\nestablished, there can be no question that they are acquired in the\ncourse of individual life; they are modifications of nervous structure\ndue to a special mode of use under the conditions of experience.\nHere, then, in the case of the nervous system, as in that of the\nbodily organs before mentioned, two co-operating factors determine\nthe limits of efficiency--heredity and use. Just as the heart and\nlungs must inherit the power of standing abnormal strain if the animal\nis to avoid elimination in times of unwonted exertion, so must the\nnervous system inherit some reserve power of dealing effectively with\nunwonted circumstances by intelligent accommodation, if the animal\nis not to fall a victim to such circumstances. In other words, at\ntimes of heightened competition those animals which can draw on a\nreserve fund of intelligent accommodation will survive, while the\nstupid blunderers will be eliminated. We may term this reserve fund of\nintelligent accommodation, this inherited ability to meet specially\ndifficult circumstances as they arise, _innate capacity_. From the\nnature of the case it must be indefinite, for it must carry with it the\nability to meet unforeseen combinations of the environing forces by new\ncombinations of the results of experience. Its distinguishing mark is\nplasticity, in contradistinction to the stereotyped fixity of typical\ninstinct. And accompanying its evolution there is probably, as we have\nseen, a dissolution of its antithesis, instinct. Thus may we account\nfor the fact that man, with his great store of innate capacity, has so\nsmall a number of stereotyped instincts.\n\nBut the dissolution of instincts is not complete. Residua are left\nin the inherited mental constitution. And these we term _congenital\ntendencies_ and _propensities_. They differ from the typical instincts\nin the fact that the definiteness of response has been lost. They\ndictate a general trend of action, but the particular application in\nbehaviour is due to intelligent accommodation. They are commonly spoken\nof as instinctive; and their mode of origin justifies the use of the\nadjective in association with the term \u201cpropensities.\u201d But it must\nbe remembered that the behaviour to which they lead is not, as such,\nwholly instinctive; it is a joint product of instinct and intelligence,\nthe general trend being due to the instinctive propensity, while the\nmode of application is guided by intelligence.\n\nThere is, however, another way in which analogous propensities may\nbe ingrained in the mental constitution, not as residual vestiges of\nold instincts, but as congenital rudiments fostered by new habits.\nIt is a well-known and familiar fact that the frequent repetition of\nintelligent accommodation in certain definite lines begets habits,\nwhich so far simulate instincts as to be commonly described in\npopular speech as instinctive. Professor Wundt indeed places them\nin the category of \u201cacquired instincts\u201d--a usage which we regard as\nunsatisfactory, seeing that it tends to mask the distinction between\nthe congenital and acquired factors in behaviour, and seeing that\nwe have the well-defined term \u201chabits\u201d for acts rendered to a large\nextent automatic through repetition. Lamarckian thinkers regard habit\nas the mother of instinct, assuming that the acquired automatism\nof one generation may be transmitted to become congenital in the\nsucceeding generation. This conclusion we provisionally reject,\nregarding the basal assumption as at present unproven. But though\nwe cannot accept the view that habit is the mother of instinct, we\nregard it as not improbable that habit may be the nurse of congenital\npropensities. Remembering that similar habits are acquired by animals\nof the same species throughout a series of succeeding generations, and\nassuming that congenital variations are constantly occurring in many\ndirections, it seems probable that some of these variations will be\ncoincident in direction with the acquired habits. Thus would arise a\ncongenital propensity to perform the habitual acts; and should they\nbe of sufficient importance in the conduct of life to be subject\nto the action of natural selection, those animals in which such\npropensities were congenital would survive, whereas those in which\nno such propensities existed would be eliminated. It is unnecessary,\nhowever, to elaborate this conception further, since it is in line with\nthat already discussed in considering the influence of intelligence in\nfostering a diversion of instinct under changing circumstances. Then we\nwere considering how habit may lead to a congenital change in an old\ninstinct; here we are dealing with the development of a new propensity.\n\nSufficient has now been said to illustrate some of the ways in which\ninstinct and intelligence interact in the evolution of behaviour. Such\ninteraction is further exemplified in the social life of animals, which\nwill be dealt with in the next chapter.\n\n\n\n\nCHAPTER V\n\n_SOCIAL BEHAVIOUR_\n\n\nI.--IMITATION\n\nThe characteristic feature of social behaviour is that it is in large\ndegree determined by the behaviour of other members of the social\ncommunity. In all animals which mate there is a temporary or more\nlasting influence on each other of the individuals which unite to\nprocreate their kind; and in those which foster their young there\nis a social relation of parents and offspring. Some of these mutual\nrelationships will be discussed, in their emotional aspects, in the\nnext chapter. Here we will consider the more general factors which\nserve to determine the course of social evolution.\n\nAmong these is commonly reckoned imitation. M. Tarde says, \u201cLa\nsoci\u00e9t\u00e9 c\u2019est l\u2019imitation.\u201d But this word, like so many others which\nare employed alike in popular speech and in more or less technical\ndiscussions, carries a somewhat wide range of meaning, and is by\nsome writers used in a broader, by others in a narrower sense. Thus\nProfessor Mark Baldwin[74] says, \u201cthat all organic adaptation in a\nchanging environment is a phenomenon of _biological_ or _organic\nimitation_,\u201d under which category will fall, therefore, the organic\nbehaviour of the protozoa and of plants. On the other hand, Professor\nE. L. Thorndike, though he admits in the lower animals \u201ccertain\npseudo-imitative or semi-imitative phenomena,\u201d has been led by\nexperiments, to be presently noticed, to the conclusion that animals\nas high in the scale of life as cats and dogs cannot form new\nassociations under the influence of imitation. \u201cIt seems sure,\u201d he\nsays,[75] \u201cfrom these experiments, that the animals were unable to\nform an association leading to an act from having seen another animal,\nor animals, perform the act in a certain situation.\u201d In face of such\napparently diverse usage it is necessary to show within what limits\nand with what qualifications the word may profitably here be used to\nindicate a factor in social evolution.\n\nProfessor Mark Baldwin\u2019s use of the term \u201cimitation\u201d can only be\nunderstood in its relation to an hypothesis of organic and mental\nevolution, which he develops with no little skill and brilliancy.[76]\nHe regards the processes of life as issuing in a great twofold\nadaptation, due to expansions and contractions,--the former\nrepresenting waxing, the latter waning vitality; and he holds that\nall special adaptations are secured by the new hold upon beneficial\nstimulations reached by the expansive out-reaching movements. \u201cAmong\nthe variations in organic forms,\u201d he says, \u201cit is easy to see that\nsome of them might react in such a way as to keep in contact with the\nstimulus, to lay hold of it, and so keep on reacting to it again and\nagain--just as our rhythmic action in breathing keeps the organism in\nvital contact with the oxygen of the air. These organisms will get all\nthe benefit or damage of the repetition or persistence of the stimulus,\nor of their own reactions, again and again; and it is self-evident that\nthe beneficial stimulations are the ones which should be maintained\nin this way, and that the organisms which did this would live. The\norganisms which reacted in such a way as to retain the damaging\nstimulations, on the other hand, by this same process, would aid nature\nin killing themselves. If this be true, only those organisms would\nsurvive which had the variation of retaining useful stimulations in\nwhat I have called, in speaking of imitation elsewhere, a \u2018circular\nway\u2019 of reacting.... So, when we come to consider phylogeny and\nontogeny together, we find that if by an organism we mean a thing of\ncontractility or irritability, whose round of movements is kept up by\nsome kind of nutritive process supplied by the environment--absorption,\nchemical action of atmospheric oxygen, etc.--and whose existence is\nthreatened by dangers of contact and what not, the first thing to do\nis to secure a regular supply to the nutritive processes, and to avoid\nthese contacts. But the organism can do nothing but move, as a whole\nor in some of its parts. So, then, if one of such creatures is to be\nfitter than another to survive, it must be the creature which, by its\nmovements, secures more nutritive processes and avoids more dangerous\ncontacts. But movements toward the source of stimulation keep hold\non the stimulation, and movements away from the contacts break the\ncontacts; that is all. Nature selects these organisms; how could she do\notherwise?\u201d\n\n\u201cThus a \u2018circular\u2019 activity is found in operation; life-processes\nissuing in increased movements, by which in turn the stimulations to\nthe life-processes are kept in action.\u201d But when a child imitates,\nhimself reproducing the \u201ccopy\u201d set for imitation, the reaction at which\nimitative suggestion aims is one which will _reproduce the stimulating\nimpression_, and so tend to perpetuate itself. The stimulus starts a\nmotor process, which tends to reproduce the stimulus, and, through it,\nthe motor process again. It is a \u201ccircular activity.\u201d Thus \u201cwe are able\nto reconstruct the theory of adaptation in such a way as to show that\nthis kind of organic selection by movement, and this kind of imitative\nselection by consciousness, are the same thing. Organic imitation\nand conscious imitation--each a circular process tending to maintain\ncertain stimulations and to avoid others--here is one thing;\u201d and to\nthis one thing the common term \u201cimitation\u201d is applied by Mr. Baldwin.\n\nThis extended usage is admitted by the author to be somewhat of an\ninnovation. But if his hypothesis be sound this need be no bar to its\nacceptance. Two salient questions must, however, receive satisfactory\nanswers. First, is all organic adaptation in a changing environment a\ncircular process--a phenomenon of organic imitation? Secondly, does\nall conscious imitation tend to reproduce the imitating stimulus?\n\nProfessor Baldwin speaks of organic imitation and conscious imitation\nas \u201ceach a circular process tending to maintain certain stimulations\nand to avoid others.\u201d Now, it may be granted that the tendency to\nmaintain or repeat certain stimulations may be regarded as a \u201ccircular\nprocess.\u201d But can the avoidance or non-repetition of others be so\nregarded? A large proportion alike of the hereditary adaptations and\nthe acquired accommodations of behaviour are directed to this avoidance\nor non-repetition of hurtful stimulations. The instinctive shrinking\nof a chick from an aggressive animal is just as much adaptive as the\nrepeated cuddling beneath the warm wing of the mother. The avoidance of\nnauseous cinnabar caterpillars is just as much an accommodation to the\nconstitution of the environment as the reiterated seizing of palatable\ngrubs. Even low down in the scale of animal life, Dr. Jennings\u2019s\nobservations on Paramecia seem to show that the retention of favourable\nstimulation is not due to its direct influence, but is the indirect\nresult of a reaction to the relatively unfavourable stimulation\nwhich occurs when the Paramecium passes away from more satisfactory\nsurroundings. A favourable environment is secured through the avoidance\nof the unfavourable. Unless, therefore, we exclude adaptive avoidance\nfrom the category of adaptations, we cannot regard all organic\nadaptation in a changing environment as a phenomenon of organic\nimitation due to a circular process tending to the reinstatement of\nstimulation.\n\nPassing to the second question--Does all conscious imitation tend\nto reproduce the initiating stimulus?--we cannot unreservedly give\nan affirmative answer. It is true that when a child more or less\nsuccessfully reproduces a sound which falls upon its ear, a like\nsound stimulus is afforded which may by a circular process incite to\nrenewed effort, and lead to yet more successful reproduction. But\nwhen Professor Baldwin\u2019s child, between nine and ten months old,\nimitated certain movements of the lips, there was no reproduction of\nthe initiating visual stimulus. A chick seeing its companions run away\nor crouch will follow suit; and this would commonly be termed an\nimitative action; but there is here no reproduction of the initiating\nstimulus. Very much of the behaviour which is usually ascribed to\nimitation produces effects in consciousness quite different from that\nof the original stimulation. It is only by selecting one\u2019s examples\nthat one finds in them evidence in favour of Professor Baldwin\u2019s\n\u201ccircular process.\u201d\n\nSince, therefore, this circular mode of activity is neither a\ncharacteristic of all conscious imitation, nor a distinguishing mark\nof all adaptive organic action, the grounds on which Professor Baldwin\nbases his extended usage of the term appear to be fallacious. And in\nthis usage we cannot follow him.\n\nTurning now to Professor Thorndike\u2019s very different contention--that\nanimals even so high as the cat and dog do not imitate in the sense\nof forming an association leading to an act from having seen another\nanimal perform the act in a certain way--we may first describe some of\nhis ingenious experiments designed to submit the matter to the test of\nobservation under controlled conditions.[77]\n\nExperiments were made with chicks in several ways. They were, for\nexample, placed in pens, from which, in each case, \u201cthere was only one\npossible way of escape, to see if they would learn it more quickly\nwhen another chick did the thing several times before their eyes. The\nmethod was to give some chicks their first trial with an imitation\npossibility, and their second without, while others were given their\nfirst trial without and their second with. If the ratio of the average\ntime of the first trial to the average time of the second is smaller in\nthe first class than it is in the second class, we may find evidence of\nthis sort of influence by imitation. Though imitation may not be able\nto make an animal do what he would otherwise not do, it may make him\ndo _quicker_ a thing he would have done sooner or later anyway. As a\nfact, the ratio is _much longer_. This is due to the fact that a chick,\nwhen in a pen with another chick, is not afflicted by the discomfort\nof loneliness, and so does not try to get out. So the other chick,\nwho is continually being put in with him to teach him the way out,\nreally prolongs his stay in. This factor destroys the value of these\nquantitative experiments, and I do not,\u201d says Mr. Thorndike, \u201cinsist\nupon them as evidence against imitation, though they certainly offer\nnone for it.\u201d\n\nChicks, from sixteen to thirty days old, were also placed in boxes from\nwhich escape was open to them by such acts as pecking at the door,\nstepping on a platform, or pecking at a tack. The method of experiment\nwas to put a chick in, leave him from sixty to eighty seconds, then\nput in another who knew the act, and on his performing it to let both\nescape. No cases were counted unless the imitator apparently saw the\nother do the thing. After about every ten such chances to learn the\nact, the imitator was left in alone for ten minutes. Out of thirteen\ncases tabulated only once was the act performed, in spite of the ample\nchance for imitation. \u201cI have no hesitation,\u201d adds Mr. Thorndike, \u201cin\ndeclaring this one\u2019s act in stepping on the platform the result of mere\naccident, and am sure that any one who had watched the experiments\nwould agree.\u201d\n\nTo test the influence, if any, of imitation in cats, the following\nmethod was adopted. A box was arranged with two compartments separated\nby a wire screen. \u201cThe larger of these had a front of wooden bars\nwith a door which fell open when a string stretched across the top\nwas bitten or clawed down. The smaller was closed by boards on three\nsides and by the wire screen on the fourth. Through the screen a\ncat within could see the one to be imitated pull the string, go out\nthrough the door thus opened, and eat the fish outside. When put in\nthis compartment, the top being covered by a large box, a cat soon\ngave up efforts to claw through the screen, quieted down, and watched\nmore or less the proceedings going on in the other compartment. Thus\nthis apparatus could be used to test the power of imitation. A cat who\nhad no experience with the means of escape from the large compartment\nwas put in the closed one; another cat, who would do it readily, was\nallowed to go through the performance of pulling the string, going\nout, and eating the fish. Record was made of the number of times he did\nso, and of the number of times the imitator had his eyes clearly fixed\non him.... After the imitatee had done the thing a number of times, the\nother was put in the big compartment alone, and the time it took him\nbefore pulling the string was noted and his general behaviour closely\nobserved. If he failed in five or ten or fifteen minutes to do so, he\nwas released and not fed. This entire experiment was repeated a number\nof times. From the times taken by the imitator to escape and from\nobservation of the way that he did it, we can decide whether imitation\nplayed any part.... No one, I am sure, who had seen the behaviour of\nthe cats would have claimed that their conduct was at all influenced by\nwhat they had seen. When they did hit the string the act looked just\nlike the accidental success of the ordinary association experiment.\nBut, besides these personal observations, we have in the impersonal\ntime-records sufficient proofs of the absence of imitation.\u201d Some\nobservations on dogs are also described. From these it appears that\nthe three individuals on which experiments were made failed to learn\nthe way of getting out of a cage from seeing another dog escape. One\nof them was also allowed to see another dog beg for meat 110 times.\nBut he never tried to imitate him and thus secure a piece of meat as a\nreward. It therefore \u201cseems sure,\u201d says Mr. Thorndike, \u201cthat we should\ngive up imitation as an _a priori_ explanation of any novel intelligent\nperformance. To say that a dog who opens a gate, for instance, need\nnot have reasoned it out if he had seen another dog do the same thing,\nis to offer instead of one false explanation another equally false.\nImitation in any form is too doubtful a factor to be presupposed\nwithout evidence.\u201d\n\nProfessor Thorndike is of opinion that monkeys are probably imitative\nin ways beyond the capacity of dogs and cats; but, at the time\nof writing, he had not substantiated his opinion, by analogous\nexperiments. If so, it will perhaps prove that they are rational\nbeings in the narrower sense defined in a previous chapter of this\nwork. For it appears that the kind of imitation which Mr. Thorndike\u2019s\nexperiments go far to disprove, is what we may term reflective\nimitation. A cat with no experience of the means of escape, one that\nhas tried to get out of the box by chance efforts in many directions\nand has failed, sees another cat perform an act acquired in this way,\nand learns nothing from the sight. This, no doubt, proves that the cat\nhad not in any sense grasped the nature of the problem before it, had\nno notion of just where the difficulty lay, had not the wit to see that\nthe performance of the other cat supplied the missing links in its own\nprevious behaviour. It is questionable whether such missing links could\nbe supplied in this way in the absence of some powers of reflection.\nThe cat is unable to form an association, leading to an appropriate\nact, from having seen another animal perform the act in a certain way,\npartly because it cannot perceive the reason of its previous failure,\nand see that the other\u2019s performance affords the requisite clue. The\nwhole gist of the chance experience interpretation of animal behaviour\nis that there must be chance experience to build on. The cat cannot\ngain this by looking on never so intently, unless it be provided with\na rational as well as a sensory eye. The act of pulling the string has\nbeen reached by the successful cat through the gradual elimination\nof many failures; it is a differentiated act, having no place in the\nprevious experience of the kitten. It has never entered into the\nconscious situation, and cannot be supplied at will by a non-rational\nbeing.\n\nAs Mr. Thorndike himself says, \u201cno cat can form an association leading\nto an act unless there is included in the association an _impulse_\nof its own which leads to the act.\u201d[78] By \u201cimpulse,\u201d Mr. Thorndike\n\u201cmeans the consciousness accompanying a muscular innervation apart\nfrom that feeling of the act which comes from seeing one\u2019s self move,\nfrom feeling one\u2019s body in a different position, etc. It is the direct\nfeeling of doing as distinguished from the idea of the act done gained\nthrough eye, etc.... The act in this respect of being felt as to be\ndone or as doing is in animals the important thing, is the thing which\ngets associated, while the act as done, as viewed from outside, is a\nsecondary affair.\u201d I take it that by \u201cimpulse\u201d is here meant what Dr.\nStout would term the direct experience involved in conation.[79] If it\nhave a place in experience distinguishable from that of stimulation\nand response it is included in what I have on a former page spoken\nof as the consciousness of behaviour as such, which was said to be\nessential. And I am surprised that Mr. Thorndike should have supposed\nthat I believe that this could by any animal be \u201csupplied at will.\u201d In\nany case it seems probable, as the result of observation, that unless\nthe consciousness of behaving in a specific manner has entered into the\nsituation as developed in experience it cannot in animals enter into\nany subsequent representative complex. And it is the absence of such\nconsciousness of behaving in a specific manner which the sight of the\nescaping cat fails to supply in Mr. Thorndike\u2019s experiments.\n\nInteresting and valuable as these experiments are, they are open\nto the criticism to which, as we have seen, his other experiments\nare also open--that the conditions are abnormal and cramped. Apart\nfrom reflective imitation, which they tend to disprove, they do not\nconduce to the kind of conscious situation which appears to be most\nfavourable for the development of intelligent imitation founded on\nhereditary tendencies and propensities. It is through such imitation\nthat, as Herr Groos says,[80] \u201canimals learn perfectly those things\nfor which they have imperfect hereditary dispositions.\u201d The kind of\nsituation which conduces to such intelligent imitation is that which\ninvolves the attitude of attention and interest rising, when these\nare sufficiently varied in their direction, into what is spoken of as\ncuriosity. These, in their natural occurrence in animals, are parts\nof, or in any case accompaniments of the conative attitude--they are\nconnected with activities and impulsive tendencies to behaviour. If\nattention and interest are directed to the behaviour of another animal,\nthe conative attitude is that of imitation. Miss Romanes has described\nhow skilfully a capuchin imitated the actions necessary to unlock a\ntrunk. It does not seem necessary to assume that reflective imitation\nis here exemplified. The monkey need not regard the key and lock as\nthe related parts of a puzzle to be practically solved, need not have\nany free idea of the difficulty it presents, need not in unlocking the\ntrunk grasp the true nature of the difficulty or have any conception of\nits solution. Every several act of the capuchin, the seizing the key,\nthe directing it here or there, and so on, is already supplied with\nthe impulse of which Dr. Thorndike speaks. Attention, itself charged\nwith impulse, directs and combines these pre-existing impulses to a new\nend. And since that which directs the attention is the act of another,\nwe call the procedure imitative. But the varied and persistent effort\ndiffers in no essential respect from that of a two days\u2019 chick, which\npecks again and again at some speck which catches its eye, or that\nof a nestling jay, which will peck for long at some nail or piece of\nwire in its cage, twisting and turning its bill in many and varied\nways. And success in opening the trunk is reached by the capuchin,\nnot, it would seem, through any real appreciation of the essential\nkernel of the practical problem, but through the chance results of\nmany varied efforts. Although in no other animals is it developed to\nso high a degree as in the monkeys, interest in the doings of others\nis an attitude by no means rare, and affords the basis of intelligent\nimitation. Perhaps the conditions in Dr. Thorndike\u2019s experiments were\nnot the best for the development of such interest in the procedure\nof another. And in any case the imitation of a particular mode of\nprocedure, reached by the gradual defining of the impulse, could hardly\nbe expected in the absence of the series of experiences by which that\ndefinition had been reached, unless the cat were capable of what has\nbeen above spoken of as reflective imitation.\n\nIf, then, we agree to exclude from the category of imitative behaviour\nin animals, on the one hand, any \u201ccircular process\u201d which may occur in\nthe same individual, and on the other hand any reflective imitation,\nsuch as is so important a factor in human education, it remains to be\nseen what may be fairly included in this category.\n\nIt is probable that in animals imitation has its foundations\nin instinctive behaviour, of which it may be regarded as the\ncharacteristically social type. If one of a group of chicks learn by\ncasual experience to drink from a tin of water, others will run up and\npeck at the water, and thus learn to drink. A hen teaches her little\nones to pick up grain or other food by pecking on the ground and\ndropping suitable materials before them, while they seemingly imitate\nher action in seizing the grain. One may make chicks and pheasants\npeck by simulating the action of a hen with a pencil point or pair\nof fine forceps. According to Mr. Peal, the Assamese find that young\njungle pheasants will perish if their pecking responses are not thus\nstimulated; and Professor Claypole tells me that this is also the case\nwith young ostriches hatched in an incubator. A little pheasant and\nguinea-fowl followed two older ducklings, one wild, the other tame, and\nseemed to wait upon their bills, to peck when they pecked, and to be\nguided by their actions. It is certainly much easier to bring up young\nbirds if older birds are setting an example of eating and drinking; and\ninstinctive acts, such as scratching the ground, are performed earlier\nif imitation be not excluded. If a group of chicks have learnt to avoid\ncinnabar caterpillars, and if then two or three from another group\nare introduced and begin to pick up the caterpillars, the others will\nsometimes again seize them, though they would otherwise have left them\nuntouched. One of my chicks, coming upon a dead bee, gave the danger\nor alarm note; another at some little distance at once made the same\nsound. A number of similar cases might be given; but what impresses\nthe observer as he watches the early development of a brood of young\nbirds, is the presence of an imitative tendency which is exemplified\nin many little ways not easy to describe in detail. It is probable,\nhowever, that these imitative tendencies or propensities are not wholly\nindefinite. The young birds do not imitate any actions, but behaviour\nof certain specific types, the imitation of which has been engrained\nthrough the action of natural selection.\n\nWhat generalization, then, can be drawn from this somewhat indefinite\ngroup of facts, to which many others of like import could be added\nfrom observations on the young of mammals? What is their relation\nto instinctive procedure in general? It would seem that they are\ncharacterized by a special relation of the external stimulus to the\nresponse. When this stimulus is afforded by the behaviour of another\nanimal, and the responsive behaviour it initiates is similar to that\nwhich affords the stimulus, such behaviour may be termed imitative. A\nchick sounds the danger note; this is the stimulus under which another\nchick sounds a similar note, and we say that the one imitates the\nother. Such an action may be described as imitative in its effects,\nbut not imitative in its purpose. Only from the observer\u2019s standpoint\ndoes such instinctive behaviour differ from other modes of congenital\nprocedure. It may be termed biological, but not psychological,\nimitation. And if it be held that the essence of imitation lies in the\npurpose so to imitate, we must find some other term under which to\ndescribe the facts. This does not seem necessary, however, if we are\ncareful to qualify the term \u201cimitation\u201d by the adjective \u201cinstinctive\u201d\nor \u201cbiological.\u201d And the retention of the term serves to indicate that\nthis is the stock on which deliberate imitation is eventually grafted.\n\nThe fact that instinctive imitation leads, under natural conditions,\nto behaviour which is already familiar to us in the species concerned,\nprevents us from recognizing the influence of this social factor\nso easily as might otherwise be the case. The abnormal arrests our\nattention more readily than the normal, and hence the cases commonly\ncited are generally those which strike us as unusual, such as the\nimitation of human sounds by the parrot. But if the young inherit a\ntendency to imitate certain actions of their parents, and if there is\namong the members of a gregarious species such instinctive imitation\nas shall tend to keep them gregarious, we have here a social factor\nin animal life of no slight importance. Just as the higher type of\nreflective imitation is of great value in bringing the human child to\nthe level of the adults who form the family and social environment,\nso, too, does the sub-conscious instinctive imitation of the lower\nanimals bring the young bird or other creature into line with the\nmembers of its own species. In broods of chicks brought up under\nexperimental conditions, there are often one or two more active,\nvigorous, intelligent, and mischievous birds. These are the leaders\nof the brood; the others are their imitators. Their presence raises\nthe general level of intelligent activity. Remove them, and the others\nshow a less active, less inquisitive, less adventurous life. They seem\nto lack initiative. From which one may infer that imitation affords\nto some extent a means of levelling up the less intelligent to the\nstandard of the more intelligent; and of supplying a stimulus to the\ndevelopment of habits which would otherwise be lacking. When a mongrel\npup, whose development Dr. Wesley Mills watched and has described, was\nintroduced to the society of other dogs, its progress was, he tells us,\n\u201cextraordinarily rapid.\u201d\n\nInstinctive imitation thus introduces into the conscious situation\ncertain modes of behaviour, and if the development of the situation as\na whole is pleasurable, there will be a tendency to its redevelopment,\nunder the guidance of intelligence, on subsequent occasions. As in\nthe case of other instincts and propensities, there is given through\ninheritance a more or less definite outline sketch of social procedure,\nwhich intelligence further defines, and refines, and shapes to more\ndelicate issues. As a rule, however, intelligence does not tend to\nmake the imitation as such more perfect. It may perfect the behaviour,\nbut not necessarily on imitative lines. In the case, however, of\nthe song and call-notes of birds, and not improbably the sounds\nof other animals, there does seem a predisposition to render the\nimitation as such more perfect. The facts, as afforded by such birds\nas the magpie, jay, starling, marsh-warbler, and mocking-bird, are\nfamiliar; and I have elsewhere[81] given some account of them. It\nmay be specially noted that we have in this case that circular mode\nof activity on which, as we have seen, Professor Mark Baldwin lays\nso much stress. Professor Thorndike seems to regard the phenomena\npresented by imitative birds as somewhat of a mystery, and as the\nresult of a specialization removed from the general course of mental\ndevelopment. And he says that, until we know whether there is in birds\nwhich repeat sounds any tendency to imitate in other lines, we cannot\nconnect these phenomena with anything found in the mammals, or use them\nto advantage in a discussion of animal imitation as the forerunner\nof human. Upon the view, however, that such imitation is primarily\ninstinctive and only secondarily intelligent, there seems no reason\nwhy we should expect to find imitation in birds running along any\nother lines than those which the hereditary instinct has marked out.\nAnd so far from being unable to use the phenomena to advantage in a\ndiscussion of animal imitation as a forerunner of human, we may perhaps\nsee in them the best examples, other than those afforded by apes, of\nthat intelligent imitation which is the precursor of the rational and\nreflective imitation of the boy or girl.\n\nIn the case of the human child we may see the three stages in the\ndevelopment of vocal imitation. First, the instinctive stage, where the\nsound which falls upon the ear is a stimulus to the motor-mechanism of\nsound production. Secondly, the intelligent stage of the profiting by\nexperience. Intelligence, as we have seen, aims at the reinstatement\nof pleasurable situations, and the suppression of those which are\nthe reverse. The sound-stimulus, the motor effects in behaviour, and\nthe resulting sound-production coalesce into a conscious situation,\nwhich appears to be pleasurable or the reverse, according as the sound\nproduced resembles or not the initiating sound-stimulus. If we assume\nthat the resemblance of the sounds he utters to the sounds he hears is\nitself a source of pleasurable satisfaction (and this certainly seems\nto be the case), intelligence, without the aid of any higher faculty,\nwill secure accommodation and render imitation more and more perfect.\nAnd this appears to be the stage reached by the mocking-bird or the\nparrot. But the child soon goes further. He reflects upon the results\nhe has reached; he at first dimly, and then more clearly realizes that\nthey are imitative; and his later efforts at imitation are no longer\nsubject to the chance occurrence of happy results, but are based on a\nscheme of behaviour which is taking form in his mind, are deliberate\nand intentional, and are directed to a special end more or less clearly\nperceived as such. He no longer imitates like a parrot; he begins\nto imitate like a man, and may, by the study of good models and the\nmaintenance of a high ideal, acquire the moving cadences of an orator.\n\nAccording to our interpretation, instinctive imitation is a factor of\nwide importance in animal behaviour, intelligent imitation, arising\nin close connection with interest in the doings of others, is a\nco-operating factor, but of intentional and reflective imitation there\nis at present no satisfactory evidence in any animal below man.\n\n\nII.--INTERCOMMUNICATION\n\nThe foundations of intercommunication, like those of imitation, are\nlaid in certain instinctive modes of response, which are stimulated by\nthe acts of other animals of the same social group. These have been\nfostered by natural selection as a means of social linkage furthering\nthe preservation, both of the individual and of the group.\n\nSome account has already been given of the sounds made by young birds,\nwhich seem to be instinctive and to afford an index of the emotional\nstate at the time of utterance. That in many cases they serve to evoke\na like emotional state and correlated expressive behaviour in other\nbirds of the same brood cannot be questioned. The alarm note of a chick\nwill place its companions on the alert; and the harsh \u201ckrek\u201d of a\nyoung moor-hen, uttered in a peculiar crouching attitude, will often\nthrow others into this attitude, though the maker of the warning sound\nmay be invisible. That the cries of her brood influence the conduct\nof the hen is a matter of familiar observation; and that her danger\nsignal causes them at once to crouch or run to her for protection is\nnot less familiar. No one who has watched a cat with her kittens,\nor a sheep with her lambs, can doubt that such \u201cdumb animals\u201d are\ninfluenced in their behaviour by suggestive sounds. The important\nquestions are, how they originate, what is their value, and how far\nsuch intercommunication--if such we may call it--extends.\n\nThere can be but little question that in all cases of animals under\nnatural conditions such behaviour has an instinctive basis. Though\nthe effect may be to establish a means of communication, such is not\ntheir conscious purpose at the outset. They are presumably congenital\nand hereditary modes of emotional expression which serve to evoke\nresponsive behaviour in another animal--the reciprocal action being\ngenerally in its primary origin between mate and mate, between parent\nand offspring, or between members of the same family group. And it\nis this reciprocal action which constitutes it a factor in social\nevolution. Its chief interest in connection with the subject of\nbehaviour lies in the fact that it shows the instinctive foundations on\nwhich intelligent and eventually rational modes of intercommunication\nare built up. For instinctive as the sounds are at the outset, by\nentering into the conscious situation and taking their part in the\nassociation-complex of experience, they become factors in the social\nlife as modified and directed by intelligence. To their original\ninstinctive value as the outcome of stimuli, and as themselves\naffording stimuli to responsive behaviour, is added a value for\nconsciousness in so far as they enter into those guiding situations by\nwhich intelligent behaviour is determined. And if they also serve to\nevoke, in the reciprocating members of the social group, similar or\nallied emotional states, there is thus added a further social bond,\ninasmuch as there are thus laid the foundations of sympathy.\n\n\u201cWhat makes the old sow grunt and the piggies sing and whine?\u201d said\na little girl to a portly substantial farmer. \u201cI suppose they does\nit for company, my dear,\u201d was the simple and cautious reply. So far\nas appearances went, that farmer looked as guiltless of theories as\nman could be. And yet he gave terse expression to what may perhaps be\nregarded as the most satisfactory hypothesis as to the primary purpose\nof animal sounds. They are a means by which each indicates to others\nthe fact of his comforting presence; and they still, to a large extent,\nretain their primary function. The chirping of grasshoppers, the song\nof the cicada, the piping of frogs in the pool, the bleating of lambs\nat the hour of dusk, the lowing of contented cattle, the call-notes of\nthe migrating host of birds--all these, whatever else they may be, are\nthe reassuring social links of sound, the grateful signs of kindred\npresence. Arising thus in close relation to the primitive feelings of\nsocial sympathy, they would naturally be called into play with special\nforce and suggestiveness at times of strong emotional excitement, and\nthe earliest differentiations would, we may well believe, be determined\nalong lines of emotional expression. Thus would originate mating\ncries, male and female after their kind; and parental cries more or\nless differentiated into those of mother and offspring, the deeper\nnote of the ewe differing little save in pitch and timbre from the\nbleating of her lamb, while the cluck of the hen differs widely from\nthe peeping note of the chick in down. Thus, too, would arise the notes\nof anger and combat, of fear and distress, of alarm and warning. If we\ncall these the instinctive language of emotional expression, we must\nremember that such \u201clanguage\u201d differs markedly from the \u201clanguage\u201d of\nwhich the sentence is the recognized unit.\n\nIt is, however, not improbable that, through association in the\nconscious situation, sounds, having their origin in emotional\nexpression and evoking in others like emotional states, may acquire\na new value in suggesting, for example, the presence of particular\nenemies. An example will best serve to indicate my meaning. \u201cIn the\nearly dawn of a grey morning,\u201d says Mr. H. B. Medlicott,[82] \u201cI was\ngeologizing along the base of the Muhair Hills in South Behar, when\nall of a sudden there was a stampede of many pigs from the fringe of\nthe jungle, with porcine shrieks of _sauve-qui-peut_ significance.\nAfter a short run in the open they took to the jungle again, and in a\nfew minutes there was another uproar, but different in sound and in\naction; there was a rush, presumably of the fighting members, to the\nspot where the row began, and after some seconds a large leopard sprang\nfrom the midst of the scuffle. In a few bounds he was in the open, and\nstood looking back, licking his chaps. The pigs did not break cover,\nbut continued on their way. They were returning to their lair after\na night\u2019s feeding on the plain, several families having combined for\nmutual protection; while the beasts of prey were evidently waiting for\nthe occasion. I was alone, and, though armed, I did not care to beat\nup the ground to see if in either case a kill had been effected. The\nnumerous herd covered a considerable space, and the scrub was thick.\nThe prompt concerted action must in each case have been started by\nthe special cry. I imagine that the first assailant was a tiger, and\nthe case was at once known to be hopeless, the cry prompting instant\nflight, while in the second case the cry was for defence. It can\nscarcely be doubted that in the first case each adult pig had a vision\nof a tiger, and in the second of a leopard or some minor foe.\u201d\n\nIf we accept Mr. Medlicott\u2019s interpretation as in the main correct,\nwe have in this case: (1) common action in social behaviour, (2)\ncommunity of emotional state, and (3) the suggestion of natural\nenemies not unfamiliar in the experience of the herd. Under uniform\nconditions of experience the alarm-notes of some birds may well call\nup, re-presentatively, salient features in previous situations.\nUnquestionably, in the parrot, the word-sounds they imitate become\nassociated with definite objects of sense-experience. In the following\ncase, a particular sound appeared to be suggestive of a particular\nsense-idea in the dog. The parent blackbirds, which built near a\nhouse in Clifton, were wont to give the alarm-note when marauding\ncats appeared in sight. This sound, it would seem, became definitely\nassociated, in the experience of a terrier, with the animals the\npresence of which called it forth; and on hearing the alarm note the\ndog would rush out into the garden, apparently, as I am informed by\nhis mistress, in fullest expectation of a pleasant worry. It is a not\nimprobable hypothesis, therefore, that in the course of evolution\nthe initial value of uttered sounds is emotional; but that on this\nmay be grafted in further development the indication of particular\nenemies. If, for example, the cry which prompts instant flight among\nthe pigs is called forth by a tiger, it is reasonable to suppose\nthat this cry would give rise to a representative generic image of\nthat animal having its influence on the conscious situation. But if\nthe second cry, for defence, was prompted sometimes by a leopard\nand sometimes by some other minor foe, then this cry would not give\nrise to a re-presentative image of the same definiteness. Whether\nanimals have the power of intentionally differentiating the sounds\nthey make to indicate different objects, is extremely doubtful. Can a\ndog bark in different tones to indicate \u201ccat\u201d or \u201crat,\u201d as the case\nmay be? Probably not. It may, however, be asked why, if a pig may\nsqueak differently, and thus, perhaps, incidently indicate on the one\nhand \u201ctiger\u201d and on the other hand \u201cleopard,\u201d should not a dog bark\ndifferently, and thus indicate appropriately \u201ccat\u201d or \u201crat\u201d? Because it\nis assumed that the two different cries in the pig are the instinctive\nexpression of two different emotional states, and Mr. Medlicott could\ndistinguish them; whereas, in the case of the dog, we can distinguish\nno difference between his barking in the one case and the other, nor do\nthe emotional states appear to be differentiated. Of course, there may\nbe differences which we have failed to detect. What may be regarded,\nhowever, as improbable, is the _intentional_ differentiation of sounds\nby barking in different tones with the _purpose_ of indicating \u201ccat\u201d\nor \u201crat.\u201d Mr. R. L. Garner, in a work[83] which unfortunately contains\nmuch hasty and immature generalization, distinguished nine sounds\nmade by capuchins. But none of these, so far as can be gathered from\nthe data given, is necessarily indicative of a particular object. All\nof them may be emotional expressions of satisfaction, discontent,\nalarm, apprehension, and so forth. In any case, there is no evidence\nfor that intentional employment of sounds, to the realized end of\nintercommunication, which would involve the exercise of an incipient\nrational faculty. Such powers of intercommunication as animals possess\nare based on direct association, and refer to the here and the now.\nA dog may be able to suggest to his companion the fact that he has\ndescried a worriable cat; but can a dog tell his neighbour of the\ndelightful worry he enjoyed the day before yesterday in the garden\nwhere the man with the biscuit-tin lives? Probably not, bark he never\nso expressively.\n\nAlthough some anecdotes are commonly interpreted as affording evidence\nof descriptive intercommunication among animals, we need the decisive\nresults of experiment before this view can be unreservedly accepted.\nSir John Lubbock, now Lord Avebury, made careful experiments with\nants, and discusses the question with his customary lucidity and\nimpartiality. \u201cMuch of what has been said,\u201d he writes,[84] \u201cas to the\npowers of communication possessed by bees and ants depends on the fact\nthat if one of them in the course of her rambles has discovered a\nsupply of food, a number of others soon find their way to the store.\nThis, however, does not necessarily imply any power of describing\nlocalities. If the ants merely follow a more fortunate companion, or\nif they hunt her by scent, the matter is comparatively simple; if, on\nthe contrary, the others have the route described to them, the case\nbecomes very different.\u201d Experiments were therefore made to decide the\nquestion. For example, when an ant returned from the discovered store\nof food to the nest, and then emerged with a following of other ants,\nshe was taken up on a slip of paper and transferred to the food. The\nfollowers, thus deprived of their leader, in nearly all cases failed to\nfind the store. \u201cI conclude, then,\u201d says Lord Avebury, \u201cthat when large\nnumbers of ants come to food they follow one another, being also, to a\nlarge extent, guided by scent. The fact, therefore, does not imply any\nconsiderable power of intercommunication.\u201d There are, moreover, some\ncircumstances which seem to strengthen this conclusion. For instance,\n\u201cif a number of slave-ants are put in a box, and if in one corner a\ndark place of retreat be provided for them, with some earth, one soon\nfinds her way to it. She then comes out again, and going up to one\nof the others, takes her by the jaws and carries her to the place of\nshelter. They then both repeat the same man\u0153uvre with other ants, and\nso on until all their companions are collected together. Now, it seems\ndifficult to imagine that so slow a course would be adopted, if they\npossessed any power of communicating description.\u201d\n\nLord Avebury is, however, of opinion that such insects can transmit\nsimpler ideas. He found, for example, that where ants were put to\na large and a small store of larv\u00e6 under similar circumstances, a\ngreater number of insects followed the ant that had discovered the\nlarger store. This may, indeed, have been due rather to a difference in\nmanner than to any intentional communication; but the fact remains that\nthrough some difference of behaviour there resulted suggestive effects\non other members of the community.\n\nBut although there can be little doubt that the behaviour of social\ninsects has suggestive value for others, it may still be regarded as\nvery doubtful whether they are able to communicate information to one\nanother by any system of language or signs, purposively employed as a\nsystem to this end. The distinguished geologist, Hague, communicated\nto Darwin[85] the effects on ants of crushing some of their number as\nthey proceeded along a definite trail. \u201cAs soon as those ants which\nwere approaching arrived near to where their fellows lay dead and\nsuffering, they turned and fled with all possible haste.\u201d \u201cWhen such\nan ant, returning in fright, met another approaching, the two would\nalways communicate, but each would pursue its own way, the second ant\ncontinuing its journey to the spot where the first had turned about,\nand then following that example.\u201d There seems nothing to show that the\n\u201ccommunication\u201d here was effective.\n\nFrom the many anecdotes of dogs calling others to their assistance, or\nbringing others to those who feed them or treat them kindly, we may\nindeed infer the existence of a social tendency and of the suggestive\neffects of behaviour, but we cannot derive conclusive evidence of\nanything like descriptive communication. And although domestic animals\nmay learn or be taught to associate the words we utter with certain\nacts or things, or may even, in a sense, communicate their wishes to\nus by special modes of behaviour--as in the case of Lord Avebury\u2019s\npoodle, Van,[86] who was taught to bring cards on which such words\nas \u201cFood\u201d or \u201cOut\u201d were printed, and in that of a cat which touches\nthe handle of the door when she wants it opened for her,--still,\nall these are founded on direct association, and are in a line with\nthe act of Mr. Thorndike\u2019s cat, which licked herself or scratched\nherself when imprisoned in a cage, such act having entered into the\nassociation-complex.\n\nSuch intentional communication as is to be found in animals, if indeed\nwe may properly so call it, seems to arise by an association of the\nperformance of some act in a conscious situation involving further\nbehaviour for its complete development. Thus the cat which touches the\nhandle of the door when it wishes to leave the room has had experience\nin which the performance of this act has coalesced with a specific\ndevelopment of the conscious situation. The case is similar when your\ndog drops a ball or stick at your feet, wishing you to throw it for\nhim to fetch. And on these lines may probably be interpreted such\nbehaviour as Romanes[87] thus described:--\u201cTerrier A being asleep in\nmy house, and terrier B lying on a wall outside, a strange dog, C,\nran along below the wall on the public road, following a dog-cart.\nImmediately on seeing C, B jumped off the wall, ran upstairs to where\nA was asleep, woke him up by poking him with his nose in a determined\nand suggestive manner, which A at once understood as a sign: he jumped\nover the wall and pursued the dog C, although C was by that time far\nout of sight round a bend in the road.\u201d Romanes did not probably intend\nto imply that A by poking B, conveyed specific information that there\nwas another dog, C, which had proceeded in a particular direction.\nThat would be descriptive communication. The meaning attaching to\nA\u2019s action was presumably similar to that which characterizes other\n\u201cmeaning\u201d for intelligent animals--the development of the situation on\nlines marked out by previous experience. Still, it is clear that such\nan act would be the perceptual precursor of the deliberate conduct of\nthe rational being by whom the sign is definitely realized as a sign,\nthe intentional meaning of which is distinctly present to thought.\nThis involves a judgment concerning the sign as an object of thought;\nand this is probably beyond the capacity of the dog. For, as Romanes\nhimself says,[88] \u201cit is because the human mind is able, so to speak,\nto stand outside of itself, and thus to constitute its own ideas the\nsubject-matter of its own thought, that it is capable of judgment,\nwhether in the act of conception or in that of predication. We have no\nevidence to show that any animal is capable of objectifying its own\nideas; and, therefore, we have no evidence that any animal is capable\nof judgment.\u201d\n\nIt seems, therefore, that the sounds made by animals, and certain other\nmodes of behaviour, may be regarded as primarily instinctive acts which\nhave been evolved with the biological end of affording suggestive\nstimuli furthering intercommunication between the members of the social\ngroup. Their performance, however, affords data to consciousness, which\nintelligence makes use of in the guidance of behaviour in accordance\nwith the results of experience. And since the similar acts performed\nby the socially linked members are in many cases closely connected with\nemotional states, there arises the further social link of community\nof feeling--that which, perhaps, more than anything else conduces to\ncommunity of action and similarity of social behaviour. Occasionally\nparticular sounds or special acts may, through constant and uniform\nassociation, indicate particular objects, such as natural enemies. But\nthere does not appear to be convincing evidence of any intentional\ndifferentiation of the means of communication, or of any use of sounds\nfor descriptive ends.\n\nStill, just as the instinctive imitation we considered in the last\nsection may be regarded as the precursor, in the animal world, of\nthe reflective and rational imitation of which we may watch the\ndevelopment in children, so may instinctive modes of intercommunication\nbe regarded as supplying the foundations on which deliberate and\nintentional communication may be based. And here imitation will be a\nco-operating factor. We see in the early stages of the development of\nchildren\u2019s language how large a share simple and direct association\ntakes in the process. For a while, indeed, there seems to be this and\nnothing more. But gradually there arises a realization of a further\nimport and purpose in the hitherto isolated associations. It is seen\nthat they symbolize elements in that incipiently rational scheme of\nthought and things which is beginning to take form in the child\u2019s mind.\nThe relationships which hold good within the conscious situations\nof daily life begin to occupy the focus of attention, and hitherto\nunappreciated word-sounds are perceived to stand out as signs for\nthese relationships. Of course the relationships[89] are implicit in\nthe conscious situations of the higher animals and of infants. Only by\nreflection can they become explicit, and rivet the attention. Something\nis needed to bring them into prominence and focus the mental eye upon\nthem. And descriptive intercommunication supplies this need. If a\ndescription, even the simplest, is to be apprehended or presented to\nthe apprehension of others, then the relationships must be rendered\nexplicit. Try to describe an ordinary visual scene, or the most\ncommonplace sequence of events, and see if you can do so without making\nclear to the mind the relationships involved. The thing is impossible.\nAn infant or a dog cannot understand the simplest possible description,\nbecause the words and suffixes which indicate the relationships have\nno meaning. The words which stand for substantive impressions may\nhave suggestive value through direct association. The word \u201ccat\u201d or\n\u201crats\u201d may have for the dog a very definite suggestive value; and hence\nsome people fancy that when they say to their dog, \u201cThere is a cat in\nthe garden,\u201d the animal understands what they say. But it is quite\nsufficient to suppose that the word \u201ccat\u201d has suggestive force, all the\nrest being for the dog mere surplusage of sound. When we talk to our\nfour-footed companions, how much can they be said to understand of what\nwe say? Perhaps a score of words have for a dog a definitely suggestive\nvalue, each associated with some simple object or action. \u201cOut,\u201d\n\u201cdown,\u201d \u201cup,\u201d \u201cwalk,\u201d \u201cbiscuit,\u201d \u201ccat,\u201d \u201cfetch,\u201d and so forth elicit\nappropriate responses. Even with these, tone is more suggestive than\narticulation, and in each word the salient feature is the chief guide.\nWhen I said \u201cWhisky,\u201d for example, to my fox-terrier, he would at once\nsit up and beg; not because his tastes were as depraved as those of\nhis master, but because the _isk_ sound, common both to \u201cWhisky\u201d and\n\u201cbiscuit,\u201d was what had for his ears the suggestive value.\n\nIn a paper on the \u201cSpeech of Children,\u201d[90] Mr. S. S. Buckman exhibits\nthe animal stage in the incipient speech of the human infant. We cannot\nhere discuss, still less criticize, his paper. One or two examples\nwill serve to illustrate how instinctive sounds may serve as the\nbasis for subsequent speech. He regards _ma_ as primarily a forcible\nexpression of an emotional state. \u201cIf the child require attention\nit makes the loudest noise which it can produce; the parting of the\nlips and opening of the mouth to the widest extent while the full\nvolume of breath is emitted produces the sound _ma_.\u201d At first the\nsound seems to have the value of a simple expression of an emotional\nstate. \u201cBut if the infant require attention it is its mother whom it\nwants, and from whom it receives this attention; therefore _ma_ very\nsoon comes to be recognized as the call for mother, and, by a further\nstep in development, as the name for mother.\u201d Here, if we accept the\ninterpretation, we have the passage from the emission of a sound as\nthe expression of emotion to the use of the sound from its association\nwith a particular object of sense-experience to indicate that object.\nSimilarly, according to Mr. Buckman, with _kah_. At first \u201ca strong\nsign of displeasure at anything nasty to the taste,\u201d it passes, we are\ntold, into a symbol for the bad; hence \u03ba\u03b1\u03ba\u03cc\u03c2; and is perhaps narrowed\ndown to the particularly offensive \u03ba\u03ac\u03ba\u03ba\u03b7. _Da_ and _ta_ are regarded\nas recognition sounds, the former being associated eventually with the\nfather, the latter with strangers. This appears somewhat hypothetical,\nbut, granting the accuracy of Mr. Buckman\u2019s interpretation, these\nsounds also illustrate again the transition from the expression of an\nemotion to sounds indicative of particular objects of experience.\n\nInteresting, however, as are such observations on the animal stage of\nsound-production in the human infant, they do not touch the crucial\nperiod in the development of language. Mr. Buckman, indeed, regards as\na remarkably dogmatic assertion Professor Max M\u00fcller\u2019s dictum that \u201cthe\none great barrier between the brute and man is language;\u201d and he tells\nus that \u201cthere are more than twelve different words in the language of\nfowls,\u201d on which assertion, in turn, the distinguished linguist whom he\ncriticizes might have something piquant to say. No doubt the difference\nof opinion turns on the definition of the word \u201clanguage.\u201d But if,\nas is now generally accepted, the sentence and not the word is the\ndistinguishing unit in language, and the copula in some form, explicit\nor implicit, is the pivot of the sentence, the wisest hen is probably\nincapable of language. The word becomes an element in language--a word\nproper--only when it assumes the office of a part of speech, that is\nto say, a constituent element in an interrelated whole. The animal\n\u201cword,\u201d if we like so to term it, is an isolated brick; a dozen, or\neven a couple of hundred such bricks do not constitute a building.\nLanguage, properly so called, is the builded structure, be it a palace\nor only a cottage; hen language, or monkey language, is, at best, so\nfar as we at present have evidence, an unfashioned heap of bricks. It\nis just because language is the expression of a portion of a scheme of\nthought that it indicates in the speaker the possession of a rational\nsoul, capable of perceiving and symbolizing the relationships of things\nas reflected in thought.\n\nHerein lies the practical value, for human advance in mental\ndevelopment, of language as a means of descriptive intercommunication.\nIt renders explicit relationships otherwise merely implicit, and forces\nthem to the front; and since these relationships are the stuff of which\nknowledge is built--without the realization of which any complex ideal\nscheme is impossible of attainment--the importance of descriptive\nintercommunication can scarcely be overestimated. And though there is\nno conclusive evidence of its occurrence among animals, yet we have in\nthem the instinctive and intelligent basis on which in due course of\nevolution it may be securely based.\n\n\nIII.--SOCIAL COMMUNITIES OF BEES AND ANTS\n\nApart from human societies the most noteworthy social communities of\nanimals are found among insects, especially in ants, bees, wasps, and\ntermites. It is true that in the mammalia we find such communities as\nthe troop of apes, the herd of cattle, the pack of wolves, the school\nof porpoises, the so-called \u201crookeries\u201d of seals, and the colonies of\n\u201cprairie dogs\u201d and of beavers; and that among birds there are analogous\ncommunities. Undoubtedly the temporary or permanent association of many\nindividuals is in such cases an advantage to the race, and confers\nmutual benefits on the associates. But in none of these cases is\ndivision of labour carried to such a high degree as among the social\ninsects. And it is through such division of labour that the social\ncommunity reaches its highest expression.\n\nIt is a somewhat remarkable fact that in man, where we find the social\ndivision of labour brought to a high pitch of perfection, and carried\nout with great nicety of accommodation to those circumstances which\ncivilization has rendered extremely complicated, there is no organic\ndifferentiation of structure among the co-operating individuals;\nwhereas, so low down in the scale of life as the colonial polype,\n_Hydractinia_, which is often found growing on the shells occupied\nby hermit crabs, there are at least three kinds of differentiated\nindividuals: nutritive polypes with mouth and tentacles; mouthless\nsensitive members; and others whose sole office is reproduction.\nBut these differentiated individuals in the colonial zoophytes are\nconnected at their bases by a common flesh; and the division of labour\nis a product of organic evolution, and is probably not in any degree\ndetermined or guided by consciousness. We may say, then, that the\ndivision of labour in the zoophyte is wholly physical, whereas in man\nit is chiefly conscious or psychical; as is also the bond of union\nbetween the several members of the colony. Intermediate between these\nextremes stand the social insects. In them there is no physical bond of\nunion, for each individual is distinct and separate; the social linkage\nis in some degree conscious under the conditions of their nurture; and\nthe division of labour is partly conscious, though probably in large\ndegree based on instinctive foundations, and partly the outcome of an\norganic differentiation of structure seen in the reproductive members\nand in the sterile workers, as exemplified in the common wood ant (Fig.\n24). In some cases the workers themselves may be divided into different\ncastes.\n\n[Illustration: FIG. 24.--Wood ant. 1, Queen; 2, male; 3, worker (from\nShipley).]\n\nSo much has been written--and well written--on the social life of\ninsect communities, that it will here suffice to indicate some of\nthe problems which arise when we endeavour to interpret the modes of\nbehaviour which have been carefully observed. In the honey-bee we have\nthe well-known differentiation of structure into drones or effective\nmales, queens or egg-laying females, and workers or ineffective\nfemales, in which the development of the reproductive organs is\narrested or modified. Distinct modes of behaviour are correlated with\nthese structural differences. When a swarm of bees leaves a hive it\ngenerally consists of the old queen-mother and a certain number of the\nworkers which are her offspring. When they have found new quarters,\nor have been safely housed under domestication, the workers busy\nthemselves in making the cells in which the queen may lay her eggs, and\nin which food may be stored. In doing this the bees act in concert,\nand though the mathematical accuracy of the form and size of the cells\nhas been much exaggerated, the comb which results is a very beautiful\nand well-adapted product of mutual co-operation in joint labour. And\nthough intelligence may, under special circumstances, modify the method\nof procedure there can be little doubt that comb-building is primarily\ndue to inherited instinct. The cells are not, however, all of the same\nsize, those for the drones being somewhat larger than the cells in\nwhich the workers are reared, while much larger and differently shaped\ncells are prepared for the future queens. If instinctive therefore--as\nit seems to be in the main--the behaviour runs into different lines,\nthe immediate causes of which, internal or external, we are not able\naccurately to assign.\n\nThe reproductive behaviour of egg-laying in the queen-mother is also\ninstinctive. It is believed that the drones are developed from eggs\nfrom which the queen bee withholds the fertilizing fluid, which she\nretains for months or years after the nuptial flight, stored in a\nspecial receptacle. And the size and shape of the drone-cell may supply\nthe stimulus through which her behaviour in this respect is determined.\nBut she lays similarly fertilized eggs in both the worker-cells and the\nqueen-cells; and in these two cases the stimulating conditions must be\ndifferent.\n\nWhen the eggs have been laid, and the grubs hatched, the worker bees\nassume new duties--the feeding and tending of the young. They eat\nhoney and pollen, which is partially digested, and supplied as pap to\nthe grubs in such quantities that they seem bathed in it; but after a\nshort time a mixture of honey pollen and water is substituted for this\npap. It is said that the drone larv\u00e6 are fed with pap for a longer\nperiod than the workers; and the queen larva undoubtedly receives far\nmore of this pap--or, perhaps, of a still richer nutritive product,\nsometimes spoken of as royal jelly--and, indeed, is supplied therewith\nthroughout larval life. It is generally believed that this high feeding\nis the cause of queen-development, and that should the queen larv\u00e6 die\nordinary worker larv\u00e6 are fed up, and produce queens nowise dissimilar\nto those developed in the royal cells. It is clear, if this be so, that\nthe behaviour of the nurses decides the difference between the future\nqueens and working bees--that is to say, the fertile and the sterile\nfemales. In any case, the feeding of the young by members of the same\ncommunity is a fact to be specially noted. It is commonly said that the\nfamily is the germ from which the social community springs; and it may\nbe added that food-collection or food-administration in some form makes\nthe difference between the family that coheres and the family that\nscatters.\n\nWhen the larv\u00e6 have been fed, each after its kind, the workers seal up\nthe cells with lids of pollen and wax; the larv\u00e6 spin cocoons, pass\ninto the pupa stage, and then change to perfect bees, which bite a way\nthrough the lid and take their place in the hive. These young bees\nnow become the nurses, while the older bees go abroad to fetch honey\nand pollen to be stored away in some of the cells. But when a queen\nemerges, her first act is to go round to the other royal cells, tear\nthem open, and sting to death the helpless occupants. Meanwhile the\nold queen may have led off the surplus population in a swarm, and the\nnew queen reigns in her stead. Idle drones have also been emerging\nfrom their cells; and when the young queen starts forth on her nuptial\nflight she is followed by the drones, mates with one of them, and\nreturns a potential mother of thousands. So long as there is abundance\nof food the useless drones are tolerated; but when there is scarcity\nthey are ejected, and drone eggs, larv\u00e6, and pup\u00e6 are said to be\ndestroyed.\n\nIn the works of Huber and others, further marvels of hive-life, some\nwell-authenticated, others more or less doubtful, are duly set forth.\nBut enough has here been said to show that a social community of bees\npresents problems of animal behaviour which are sufficiently difficult\nof explanation. How far is the behaviour instinctive? How far is it\ndue to experience individually acquired? Are we constrained to admit\na rational factor? If so, is it, like human reason, the result of\ngeneralization from experience of the relationships of phenomena? Or\nare there features of insect psychology which differ from any of which\nwe have firsthand knowledge? These questions are more easily put than\nanswered. As in the case of bird-migration, so too in that of the\nsocial life of bees, there is much that honesty forces us to confess\nour inability satisfactorily to explain.\n\nSo, too, is it in the social life of ants. Among these insects the\nmales and perfect females bear wings, though these appendages may be\nsubsequently shed. In some kinds, however, there are also wingless\nmales or females capable of exercising the reproductive function. The\nworkers are wingless, and are often of two or three kinds, differing\nin form and appearance, and in some cases playing different parts in\nthe social economy. There is also, in some cases, a separate class\nof large-headed soldier ants; so that differentiation of structure\namong the sterile females is carried further in ants than in bees.\nTheir nests generally consist of an elaborate system of chambers and\npassages, either built with pine-needles, as in our common wood ant,\nor hollowed out in the earth or in wood, or sometimes built with a\npaper-like material, or formed of rolled leaves. It is said that a\ncommon ant in Eastern Asia (_\u0152cophylla smaragdina_) \u201cforms shelters\non the leaves of trees, by curling the edges of leaves and joining\nthem together.... The perfect ant has no material with which to fasten\ntogether the edges it curls; its larva, however, possesses glands that\nsecrete a supply of material for it to form a cocoon with, and the\nants utilize the larv\u00e6 to effect their purpose.\u201d[91] This has recently\nbeen confirmed by Mr. E. G. Green, Government entomologist, at the\nBotanic Gardens at Peradeniya, Ceylon. \u201cHe has seen ants actually\nholding larv\u00e6 in their mouths and utilizing them as spinning machines.\nTo find out what would be done, some leaves were purposely separated\nby Mr. Green. The edges of the leaves were quickly drawn together by\nthe ants, and, about an hour later, small white grubs were seen being\npassed backwards and forwards across the gaps made in the walls of the\nshelter. A continuous thread of silk proceeded from the mouth of the\nlarva, and was used to repair the damage.\u201d[92] This is a remarkable\nact of apparently intelligent behaviour. But when we remember how much\nof the time of ants is occupied in carrying about their larv\u00e6, it is\nhardly an act of which it can be affirmed that it could not arise as\nthe result of chance experience.\n\nIn some cases two different genera are found in the same nest, with\nseparate chambers and passages, as in the case of the robber-ant\n(_Solenopsis_) and the slave-ant (_Formica fusca_). The orifices by\nwhich the former enter are too small to allow of the entrance of the\nlatter, \u201chence the robber obtains an easy living at the expense of the\nlarger species,\u201d for \u201cthey make incursions into the nurseries, and\ncarry off the larv\u00e6 as food.\u201d\n\nIn a few cases the foundation of a new colony has been carefully\nwatched. Blockmann was successful in observing the formation of new\nnests by _Componotus ligniperdus_ at Heidelberg. \u201cHe found under\nstones, in the spring, many examples of females, either solitary\nor accompanied only by a few eggs, larv\u00e6, or pup\u00e6. Further, he\nwas successful in getting isolated females to commence nesting in\nconfinement, and observed that the ant that afterwards becomes the\nqueen, at first carries out by herself all the duties of the nest.\nBeginning by making a small burrow, she lays some eggs, and when these\nhatch, feeds and tends the larv\u00e6 and pup\u00e6: the first specimens of these\nlatter that become perfect insects are workers of all sizes, and at\nonce undertake the duties of tending the young and feeding the mother,\nwho, being thus freed from the duties of nursing and of providing food\nwhile she is herself tended and fed, becomes a true queen-ant. Thus\nit seems established that, in the case of this species, the division\nof labour found in the complex community does not at first exist,\nbut is correlative with increasing numbers of the society. Further\nobservations as to the growth of one of these nascent communities, and\nthe times and conditions under which the various forms of individuals\ncomposing a complete society first appear, would be of considerable\ninterest.\u201d[93]\n\nThe queen does not, as in the case of the bee, deposit her eggs in\nseparate cells where they are tended by nurses. The eggs, which are\nlaid in the chambers of the nest, are subjected to much licking by\nthe nurses; the larv\u00e6 are, moreover, moved about from place to place,\nso as to be subjected to the requisite conditions of moisture and\ntemperature. They are carefully cleaned, and after they have passed\ninto the pupa stage the emerging insects are stripped of a delicate\ninvesting skin. And not only do the ants assiduously feed their\nyoung; those who have gone forth and drunk their fill of sweet juices\nfeed those who have remained behind. Forel took some specimens of\n_Componotus ligniperdus_, \u201cand shut them up without food for several\ndays, and thereafter supplied some of them with honey, stained with\nPrussian blue; being very hungry, they fed so greedily on this that\nin a few hours their hind bodies were distended to three times their\nprevious size. He then took one of these gorged individuals, and\nplaced it among those that had not been fed. The replete ant was at\nonce explored by touches of the other ants and surrounded, and food\nwas begged from it. It responded to the demands by feeding a small\nspecimen from its mouth, and when this little one had received a good\nsupply, it in turn communicated some thereof to other specimens; while\nthe original well-fed one also supplied others, and thus the food was\nspeedily distributed. This habit of receiving and giving food is of\nthe greatest importance in the life-history of ants.\u201d[94] It affords\nthe basis or starting-point of the keeping of aphides, the making of\nslaves, the curious development of honey-pot ants, and in some cases\nthe association with ants of other insects.\n\n[Illustration: FIG. 25.--Beetle soliciting food from Ant (after\nWasmann).]\n\nSome of these insects, of which there are many species belonging to\nseveral orders, are parasitic; others appear to be hostile, and yet are\nable to maintain themselves in the nest; others simply live side by\nside with the ants, which seem to be neither hostile nor friendly to\nthem. In some of these cases the biological purpose of the association\nis unknown, while in others the ant serves as a model which the\nassociated insect mimics. Thus in the nest of an Indian ant (_Sima\nrufa-nigra_) occur a small wasp and a spider which, to some extent in\nform and more markedly in coloration, mimic their hosts. \u201cWherever you\nfind this species in any numbers,\u201d says Mr. Rothney,[95] \u201cif you watch\na few moments, you will see a mimicking spider, _Salticus_, running\nabout among the ants, which it very closely resembles in appearance,\nmuch more so in life than in set specimens placed side by side; I have\nseen numbers on the most friendly footing with the ants, though I\nhave never seen them enter their burrows.... They are, I should say,\nthe only friends the ant has, with the exception of a sand-wasp, a\nnew species of _Rhinopsis_ since described by Mr. Cameron, which also\nvery closely mimics the ant, and which, on first observing among the\nworkers, I took to be the male.\u201d But there are some beetles which\nare not only tolerated, but fed by the ants with which they live. In\nthe case of the genera _Atemeles_ and _Lomechusa_, which are always\nfound in or near ants\u2019 nests, the good offices are reciprocal, for the\nbeetles \u201chave patches of yellow hairs, and these secrete some substance\nwith a flavour agreeable to the ants, which lick the beetles from time\nto time. On the other hand, the ants feed the beetles; this they do by\nregurgitating food, at the request of the beetle, on to their lower\nlip, from which it is then taken by the beetle. The beetles in many of\ntheir movements exactly resemble the ants, and their mode of requesting\nfood, by stroking the ants in certain ways, is quite ant-like. So\nreciprocal is the friendship, that if an ant is in want of food the\nbeetle will in its turn disgorge for the benefit of its host. The young\nof the beetles are reared in the nests by the ants, who attend to them\nas carefully as they do to their own young. The beetles are, however,\nfond of the ants\u2019 larv\u00e6 as food, and, indeed, eat them to a very large\nextent, even when their own young are receiving food from the ants.\nWasmann (to whom we are indebted for most of our knowledge on this\nsubject) seems to be of opinion that the ants scarcely distinguish\nbetween the beetle larv\u00e6 and their own young; one unfortunate result\nfor the beetle follows from this, viz. that in the pupal state the\ntreatment that is suitable for the ant larv\u00e6 does not agree with the\nbeetle larv\u00e6. The ants are in the habit of digging up their own kind,\nand lifting them out and cleaning them during their metamorphosis: they\ndo this also with the beetle larv\u00e6, with fatal results; so that only\nthose that have the good fortune to be forgotten by the ants complete\ntheir development.\u201d[96]\n\nAphides, or plant-lice, yield to the solicitations of ants, which\nstroke them with their antenn\u00e6, by emitting a drop of sweet and viscid\nsecretion, and it appears that the caress of the ant is the natural\nstimulus for the emission of the drop. Not only, however, do the ants\ngo forth in search of aphides in their natural haunts, they bring them\nto the neighbourhood of the nest, and may even impound them by building\na wall of earth round and over them. Huber stated that ants collected\nthe eggs of the aphides and tended them in their nests, and the\naccuracy of the observation has been shown by Lord Avebury and others.\n\u201cThe aphid eggs are laid early in October, on the food plant of the\ninsect. They are of no direct use to the ants, yet they are not left\nwhere they are laid, where they would be exposed to the severity of the\nweather and to innumerable dangers, but brought into the nests by the\nants, and tended by them with the utmost care through the long winter\nmonths until the following March, when the young ones are brought out\nand again placed on the young shoots of the daisy.\u201d[97] Dr. McCook\nnoticed that ants, returning from the trees on which aphides abounded,\nfed others near the nests, and he regarded this as a case of division\nof labour, the foragers obtaining food for the nurses which remained in\nor near the nest.\n\nA further division of labour, carried to lengths which seem almost\nabsurd, is found in the honey-pot ant of the United States and Mexico.\nThe juice on which these ants feed is obtained from an oak-gall.\nForagers go forth at night and return distended with the sweet fluid,\nand, having fed the ordinary workers in the nest, apparently discharge\nthe balance of their store into living honey-pots, which remain in\nthe nest and preserve the food till it may be required by the members\nof the community. Their abdomens are enormously distended, they never\nleave the nest, and they seem to form a distinct caste, whose function\nit is to passively accumulate stores of reserve food for the community.\nCuriously enough the same peculiar social arrangement is found in\ndifferent genera living as far apart as Mexico, Australia, and South\nAfrica.\n\n[Illustration: FIG. 26.---Honey-pot Ant.]\n\nThere is no doubt that in some cases the division of labour is not\nrestricted to the individuals of the same species, but that other\nspecies are introduced into the nest to perform certain functions--thus\ngiving rise to the so-called slavery among ants. This is carried to\nan extreme in the European species _Formica rufescens_, the males and\nqueens of which do no work, while the sole function of the workers\nis to capture slaves of the smaller species _Formica fusca_. In\nassociation with this specialized mode of instinctive behaviour, \u201ceven\ntheir bodily structure has undergone a change; their mandibles have\nlost their teeth, and have become mere nippers, deadly weapons indeed,\nbut useless except in war. They have lost the greater part of their\ninstincts: their art--that is, the power of building; their domestic\nhabits--for they take no care of their own young, all this being done\nby the slaves; their industry--they take no part in providing the\ndaily supplies; if the colony changes the situation of its nest, the\nmasters are all carried by the slaves to the new one; nay, they have\neven lost the habit of feeding.... I have had a nest of this species\nunder observation for a long time, but never saw one of the masters\nfeeding. I have kept isolated specimens for weeks, by giving them a\nslave for an hour or two a day to clean and feed them, and under these\ncircumstances they remained in perfect health, while, but for the\nslaves, they would have perished in two or three days.\u201d[98]\n\nIn this matter, we have in different species successive stages in the\ndevelopment of the instinctive behaviour which is thus carried so far\nin _Formica rufescens_. Our English ants, of the species _Formica\nsanguinea_, have fewer slaves and are less dependent on them; they\ncan feed and forage for themselves, and during migration carry their\nslaves--which are of the same species as in the other case--instead of\nbeing carried by them. In the nests of the common wood ant or horse\nant (_Formica rufa_) there are occasionally a few slaves. Lord Avebury\nthinks it likely that they are developed from larv\u00e6 or pup\u00e6, originally\ntaken for food, which have by chance come to maturity in the nest of\ntheir captors.\n\nBut one more incident in the social life of ants can here be\nnoticed--though many others could be given did space permit. The\nleaf-cutting ants of America form paths from their nests to suitable\ntrees, from which to obtain the small coin-like leaf fragments, which\nthey carry in the mandibles, and hence have gained the name of umbrella\nor parasol ants. These paths are sometimes underground; and Mr. McCook\nmeasured one which ran at a depth of some 18 inches beneath the surface\nfor 448 feet, and was then continued for another 185 feet to the tree\nwhich the ants were stripping. The whole path was in an almost perfect\nstraight line from nest to tree. The leaf fragments are stored in large\nquantities in the nest, and it was long a matter of uncertainty for\nwhat purpose they were collected. The problem was solved by Alfred\nM\u00f6ller, who found that the leaves, which are subdivided and masticated\nby a special set of workers within the nest, form the appropriate\nmaterial in which the threads of a fungus ramify and flourish. This\nfungus is tended by the ants with great care, and is made to produce a\nspecially modified form of growth, not found under other circumstances,\nin the form of white aggregations, termed by M\u00f6ller \u201cKohlrabi clumps.\u201d\nThese form the principal food of the ants; and the spongy mass of earth\nand leaves is called the fungus garden. \u201cIf a nest be broken into\nand the fungus garden scattered, the ants collect it as quickly as\npossible, especially the younger parts, taking as much trouble over it\nas over the larv\u00e6. They also cover it up again as soon as possible to\nprotect it from the light.\u201d[99]\n\nAgain, it may be asked with regard to the social life of ants as\nwith respect to that of bees--How far is their complex behaviour\ninstinctive? How far is it due to imitation? What part does\nintelligence play, and under what conditions of acquisition? Is reason,\nin the restricted sense of the word, a factor in the development of\nthe behaviour? I cannot answer these questions, and am of opinion that\nmuch detailed observation is yet needed before we can do much more\nthan speculate in the matter. Much indeed has been done, but yet more\nremains for future investigation.\n\nThe conditions under which much of the behaviour is carried out seem to\nindicate strong instinctive tendencies which give an hereditary trend\nto the direction which the social behaviour takes. Dr. Bethe,[100]\nindeed, goes so far as to regard the behaviour as almost entirely\ninstinctive, affording little evidence of that modifiability of\nreactions which indicates intelligent guidance. He shows as the result\nof careful experiment that the behaviour of ants to friends and enemies\nare direct reactions to smell. Enemies washed with the excretions of\nmembers of the nest are treated as friends, notwithstanding their\ndifferent colour, size, and general appearance. By scent, too, they\nfollow the lead of others and retrace their way to the nest; this, he\nsays, is not the result of a mental process, but is the reaction of a\ncomplicated reflex mechanism. As the outcome of careful observation,\nDr. Bethe\u2019s conclusions are of great value and interest. But he seems\nto go too far in denying to ants any power of intelligent accommodation\nto circumstances. If we admit intelligence, then the fact that the\ninsects come forth in the midst of a community in full social activity\nwould tend to the imitative or intelligent acquisition of like modes\nof procedure. It is difficult to distinguish the share taken by these\ntwo factors which may well co-operate. And if natural selection is\nexercising its influence through the elimination of those which do not\nfall into line in social behaviour, there would be ample opportunity\nfor the survival of coincident variations.[101] If one may be allowed\nto speculate, it seems probable that the interaction of instinct\nand intelligence will be found with fuller knowledge to suffice for\nthe explanation of the facts, without calling in the known but here\nimprobable factor of rationality or any factors unknown elsewhere in\npsychology.\n\nSome interesting observations of Lord Avebury\u2019s are sometimes quoted\nas evidence that ants are lacking in intelligence, but (if we accept\nthe distinction already drawn[102]) they seem rather to show the lack\nof reason. \u201cI placed food,\u201d he says,[103] \u201cin a porcelain cup, on a\nslip of glass surrounded by water, but accessible to the ants by a\nbridge, consisting of a strip of paper two-thirds of an inch long and\none-third wide. Having then put an ant (_Formica nigra_) from one of\nmy nests to this food, she began carrying it off, and by degrees a\nnumber of friends came to help her. When about twenty-five ants were\nso engaged, I moved the little paper bridge slightly, so as to leave a\nchasm just so wide that the ants could not reach across. They came to\nthe edge and tried hard to get over, but it did not occur to them to\npush the paper bridge, though the distance was only about one-third of\nan inch, and they might easily have done so. After trying for about a\nquarter of an hour they gave up the attempt and returned home. This I\nrepeated several times. Then, thinking that paper was a substance to\nwhich they were not accustomed, I tried the same with a bit of straw\none inch long and one-eighth of an inch wide. The result was the same.\nAgain, I placed particles of food close to and directly over the nest,\nbut connected with it only by a passage several feet in length. Under\nthese circumstances it would be obviously a saving of time and labour\nto drop the food on to the nest, or at any rate to spring down with\nit, so as to save one journey. But though I have frequently tried the\nexperiment, my ants never adopted either of these courses. I arranged\nmatters so that the glass on which the food was placed was only raised\none-third of an inch above the nest. The ants tried to reach down, and\nthe distance was so small that occasionally, if another ant passed\nunderneath just as one was reaching down, the upper one could step on\nto its back, and so descend; but this only happened accidentally, and\nthey did not think of throwing the particles down, nor, which surprised\nme very much, would they jump down themselves. I then placed a heap of\nmould close to the glass, but just so far that they could not reach\nacross. It would have been quite easy for any ant, by moving a particle\nof earth for a quarter of an inch, to have made a bridge by which the\nfood might have been reached, but this simple expedient did not occur\nto them.\u201d\n\nNow, when we remember that the method of intelligence is to profit\nby chance experience, while the method of reason is, with foresight\nand intention, to adapt means to ends, we shall see that to move a\nstraw even a quarter of an inch, or to make a bridge with particles\nof mould, would require rational and not merely intelligent powers.\nChance experience would not supply the necessary data to be utilized\nby intelligence when repetition had established an association in the\nconscious situation. Granting that the ants were intelligent but not\nrational, they could not be expected to overcome the difficulties,\nsimple as they seem to us, which Lord Avebury placed in their path. Had\nthey been overcome the fact would be more difficult to explain than the\nuse of a stone tool by the sand wasp, since this could more readily be\nhit upon by chance experience. And what these valuable experiments, of\nwhich kind more are needed, seem to show is, that the ant, probably\nthe most intelligent of all insects, has no claim to be regarded as a\nrational being.\n\n\nIV.--ANIMAL TRADITION\n\nIn that interaction between instinct and intelligence which, when\nfurther detailed work has sifted and purified our knowledge of the\npsychology of animal communities, may prove sufficient to account for\nthe well-established facts, animal tradition will probably have to be\nrecognized as of no little importance. When a newly emerging ant or\nbee, or a young bird or mammal is born into a community where certain\nmodes of behaviour are already in full swing, an imitative tendency\nof the follow-my-leader type may lead it to fall in line with the\ntraditional habits. It is said that young ants follow the older workers\nabout the nest, and are \u201ctrained to a knowledge of domestic duties,\nespecially in the case of larv\u00e6.\u201d On the other hand, we have seen that,\nin certain observed cases, the queen ant is the solitary starting-point\nof a new community, and that the division of labour follows with the\nincreasing numbers of the newly formed social group; so that, in such\ncases, whatever part tradition may play in the later phases of social\nlife, it cannot afford a sufficient account of the division of labour\nin the earlier history of the community. We need, however, fuller\ninformation concerning the continued life-history of such communities\nunder natural conditions, and as to how far they remain self-contained\nwithout any incorporation of older members from adjoining nests. In\nthe case of bees, where the old queen departs with a swarm, there may\nbe greater continuity of tradition. But how far this is a necessary\nfactor in social development is at present a matter of conjecture. In\nthe herd of mammals and the flock of birds, and in all the family and\nsocial life in these classes of animals, the example of elders, without\nany imitation of the higher reflective type, can scarcely be without\nits influence on the behaviour of the young which, one would suppose,\nwould tend to fall in with the ways which had become traditional in\nthe species. Professor Wesley Mills tells us that a mongrel pup, whose\npsychical development he carefully watched, showed \u201cextraordinarily\nrapid\u201d progress when he was introduced to the society of other dogs,\nand was thus subjected to the influence of canine tradition.\n\nHow far this influence extends in animal communities--how far it\nis either a necessary or even an important contributory factor in\nthe development of certain modes of behaviour--is at present in\nlarge degree a matter of speculation. And the only justification\nfor speculation in science is that it may open our eyes to modes of\ninfluence the range and limits of whose effects may be submitted to the\ntouchstone of careful observation, and, if possible, experiment. In\nthis instance it is rather the indefiniteness of the evidence before us\nthan its absence that stands in the way of any profitable discussion of\nthe problem from the evidential point of view. And this indefiniteness\nis partly due to the fact that the need of observation is not realized,\nbecause this factor in animal behaviour has not been distinguished with\nsufficient clearness. It is worth while, therefore, to devote a short\nspace to a consideration of the relation of this tradition to instinct\nand intelligence with a view to the focussing of observation on the\nfacts by which it may be further elucidated.\n\nIn the first place, it is probable that, as in other modes of animal\nbehaviour, traditional procedure is founded on an instinctive basis.\nThis must be an imitative tendency of the broad follow-my-leader\ntype indicated in the first section of this chapter. And this would\nafford wide instinctive foundations, which would owe their hereditary\ncharacter to the fact that, under natural selection, those individuals\nin the community would survive which fell into line with the adaptive\nbehaviour of their companions, while those which failed in this respect\nwould be eliminated as more or less isolated outsiders, standing apart\nfrom the social life. In illustration we may take a hypothetical\ncase, founded, however, upon observation. The Rev. S. J. Whitmee, a\nmissionary in Samoa, believes that the tooth-billed pigeon of these\nislands (_Didunculus strigirostris_) \u201chas probably been frightened when\nroosting, or during incubation, by attacks of cats, and has sought\nsafety in the trees. Learning, from frequent repetition of the fright,\nthat the ground is a dangerous place, it has acquired the habit of\nbuilding, roosting, and feeding on the high trees; and this habit is\nnow operating for the preservation of this interesting bird, which a\nfew years ago was almost extinct.\u201d[104] Now, in this case, the young\nbirds which followed the lead of those who, under experience, had\nacquired the habit, would stand a better chance of survival than those\nwho, failing to do so, were caught napping on the ground. In further\nillustration, we may take the case of two species of rats found by\nMr. C. M. Woodford on one of the Solomon Islands. These two species\nare regarded by Mr. Oldfield Thomas as slightly altered descendants\nof one parent species, with adaptations due to the fact that, of this\noriginal species, some have adopted a terrestrial, others an arboreal\nlife. Thus _Mus rex_ lives in trees, has broad footpads, and a long\nrasp-like, probably semi-prehensile tail; while _Mus imperator_ lives\non the ground, has smaller pads, and a short smooth tail. How far the\ndifferent modes of behaviour in the two species may have been fostered\nby the influence of tradition we do not know; but it is not improbable\nthat such an influence would be a co-operating factor in the process of\nsegregation, and that in the course of time each form has been adapted\nto its special environment through the elimination of those individuals\nwhich were not in harmony with the conditions of their life.\n\nSuch a case--admittedly hypothetical in the interpretation put upon the\nfacts--may help us to see how the general instinctive follow-my-leader\ntendency might become specialized in certain essential lines of racial\nbehaviour, and how, under natural selection, coincident variations in\nthe line of traditional acts might become more and more definitely\ninherited as, at first, strong instinctive tendencies, and eventually\nmore stereotyped modes of instinctive behaviour. This, indeed, may have\nbeen the mode of origin of some of the social instincts.\n\nReverting, however, to the stage where the general instinctive\nfollow-my-leader tendency is only partly or incompletely specialized\nalong particular lines of behaviour, we should have at this stage\ncertain hereditary trends of action, dependent on stimuli afforded\nby the behaviour of others, but needing, for their guidance to finer\nissues and more adequate and highly perfected performance, the play\nof intelligence and the satisfaction of nascent social impulses. In\nthe economy of the hive or the nest there are, no doubt, instinctive\ntendencies and predispositions; but there is also something more than\norganic heredity with its transmitted modes of behaviour analogous\nto the inherited form and structure of the body or its parts.\nConsciousness exerts a guiding influence. The insect is not independent\nof experience, but is capable of profiting by the teachings of that\nfertile mother of all intelligent behaviour. It is unnecessary,\nhowever, to insist on the fact that such insects are something more\nthan instinctive automata, but are guided in their behaviour by the\nresults of experience. Many careful observers lay stress upon this;\nif, indeed, they do not go further and claim for the social insect the\nhigher rational faculty. \u201cWhen we see,\u201d says Lord Avebury,[105] \u201can\nant-hill tenanted by thousands of industrious inhabitants, excavating\nchambers, forming tunnels, making roads, guarding their home, gathering\nfood, feeding the young, tending their domestic animals--each one\nfulfilling its duties industriously, and without confusion--it is\ndifficult altogether to deny to them the gift of reason; and the\npreceding observations tend to confirm the opinion that their mental\npowers differ from those of man, not so much in kind as in degree.\u201d\n\nIf the term \u201creason\u201d be here accepted in the broad sense, and not\nin the narrower sense before indicated, this passage will probably\nbe endorsed by the majority of those who have paid any attention to\nthe subject. Even those who regard \u201creason,\u201d in the more restricted\nacceptation of the term, as outside any scheme of evolution, since it\ndiffers in kind and not merely in degree, would probably deny this\nfaculty to ants. In any case the passage expresses the conviction of\na close and singularly unprejudiced observer, that the doings of ants\ninvolve conscious guidance in the light of experience individually\nacquired.\n\nAnd yet the behaviour of different species of ants, each after its\nkind, is remarkably constant--so constant that, to use the words of Dr.\nPeckham in another connection, it is characteristic of the species, and\nwould be an important part of any definition of the insect based upon\nits habits. And some part of this constancy may be due to tradition,\nthough much of it may result from strong instinctive tendencies which\nintelligence guides to similar ends, because the conditions are similar\nin successive generations of social insects.\n\nFrom the point of view of observation, however, it is particularly\ndifficult to distinguish the part played by tradition as a\npsychological influence from that played by what we have above\ndescribed as instinctive imitation. In our study of other modes of\ninstinctive behaviour we can isolate an individual, or group of young\nindividuals, and observe how far certain acts are performed prior\nto any experience. Thus chicks behave in certain instinctive ways\nunder conditions which preclude their learning from the hen or other\nolder birds--so that tradition cannot be operative. But where social\nbehaviour is concerned, such methods of observation are necessarily\nexcluded, since isolation involves the absence of the social factor.\nAnd if certain instinctive acts require for their due performance\nthe stimulus of the like performance in others, what is this but a\nform of instinctive tradition; and how are we to distinguish it from\nintelligent tradition, where a psychological factor has freer play\nand exercises guidance over the performance? In the present state\nof our knowledge we can do no more than suggest, as not improbable,\nthat tradition passes through three phases: the first in which it is\ninstinctive; the second in which it becomes intelligent through the\nsatisfaction which the due performance of traditional acts arouses in\nconsciousness; and the third in which, at any rate in man, it takes\non a rational form, and is made to accord with an ideal scheme, the\nproduct of conceptual thought and of reflection on data which have\nbeen generalized and considered in their due relationships to the\nscheme which takes definite form in the mind. Whether in the social\ncommunities of insects or those of beavers, among mammals, or rooks\namong birds, tradition has begun to pass into the third or rational\nstage, we do not know. It may be so, but probably the development along\nthese lines has not been carried far. Presumably in the ant, rook, and\nbeaver anything like an ideal scheme of thought based on reflection, if\nit exist, is as yet exceedingly indefinite.\n\nBut even supposing that no animal has yet risen beyond the second or\nintelligent stage, it is none the less important to realize that we\nhave here, in animal life, the foundations on which may be raised what\nmay, perhaps, be regarded as one of the characteristic features of\nhuman progress. This characteristic is the transference of evolution\nfrom the organism to the environment handed on from generation to\ngeneration. Thus man, \u201cavailing himself of tradition, is able to\nseize upon the acquirements of his ancestors at the point where they\nleft them.\u201d[106] Thus \u201che has slowly accumulated and organized the\nexperience which is almost wholly lost with the cessation of individual\nlife in other animals.\u201d[107] But he is able to do so through the\nextension, refining, and fixing of that instinctive and intelligent\ntradition which begins to take form in animal communities.\n\n\nV.--THE EVOLUTION OF SOCIAL BEHAVIOUR\n\n\u201cAnimals of many kinds,\u201d said Darwin,[108] \u201care social; every one\nmust have noticed how miserable horses, dogs, sheep, etc., are when\nseparated from their companions. The most common mutual service in\nthe higher animals is to warn one another of danger. Every sportsman\nknows how difficult it is to approach animals in a herd or troop.\nWild horses and cattle do not, I believe, make any danger-signal; but\nthe attitude of any one of them who first discovers an enemy warns the\nothers. Rabbits stamp loudly on the ground with their hind feet as a\nsignal; sheep and chamois do the same with their fore feet, uttering\nlikewise a whistle. Many birds and some mammals post sentinels. The\nleader of a troop of monkeys acts as such, and utters cries expressive\nboth of danger and of safety. Social animals perform many little\nservices for each other: horses nibble, and cows lick each other;\nmonkeys search each other for external parasites, and are said to\nremove thorns and burrs. Social animals mutually defend each other.\nBull bisons in North America, when there is danger drive the cows and\ncalves into the middle of the herd, whilst they defend the outside.\nAmong baboons the old males come forward to the attack. Wolves hunt in\npacks; and pelicans fish in concert.\n\n\u201cIt has often been assumed,\u201d continues Darwin, \u201cthat animals were in\nthe first place rendered social, and that they feel as a consequence\nuncomfortable when separated from each other, and comfortable whilst\ntogether; but it is a more probable view that these sensations were\nfirst developed, in order that those animals which would profit by\nliving in society should be induced to live together, in the same\nmanner as the sense of hunger and the pleasure of eating were, no\ndoubt, first acquired in order to induce animals to eat. The feeling\nof pleasure from society is probably an extension of the parental and\nfilial affections, since the social instinct seems to be developed by\nthe young remaining long with their parents; and this extension may be\nattributed in part to habit, but chiefly to natural selection. With\nthose animals which were benefited by living in close association,\nthe individuals which took the greatest pleasure in society would\nbest escape various dangers; while those which cared least for their\ncomrades, and lived solitary, would perish in greater numbers. In\nhowever complex a manner the feeling of sympathy may have originated,\nas it is one of high importance to all those animals which aid and\ndefend one another, it will have been increased through natural\nselection; for those communities which included the greatest number of\nthe most sympathetic members would flourish best, and rear the greatest\nnumber of offspring.\u201d\n\nIt is impossible to improve upon this pithy description of the salient\nfacts, and terse explanation in terms of the hypothesis of natural\nselection. It may, perhaps, be urged that, on this hypothesis, the\norigin of the social state, through a biological association of\nindividuals, probably neither preceded nor followed the development of\na psychical bond arising from the sense of satisfaction and comfort\nafforded by social life, but that both originated _pari passu_. If\nthe linkage was primarily instinctive, its intelligent continuance\ncould only be effected through the pleasure social behaviour carried\nwith it, and the discomfort of separation from the community. No\ninstinctive acts would be persistently repeated, under the guidance of\nindividual experience, if that experience proved bitter and not sweet.\nAn animal with thwarted instincts is one with unsatisfied impulses;\nits biological and its psychological tendencies are alike unfulfilled.\nWhat Darwin saw and wished to enforce, however, was that the psychical\nlink of conscious satisfaction was a necessary prerequisite of the\ncontinuance and further evolution of sociability; and that without the\nintegrating bonds of sympathy any advance of social development was\nimpossible.\n\nIn two able and interesting articles in the _Nineteenth Century_\nreview,[109] on \u201cMutual Aid among Animals,\u201d Prince Kropotkine gives a\nuseful and sufficiently detailed summary of the chief facts concerning\nthe social relationships which have been observed in the animal\nkingdom--including, perhaps, some rather apocryphal instances,--and\ncombats Huxley\u2019s statement[110] that, \u201cbeyond the limited and temporary\nrelations of the family, the Hobbesian war of each against all is the\nnormal state of existence\u201d among animals and primitive men. \u201cLife in\nsocieties,\u201d says Prince Kropotkine, \u201cis no exception in the animal\nworld. It is the rule, the law of nature, and it reaches its fullest\ndevelopment with the higher vertebrates. Those species which live\nsolitary, or in small families only, are relatively few, and their\nnumbers are limited.\u201d[111] \u201cLife in societies enables the feeblest\ninsects, the feeblest birds, and the feeblest mammals to resist, or to\nprotect themselves from, the most terrible birds and beasts of prey; it\npermits longevity; it enables the species to rear its progeny with the\nleast waste of energy, and to maintain its numbers, albeit with a very\nslow birth-rate; it enables the gregarious animals to migrate in search\nof new abodes. Therefore, while fully admitting that force, swiftness,\nprotective colours, cunningness, and endurance to hunger and cold,\nwhich are mentioned by Darwin and Wallace, are so many qualities making\nthe individual or the species the fittest under certain circumstances,\nwe maintain that under _any_ circumstances sociability is the greatest\nadvantage in the struggle for life.... The fittest are thus the most\nsociable animals, and sociability appears as the chief factor in\nevolution, both directly, by securing the well-being of the species\nwhile diminishing the waste of energy, and indirectly by favouring the\ngrowth of intelligence.\u201d[112] And summarizing his argument, Prince\nKropotkine says,[113] \u201cWe have seen how few are the animal species\nwhich live an isolated life, and how numberless are those which live\nin societies, either for mutual defence, or for hunting and storing\nup food, or for rearing their offspring, or simply for enjoying life\nin common. We have also seen that, though a good deal of warfare goes\non between different species, or even different tribes of the same\nspecies, peace and mutual support are the rule within the tribe, or the\nspecies; and that those species which best know how to combine, and to\navoid competition, have the best chances of survival and of further\nprogressive development. They prosper, while unsociable species decay.\u201d\n\nPrince Kropotkine seems, however, to push his argument too far.\nThe assertion that the fittest are the most sociable animals, that\nsociability appears as the chief factor in evolution, and that\nunsociable species decay, is not likely to be accepted without\nqualification by zoologists. What grounds have we for saying that the\nsolitary wasps are less fit than the social wasps? Each has a fitness\naccording to its kind. Can it be maintained that the unsocial tiger\nis less fit than the social jackal? And can it be said that tigers,\nwhich are reported absolutely to swarm in Java and Sumatra, exemplify\nthe decay of an unsociable species? Is it seriously contended that\nthe hawk, which may be successfully mobbed by a number of wagtails,\nis less fit than his more social assailants? And are the unsocial\nraptorial birds decaying species? Such questions might be asked by the\nscore. And the answer in every case is that the social and unsocial\nalike are fitted to their several states of life. In fact, it might\nbe contended, with every whit as much if not more cogency, that\nsociability is nature\u2019s device for enabling the weaker, and hence in\nthemselves the less fit, to resist the attacks and encroachments of the\nstronger and individually fitter. Discussing the possibilities of human\nancestry, Darwin said:[114] \u201cIn regard to bodily size or strength, we\ndo not know whether man is descended from some comparatively small\nspecies like the chimpanzee, or from one as powerful as the gorilla.\nWe should, however, bear in mind that an animal possessing great size,\nstrength, and ferocity, which, like the gorilla, could defend itself\nfrom all enemies, would not perhaps have become social; and this would\nmost effectually have checked the acquirement of the higher mental\nqualities, such as sympathy and the love of his fellows. Hence it\nmight have been an immense advantage to man to have sprung from some\ncomparatively weak creature.\u201d\n\nZoologists, again, will hardly accept without question Prince\nKropotkine\u2019s assertion that \u201clife in societies is no exception in the\nanimal world, but is the rule, the law of nature.\u201d Many will contend,\non the other hand, that life in societies with anything like division\nof labour, or with mutual aid (and this seldom carried far), is, taking\nthe animal kingdom as a whole, of comparatively rare occurrence, though\nnone the less noteworthy where it exists. And, in any case, it seems\nsomewhat extravagant to say that sociability is the chief factor in\nevolution. No doubt it might be plausibly urged that human society is,\nfrom man\u2019s point of view, the highest product of evolution; that in\nattaining to this end sociability has been the leading factor; and that\nobviously the leading factor in the evolution of the highest product\nmay properly be called the chief factor in evolution. But Prince\nKropotkine apparently means that sociability is the chief factor, not\nonly in this evolution, but in all organic, or, at least, all animal\nevolution. In this he will receive the support of but few zoologists.\nBy some extravagance of statement he has weakened his own case,\nwhich is otherwise not lacking in points of weakness. The legitimate\ninferences from animal behaviour are, that co-operation is in some\ncases a factor in the evolution of a successful species, that in human\nprogress it has been an important factor giving strength to a creature\nweak in tooth and claw, and that this factor has co-existed, and still\ncoexists, with that of competition, in the absence of which the race\nwould be dragged down to lower levels of efficiency by the incubus of\nweaklings.\n\nTo Professor Alfred Espinas[115] we owe the best and fullest discussion\nof the social life of animals, and to his work the reader may be\nreferred for a careful and, for the most part, unstrained and unbiassed\nconsideration of the phenomena. In common with others who have\ndevoted serious attention to the subject, he sees in the family the\nstarting-point of the higher and more comprehensive social group, or\n\u201cpeuplade.\u201d Prince Kropotkine seems, indeed, to combat this view; but\nthe divergence of opinion is more apparent than real. He tells us[116]\nthat anthropology \u201chas established beyond any doubt that mankind did\n_not_ begin its life in the shape of small isolated families. Far\nfrom being a primitive form of organization, the family is a very\nlate product of human evolution.... Societies, bands, or tribes--not\nfamilies--were thus the primitive form of organization of mankind and\nits earliest ancestors.\u201d And in support of his views he adduces the\nsexual communism which is said to be found in the lowest savages,\nand briefly traces the development of monogamy and the genesis of\nthe family ideal as we conceive it. It may at once be admitted that\nin all probability mankind did not have its origin in small isolated\nfamilies. If we do not admit this we must accept the alternative\nhypothesis, that man was developed from an unsocial ancestor. For\nthough the biological family is the starting-point of the community,\nit does not of course follow that wherever there is so much coherence\nbetween parents and offspring as to form a temporary family group, a\nsocial community must in due course arise. In such unsocial carnivora\nas the tiger, the temporary linkage of family life is strong while it\nlasts. But though mankind presumably originated in a prehuman race that\nhad already reached some degree of social coherence, there remains\nbehind the question--what was the origin of this social group? And to\nthis question, Prince Kropotkine, in common with Darwin and Espinas,\nwould probably answer without hesitation, that the primeval germ of\nthe social community lay in the prolonged coherence of the group of\nparents and offspring. In the unsocial animals the family separates and\ndisintegrates before the offspring mate. But if the family continue to\ncohere, the mating of offspring will give rise to the continuity of\ncoherence found in the herd, or troop, or tribe. For new family groups\nwill be constantly arising before the old family groups have ceased to\nbe associated. Thus would be afforded more opportunity for tradition\nthan among the unsocial animals.\n\nHow, then, can it be said that, \u201cfar from being a primitive form of\norganization, the family is a very late product of human evolution\u201d?\nBy using the word \u201cfamily\u201d in a sense somewhat different--nay,\nwidely different--from that in which it is employed in a biological\ndiscussion. In the latter usage sexual communism is not excluded; A.,\nB., and C., D. may have offspring this season; A., D., and C., B.\nnext season. In each season there are family groups with interchange\nof partners. This does not, however, conform with our conception of\nthe family as realized under civilization. Herein, in fact, lies the\nessential difference between the human and the animal family. The one\nis a realized ideal; the other is merely a natural occurrence. Even in\nthe case of monogamous animals, mating for life is probably not conduct\nin conformity with an ideal, but is due to the fact that instinctive\ntendencies have taken this line of direction. On the other hand, in\nmonogamous communities of mankind, there is, unfortunately, evidence\nthat in some cases the ideal is not strong enough to prevent presumably\nancestral tendencies in the direction of communism.\n\nThe basis of human social conduct is unquestionably to be traced\nin the social behaviour of animals, in inherited tendencies to\nco-operation and mutual help, in the bonds of sympathy arising through\nthe satisfaction of impulses towards such behaviour, and perhaps, to\nsome extent, in the influence of tradition. It is not, however, until\nthis tradition is rendered, through descriptive communication, more\ncontinuous and more effective; it is not until an ideal of mutual\naid, and social conduct generally, takes form and is rendered common\nto the tribe; it is not until the more or less realized conceptions\nof one generation are handed on to become the environment under which\nthe succeeding generations are nurtured; it is not indeed until man\nconsciously and reflectively aims at the bettering of his environment\nin accordance with standards rationally conceived and deliberately\ncarried into execution; that a new _r\u00e9gime_ of civilized progress,\nelsewhere unknown in nature, takes definite form. Under this _r\u00e9gime_,\nthe elimination of failures through natural selection, though it may\nnot be entirely superseded, plays a subordinate part; alongside the\norganic continuity which is due to physical heredity, there runs a\ncontinuity of tradition through social inheritance.\n\nHuman civilization is an embodiment of reason, a product of reflection,\na realization of ideals conceived by the leaders of mankind. All this\nforms the environment of each one of us. And it is this environment\nwhich is undergoing progressive evolution and playing on the rational\nfaculties of those which are submitted to its moulding influence.\nThere is no sufficient evidence of anything of the kind in the social\ncommunities of animals. This, of course, must be accepted merely as an\nexpression of opinion. But on the hypothesis that animals are rational\nbeings, capable of reflection, it is difficult to understand why they\nshould remain at so low a level of social achievement. The absence\nof powers of descriptive intercommunication is often assigned as the\ncause of their comparatively unprogressive condition; but it may be\nregarded as the sign, rather than the cause, of their lack of reason in\nthe more restricted sense of the term. We cannot, however, enter into\nthe much-disputed question whether reason is the product of language,\nor language the outcome of reason. Perhaps the safest position is to\nassume that rationality and true speech are in large measure different\naspects of one evolutionary movement--speech arising out of such\npreceding modes of communication as were considered in the second\nsection of this chapter; reason developing out of intelligence which\nsupplies its necessary data. It is sometimes said that, notwithstanding\ntheir powers of speech, savages in their social relations show little\nadvance on animal communities. But surely such statements must be made\nin forgetfulness of the fact that savage customs almost invariably\nindicate the presence and sway of ideals which puzzle us from their\nquaintness, and from the fact that they seem contrary to the dictates\nof intelligence and due to motives and conceptions the nature and force\nof which we find it difficult to estimate. The passage from intelligent\nsocial behaviour to the rationality which has assumed such strange\naspects among existing savages took place somewhere at some time in the\npast; and the stages of its evolution are hidden from our view. All\nwe can say is, that it is possible to trace in animal behaviour some\nof the instinctive tendencies and intelligent modes of accommodation\nto social circumstances, together with the germs of imitation,\nintercommunication, and tradition, and the establishment of bonds of\nsympathy, without which the subsequent stages of evolution would be\ninconceivable.\n\n\n\n\nCHAPTER VI\n\n_THE FEELINGS AND EMOTIONS_\n\n\nI.--IMPULSE, INTEREST, AND EMOTION\n\nAny discussion of animal behaviour must deal largely with what is\ntermed the conative aspect of consciousness. \u201cThe states designated by\nsuch words as _craving_, _longing_, _yearning_, _endeavour_, _effort_,\n_desire_, _wish_, and _will_,\u201d says Dr. Stout, in his admirable \u201cManual\nof Psychology,\u201d[117] \u201chave one characteristic in common. In all of\nthese there is an inherent tendency to pass beyond themselves and\nbecome something different. This tendency is not only a fact, but an\nexperience; and the peculiar mode of being conscious, which constitutes\nthe experience, is called _conation_.\u201d Closely associated with this\nconation is _impulse_, which Dr. Stout defines as \u201cany conative\ntendency, so far as it operates by its own isolated intensity, apart\nfrom its relation to a general system of motives. Action on impulse\nis thus contrasted with action which results from reflection and\ndeliberation.\u201d[118] In the interpretation we have advocated, animals\nare essentially creatures of impulse, and not to any large extent,\nif at all, reflective agents. And their impulses may be associated\neither with their inherited and congenital behaviour, or with that\nwhich is due to acquired experience. In other words, their impulses may\nbe divided broadly into two classes, the one instinctive, the other\nacquired.\n\nDr. Stout says that conation is not only a fact, but an experience.\nNow, first as to the fact. It seems to be the correlative in\nconsciousness of the behaviour of the nervous system under stimulation.\nLet us take some simple case such as that, for example, of a hungry\nchick pecking at a grain of corn. This is explained from the\nphysiological point of view by saying that internal and external\nstimulation--internal from the digestive organs and system in need\nof food, external through the eye--gives rise to a state of unstable\nequilibrium in the nerve-centres; and that, when the instability\nreaches a certain value, the nervous system discharges into the\nmotor organs, the chick pecks, and stable equilibrium is restored.\nThe tendency to discharge in some way under stimulation is an\nessential characteristic of a nervous system. It is one of the facts\nof physiological science. So, too, the conative tendency is one of\nthe facts of psychological science; it is a change in the situation\nintroduced by the effects of the physiological discharge.\n\nLet us here parenthetically notice that the physiological tendency\nin the nervous system is an evolved complication and a specialized\ndevelopment of one of the fundamental properties of protoplasm--that\nwhich is often spoken of as irritability. One of the characteristics\nof all living matter is its \u201cexplosive\u201d instability. So that at the\nvery threshold of organic behaviour we have the analogue of that which,\nin its developed form, becomes the tendency of the nervous system to\ndischarge as the result of stimulation. The conative tendency of the\npsychologist, therefore, has its roots deep down in the elemental germs\nof all organic life.\n\nAnd this conative tendency is, says Dr. Stout, not only a fact but an\nexperience. Let us return to our hungry chick that pecks at a grain of\ncorn. And let us grant that as the result of stimulation there arise\nstates of consciousness which we describe as a feeling of hunger and\nthe sight of the grain of corn. The nervous system now discharges;\nand there are introduced into the situation a further group of data,\nthe motor consciousness of the actual behaviour, sensory data from\nthe results of the act, the seizing of the grain and so forth. The\nsituation has unquestionably changed. But is there any specific\nconsciousness of the conative tendency as such? Is there any \u201cpeculiar\nmode of being conscious which constitutes the experience which is\ncalled conation\u201d? It is difficult to say. Hence we find differences of\nopinion among psychologists as to what, from the psychological point\nof view, the impulse actually is. Is it simply the conscious situation\nprior to the response? Is it a feeling of the change from the initial\nto the succeeding phase? Or are new data introduced apart from those\nafforded by stimulation on the one hand and response on the other? We\nwill not attempt to decide. Without determining its exact nature we\nmay rest content with the very general statement that impulse is a\nconcomitant of a change in the conscious situation.\n\nThere is, however, a use of the term concerning which it seems\nnecessarily to enter a word of protest. Impulse is by some regarded as\nthe underlying cause of the conative tendency. Now science, as such,\nhas nothing whatever to do with underlying causes. If, as a matter\nof observation and inference, we have reason to believe that there\nis such a tendency, science simply accepts the fact, and endeavours\nto formulate the conditions under which it arises, and to trace its\nobserved or inferred antecedents. No doubt many of us find it difficult\nor impossible to rest content with the strictly scientific position,\nthat of unquestioning acceptance of the facts of nature as we find\nthem given in experience. We say: Here is an observed tendency the\nconditions and antecedents of which are described by science. But what\ncauses the tendency; what is the impelling force? Now to such questions\nscience can give no answer. Science deals with phenomena, and tries to\ntell us all about their conditions and their antecedents. But whenever\nScience is asked: \u201cWhat is the underlying cause of the phenomena,--that\nwhich calls them into being?\u201d Science should always give one answer\nand one only: \u201cFrankly, I do not know; that lies outside my province;\nask my sister Metaphysics.\u201d Science ought to have nothing whatever to\ndo with force as the underlying cause of anything in this universe of\nphenomena. And impulse, as the impelling force which calls a conative\ntendency into being, is a metaphysical, not a scientific conception.\n\nWe need not further discuss the psychological nature of impulse.\nIndeed, the little that has been said would not have been necessary\nto our inquiry were it not that we frequently have occasion to speak\nof animals as \u201ccreatures of impulse,\u201d and to refer to their behaviour\nas due to impulse. What do we mean by such expressions? If we regard\nconative tendency as a fact (whatever may be said for or against its\nbeing also a specific experience), and if this fact is the tendency\nof the conscious situation to develope in certain definite ways, then\nwe may define _impulse_ with sufficient clearness by saying, with\nDr. Stout, that it is characterized by being unreflective. Conative\ntendency thus comprises two categories--impulse and volition; the one\nunreflective, the other involving deliberation.\n\nBefore passing on to consider how impulse is partly determined by the\nfeeling-tone and the emotional attributes of the conscious situation,\nwe may first draw attention to the important way in which the results\nof conative tendency afford the data through which consciousness\nattains its unity in the midst of diversity of experience.\n\nWe said that the impulses might be divided broadly into two\nclasses--the one instinctive, the other acquired. Now, from the\npoint of view suggested by a study of behaviour, if not also, as I\nam disposed to think, from the more general standpoint of a genetic\nstudy of mental development, it is convenient to start with the\ninstinctive act and the conscious situation it implies. We have here\na piece of experience which, if we may so phrase it, hangs together;\nin which experience of things in the environment is included in the\nsame elemental synthesis with that of bodily acts in organic relation\nto these things. It is closely linked, on the one hand, with a\nforegoing act of attention, itself of the instinctive type; closely\nlinked, on the other hand, with the results of behaviour through\nwhich the environing things call forth a new conscious situation\nand evoke a further response. Thus not only does the experience of\nan instinctive act hang together, but a series of such acts do so\nlikewise. And coalescent association not only links and groups the\nelements within the situation called forth by the single act, but\ncomprises also the elements of the developing situation afforded\nby the whole series. We see this in the young chick, where, as the\nresult of experience, attention is emphasized where the material is\npalatable, and lapses where it is nauseous--such nauseous substances\nbeing soon ignored. Furthermore many environing things appeal in\ndifferent ways to the same limited number of sense organs, while the\nsame motor organs respond in different ways in successive modes of\ninstinctive behaviour. The same brain forms the physical basis of\nvaried situations overlapping in many ways, and receives afferent\nmessages from the same body. Hence, in its organic unity it affords\nthe conditions for an underlying stratum of mental unity, amid all\nthe diversities of experience; while the multiplicity of messages\non the one hand from external things, and on the other hand from\ninternal happenings, lays the foundations of a differentiation between\nthe external world and the self--a differentiation long to remain\nimplicit, and only to be rendered explicit on a far higher level of\nmental development. For at this early stage, and perhaps throughout\nanimal life, \u201cthere is no single continuous self contrasted with a\nsingle continuous world. Self, as a whole, uniting present, past, and\nfuture phases, and the world as a single coherent system of things and\nprocesses, are ideal constructions, built up gradually in the course\nof human development. The ideal construction of self and the world\nis comparatively rudimentary in the lower races of mankind, and it\nnever can be complete. On the purely perceptual plane [with which we\nare now dealing] it has not even begun.\u201d[119] But though the ideal\nconstructions of self and the world have not, as Dr. Stout says,\nat this stage, even begun, yet, as the same author observes,[120]\n\u201canimals distinguish in the environment, and treat as a separate thing,\nwhatever portion of matter appeals to their peculiar instincts, and\naffords occasion for their characteristic modes of activity.\u201d And this\ndifferentiation of specially interesting things from each other, and\nfrom their relatively uninteresting surroundings, must be accompanied\nby some differentiation of these things from themselves as affected\nby them and reacting to them. So that here, as we have seen to be the\ncase in other matters, what is commonly called the perceptual life of\nanimals affords the rough-hewn materials from which ideal constructions\nmay be elaborated by rational beings.\n\nWe cannot here attempt to do more than barely indicate the manner\nin which the perceptual process in animals may acquire unity and\ndiversity--unity through the functioning of the same brain and body,\ndiversity from the different modes of functioning and the differential\neffects of diverse modes of stimulation. The interesting point for us\nin our special inquiry is that it is through behaviour that all this is\nbrought about.\n\nAs we interpret the facts, the restless activity of the young is\nprimarily a biological fact, and is to be dealt with as an organic\nproblem--a complication of the fundamental irritability of protoplasm.\nBut it is also an essential condition to the acquisition of conscious\nexperience; and the more there is of it in varied modes the wider is\nthe range of the data afforded to consciousness. Congenital behaviour\nis thus the goal of organic heredity, and the starting-point of\nconscious accommodation and adjustment; it is the biological end of\nvariation, and affords the means to intelligent modification.\n\nSo much for some of the results of conative tendency. Not only does\nit secure adaptation or adjustment to the environment, but it affords\nthe conditions of mental development by which further accommodation is\nrendered possible. But, in addition to the attainment of biological\nends, in addition to the furtherance of survival in the struggle for\nexistence, mental development has another aspect. All sensory data,\nwhether from the special senses, from the motor processes concerned in\nresponsive behaviour, or from other sources, may, and perhaps always\ndo, carry with them some amount of what is termed _feeling-tone_,\ngiving rise to a net result in consciousness which we call pleasure\nor the reverse. Pleasure or satisfaction--however we name that which,\nthough vague and indeterminate in outline, is a very real attribute\nof the conscious situation--affords its sanction to certain modes of\nconation, and may thus be regarded as the psychological end of their\ncontinuance or their repetition. It is partly, no doubt, a direct\nadjunct of sight, hearing, taste, and so forth, and of smooth and\neasy movements of the body and limbs; but it is partly due to a great\nbody of stimulation coming from many parts of the organic system. The\nblood-vessels are dilated or contracted, the heart\u2019s action increased\nor diminished; respiration is deepened or the reverse, and its rhythm\nmay be altered; glands are thrown into a state of activity; the tone of\nthe muscles is affected, and there may be either incipient contraction\nor relaxation. These are primarily organic effects; but they influence\nthe conscious situation, and are themselves suffused with feeling-tone.\nFor, from all the parts so affected, messages are carried in to the\nbrain, and such afferent messages afford data to consciousness. It may\nbe that the experience of the conative tendency, for which Dr. Stout\nand others claim a distinctive place in consciousness, is largely due\nto afferent messages from the motor organs incipiently innervated in\npreparation for the behaviour which follows. In any case these probably\nform very important elements in the conscious situation antecedent to\nthe actual response. In what we may term motor attention--the state\nwell exemplified by a cat in the strained pause which precedes the\nspring on to the prey, or in ourselves when we poise before a dive\nor hold the billiard cue in preparation for a delicate stroke--this\nincipient innervation, felt through afferent messages from the parts\nthus braced for action, enters with much distinctness into the\nconscious situation. In sensory attention, on the other hand, reflex\nacts have actually taken place, having for their end and purpose the\nfocussing of the sense organs on the object which stimulates them,\nso that in this way further and more effective stimulation may be\nreceived. But, as the sense organ is steadily held to the focus, and\nmade effectually to cover the stimulating thing, the motor apparatus\nconcerned is kept on the strain, and is all the while contributing data\nto the conscious situation.\n\nIn primary genesis attention, both motor and sensory, is unquestionably\norganic and reflex in its nature. It is a product, and an invaluable\nproduct, of biological evolution. Without this as a basis, the higher\nforms of attention under conscious guidance would be impossible. For\nall these higher forms are modifications and complications of what is\ngiven in organic heritage. Here, as elsewhere throughout the whole\nrange of behaviour, consciousness only guides to finer issues what is\npresented to it in rough outline, or in isolated fragments, as the\noutcome of biological evolution. But the organic responses afford\nthe data which consciousness uses that it may mould and fashion the\nbehaviour so as to reach higher and more complex modes of adjustment.\n\nLest a familiar form of words should give rise to misapprehension,\nit may here be stated that, when we say that consciousness moulds\nand fashions behaviour, we do not intend to imply that consciousness\nis an underlying cause. We are not using the term consciousness in\na metaphysical sense. We mean that consciousness is the expression\nof certain conditions under which behaviour is guided. Instead of\nsaying, therefore, that consciousness utilizes certain sensory data,\nit would be more correct to say that it _is_ the sum-total of these\ndata which are the psychical expression of certain brain conditions\nunder which behaviour, as a matter of fact, takes a given set or\ndirection. We use the word consciousness, then, not in its metaphysical\nsense of an underlying cause or force, but in its scientific sense,\nas the concomitant of certain antecedent conditions. Our common modes\nof speech lend themselves with misleading facility to metaphysical\nassumptions, all the more insidious since they are not consciously\nacknowledged as such. And not only what we comprise under the broader\ngroup-name \u201cconsciousness,\u201d but what we include under narrower\ngroup-names, such as \u201cimpulse,\u201d \u201cvolition,\u201d \u201cinstinct,\u201d \u201cintelligence,\u201d\n\u201creason,\u201d and the like, often do duty as underlying causes of the\nphenomena, which, from the scientific point of view, they do no more\nthan name.\n\nWe often say, for example, that _interest_ guides behaviour in this\ndirection or in that. But such interest must not be regarded as an\nimpelling force; it is an attribute of the conscious situation, more or\nless suffused with feeling-tone. It is not easy to define; but it seems\nto take on its distinctive character when re-presentative elements\ncontribute what Dr. Stout[121] terms \u201cmeaning\u201d to the conscious\nsituation. The meaning in the early stages of mental development is,\nhowever, merely perceptual, and not that which comes much later--that\nwhich is implied in the phrase \u201crational significance.\u201d In the chick\nwhich has tasted a cinnabar caterpillar the situation evoked by the\nsight of this larva has meaning in virtue of the actual experience.\nBut, in this case, the meaning is not conducive to continued interest,\nsince it checks, rather than stimulates, behaviour. At first, indeed,\nthere may be the repellent interest of aversion. But this passes by,\nand the larv\u00e6 are soon ignored. Small worms also acquire meaning, and\nhere the interest is attractive, and is stimulated afresh each time\nthe meaning is reinforced by repetition of the act of seizing and\nswallowing.\n\nWe have seen that it is through behaviour that things become\ndifferentiated from their surroundings, and acquire relative\nindependence in experience. It is through behaviour that what we have\ntermed conscious situations develop. The thing is the centre or nucleus\nof a developing situation--that which starts the behaviour, and towards\nwhich the behaviour is directed; or, since the behaviour may be that\nof avoidance or escape, we should, perhaps, rather say, it is that to\nwhich the behaviour has reference. Now, if interest is the feeling-tone\nattaching to the whole attentive situation, and if the nucleus of the\nsituation is the thing, it naturally follows that the thing becomes\nthe centre of interest. The mouse is a centre of absorbing interest to\nthe cat, her eggs to the mother-bird, his mate to the sparrow in the\nspring. Companions are centres of abiding interest to social animals,\nbecause they are also the centres of social behaviour and the conscious\nsituations arising thereout; because they evoke in special ways the\nattentive situation.\n\nThe differentiated thing being thus a centre of interest, a relatively\nfixed nucleus in a changing conscious situation, the development of\nwhich is due to behaviour, there can be no question that, among social\nanimals, the companion becomes a peculiar and specialized centre.\nAround him develops a particular type of behaviour. Towards him the\nreactions are of a quite distinctive kind. Mother and offspring, mate\nand mate, are reciprocal centres of interest. To the offspring the\nparent is a common centre of interest. As they grow up together, what\nis of interest to one is likewise of interest at the same time to\nothers. Imitation begets similarity of conscious situations. In many\nways such community of interest is fostered; and through this community\nof interest the conscious situations acquire their distinctively social\ncharacter. Not only is the companion, as the nucleus of a situation,\na thing which reacts in altogether special ways, so that it becomes\ndifferentiated from other things as something the meaning of which,\nand the interest in which, are _sui generis_ and unique in type; but\nit enters into other situations in ways that are also peculiar and\ncharacteristic. A worm is thrown to a couple of chicks, and is to each\na centre of interest--the nucleus of a situation involving appropriate\nmodes of behaviour. But into this situation there enters for each of\nthem, in a quite peculiar and distinctive way, the action and behaviour\nof the other chick. The situation is complicated by the introduction of\na second centre of interest, and the behaviour has reference to both\ncentres. Instead of quietly and leisurely dealing with the worm in\naccordance with its special meaning, as it does when there is no rival\nin the field, the chick darts at it, and bolts with it in accordance\nwith the special meaning which its neighbour\u2019s presence, under such\ncircumstances, has acquired. And this different behaviour carries with\nit a felt difference in the conscious situation--the interest of which\nis centred in the companion. Or take the case of a herd of cattle,\nwhich attacks a common enemy. The enemy is the primary nucleus of the\nsituation, but it is profoundly modified by the presence of companions\nby which the behaviour of attack is determined. The situation is\nsocial, and not merely individual, and a social interest suffuses it,\nand gives it a distinctive character.\n\nIn this social interest probably arise the germs--but only the\ngerms--of the sense of personality. Some, indeed, go so far as to\nurge that we learn to know ourselves only through knowing others. The\ngenetic order, so far as there is an order, is, they say, not first\nthe ego and then the alter, but first the mother and companions and\nthen through them the self. Or, to put this point of view in a less\nquestionable form, it is only through the reaction of one on the other\nthat the two are differentiated. Be this as it may, it is only through\nthe action of environment on the organism, and the reaction of the\norganism on the environment in behaviour, that experience becomes\npolarized into subject and object. Let it be clearly understood that\nfor the animal, in all probability, subject and object are not clearly\ndistinguished, and set over against each other in the antithesis of\nthought. Only late in mental development are the self and the world\ndistinguished in subtle analysis as different aspects of the common\nexperience in which both have their inseparable being. Animals, and\nperhaps the majority of mankind, never trouble themselves about object\nand subject as clearly realized products of conception and reflective\nthought. For these concepts are exceedingly subtle. And here, too, the\nexternal aspect of experience has the precedence, so far as there is\nprecedence. A healthy lad from the moment he gets up in the morning\ntill the moment he goes to bed, lives chiefly in the objective aspect\nof experience, an aspect which is in us chiefly associated with the\nproducts in consciousness of the leading senses of sight and hearing.\nBut the subjective aspect creeps in when he is hurt, when he is hungry,\nwhen he is fatigued. He does not argue about the matter, or formulate\nit in definite terms. He just dimly feels that the interest has\nsomehow shifted. Still more dimly does the animal feel that, apart from\nexternal interests which prompt nine-tenths of its behaviour, chiefly\nthrough the senses of sight, hearing, and smell, there are also matters\nin which the interest has somehow shifted to his own body. For the germ\nof self is essentially an embodied self. And perhaps the emotions,\nwhich ring through the system for some time after the external cause\nhas been removed, serve in some degree to aid in this dimly felt\nshifting of interest.\n\nWhatever may be the exact psychological nature of the emotions--and\nthere has been much discussion of the question--it may be regarded\nas certain that they introduce into the conscious situation elements\nwhich contribute not a little to the energy of behaviour. They are\nimportant conditions to vigorous and sustained conation. And so\nclosely interwoven are these elements with the whole situation in\nits impulsive aspect, that their disentanglement, in psychological\nanalysis, is a matter of extreme difficulty. I have elsewhere[122]\ndevoted some space to the consideration of the matter. I there follow\nProfessor William James in regarding organic effects, other than motor\nsensations, as specially characteristic of the emotions in their\nprimary genesis. The cold sweat, the dry mouth, the catch of the\nbreath, the grip of the heart, the abdominal sinking, the blood-tingle\nor blood-stagnation--these and their like, in varied modes and degrees,\ncharacterize the emotions of fear, dread, anger, and so forth, when\nthey rise to any pitch of intensity, and contribute largely to their\nsharpness and piquancy. These organic effects may be regarded as part\nof the private and individual business of the body; but in experience\nthey closely coalesce with the motor effects through which the animal\nhas to deal in practical behaviour with that which evokes the emotion.\n\nOn this view these organic states which contribute characteristic\nelements in the emotional consciousness are due to afferent data from\nthe vascular system and visceral organs, just as motor consciousness\nis due to afferent data from the parts concerned in overt behaviour.\nBut, associated with emotional states, there are also certain motor\nreactions, which we speak of as their \u201cexpression\u201d--so carefully\ndiscussed and elucidated by Darwin,--and these unquestionably\ncontribute data to consciousness which coalesce with those afforded\nby the visceral and vascular elements. The whole is commonly suffused\nwith feeling-tone, and the object which excites the emotion is a\ncentre of pleasurable or painful interest. Representative elements, as\nexperience develops, crowd into the conscious situation and render it\nmore complex. And in addition to all this, there is, apart from the\nmotor expression, the strenuous behaviour of flight or attack, or other\nmode of vigorous procedure which we commonly speak of as the outcome\nof the emotional state. The conscious situation, in the case of an\nenraged or scared animal actually behaving as such, is thus exceedingly\ncomplex. And it should be understood that in urging the importance of\nvascular and visceral elements, this complexity is nowise denied. What\nis suggested is that these elements are essential, and that they serve\nto characterize the distinctively emotional factor in the situation,\nthat in any case they heighten the conative tendency.\n\nSufficient has now been said to indicate--but scarcely more than\nindicate--the importance of feeling-tone, interest, and emotion\nin determining the nature, character, and effective energy of the\nconscious situations which arise in the course of animal behaviour.\nThey largely influence, and in part direct, the course of the conative\ntendency. But they also occur as its sequel. In animal, as in human\nlife, the successful attainment of the end towards which conation\nsets is highly pleasurable. The equilibrium that is reached after\ninstability, though it marks the close of present endeavour, leaves\nafter-effects in consciousness in a sense of satisfaction which enters\nre-presentatively into later situations and helps to further more\nstrenuous endeavour.\n\n\nII.--PLAY\n\n\u201cThere are two quite different popular ideas of play,\u201d says Professor\nGroos, in his admirable work on \u201cThe Play of Animals.\u201d \u201cThe first is\nthat the animal (or man) begins to play when he feels particularly\ncheerful, healthy, and strong; the second that the play of young\nanimals serves to fit them for the tasks of later life.\u201d The former\nview, in which the latter may be included incidentally as a result, is\nclosely associated with the names of Schiller,[123] who suggested it,\nand of Mr. Herbert Spencer,[124] who developed it. Mr. Wallaschek[125]\nexpresses the conception briefly and clearly when he says, \u201cIt is the\nsurplus vigour in more highly developed organisms, exceeding what is\nrequired for immediate needs, in which play of all kinds takes its\nrise, manifesting itself by way of imitation or repetition of all those\nefforts and exertions which are essential to the maintenance of life.\u201d\nThat surplus vigour is often a condition favouring the manifestation\nof play is probable enough, and seems to be supported by observation\nand experience; but that it is likewise a condition favouring the\nchase, combat, mating, and much of the serious business of animal life\nseems equally unquestionable. Success in all these matters is largely\ndetermined by overflowing energy. In play, however, this surplus vigour\nfinds vent when there is no serious occasion for its exercise. But, as\nProfessor Groos says,[126] \u201cwhile simple overflow of energy explains\nquite well that the individual who finds himself in a condition of\noverflowing energy is ready to do something, it does not explain how\nit happens that all the individuals of a species manifest exactly the\nspecific kind of play expression which prevails with their own species,\nbut differs from every other.\u201d And if to this it be replied, that the\nspecific kind is determined by repetition or imitation of what we have\ncalled the serious business of animal life, Professor Groos\u2019s rejoinder\nis,[127] that \u201cthe conception of imitation here set forth--namely,\nas the repetition of serious activities to which the individual has\nhimself become accustomed--cannot be applied directly to the primary\nphenomena of play--that is, to its first elementary manifestations\u201d\nprior to any experience of these serious activities. The repetition\n(with a difference!) is in such cases not the re-enactment of what has\nbeen previously performed in full earnest by the individual, but rather\nthe reappearance in the young of ancestral modes of procedure--in\nother words, its specific character is such because it is a piece of\ninstinctive behaviour or arises from instinctive proclivities. And this\nis the central point of the interpretation elaborated with great skill\nand candour by Professor Groos. Play is instinctive; and its biological\nvalue lies in the training it affords for the subsequent earnest of\nlife.\n\nBefore leaving the surplus energy theory of play one more point\nmade by Professor Groos may be mentioned. He contends that, though\nsuperabundant energy is a favouring condition of animal play (as it\nis, indeed, of all animal behaviour), still it is not a necessary\ncondition. Animals often play when they are tired out. \u201cNotice a kitten\nwhen a piece of paper blows past. Will not any observer confirm the\nstatement that, just as an old cat must be tired to death or else\nalready filled to satiety if it does not try to seize a mouse running\nnear it, so will the kitten, too, spring after the moving object,\neven if it has been exercising for hours and its superfluous energies\nare entirely disposed of? Or observe the play of young dogs when two\nof them have raced about the garden until they are forced to stop\nfrom sheer fatigue, and they lie on the ground panting, with tongues\nhanging out. Now one of them gets up, glances at his companion, and\nthe irresistible power of his innate longing for the fray seizes him\nagain. He approaches the other, sniffs lazily about him, and, though he\nis evidently only half inclined to obey the powerful impulse, attempts\nto seize his leg. The one provoked yawns, and in a slow, tired kind\nof way puts himself on the defensive; but gradually instinct conquers\nfatigue on him too, and in a few minutes both are tearing madly about\nin furious rivalry until want of breath puts an end to the game. And so\nit goes on with endless repetition, until we get the impression that\nthe dog waits only long enough to collect the needed strength, not till\nsuperfluous energy urges him to activity.\u201d[128]\n\nComing now to Professor Groos\u2019s interpretation of play, we find in it,\nperhaps for the first time in the literature of the subject, adequate\nstress laid on its biological value. \u201cThe play of young animals,\u201d he\nsays,[129] \u201chas its origin in the fact that certain very important\ninstincts appear at a time when the animal does not seriously need\nthem.... Its utility consists in the practice and exercise it affords\nfor some of the more important duties of life, inasmuch as selection\n[in the higher animals] tends to weaken the blind force of instinct,\nand aids more and more the development of independent intelligence as\na substitute for it. At the moment when intelligence is sufficiently\nevolved to be more useful in the struggle for existence than the most\nperfect instinct, then will selection favour those individuals in\nwhom the instincts in question appear earlier and in less elaborated\nforms--in forms that are merely for practice and exercise,--that is\nto say, it will favour those animals which play.... Animals cannot be\nsaid to play because they are young and frolicsome, but rather they\nhave a period of youth in order to play; for only by so doing can\nthey supplement the insufficient hereditary endowment with individual\nexperience, in view of the coming tasks of life.\u201d\n\nSome stress is here laid on the fact that important instincts appear\nat a time when the animal does not seriously need them. It seems to\nimply the doctrine of what biologists term \u201cacceleration\u201d--which means\nthe development of an organ or mode of behaviour at an earlier period\nin the descendants than that at which it appeared in the ancestors.\nThus the adult fighting or hunting instinct of past generations appears\nin the young to-day as a fighting-play or a hunting-play. It is open\nto question, however, whether either the instinctive behaviour or\nthe conscious situation in the one case and the other is so nearly\nidentical that the playful fight or hunt can fairly be called the\nsame instinctive procedure as the serious combat or chase. We may\nhold, with Professor Groos, that the one is an invaluable preparation\nfor the other without identifying them as the same behaviour under\ndifferent conditions. Indeed the conditions are so different that the\nidentification seems strained. The question may be left open, however,\nwithout impairing the value of Professor Groos\u2019s suggestion. And we\nmay divide the preparatory behaviour in what is commonly called play\nunder two heads: first, general preparation for varied modes of serious\neffort in after-life; and secondly, special preparation for particular\nforms of this after-effort. Under the first will fall what Professor\nGroos terms experimentation and movement play, including what Dr.\nStout, who fully realizes its importance, calls \u201cmanipulation\u201d;[130]\nunder the second, such forms as hunting-play and fighting-play.\n\nNothing is more characteristic of the young of intelligent animals than\nthe variety and persistency of their behaviour, their sensitiveness\nto stimuli of many different kinds, their restlessness of swiftly\nchanging attention and response, with occasional pauses of continued\neffort in some special direction. Constantly on the alert, they exhibit\nin all its shifting phases behaviour which we interpret as indicating\ncuriosity, inquisitiveness, love of mischief, destructiveness, and so\nforth. The facts are so familiar to every observer of young animals\nthat it is unnecessary to give any detailed illustration. Watch\na kitten in this stage of its development and carefully note its\nbehaviour during half an hour; the variety of effort, the _r\u00f4les_\nplayed by trial, failure, and success, the gain of skill and control\nover behaviour, will at once be evident. Or devote an equal space of\ntime to observing young jays, magpies, or jackdaws. Every projecting\npiece of wire or bit of wood in their cage is pulled at this way and\nthat way, from above, from below, from the side. Now one, then another,\nloose object is picked up and dropped, turned over, carried about,\npulled at, hammered at, stuffed into this corner and into that, and\nexperimented with in all possible ways. Then the wise bird goes to\nsleep, and wakes up again only to resume with new zest its persistent\nand varied efforts, by which it becomes acquainted with all the details\nof its environment. Watch young birds on the wing gaining their\nmastery of the air in flight, young seals tumbling in the water, young\nfoals scampering and kicking up their heels in the meadows. A little\nobservation, as occasion serves, a little attention to the progress\ntowards an adequate experience of the meaning of things, towards\nmore complete control, and increased nicety of behaviour, whether in\nreference to their surroundings, or in powers of finished locomotion,\nwill serve to bring home what Professor Groos includes under\nexperimentation and movement plays. He regards it all as play, since it\nseems to have no serious end, and is just a preparation for the sterner\nrealities of adult life. And for human beings, whose work is so largely\nenforced, the freedom and evident joy of it all suggests the play which\nhas acquired for us the meaning of relaxation from irksome effort, and\nglad abandonment to less constrained modes of behaviour. But in young\nanimals such play is, after all, the serious business of their time of\nlife. Its import for their future welfare can scarcely be overestimated.\n\nAnd its import is in large degree psychological. If we watch a young\npuppy or kitten learning gradually to deal effectively with some\ndifficulty in its extending environment, we see that it puts forth its\nefforts at first in a somewhat random and indefinite fashion. It is one\nof those animals in which intelligence has been evolved to supersede\nand become the more plastic substitute for instinct. The random and\nindefinite movements, are in detail reflex responses to stimuli.\nBut whereas, in a piece of highly elaborated instinctive behaviour,\nsuch reflexes are grouped into a whole which is co-ordinated through\ninherited nervous mechanism; in the case of the acts of the puppy\nor kitten they have to be further co-ordinated, or more elaborately\ngrouped, through experience. To act in one way some of the reflexes\nhave to be checked as redundant and not to the point: to act in another\nway other reflexes have to be similarly checked; and in a third way,\nyet others. But in all three some of the reflexes are utilized to\ndifferent ends. Many conscious situations contain common elements; and\nthis tends to give unity to the developing experience. But they contain\nalso elements and groupings which afford that diversity without which\nconscious behaviour could not be accommodated to them. So that we\nhave here the conditions under which what is technically termed \u201cthe\nconcomitant differentiation and integration of experience\u201d can proceed.\n\nAnd if we speak of the instinct of experimentation we must remember\nthat what we are dealing with is rather an innate tendency or\ninstinctive propensity than a definite and relatively clean-cut piece\nof instinctive behaviour. It comprises a great number of inherited\nreflex acts, and may perhaps be fairly called instinctive in detail.\nBut experimentation must be regarded rather as the proximate end of\na conative tendency, or group of conative tendencies, whose ultimate\nbiological end is success in dealing with the environment in the\nsterner struggle for existence during adult life. The tendency\nis inherited, and therefore falls under the head of instinctive\npropensity. But \u201cexperimentation\u201d is a group-term under which we\ncomprise the general drift of varied modes of behaviour, founded indeed\non a congenital basis, but receiving its stamp and character from\nwhat is acquired in the course of the experience it provides. It is\nessentially a process whereby the conscious situations acquire what\nDr. Stout terms meaning; and is specially interesting as affording an\nexample of the way in which intelligence moulds and refashions a number\nof disconnected reflex responses. And if, following Professor Groos,\nwe call it play, it is a little difficult to see how it can be brought\nin line with his statement[131] that \u201cthe play of youth depends on\nthe fact that certain instincts, especially useful in preserving\nthe species, appear before the animal seriously needs them.\u201d Does\nexperimentation occur before it is needed in the economy of animal\nbehaviour? And might we not with equal truth say that the play of youth\ndepends on the fact that certain acquired habits, especially useful in\npreserving the species, are gained before the animal seriously needs\nthem?\n\nPassing now to those forms of play which afford more special\npreparation for particular forms of after-effort, under which fall\nsuch types as hunting-play and fighting-play, we may refer the reader\nto the copious examples so carefully collected by Professor Groos.\nThe way in which a kitten pats a cork or a ball, making it roll and\nthen pouncing upon it, is a characteristic example of animal play.\nValuable as a preparation for dealing successfully with a mouse when\noccasion shall arise, this is a specialized form of experimentation;\nand it is more obviously in line with the hunting-behaviour of later\nlife than is general experimentation with any particular modes of\nfuture behaviour. Still it is essentially experimentation, with the\ninstinctive propensity setting in more definite channels. Its value\nlies in the acquisition of skill under circumstances easier than those\npresented in the serious chase. So, too, in the case of the playful\ntussles of puppies or in that of the kitten, which not only shows\nplayful fight to its brothers and sisters, but also to its mother,\nwho responds by holding down the struggling and scratching little\ncreature. Unquestionably, there is an instinctive propensity; much of\nthe detail, and some of the grouping, exhibit inherited reflexes due to\nspecial modes of stimulation. No doubt many of these responses occur\nin a similar but more emphatic way in a serious fight, and yet we may\nhesitate before committing ourselves to the theory of acceleration.\nIt is at least equally probable that play as preparatory behaviour\ndiffers in biological detail (as it almost certainly does in emotional\nattributes) from the earnest of after-life, and that it was evolved\ndirectly as a preparation, as a means of experimentation through which\ncertain essential modes of skill were acquired,--those animals in\nwhich the preparatory play propensity was not inherited in due force\nand requisite amount being worsted in the combats of later life, and\neliminated in the struggle for existence. For, in the preparatory\ntussles and squabbles and playful fights of young animals, experience\nis gained without serious risk to life and limb.\n\nThe modifications of Professor Groos\u2019s biological interpretation of\nplay which we would suggest are so slight that we may be said to accept\nit almost unreservedly. The play of youth, we may urge, depends on\ninstinctive propensities to experimentation in varied ways, some of\nmore general and others of more special import; and the value of such\nexperimentation lies in the fact that it is a means of acquiring,\nunder circumstances more easy and less dangerous than those of sterner\nlife, experience and skill for future use. In a word, play depends on\ninstinctive propensities of value in education.\n\nPassing now to a brief consideration of the feelings and emotions\nwhich we may suppose to accompany play, we may place first those which\ncharacterize, from this point of view, general experimentation. We have\nhere rapidly varying situations charged with conative impulse, the\nsatisfaction of which must bring pleasure--the occasional thwarting\nof which is probably toned with the opposite--the latter serving,\nthrough contrast, to enhance the satisfaction of ultimate success. Both\npleasure and its antithetical state of feeling are primarily matters of\nthe conscious situation as a whole, and even in ourselves are difficult\nto distribute in analysis. But assuredly no small share of the total\nproduct must be assigned to the successful behaviour which consummates\nthe conative tendency. Indeed, it is the thwarting of free action which\nis the source of much of the discomfort of the young. Unimpeded and\nvigorous behaviour also brings with it secondary effects in organic\nprocesses--fuller heart-beat, freer circulation, deeper respiration,\nbetter digestion, firmer muscular tone, and so forth--which have a\nmarked effect on the conscious situation, and aid in producing that\nemotional tone which cannot, perhaps, be named in better terms than\n\u201cgood spirits\u201d and the joy of existence, so forcibly suggested during\nthe free play of youth. On the other hand, there is no more piteous\nsight than that afforded by the young animal, \u201ccabined, cribbed,\nconfined,\u201d suffering from _ennui_ and depression--all its organic\nprocesses sluggish and craving to be quickened into the natural vigour\nof life, not creeping slowly through the veins, but coursing at full\nflood.\n\nIn the psychological aspect of play Dr. Groos assigns perhaps the first\nplace to pleasure in the possession of power, or, as Preyer phrases\nit, pleasure in being a cause. We must be careful, however, lest in\nusing such expressions we seem to imply that animals--even quite young\nanimals--are capable of entertaining ideas which belong to a much\nlater stage of mental development. Speaking of \u201cjoy in ability or\npower,\u201d Professor Groos says,[132] \u201cThis feeling is first a conscious\npresentation to ourselves of our personality as it is emphasized by\nplay.... But it is more than this; it is also delight in the control\nwe have over our bodies and over external objects. Experimentation\nin its simple as well as its more complicated forms is, apart from\nits effect on physical development, educative in that it helps in the\nformation of causal associations.... The young bear that plays in the\nwater, the dog that tears a paper into scraps, the ape that delights\nin producing new and uncouth sounds, the sparrow that exercises its\nvoice, the parrot that smashes his feeding trough--all experience\nthe pleasure in energetic activity, which is, at the same time, joy\nin being able to accomplish something.\u201d But those who agree with Dr.\nStout, as I do without hesitation, in denying personality (save in a\nvery embryonic condition) and the conception of causation to animals\nin the perceptual stage of mental evolution, though they may find in\nDr. Groos\u2019s contention a central core of truth, will be unable fully\nto accept his manner of presenting it. \u201cAny single train of perceptual\nactivity,\u201d[133] says Dr. Stout, \u201chas internal unity and continuity.\nBut where conscious life is mainly perceptual, the several trains of\nactivity are relatively isolated and disconnected with each other. They\ndo not unite to form a continuous system, such as is implied in the\nconception of a person. We must deny personality to animals.\u201d To this\nI would merely add that, even where perceptual continuity in animals\nreaches its maximum, it is not reflectively grasped as a whole, and the\nideal construction of the personal ego is not conceived as antithetical\nto the impersonal world of objects. With what Dr. Stout says about\ncausality I am in complete agreement. \u201cWe must notice,\u201d[134] he urges,\n\u201cthe essential difference which separates the merely perceptual\ncategory from that of ideational and conceptual thought. The perceptual\ncategory is always purely and immediately practical in its operation.\nIt is a constitutive form of thought only because it is a constitutive\nform of action. The question \u2018Why?\u2019 has no existence for the merely\nperceptual consciousness. It does not and cannot inquire how it is\nthat a certain cause produces a certain effect. It does not and cannot\nendeavour to _explain_, to analyze conditions so as to present a cause\nas a _reason_. It does not compare different modes of procedure or\ndifferent groups of circumstances, so as to contradistinguish the\nprecise points in which they agree from those in which they disagree,\nand in this way to explain why a certain result should follow in one\ncase and a different result in another case. Causality in this sense\ncan only exist for the ideational consciousness, and the development\nof the ideational consciousness in this direction is a development of\nconceptual thinking--of generalization.\u201d\n\nWherein, then, lies the central core of truth in Professor Groos\u2019s\ncontention? In the satisfaction that arises from the success of any\nconative activity. We see that the animal striving and doing falls\nwithin our conception of a cause, in the scientific sense of the\nword,--a relatively constant and continuous antecedent of diverse\nsequent effects. We infer that pleasure accompanies the satisfaction of\nthe multifarious conative impulses. The pleasure is the animal\u2019s; the\nconception of causality and of self as a continuous person, still the\nsame amid diversity of conscious situations, is ours. If we bear this\nin mind there can be no objection to our attributing to animals joy\nin ability or power. It is the pleasure derived from that successful\nconation whereby animals fall into the category of causes within the\nscheme of our rational thought.\n\nIn fighting-play and hunting-play, too, there arise in more specific\nforms the pleasures of successful conation with the antithetical\nfeelings accompanying thwarted conation. And these are distinguished\nfrom earnest, partly because the companion or the inanimate substitute\nfor prey is the centre of a different situation from that afforded by\nan enemy or the natural object of the chase; partly by the absence of\ncertain insistent emotional states which characterize earnest and the\nserious business of life. In fighting, this is anger. And we often see\nthe tendency of this to arise in the midst of fighting-plays, and at\nonce say that it becomes serious and passes into fighting in earnest.\nIndeed, some tinge of earnest, with its fuller emotional tone, forms\npart of the preparation for future life, and so far falls within the\ndefinition Professor Groos gives of play. From which we may see that\nplay is not easily marked off from other forms of conation.\n\nBrief reference to the element of \u201cmake-believe,\u201d which Dr. Groos\nassigns to the higher forms of play, may be reserved for our fourth\nsection; and some further discussion of its psychological aspect to the\nconcluding chapter.\n\n\nIII.--COURTSHIP\n\nWe have seen that Professor Groos regards play as the practice and\npreparation for the serious business of animal life. Founded on\ninstinctive tendencies, it has its biological value in the acquisition\nof practical acquaintance with the environment, and of skill in\ndealing with it effectually. It is an education in behaviour of the\nutmost service in view of the struggle for existence. It is full of\nthe pleasure derived from the satisfaction of innate impulse, the\nsuccess of conative effort, and the diffused sense of well-being which\naccompanies a life of action, free and unrestrained. This freedom and\ngladness lead us to call it play; but we must not draw the inference\nthat the playful animal knows that it is playing, or forms any\nconception of the antithesis between work and play, which is a product\nof late development.\n\nIn laying stress on the biological value of certain modes of behaviour\nwhich we thus call play, a value which lies in the practice and\npreparation they afford for life\u2019s more earnest work, Professor Groos\ndeserves our hearty thanks. Nor need our thanks be less hearty if we\nfind that he has in some degree been anticipated by Darwin; for he has\nelaborated with systematic care what Darwin suggested incidentally.\n\u201cNothing is more common,\u201d said Darwin,[135] \u201cthan for animals to take\npleasure in practising whatever instinct they follow at other times for\nsome real good. How often do we see birds which fly easily, gliding and\nsailing through the air, obviously for pleasure! The cat plays with the\ncaptured mouse, and the cormorant with the captured fish. The weaver\nbird, when confined in a cage, amuses itself by neatly weaving blades\nof grass between the wires of its cage. Birds which habitually fight\nduring the breeding season are generally ready to fight at all times;\nand the males of the capercailzie sometimes hold their _Balzen_, or\n_leks_, at the usual place of assemblage during the autumn. Hence it is\nnot at all surprising that male birds should continue singing for their\nown amusement after the season of courtship is over.\u201d\n\nIn the behaviour of courtship we have what is essentially part of the\nserious business of animal life. And in including it under the heading\nof \u201cLove Plays,\u201d Professor Groos may seem to be forgetful of his own\ndefinition of play. He is, however, too clear a thinker not to see, and\ntoo honest an exponent not to say, that much of the emotional behaviour\ncommonly regarded as courtship falls outside his main thesis \u201cin being,\nstrictly speaking, not mere practice preparatory to the exercise of\nan instinct, but rather its actual working.\u201d[136] But behaviour of\na somewhat similar kind is seen in young animals before the time of\nmating has arrived, and is exemplified both in young and adults under\ncircumstances different from those which distinguish what we may term\nthe pairing situation. This, at any rate, may be regarded as a form of\nexperimentation and practice in the arts of courtship. On different\ngrounds does Professor Groos attempt to justify the inclusion of actual\ncourtship under the head of play. For it may also, he thinks, even at\nthe time of its serious exercise, be to some extent artful, involving\n\u201cmake believe,\u201d and therefore playful in a somewhat different and more\nsubtle sense; but a brief reference to \u201cmake believe\u201d we may reserve\nfor our next section.\n\nThere can be no question that special modes of behaviour often\ncharacterize the pairing situation, and that these not only exemplify\nan instinctive tendency, but from their constancy and relative\ndefiniteness constitute types of instinctive behaviour. They would\nform parts of any definition of a species founded not on structure but\non behaviour. And if animals have feelings and emotions at all--if\nthey are not Cartesian automata, which merely _seem_ to be guided in\ntheir actions by consciousness--there can be but little question that\nthe behaviour which characterizes the sexual situation is unusually\ncharged with feeling-tone, and accompanied by all those adjuncts\nwhich distinguish an emotional state, broadly considered. This matter\nis of no little importance in our interpretation of the phenomena\ndescribed as courtship. Do the accompanying feeling-tone and the state\nof emotional exaltation influence the behaviour, or would it run a\nsimilar course in the absence of any such accompaniments? If, as we\ncan scarcely doubt, the consciousness attending the situation does\nprofoundly influence the behaviour, the further question arises--Is\nthis influence mainly the result of the presence and behaviour of an\nindividual of the opposite sex? To this, again, we must answer that,\nso far as we can learn by observation, behaviour unquestionably is\ndetermined by such influence in the serious business of courtship. And\nthen the further question arises--Is it a matter of indifference what\nthe appearance and behaviour of the individual of the opposite sex may\nbe? Are A., B., C., and the rest of the male alphabet, precisely alike\nin stimulating in a similar manner, and to a similar degree, the sexual\nimpulse of the female? If we admit any differential influence, and if\nthis influence takes effect in the sexual union to which courtship is\npreparatory, we so far admit the efficacy of that which Darwin termed\nsexual selection.\n\nLet us, however, before proceeding with general considerations, present\none or two examples of the facts which observation has furnished with\nregard to specialized modes of behaviour at the time of pairing.\nSpeaking of American night-hawks, Audubon says, \u201cTheir manner of flying\nis a good deal modified at the love season. The male employs the most\nwonderful evolutions to give expression to his feelings, conducting\nthem with the greatest rapidity and agility in sight of his chosen\nmate, or to put to rout a rival. He often rises to a height of a\nhundred metres and more, and his cries become louder and louder as he\nmounts; then he plunges downward with a slanting direction, with wings\nhalf open, and so rapidly that it seems inevitable that he should be\ndashed to pieces on the ground. But at the right moment, sometimes when\nonly a few inches from it, he spreads his wings and tail, and, turning,\nsoars upward once more.\u201d[137] Mr. Strange, quoted by Darwin[138] says\nof the satin bower-bird, \u201cat times the male will chase the female all\nover the aviary, then go to the bower, pick up a gay feather or a large\nleaf, utter a curious kind of note, set all his feathers erect, run\nround the bower and become so excited that his eyes appear ready to\nstart from his head; he continues opening first one wing, and then the\nother, uttering a low, whistling note, and, like the domestic cock,\nseems to be picking up something from the ground, until at last the\nfemale goes quietly towards him.\u201d\n\nDarwin describes how, in the Argus pheasant,[139] \u201cthe immensely\ndeveloped secondary wing-feathers are confined to the male, and each\nis ornamented with a row of from twenty to twenty-three ocelli, each\nabove an inch in diameter. These beautiful ornaments are hidden until\nthe male shows himself before the female. He then erects his tail, and\nexpands his wing-feathers into a great, almost upright, circular fan or\nshield, which is carried in front of the body. The ocelli are so shaded\nthat, as the Duke of Argyll remarks, they stand out like balls lying\nloosely within sockets. But when I looked at a specimen in the British\nMuseum, which is mounted with the wings expanded and trailing downward,\nI was,\u201d adds Darwin, \u201cgreatly disappointed, for the ocelli appeared\nflat or even concave. Mr. Gould, however, soon made the case clear to\nme, for he held the feathers erect, in the position in which they would\nnaturally be displayed, and now, from the light shining on them from\nabove, each ocellus at once resembled the ornament called a ball and\nsocket.\u201d The primary wing-feathers are scarcely, if at all, inferior in\nbeauty to the secondaries, though the markings are quite different, the\nchief ornament being a space parallel to the dark-blue shaft, which in\noutline forms a perfect second feather lying within the true feather.\n\u201cNow the secondary and primary wing-feathers are not at all displayed,\nand the ball and socket ornaments are not exhibited in full perfection,\nuntil the male assumes the attitude of courtship.\u201d\n\nIt is unnecessary to describe the song of birds which is generally, but\nnot always, at its best during the period of pairing. Bechstein, who\nkept birds during his whole life, and studied them with care, asserts\nthat \u201cthe female canary always chooses the best singer, and that in a\nstate of nature the female finch selects that male out of a hundred\nwhose notes please her most.\u201d[140]\n\nThus we are led back to sexual selection. If we are satisfied that the\nmales of certain species do as a matter of fact behave in specific\nand distinguishable ways at the breeding season, and in presence of\ntheir would-be mates, the question is, What, if any, is the biological\nvalue of such behaviour? What has fostered and guided it in the course\nof its evolution? From the case of the Argus pheasant, which is only\na sample of the large class of cases in which the male has special\nadornments, we see that the behaviour has often direct relation to the\ndisplay of such plumage, or, in some apes, of coloured surfaces, so\nthat behaviour and ornamentation must be taken together. The essence\nof Darwin\u2019s contention is, that the adornments and behaviour give rise\nto a situation through which the female is stimulated or excited to\naccept the male; that the male in which they are best developed gives\nrise to the most effective situation, produces most excitement, and\ntherefore has the best chance of acceptance, being \u201cunconsciously\npreferred;\u201d[141] and that he thus begets offspring which inherit his\nadornments and modes of behaviour, such inheritance being, however,\nconfined to the males. Thus sexual selection takes effect through\npreferential mating, whereby certain hereditary traits are transmitted\nand become racial characteristics. And this is brought about through an\nappeal to consciousness, and seems to involve choice--generally that of\nthe female.\n\nNow, as I have elsewhere urged,[142] the hypothesis of sexual selection\nhas often been placed in a false light by the introduction of the\nunnecessary supposition that the hen bird, for example, must possess a\nstandard or ideal of \u00e6sthetic value, and that she selects that singer\nwhich comes nearest to her conception of what a songster should be.\nDarwin occasionally expressed himself unguardedly in the matter; he\nsays, for example, that the female appreciates the display of the\nmale, and places to her credit a taste for the beautiful.[143] But he\nalso distinctly states that \u201cit is not probable that she consciously\ndeliberates; she is most excited or attracted by the most beautiful, or\nmelodious, or gallant males.\u201d[144] This is all that is really necessary\nfor the theory of sexual selection. The hen accepts that mate which by\nhis song or otherwise excites in sufficient degree the pairing impulse;\nif others fail to excite this impulse, they are not accepted. Even\nMr. A. R. Wallace, who rejects the theory save in a very subordinate\nform, says[145] that \u201cit may be admitted, as highly probable, that the\nfemale is pleased or excited by the display,\u201d and speaks[146] of a\npossible choice of \u201cthe most vigorous, defiant, and mettlesome male,\u201d\ngiving, moreover,[147] several telling examples of preferential mating.\nStripped of all its unnecessary \u00e6sthetic surplusage, at any rate so far\nas this implies an \u00e6sthetic ideal, or \u00e6sthetic motive, the hypothesis\nof sexual selection suggests that the accepted mate is the one which\nadequately evokes the pairing impulse.\n\nHere Dr. Groos makes an interesting and important contribution to the\nsubject. He lays stress on the coyness and reluctance of the female,\nand illustrates it by examples derived from observation. \u201cThus the\nfemale cuckoo answers the call of her mate with an alluring laugh that\nexcites him to the utmost, but it is long before she gives herself\nup to him. A mad chase through tree-tops ensues, during which she\nconstantly incites him with that mocking call, till the poor fellow\nis fairly driven crazy. The female kingfisher often torments her\ndevoted lover for half a day, coming and calling him, and then taking\nto flight. But she never lets him out of her sight the while, looking\nback as she flies and measuring her speed, and wheeling back when he\nsuddenly gives up the pursuit. The bower-bird leads her mate a chase\nup and down their skilfully built pleasure-house, and many other birds\nbehave in a similar way. The male must exercise all his arts before her\nreluctance is overcome. She leads him on from limb to limb, from tree\nto tree, until it seems that the tantalizing change from allurement to\nresistance must include an element of mischievous playfulness.\u201d[148]\n\nProfessor Groos regards the instinctive coyness of the female as the\nmost efficient means of preventing the too early and too frequent\nyielding to sexual impulse.[149] He thinks it probable that \u201cin order\nto preserve the species the discharge of the sexual function must\nbe rendered difficult, since the impulse to it is so powerful that,\nwithout some such arrest, it might easily become prejudicial to that\nend. This same strength of impulse is,\u201d he adds,[150] \u201citself necessary\nto the preservation of the species; but, on the other hand, dams must\nbe opposed to the impetuous stream, lest the impulse expend itself\nbefore it is made effectual, or the mothers of the race be robbed\nof their strength, to the detriment of their offspring.\u201d It has its\norigin in the general fact that, before any important motor discharge\ntakes place, there is apt to be a preparatory and gradually increasing\nexcitement. But this is specially emphasized in association with the\nsexual impulse. As Professor Zeigler wrote, in a private communication\nto Dr. Groos,[151] \u201cAmong all animals a highly excited condition of the\nnervous system is necessary for the act of pairing, and consequently we\nfind an exciting playful prelude very generally indulged in.\u201d\n\nCourtship may thus be regarded from the physiological point of view\nas a means of producing the requisite amount of pairing-hunger; of\nstimulating the whole system and facilitating general and special\nvascular changes; of creating that state of profound and explosive\ninstability which has for its psychological concomitant or antecedent\nan imperious and irresistible craving. This not only overcomes the\ncoyness of the female, but generates and strengthens the ardour of\nthe male--a point on which, perhaps, Professor Groos does not lay\nsufficient stress. For the process is reciprocal; and though the male\nleads in the ardour of courtship, yet this ardour constantly grows till\nat last it overcomes the barriers of reluctance. Courtship is thus\nthe strong and steady bending of the bow that the arrow may find its\nmark in a biological end of the utmost importance in the survival of a\nhealthy and vigorous race.\n\nThe coyness and reluctance of the female afford the conditions under\nwhich the bow is bent to the full. But they also afford the conditions\nof the apparent act of choice. This takes the place, on the perceptual\nplane of mental development, of that deliberation which precedes the\nhigher act of choice on the ideational plane. For psychology, as well\nas for biology, then, Dr. Groos\u2019s suggestion is a welcome and helpful\none. Both upholders of sexual selection and critics of that hypothesis,\nhave been apt to regard the choice of a mate in animals from too\nanthropomorphic a point of view--to look upon it as the outcome of\nrational deliberation, of weighing in the \u00e6sthetic balance the relative\nattractiveness of this suitor and of that, and of reaching a definite\nconclusion that the one is to be accepted because he behaves or is\nadorned in such and such a way, while the other is to be rejected\nbecause he falls below all reasonable standards of requirement. The\nchoice exercised by the female, if so we term it, is far simpler and\nmore na\u00efve. Indeed, Professor Groos goes so far as to say that on his\nhypothesis the element of choice is altogether abolished. \u201cIt is the\ninstinctive coyness of the female,\u201d he says,[152] \u201cthat necessitates\nall the arts of courtship, and the probability is that seldom or never\ndoes the female exert any choice. She is not awarder of the prize, but\nrather a hunted creature. So, just as the beast of prey has special\ninstincts for finding his prey, the ardent male must have special\ninstincts for subduing female reluctance. According to this theory,\nthere is choice only in the sense that the hare finally succumbs to the\nbest hound, which is as much as to say that the phenomena of courtship\nare referred at once to natural selection.\u201d He reaches this conclusion,\nhowever, by gradual stages. He first urges[153] that \u201cit would be\nabsurd to affirm that all bird songs originate in a conscious \u00e6sthetic\nand critical act of judgment on the part of the female. A conscious\nchoice either of the most beautiful or the loudest singer is certainly\nnot the rule, and probably never occurs at all. But,\u201d he adds, \u201cis it\nnot still a choice, though unconscious, when the female turns to the\nsinger whose voice, whether from strength or modulation, proves most\nattractive? Even if the song is primarily a means of recognition or an\ninvitation from the male, still the psychological effect must be that\nthe female follows the songster that excites her most, and so exerts a\nkind of unconscious selection.\u201d\n\nThe phrase \u201cunconscious choice\u201d is, however, somewhat unsatisfactory,\nespecially when we remember that it is used to indicate the result\nof a direct appeal to the conscious situation. If, however, we say\nthat it is perceptual choice arising from impulse as distinguished\nfrom ideational choice due to motive and volition, we see that the\ndistinction is in line with that which we have drawn again and again,\nand which Dr. Stout so well emphasizes in his \u201cManual of Psychology.\u201d\nBut we have also drawn the distinction between instinctive behaviour\nprior to individual experience, and intelligent behaviour the result\nof such experience. Under which of these classes does the behaviour\nof the female during courtship fall? Professor Groos, in the further\ndevelopment of his hypothesis, seems to place it in the instinctive\ncategory. \u201cInstead of a conscious or unconscious choice, of which we\nknow nothing certain,\u201d he says,[154] \u201cwe have the need of overcoming\ninstinctive coyness in the female, a fact familiar enough, but hitherto\nnot sufficiently accounted for. Then the question no longer is, which\namong many males will be chosen by the female, but which one has the\nqualities that can overcome the reluctance of the female whom he woos.\nSexual selection would then become a special case of natural selection.\u201d\n\nI am unable to follow Professor Groos in this view, which I find it\nrather difficult to reconcile with such statements as that already\nquoted, in which he says that the female\u2019s \u201ctantalizing change from\nallurement to resistance seems to include an element of a mischievous\nplayfulness.\u201d It is more probable that instinctive coyness and\nreluctance afford the conditions under which experience of the\npleasures of courtship may be gained. It is said that a flirt, when\ntaken to task for her conduct at ball and picnic, justified it by\nasking demurely how else she was to gain that wide experience of men\nwhich was absolutely necessary to guide her in exercising a wise and\nbecoming choice. Let us hope that when the fateful time arrived she\nacted with due deliberation. Now the coquetry of birds affords the\nopportunity of gaining just such experience in the light of which a\nperceptual choice may be made.\n\nLet us remember that courtship is, as Darwin said, \u201ca prolonged\naffair,\u201d and that coyness is a means to its prolongation. And let us\nremember that in simple cases, as also in more complex matters, the\nintelligent exercise of choice depends upon what Dr. Stout terms the\nacquisition of meaning. \u201cThe chicken does not, at first,\u201d he says,[155]\n\u201cdistinguish between what is edible and what is not. This it has to\nlearn by experience. It will at the outset peck at and seize all worms\nand caterpillars indiscriminately. There is a particular caterpillar\ncalled the cinnabar caterpillar. When this is first presented to the\nchicken it is pecked at and seized, like other similar objects. But\nas soon as it is fairly seized it is dropped in disgust. When next\nthe chicken sees the caterpillar, it looks at it suspiciously, and\nrefrains from pecking. Now, what has happened in this case? The sight\nof the cinnabar caterpillar re-excites the total disposition left\nbehind by the previous experience of pecking at it, seizing it, and\nejecting it in disgust. Thus the effect of these experiences [what\nI have termed the conscious situation] is revived. The sight of the\ncinnabar caterpillar has acquired a _meaning_.\u201d Take now the case of a\ncoy hen bird, to whom several males pay court. The sight of this one,\nbehaving after his kind, excites in small degree the sexual impulse and\nemotions. Her heart beats but little the faster for all his antics,\nher respiratory rhythm is scarcely affected, her feathers, like her\nfeelings, remain comparatively unruffled. He has acquired meaning from\nthe reaction to his presence; it is not, however, a very attractive\nmeaning. But that other, perhaps from mere persistency, perhaps because\nhe is more \u201cvigorous, defiant, and mettlesome\u201d (she, at any rate,\ncertainly knows not why), deeply stirs her organic being, sets her all\naglow, and breaks down the barriers of her coyness. And this he does\nbecause he is the centre of a conscious situation which has acquired,\nthrough her experience of his presence, a meaning and an interest that\nare at last irresistibly attractive. It is a choice from impulse, not\nthe result of deliberation; but it is a choice which is determined\nby the emotional meaning of the conscious situation. And it is the\nreiterated revival of the associated emotional elements which generates\nan impulse sufficiently strong to overcome her instinctive coyness and\nreluctance.\n\nAnd this coyness is the natural correlative of the ardour of the male,\nan ardour increased by his courtship antics. If the female yielded\nreadily and at once, the behaviour of courtship would never have been\nevolved. Superabundant vigour in the male is, no doubt, a favourable\ncondition of courtship, as it is of play; but neither is it a _sine\nqu\u00e2 non_, nor in any case does it, or can it, afford any guidance of\nbehaviour into just those specific channels in which we find it setting\nduring the breeding season. If sexual selection be not a _vera causa_\nof the specific direction, we have at present no other hypothesis which\nin any degree fits the facts. And to the criticism of those who, like\nMr. W. H. Hudson, urge that dance and song, and a\u00ebrial evolutions in\nbirds, are seen at times when the immediate business of courtship forms\nno part of the situation, Professor Groos\u2019s theory of play affords\na sufficient answer. If courtship, whose biological end is of such\nsupreme importance, forms a central feature in the serious business of\nanimal life; and if play is the preparation and practice for behaviour\nof biological importance; we should expect to find manifestations (with\nan emotional difference, and no doubt many differences in detail) of\nall those actions, the due performance of which, in the supreme hour of\ncourtship, will alone enable the adequately prepared and well-practised\nmale to overcome the reluctance of the female, and beget offspring to\ntransmit his instinctive and emotional tendencies.\n\n\nIV.--ANIMAL \u201c\u00c6STHETICS\u201d AND \u201cETHICS\u201d\n\nIn this section we shall consider some types of behaviour which suggest\nsituations that contain the germs of \u00e6sthetics and ethics, with a\nview to determining, so far as possible, the principles on which they\nshould be interpreted. This is a peculiarly difficult subject; for\nwe are endeavouring to get behind the behaviour, and to infer the\nmental conditions which accompany it, and through which it assumes its\ndistinctive character. The difficulty is twofold: first, because, as\nDr. Stout puts it,[156] \u201chuman language is especially constructed to\ndescribe the mental states of human beings, and this means that it is\nespecially constructed so as to mislead us when we attempt to describe\nthe workings of minds that differ in any great degree from the human;\u201d\nand secondly, because, to quote the same careful thinker,[157] \u201cthe\nbesetting snare of the psychologist is the tendency to assume that an\nact or attitude which in himself would be the natural manifestation\nof a certain mental process must, therefore, have the same meaning in\nthe case of another. The fallacy lies in taking this or that isolated\naction apart from the totality of conditions under which it appears.\nIt is particularly seductive when the animal mind is the subject of\ninquiry.\u201d\n\nWe must, therefore, base our method of procedure on some definite\nprinciple. The canon of interpretation which I have elsewhere\nsuggested[158] is, that we should not interpret animal behaviour as the\noutcome of higher mental processes, if it can be fairly explained as\ndue to the operation of those which stand lower in the psychological\nscale of development. To this it may be added--lest the range of\nthe principle be misunderstood--that the canon by no means excludes\nthe interpretation of a particular act as the outcome of the higher\nmental processes, if we already have independent evidence of their\noccurrence in the agent. Now, the conclusion to which we are led by\ndirect experiment and a critical study of the actions of animals whose\nlife-history is known to us is, that most of their behaviour--perhaps\nall--is due to what Dr. Stout terms the perceptual, as opposed to the\nideational, exercise of cognition. Their behaviour can be explained\nwithout having recourse to the hypothesis that they reflect, and attain\nto ideal schemes as the result of abstraction and generalization\nconsciously directed to this end. Rather than repeat what I have\nalready said, I will quote Dr. Stout\u2019s summary of the position to\nwhich he, too, has been led. \u201cThe vast interval,\u201d he says,[159]\n\u201cwhich separates human achievements, so far as they depend on human\nintelligence, from animal achievements, so far as they depend on animal\nintelligence, is connected with the distinction between perceptual and\nideational process. Animal activities are either purely perceptual,\nor, in so far as they involve ideas, these ideas serve only to prompt\nand guide an action in its actual execution. On the other hand, man\nconstructs \u2018in his head,\u2019 by means of trains of ideas, schemes of\naction before he begins to carry them out. He is thus capable of\novercoming difficulties in advance. He can cross a bridge before he\ncomes to it.\u201d\n\nIt has already been stated that in the intelligent behaviour of animals\nunder man\u2019s teaching he is the rational agent, they his willing slaves.\nThis may be here again illustrated to enforce the distinction drawn\nby Dr. Stout in the above passage. Those who have seen a shepherd\u2019s\ndog working sheep on a moorland fell, and have taken the trouble to\nascertain how the results he sees have been attained, will appreciate,\non the one hand, how well the dog knows and responds to the signals of\nhis master, and, on the other hand, how completely all initiation is\nin the master\u2019s mind, not that of the keenly intelligent dog. Those\nwho merely witness such a performance without inquiry or investigation\nwill probably misunderstand the whole matter. In the north of England\ncompetitions are not uncommon where, say, three sheep have to be driven\nover a definite course, between certain posts and round others,\nthrough narrow passages and into a fold--all within a certain time\nlimit. At such a competition success depends on two things: first,\nthe training of the dog to respond at once to some six or eight\nwhistle-signals, often accompanied by gestures and movements of a\nstick; and secondly, the judgment of the shepherd. The signals, given\nin different whistle-tones and inflections, have for the dog meaning,\nsuch as drive straight on, from this side, from that, stop, lie down,\ncreep, and so forth. The dog\u2019s whole business is to obey these signals.\nAnd the instant response of a well-trained dog is admirable. But in the\nwhole proceeding he is merely the executant of his master\u2019s orders.\nHe originates no important step. And if you listen to the criticisms\nby other shepherds during a competition you will find that they are\nmainly passed on the judgment shown by the master, and only in palpable\nfailures in obedience on the behaviour of the dog. The intelligent\nanimal is what he is trained to be--one whose natural powers are under\nthe complete control of his master with whom the whole plan of action\nlies.\n\nSince, then, in the cognitional field we find no independent evidence\nof the higher processes, we are bound, in accordance with our canon, to\ninterpret emotional situations on similar principles, unless we find in\nthem outstanding facts which cannot be explained in this way.\n\nIn considering the pairing situation we urged that the framing of an\nideal of beauty to which a given suitor approaches, or from which\nhe falls short, is unnecessary for the interpretation of the facts.\nWe should not in strictness, therefore, speak of \u201can appreciation\nof beauty\u201d or \u201ca taste for the beautiful\u201d in birds, since such\nexpressions almost inevitably imply that these creatures have reached\nsome conception of beauty as distinguished from and contrasted with\nugliness. At the same time the hen certainly appears to enjoy the\nsituation of which the plumed cock, attitudinizing thus, forms the\ncentre of interest--through which he acquires meaning. Although,\ntherefore, there is probably no ideal or standard of beauty, there are\nafforded the data in experience from which, were the bird capable of\nreflection, such an ideal might, in ideational sublimation, be derived.\nBefore comparison, abstraction, and generalization can be applied,\nin the reflective laboratory of thought, there must be suitable\nexperiences to form the raw material on which these rational processes\ncan be exercised. Long ere, in the course of mental evolution, the\ncorrelative conceptions implied in the phrase \u201cbeautiful or ugly\u201d had\ntaken definite form, perceptual situations must have arisen, where, by\ndirect appeal to the senses, by the diffused effects of stimulation\nand their accompanying feeling-tone, and by the natural satisfaction\nof mere impulse, the foundations were laid of that appreciation of the\nbeautiful which forms the reflective superstructure we build upon them.\nIndeed, the pleasure and satisfaction attending particular situations,\nas they severally arise, appear to contain the perceptual germs of what\nin later development becomes \u00e6sthetic appreciation.\n\nThe bird which, having completed its nest, eyes it with apparent\nsatisfaction, may well have the germs of that which, when rendered\nschematic in our thought, we call taste. Dr. Gould, indeed, states that\ncertain humming-birds decorate their nests \u201cwith the utmost taste,\u201d\nweaving into their structure beautiful pieces of lichen. And the\ngardener bower-bird collects in front of its bower flowers and fruits\nof bright and varied colours. What meaning these carry in the conscious\nsituation we do not know; we can only suppose that they incidentally\ncontribute to the heightening of the sexual impulse, and have been\nevolved as a means of stimulation to the biological end towards which\nsexual selection is unconsciously directed. For it is probable that all\nthe situations with which pleasure and satisfaction are in high degree\nassociated are, in primary origin, closely connected with behaviour\ndirected, through natural or sexual selection, to some definite\nbiological end, or, in brief, with behaviour of biological value. And\nit is, perhaps, not improbable that the states of consciousness most\nhighly toned with strong emotion have their origin in those situations\nwhich arise amid the pairing, parental, and companiable relations of\nanimal life.\n\nWe have already said that the companion, as the nucleus of a situation,\nis a thing which reacts in altogether special ways, so that it becomes\ndifferentiated from other things as something the meaning of which, and\nthe interest in which, are _sui generis_ and unique in type. It becomes\nthe centre of emotional situations, which we ascribe to rivalry,\nemulation, jealousy, and so forth. And we have also drawn attention to\nthe view that the genetic order, so far as there is an order, is not\nfirst the ego and then the alter, but first the mother and companions\nand then through them the self. We learn to know ourselves only through\nknowing others. We must now ask the question--a question which must be\nanswered before we can touch on the possible ethics of animals--how\nfar, and in what sense, the social animal regards others as of like\nnature to itself, and capable also of like feelings and emotions.\nStated in this form we must, I think, answer the question in the\nnegative. The expression, \u201cof like nature to itself,\u201d implies that the\nself has already taken more or less definite form, and that the animal\ninfers that, since the alter behaves and reacts in like manner to the\nego, it also is an ego. This is distinctly an act of reasoning. As\nClifford phrased it, the companion becomes an _eject_. We can never by\ndirect experience become acquainted with the feelings of others, but we\ncan endow them ejectively with personality analogous to our own.\n\nBut, though it is exceedingly doubtful whether any animal can regard\nits companion as an \u201ceject,\u201d may there not be a perceptual anticipation\nof the ideational process that comes with later-developed reflection? A\ndecade ago I gave the following answer to this question: \u201cFor myself,\nI cannot doubt that animals project into each other the shadows of\nthe feelings of which they are themselves conscious.\u201d[160] Professor\nMark Baldwin speaks of the stage at which this takes place, as the\n\u201cprojective stage\u201d of development. \u201cNow, in the fact,\u201d he says,[161]\n\u201cof herding, common life and arrangements for the protection of the\nherd, animal societies of various kinds, animal division of labour,\netc.,--whatever be the origin of it,--we have what seems to be such\nan epoch in animal life. These creatures show a real recognition\nof one individual by another, and a real community of life and\nreaction, which is quite different from the individualism of purely\nsensational and unsocial consciousness. And yet it is just as different\nfrom the reflective organization of human society, in which the\nself-consciousness and personal volition of the individual play the\nmost important _r\u00f4le_. I see no way of accounting for the gregarious\ninstinct anywhere, except on the assumption of such a projective epoch\nof animal consciousness.\u201d\n\nNow, in endeavouring to realize how the situation feels to an animal\nin this projective stage, the first difficulty we encounter is\nthat of divesting ourselves of those products of reflection which\ncharacterize our own mental situation; and to avoid what Dr. Stout,\nin the passage above quoted,[162] terms the psychologist\u2019s besetting\nsnare. The second difficulty is to grasp that, in experience, subject\nand object are inseparable, however clearly we may learn to perceive\nthat they are distinguishable aspects of that experience. If the\nsubject is eventually regarded as that which experiences, and the\nobject as that which is experienced, it is surely obvious that each is\nnecessary to the other. But, before these different aspects are clearly\ndistinguished, there is, in the perceptual stage of mental development,\nwhat we may term a distribution of the items of experience among the\ncentres of interest.\n\nIn illustration of the kind of distribution which we may suppose to\ncome naturally to an animal, in what Professor Baldwin terms the\nprojective epoch, let us take three animal situations: first, a chick\npecks at a soldier-beetle, and finds it nauseous; secondly, a hen-bird\nhears the joyous song of her mate; thirdly, a puppy in play bites\nits companion, and receives a painful nip in return. Each of these\nconstitutes an experience-situation; assuming that the results of the\nexperience are distributed, how may we suppose them to be allocated?\n\nIn the first case, the soldier-beetle is the centre of interest in the\nsituation. As the situation develops, the element of nauseousness is\nintroduced. As Dr. Stout puts it, this is what gives the soldier-beetle\nmeaning. Can it be doubted that, if there be any distribution, the\nnauseousness, though it is altogether what we have learnt to call\na subjective affection, attaches itself to the soldier-beetle? The\nplain man, unsophisticated by Berkeleyan discussion, says simply, in\nsuch cases, \u201cThe thing is nauseous.\u201d And this probably indicates the\nna\u00efve and primitive distribution. Turning now to our second example,\nwhen the hen hears the courtship song the mate is the centre of a\nsituation suffused with pleasurable feeling. How is the joyousness,\nagain essentially subjective for our later thought, distributed?\nSurely, if at all, on the mate who forms the centre of interest. This\nit is which gives him meaning. The joy of the bearer is projected on\nto the singer. Not entirely, perhaps; the hen literally, on Professor\nJames\u2019s theory of the emotions, feels her heart-beat quickened by his\npresence, and the delightful ruffling of her feathers. But our aim is\nnot to deny that the germs of the subjective arise in the midst of such\nsituations, but to contend that some at least of the joyous character\nof the situation attaches to the song of the singer, that some of the\nfeeling is projected, and that this is what gives the mate meaning. In\nour third case, the playful puppy bites his companion, and is sharply\nbitten in return. Pain enters into the coalescent situation as a whole.\nHow is it distributed? In the phraseology of association, the nip he\ngives is closely linked with the pain he receives. By coalescence\nthe pain and the nip form parts of the developed situation. But the\ncompanion is the centre of interest. And part of the pain is probably\nprojected on this centre. That such projection actually occurs is\nrendered probable by such cases as the following, which was told me\nsome years ago. A child, whose exact age I have forgotten if I then\nascertained, was pricked by a pin, and he said, \u201cPin \u2019urted; poor pin.\u201d\nIt is, indeed, not unlikely that with animals the outward projection\nof feeling is widely distributed over inanimate, as well as animate,\nobjects, and that its due restriction comes far later in development,\nof which the so-called personification of lifeless things by savages\nmay be a relic. In any case, the give-and-take of play in young\nanimals, and the after-earnest of courtship and fighting, would seem to\nafford ample opportunity for the external and internal distribution of\nfeeling which sows the seed in perceptual life of that which blossoms\ninto self and alter in the reflective life of ideational thought.\n\nAlthough, therefore, an animal cannot conceive its companion as another\nself of similar nature, and with like passions to his own, yet a\nconsiderable share of the feeling-element of the conscious situation\nis projected on to that companion as the chief centre of interest. And\nif it be said that this is his feeling and not his neighbour\u2019s, the\nobjection will be seen to lose its force, so soon as it is realized\nthat even man has no experience of any feelings save his own. The only\nway we can reach fellow-feeling is through sympathy; and sympathy has\nits roots in the projective process we have endeavoured to describe.\nWe endow our neighbours with natures as sensitive to pain and pleasure\nas our own. This is a pre-requisite to the social relationships termed\nethical. But when we hear people say, and find even Mr. Romanes\nputting on deliberate record,[163] that \u201cthe feelings which prompt a\ncat to torture a captured mouse can only be assigned to the category\nto which, by common consent, they are ascribed--delight in torturing\nfor torture\u2019s sake,\u201d I venture to think that common consent, if such\nit be, is wrong. As I said a dozen years ago,[164] before Professor\nGroos had so carefully elaborated his theory of play, \u201cthe cat or\nkitten plays with the mouse not from innate cruelty, but for the sake\nof getting some little practice in the most important business of cat\nlife. Only man, who has the capacity for nobler things, can be cruel\nfor cruelty\u2019s sake;\u201d and this is the direction in which Dr. Groos\u2019s\nopinion[165] tends to set. Mr. Romanes might have learnt a lesson in\ncaution from his sister, who at first attributed a sense of shame to\nthe capuchin she so carefully studied, but subsequently was led to\nadopt a simpler interpretation. \u201cHe bit me in several places to-day,\u201d\nshe says, in her admirable diary,[166] \u201cbut he seemed ashamed of\nhimself afterwards, hiding his face in his arms, and sitting quiet for\na time.\u201d She adds, however, in a footnote: \u201cOn subsequent observation,\nI find this quietness was not due to shame at having bit me; for\nwhether he succeeds in biting any person or not, he always sits quiet\nand dull-looking after a fit of passion, being, I think, fatigued.\u201d\n\nShame is an ethical feeling. And as we have briefly discussed the\ngerms of \u00e6sthetics in animals, so we may now as briefly consider the\ngerms of ethics. In its developed form ethics is one of the \u201cnormative\nsciences\u201d involving standards of right and wrong. It is, as Professor\nMackenzie says,[167] \u201cthe science of the ideal in conduct.\u201d It involves\na standard of \u201cought,\u201d the product of reflection and generalization.\nConduct is compared with the ideal, and perceived to be either below,\nup to, or perhaps beyond, the normal standard accepted by civilized\nmankind. This involves a judgment; and so far as conduct is shaped in\naccordance with the ideal we attribute the guidance to ethical motives.\nSuch ideals, such judgments, and the control of conduct through the\nplay of such motives, are probably beyond the mental capacities of\nanimals. They belong to the ideational stage of mental development,\nwhen the conative tendency becomes volitional; not to the perceptual\nstage, when it is impulsive. They do not enter into the conscious\nsituation as it takes form in the animal mind. Behaviour has not in\nthem acquired ethical meaning, since in developed ethics, as normative,\nsuch meaning always has reference to the norm, or standard. A real\nsense of shame implies that our acts have fallen below our ideal.\n\nIt may be said that we cannot prove that animals do not frame such\nideals. But, if we accept the canon of interpretation above laid\ndown, what has to be proved is that they do frame them. Is there any\ncase among the hundreds that are popularly adduced to show that dogs\nare ashamed of themselves, that they possess a sense of justice,\nthat they feel the prick of conscience, that on the one hand they\nknow when they have done wrong, or on the other hand enjoy a sense\nof conscious rectitude--is there any particular case so described in\nthe popular phraseology of anecdote, which could not be more simply\ndescribed as the direct outcome of the coalescent situation, without\nthe introduction of any implied reference to a standard of behaviour\nreached by reflective thought? The pug that has taken a nap on the\ndrawing-room sofa, leaps down and slinks off with a \u201cguilty\u201d look on\nhis master\u2019s approach. One can surely picture the previous situations,\nand be tolerably certain that they contained an element of reproof or\nsomething more energetic. The poodle that has successfully performed\nhis tricks bounds to his mistress with an air of duty well performed.\nHas he never been petted and patted under such circumstance? Routine in\nmany animals--so often creatures of habit--begets a customary sequence,\nthe breach of which is at once felt. To this I ventured[168] to\nascribe the conduct of the turnspit dog reported by Arago. He refused\nwith bared teeth to enter out of his turn the drum by which the spit\nwas rotated. The companion dog was put in for a few moments and then\nreleased; whereupon the dog which before had been so refractory seemed\nsatisfied that his turn for drudgery had come, and, entering the wheel\nof his own accord, began turning the spit as usual. The bared teeth may\nbe here perhaps ascribed to an outraged sense of justice. But is it not\na more simple, and just as probable, supposition that the behaviour\nwas due to breach of customary routine. A trainer with whom I had some\nconversation on this matter pointed out a collie bitch, and said, \u201cIf\nI put her through her tricks in the usual order she does them like an\nangel; but if I try and make her alter the order she snaps and sulks\nlike the devil.\u201d\n\nI have elsewhere[169] expressed my opinion that, though animals may\nbehave in ways which may tend to mislead us, they do not act with\nintent to deceive. A dog is described[170] as \u201cshowing a deliberate\ndesign of deceiving\u201d because he hobbled about the room as if lame and\nsuffering from pain in his foot. But may not this be simply due to the\nfact that chance experience had led to a situation through which a\nhobbling gait had acquired the meaning of more petting and attention\nthan usual? To behave with deceit as a deliberate motive implies the\nidea that the action will be interpreted as having a significance\ndifferent from that which it really has. It is only possible on the\nideational plane of mental development. It implies, too, from the\nethical standpoint, a conscious departure from the standard of truth.\nThe black that is acted has conscious reference and relation to the\nwhite that is not black. Few, however, will credit animals with deceit\nof this fully conscious and deliberate kind. Like the fibs of little\nchildren, the apparent deceit of animals is probably merely behaviour\nwhich has been associated in experience with pleasant results.\n\nThe case of shamming sickness, quoted from K. Russ, is thus interpreted\nby Professor Groos.[171] And yet he adds, \u201cWhen we see deception used\nso effectively to serve practical ends, examples of which are very\ncommon, it can hardly be doubted that there is in all probability\nmore consciousness of shamming in play than we have any means of\ndemonstrating.\u201d And elsewhere in the same work he observes,[172]\n\u201cMany a grown animal still takes pleasure in the mock combats that he\nlearned in youth. From a psychological point of view this phenomenon\nis especially noteworthy, from the fact that the adult animal, though\nalready well acquainted with real fighting, still knows how to keep\nwithin the bounds of play, and must therefore be consciously playing\na _r\u00f4le_, making believe.\u201d I fail, however, to see the justification\nfor the \u201ctherefore.\u201d Surely the difference of behaviour in this\nexample, and in other such examples, is sufficiently explained\nas the outcome of diverse situations, without having recourse to\nanything so psychologically complex as the conscious self-illusion of\nmake-believe--interesting and important as this is in the psychology\nof children. To suppose that a monkey who nurses a bit of blanket has\nany ideas about its being a make-believe baby is _not_ to interpret the\nbehaviour of animals in accordance with the canon we have adopted for\nour guidance.\n\nTo return to the \u201cethics\u201d of animals. I have urged that ethical ideas,\nproperly so called, have no place in their psychology. But just as the\npleasure and satisfaction attending particular situations, as they\nseverally arise, appear to contain the perceptual germs of what in\nlater development becomes \u00e6sthetic appreciation; so, too, do they also\ncontain the perceptual germs of what becomes, through reflection in\nman, ethical approbation. And the situations in which these ethical\ngerms must be sought are those which entail behaviour for the good\nof the social community. Indeed, we may go so far as to say that the\nperceptual foundations of ethics are laid in the social instincts.\nThe satisfaction or dissatisfaction arising from the performance or\nnon-performance of instinctive behaviour, evolved for the biological\nend of the preservation of the social community, is the perceptual\nembryo from which conscience is developed. Professor Mackenzie has\nindicated the ambiguities in the use of the term \u201cconscience.\u201d \u201cIt is,\u201d\nhe says,[173] \u201csometimes used to express the fundamental principles\non which the moral judgment rests; at other times it expresses the\nprinciples adopted by a particular individual; at other times it\nmeans \u2018a particular kind of pleasure or pain felt in perceiving our\nown conformity or nonconformity to principle.\u2019[174] This last seems\nto me,\u201d adds Mr. Mackenzie, \u201cthe most convenient acceptation of the\nterm, except that I should prefer to say simply that it is a feeling of\npain accompanying and resulting from our nonconformity to principle.\u201d\nAccording to this definition the existence of a principle or ideal is\npresupposed; and the fact that Professor Mackenzie lays stress upon the\npain of nonconformity, shows that the ideal is a high one. In the case\nof the animal, however, such an ideal of right conduct has probably not\ntaken form. But Mr. Mackenzie also speaks of the \u201cquasi-conscience\u201d\nbegotten of custom. This comes nearer to the feeling which animals may\nbe supposed to have when their behaviour does not accord with that\nwhich through instinct or habit is the usage of the community. And\nif, as seems to be shown by observation, animals sometimes punish the\nbreaches of such usage--when, for example, cats punish their kittens\nfor uncleanliness--the quasi-conscience will assume a more developed\nform.\n\nWe may say, then, that the perceptual data are given in animal\nexperience from which, in ideational sublimation, ethical ideals may be\nderived by a process of reflection and generalization. As in the case\nof \u00e6sthetics, so in that of ethics; long ere, in the course of mental\nevolution, the correlative conceptions implied in the phrase \u201cright or\nwrong\u201d had taken definite form, perceptual situations must have arisen\nin which behaviour carried with it the feelings of satisfaction or the\nreverse which laid the foundations of that approbation of the right\nwhich forms the superstructure we build upon them by the exercise of\nreflective thought.\n\n\nV.--THE EVOLUTION OF FEELING AND EMOTION\n\n\u201cWhatever conditions,\u201d says Dr. Stout,[175] \u201cfurther and favour\nconation in the attainment of its end, yield pleasure. Whatever\nconditions obstruct conation in the attainment of its end, are sources\nof displeasure. This is the widest generalization which we can frame,\nfrom a purely psychological point of view, as regards the conditions of\npleasure and displeasure respectively.\u201d Here Dr. Stout seems carefully\nto avoid the commonly accepted and much advertised conclusion, that\npleasure and pain (to use this more familiar word as the antithesis\nof pleasure) are themselves the end of conative endeavour. And he is\nso far right that they by no means constitute the sole or indeed the\nprimary end of all conative process. Attention is a conative act; but\nits primary end is not pleasure, but rather, as Dr. Stout says,[176]\nthe fuller presentation of the object. No doubt this brings pleasure;\nbut the fuller presentation comes first, and carries the pleasure with\nit. Instinctive response to felt stimulus falls within the conative\nattitude. In it there is that \u201cinherent tendency to pass beyond itself\nand become something different,\u201d which Dr. Stout assigns to conation as\nits chief characteristic. But the end is not pleasure, but simply the\ninstinctive behaviour. And if we say that the attainment of this end\ndoes bring satisfaction, which is a form of pleasure, Dr. Stout would\nprobably reply that this is rather a result of the process than its\ntrue end.\n\nNow, in such cases, what we are really dealing with is a class of\n_organic_ processes having conscious accompaniments. No doubt the\nconscious accompaniments are of importance; they certainly cannot\nbe neglected by the psychologist: but their feeling-tone does not\nconstitute that which makes instinct run its course. And I have\nintroduced the subject for present discussion in this way to reinforce\nwhat has already been repeatedly urged in the foregoing pages, that\nindividual behaviour, in its first intent, is a biological legacy\nwith ends predetermined through heredity. The inherent tendency to\npass beyond itself and become something different, which for the\nold psychology was a heaven-sent impulse, or, as Addison said, \u201can\nimmediate impression from the first Mover and the Divine energy acting\nin the creatures,\u201d becomes for the new psychology an organic bequest.\nBut the attainment of ends thus already predetermined has feeling-tone,\nboth as process and in its resulting consciousness, and this\nfeeling-tone serves to modify, through the situation it introduces,\nfuture behaviour, and thus, in a sense, affords a new end to subsequent\nconation.\n\n\u201cLife,\u201d wrote James Martineau,[177] \u201cis a cluster of wants physical,\nintellectual, affectional, moral, each of which may have, and all\nof which may miss, the fitting object. Is the object withheld or\nlost? there is pain: is it restored or gained? there is pleasure:\ndoes it abide or remain constant? there is content. The two first\nare cases of disturbed equilibrium, and are so far dynamic that they\nwill not rest till they reach the third, which is their posture of\nstability and their true end.\u201d This is an adequate description of the\nessential features in conative process. But in genetic precedence,\nas in individual development, the physical wants come first, and,\nat the outset of behaviour, the satisfaction or content is not and\ncannot be foreseen, since it has never yet entered into experience.\nTo adopt a distinction suggested by Professor Mackenzie,[178] the\nconation is _purposive_, since we see that an end is involved, but not\n_purposeful_, since there is no definite consciousness of the end aimed\nat. But when experience has introduced feeling-tone into the situation,\nwe may say that this, in a sense, introduces a new end to subsequent\nbehaviour.\n\nMr. Herbert Spencer has said[179] that pleasure is that which we seek\nto bring into consciousness and retain there; pain, that which we seek\nto get out of consciousness and keep out. May we assert, then, that,\nin the modification of behaviour due to experience, the pleasure to be\ngained or the pain to be avoided is the psychological end? Certainly\nnot without qualification, unless we be among those who are content\nto accept any form of words which gives a general sort of notion of\nthe kind of thing which we suppose is meant, and which is probably\nmore or less correct. We want here and now to get clear ideas, and to\nexpress them with some approach to accuracy. To say that pleasure is\nthe psychological end of intelligent behaviour is to put the matter\ntoo subjectively and in too abstract a form. Professor Mackenzie has\nclearly indicated the ambiguity in the word \u201cpleasure.\u201d \u201cPleasure,\u201d he\nsays,[180] \u201cis sometimes understood to mean agreeable _feeling_, or\nthe feeling of satisfaction, and sometimes it is understood to mean an\n_object_ which gives satisfaction. The hearing of music is sometimes\nsaid to be a pleasure, but of course the hearing of music is not a\nfeeling of satisfaction; it is an object that gives satisfaction.\nGenerally, it may be observed that when we speak of \u2018pleasures\u2019 in\nthe plural, or rather in the concrete, we mean objects that give\nsatisfaction; whereas when we speak of \u2018pleasure\u2019 in the abstract, we\nmore often mean the feeling of satisfaction which such objects bring\nwith them.\u201d May we not go a step further, but entirely in the same\ndirection, and say that pleasure is a constituent part of the concept\nself as an object of thought or desire; that its proper sphere is in\nthe ideational consciousness; and that, as we interpret the animal\nmind, it has no place as such therein? The hedonist regards pleasure as\nthe most excellent and distinctive characteristic of his ideal self and\nhis ideal community. But animals have not risen or fallen to the level\nof hedonism. Pleasure is not for them a motive of conduct, though nice\nobjects, as such, are attractive, and through them impulse acquires\ndirection and force.\n\nIf, in animal psychology, we are to use the words pleasure and pain\n(as the antithesis of pleasure)--and they seem more properly to belong\nto a plane of mental development to which animals probably have not\nattained--we may say that the pleasure or the pain which attaches\nto any centre of interest in the situation is that which gives it\nattractive or repellent meaning; it furthers conation either towards\nor, as Hobbes would say, fromwards. But if we put the matter in this\nsomewhat abstract form, let us keep in view, if it be only in the\nbackground of our thought, the kind of concrete example which may\nbe adduced in its illustration--the dog with his attractive bone,\nthe kitten that has raced off at sight of him, the cock-sparrow with\ntrailing wings hopping after his mate, the falcon stooping on her\nquarry, the rabbit diving into his burrow at sight of the fox, and so\nforth. If we have such cases in view, where the centre of the situation\nhas acquired or is acquiring meaning, a meaning which in large degree\nattaches to the external nucleus of the situation with only the germs\nof subjective reference, we may, perhaps, summarize the position by\nsaying that in each case some pleasure to be gained or some pain to be\navoided is the psychological end of conation.\n\nBut in each case the conation has also a biological end--the\npreservation and conservation of the race. \u201cAn animal,\u201d said\nDarwin,[181] \u201cmay be led to pursue that course which is most beneficial\nto the species by suffering, such as pain, hunger, thirst, or fear; or\nby pleasure, as in eating and drinking, and in the propagation of the\nspecies; or by both combined, as in the search for food.\u201d The important\npoint here to notice is that the two ends agree--the psychological\nend of the attainment of pleasure and the avoidance of pain, and the\nbiological end of race preservation. Under the joint influence of\npleasure and pain, the needle of animal life sets towards the pole of\nbeneficial action.\n\nThis consonance of end was in old days ascribed to the beneficent\nforesight of the Creator. The modern view, that it is a product of\nevolution, does not necessarily ascribe it to any other ultimate cause.\nFor many still piously hold that evolution is only a name which we give\nto the method of creation. And there is not a fact or generalization in\nscience by which such a conclusion can be disproved, for the premises\nlie outside the field of scientific inquiry. But the consonance of\nend is, for science, a remarkable fact, and one worthy of attentive\nconsideration.\n\nWe have already seen that, if the claim for the inheritance of acquired\ncharacters be, on the evidence, judged unproven, and if instinct cannot\nbe ascribed to transmitted habit, or regarded as a legacy of that which\nhas been ancestrally acquired, the only scientific explanation of\ninstinctive behaviour is one which involves the principle of natural\nselection. But no one doubts that, in the course of experience, animals\nacquire modes of procedure which are beneficial to the race. This is\nwell seen in the play of animals as interpreted by Professor Groos.\nNow, why do animals play? From the psychological point of view, because\nthey like it; from the biological point of view, because they thus gain\npractice and preparation for the serious business of their after-life.\nBut why do they like it? because, under natural selection, those who\ndid not like it, and therefore did not play, proved unfit for life\u2019s\nstruggle, and were eliminated. Suppose that an animal were born with a\nrooted hereditary aversion to everything nutritious and an inherited\nhunger for anything harmful and unfit for food. What chance would it\nstand of survival? Hereditary likes and dislikes determine the general\ncourse of acquired behaviour, just as hereditary nerve-connections\ndetermine the course of instinctive behaviour. Wherein, then, lies\nthe difference between the two? In the fact that in the one case the\nnerve-connections are transmitted ready-made, while in the other they\nresult from association or coalescence in the course of individual\nlife. But in both cases the pursuit and attainment of the beneficial\nbrings satisfaction.\n\nNow, the consonance of end has long been regarded as an inevitable\ndeduction from the hypothesis of evolution. \u201cThat pains are\ncorrelatives of actions injurious to the organism,\u201d wrote Mr. Herbert\nSpencer in his \u201cPrinciples of Psychology,\u201d[182] \u201cwhile pleasures are\nthe correlatives of actions conducive to its welfare, is an induction\nnot based on the vital functions only. It is an inevitable deduction\nfrom the hypothesis of evolution, that races of sentient creatures\ncould have come into existence under no other conditions. Those\nraces of beings only can have survived in which, on the average,\nagreeable or desired feelings went along with activities conducive to\nthe maintenance of life, while disagreeable and habitually avoided\nfeelings went along with activities directly or indirectly destructive\nof life, and there must ever have been, other things being equal, the\nmost numerous and long-continued survivals among races in which these\nadjustments of feelings to actions were the best, tending ever to\nperfect adjustment.\u201d And he safeguards the position by adding: \u201cIt is\nfrequently taken for granted that the beneficial actions secured must\nbe actions beneficial to the individual; whereas the only necessity is\nthat they shall be beneficial to the race.\u201d\n\nThis aspect of the consonance is now quite familiar; but let us\ncarefully note how completely dependent it is on natural selection. Mr.\nHerbert Spencer\u2019s testimony is especially valuable, since he has always\nlaid much stress on the hereditary transmission of acquired characters\nand still holds[183] \u201cthat the inheritance of functionally-caused\nalterations has played a larger part than Darwin admitted even at the\nclose of his life; and that, coming more to the front as evolution has\nadvanced, it has played the chief part in producing the highest types.\u201d\nNow, in these types we certainly find a wide range of consonance\nbetween the psychological and the biological ends of behaviour; of\nwhich the phenomena of play may again be adduced as an example. Hence\nthe special value of Mr. Herbert Spencer\u2019s testimony to the part played\nby natural selection in establishing the consonance. \u201cOnly those races\nof beings,\u201d he says, \u201c_can have survived_ in which, on the average,\nagreeable feelings went along with activities conducive to life;\u201d and\nagain, \u201cThe most numerous _survivals_ must ever have been among races\nin which these adjustments of feelings to actions were the best.\u201d The\nstress is here laid on the survival of those in which the consonance\nhas obtained; the elimination of those in which it was absent: that\nis to say, on natural selection. And where else can it be laid? It is\nnot the sort of thing which could be acquired. Suppose that, as we\nsuggested above, an animal were born with a rooted hereditary aversion\nto everything nutritious and an inherited hunger for anything harmful\nand unfit for food. Under what conceivable conditions could such an\nanimal acquire a complete change of its affective nature? Animals like\nthings or they do not like them; only to a very limited extent, if at\nall, under natural conditions, can they learn to like them. We, indeed,\ncan in some degree learn to take pleasure in that which at first, and\nby nature, is distasteful; but we do so by some external constraint, or\nfrom some motive of ideational origin. We put pressure upon ourselves,\nor have pressure put upon us, repeatedly to perform some irksome task;\nwe fall into routine and custom; and the performance becomes so far\nsecond nature that its discontinuance produces an uncomfortable sense\nof something lacking in the daily round. Perhaps domestic animals learn\nto like the good offices we force them to perform for us. But here we\nhave the element of external constraint, which is wholly, or almost\nwholly, absent under natural conditions. And there is no evidence\nthat such acquired likings are inherited. That, however, is another\nquestion. Our present point is that, under nature, the conditions of\nsuch acquisition are lacking; so that, there being no acquisition,\nthere is, in this case, nothing acquired to be transmitted.\n\nBut, so far as behaviour is concerned, \u201cfunctionally caused\nalterations\u201d are those due to the exercise of intelligence, by which\nthe behaviour acquires direction and character in reference to the\nmeaning introduced into the situations. See, then, the position\nto which we are logically driven. The acquisition of that which\nhas beneficial value in behaviour depends on a consonance between\npsychological and biological end. But this consonance is dependent\non survival, and, apart from special creation, or some kindred\nhypothesis such as Leibnitzian harmony, can be due to nothing else.\nEven if we grant, therefore, that the effects of acquisition are\ninherited, the conditions of beneficial acquisition are dependent on\nnatural selection. And thus the inheritance of acquired characters,\nwhich is so often urged as a principle of evolution independent of\nnatural selection, is, so far as intelligent behaviour is concerned,\nindirectly, if not directly, due to this very natural selection of\nwhich it is said to be independent. Surely, under these circumstances,\nthe hypothesis in question may be said to be not only unproven, but\naltogether unnecessary.\n\nAnd what is true of those diverse feelings which we group under\nthe concepts pleasure and pain respectively, is true also of those\nmore complex dispositions which we call emotional--using this term\nin a broad and comprehensive sense. We say that in their primary\nmanifestations they are instinctive; and they certainly seem to\naccompany organic behaviour due to co-ordinated reflex actions. But\nthe emotion, as instinctive, is a matter only of its first occurrence.\nIn the course of experience it enters into conscious situations, the\ncentres of interest in which have acquired meaning.\n\nTake a particular case.[184] Your dog is dozing on the lawn in the\nsunshine. Suddenly he raises his head, pricks his ears, scents the air,\nlooks fixedly at a gap in the hedge, and utters a low growl. Place\nyour hand on his shoulder, and you will find that his muscles are all\na-tremble; on his ribs, and you will feel how strongly his heart is\nbeating. Soon the growing excitement leads to vigorous action, and he\ndarts through the gap. You follow him across the lawn, look over the\nhedge, and see him facing his old enemy, the butcher\u2019s cur. They are\nmoving slowly past each other, head down, teeth bared, back roughened.\nYou whistle softly. Such a call would generally bring him bounding to\nyour feet; but now it is apparently unheard, at any rate unheeded. The\ntwo dogs have a short scuffle, and the cur slinks off. Your dog races\nafter him; and he flees, yelping. The situation is over. Spot returns,\nwagging his short tail, jumps up at you playfully, and then lies down\nagain on the grass. But now and then, for ten minutes or so, he raises\nhis head and growls softly.\n\nLet us briefly analyze the dog\u2019s condition and actions, reading into\nthem, conjecturally, the accompaniments in consciousness. As he lies\non the lawn, he receives a sense-stimulus, auditory or olfactory. It\nhas already acquired meaning, from many a tussle with the butcher\u2019s\ncur. It has organic effects, and it generates a conscious situation\nwhich has acquired complexity through coalescence. As the result of\nthis situation the head is raised, the ears pricked, and so on. The\ndog is on the alert. His attention is aroused. The muscles of neck,\neyes, ears, are brought into play in such a way as to bring the senses\nto bear on the exciting object. He probably sees the cur through the\ngap in the hedge. The muscles of the frame are innervated so as to be\nin a state of preparation to act rapidly and forcibly. At the same\ntime the vaso-motor system is disturbed, the heart-beat is quickened,\nrespiration is altered; there is probably hardly an organ in the body\nwhich remains unaffected. Then the dog rushes through the hedge,\nand stands with bared teeth before his antagonist. A whole set of\nappropriate muscles are now strongly innervated. There is, perhaps,\na double innervation, stimulating to activity and yet restraining\nfrom action. He bares his teeth and growls deeply. Attention is so\nconcentrated that he heeds not, perhaps does not hear, his master\u2019s\nwhistle. He is keenly on the alert. The blood-system, respiratory\norgans, and all his inner machinery are still pulsating with nervous\nthrills; his back is up. Then he sees his chance, and flies at his\nopponent. Much that he has learnt in play, and all that he has learnt\nin earnest, comes to his aid in the short angry scuffle. And what we\ncall his emotion of anger spurs him on to the fight; the cowardly dog\nin which this is lacking or is replaced by fear is spurred to flight.\nEach may contribute to self-preservation, but in different ways.\n\nNow, we shall not attempt to determine how the distinctively emotional\nelements arise. Some think they arise by a sort of irradiating nervous\ndiffusion in the nerve-centres as a direct result of the originating\nstimulus. Mr. Rutgers Marshall regards them as due to the motor\nactivities in fight or flight; Professor William James contends that\nthey have their source in the visceral affections of heart, lungs,\nglands, and so forth; Professor Lange attributes them to vaso-motor\neffects. The problem is a difficult one, and hard to determine by\nexperiment; for we have to deal with a matter of primary genesis, of\nhow they are at the outset introduced into the conscious situation.\nExperiments on animals which have already gained emotional experience\ncannot decide the question of genesis. Professor Sherrington, for\nexample, has shown[185] that, after severance of the spinal cord in\nthe lower region of the neck, and of the vagus nerves, by which \u201ca\nhuge field of vascular, visceral, cutaneous, and motor reaction\u201d\nwere \u201cdeprived of all connection with the nervous centre necessary\nto conscious response,\u201d \u201cthe emotional states of anger, delight at\nbeing caressed, fear and disgust were developed with, as far as could\nbe seen, unlessened strength.\u201d But the avenues of connection were\nclosed _after_ the motor and visceral effects had played their parts\nin the _genesis_ of the emotion on the hypothesis that the emotion is\nthus generated. Although new presentative data of this type were thus\nexcluded, their re-presentative after-effects in the situation were\nnot excluded. It is, moreover, an essential part of Professor James\u2019s\ndoctrine, as I provisionally accept it, that the \u201cexpression\u201d and the\nvisceral and vascular efforts are independent results of stimulation in\ncertain ways, and that these independent results are conjoined through\nnatural selection. Suppose we sever the connection through which the\none takes effect, there is no reason to expect that the manifestation\nof the other would cease. Professor Sherrington cut off the channels of\ncommunication with the visceral and vascular apparatus: if the channels\nof expression remained open there is no reason why such expression\nshould cease.\n\nWe need not, however, for our present purpose, attempt to ascertain how\nthe distinctively emotional characteristics arise. It is sufficient\nthat they are presumably present in the situation. Now, as Dr. Stout\nwell points out,[186] the emotions generally presuppose the existence\nof certain specific tendencies. \u201cThe anger produced in a dog by\ntaking away its bone presupposes the specific appetite for food. The\nanger produced in it by interfering with its young presupposes the\nspecific tendency to guard and tend its offspring. So the presence of\na rival who interferes with its wooing causes anger because of the\npre-existence of the sexual impulse.\u201d In general, we may say that\nemotional states are, under natural conditions, closely associated with\nbehaviour of biological value--with tendencies which are beneficial\nin self-preservation or race-preservation--with actions that promote\nsurvival, and especially with the behaviour which clusters round the\npairing and parental instincts. The value of the emotions in animals\nis that they are an indirect means of furthering survival. But how has\nthe close association between emotional condition and the biological\nend it furthers been established? Again, we must say that under natural\nconditions it is not the sort of thing which could be acquired. And\nagain we must urge that natural selection through survival is, apart\nfrom some theory of pre-established harmony, the only hypothesis in the\nfield on which the close association can be explained.\n\nThere is one more point to which attention may be drawn. If there be\none thing, and there certainly are not many, on which all writers on\nthe emotions are agreed, it is as to their vagueness. They do not\nreadily submit to definition, and cannot be described in a sentence.\nThis is not due to any indefiniteness of biological end, nor to much\nindefiniteness in the mode of \u201cexpression;\u201d it is due, rather, to\nan inherent dimness and haziness of psychological outline. We seem\nunable to focus them and get a clear-cut result. This is, no doubt,\nin part due to the complexity of emotional states. But, may it not be\nlargely due to the fact that there is no necessity for definiteness?\nThey fulfil their purpose just as well if they are vague. It is quite\nnecessary for the dog to have a clear-cut impression of his antagonist;\nand, on the cognitive side of consciousness, meaning must be in some\ndegree definite to be of real value. But, so long as the emotion raises\nthe temperature, so to speak, to the boiling-point of vigorous action,\nit matters little what the psychological source of heat may be. If this\nbe so, we should expect an emotional vagueness, since natural selection\nputs no premium upon emotional definiteness. And from this it follows,\nas a corollary, that, whereas we may infer that an animal\u2019s perceptual\nproducts are probably closely similar to our own, since sight, touch,\nhearing, smell, and taste are of value in so far as they convey\ndefinite meaning, in interpreting their feelings and emotions we have\nless secure grounds of inference, since all that is requisite is that\nthere should be a sufficiently high emotional temperature to afford the\nconditions for definite and vigorous action.\n\nIn conclusion, then, we may say that the primary purpose of the\nevolution of feeling and emotion is to promote beneficial behaviour,\nand that the observed consonance of the psychological end of attaining\nsatisfaction, and the biological end of securing survival, seems to be\ndue to natural selection--is, indeed, scarcely explicable on any other\nnaturalistic hypothesis.\n\nA word of warning may be added. We have repeatedly spoken of biological\nand psychological ends. By this we mean what seems to the observer, as\nan interpreter of natural processes, the purpose and object of their\nexistence. But the word \u201cend\u201d is often used in such a way as to imply\nforesight and contrivance on the part of a rational being. We have not\nused it in this sense. Whether the whole of nature, including animal\nbehaviour, is driven onwards to definite ends by an underlying Cause,\nis a metaphysical question. It is not one on which science has any\nright to express an opinion one way or the other. Science deals with\nthe phenomena; the causes of their being lie outside her province.\n\n\n\n\nCHAPTER VII\n\n_THE EVOLUTION OF ANIMAL BEHAVIOUR_\n\n\nI.--THE PHYSIOLOGICAL ASPECT\n\nAt the outset of our inquiry, we used the word \u201cbehaviour\u201d in a wide\nand comprehensive sense. Thus broadly used, I said, the term in all\ncases indicates and draws attention to the reaction of that which\nwe speak of as behaving in response to certain surrounding forces\nor circumstances which evoke the behaviour. The behaviour of living\ncells is dependent on changes in their environment; that of deciduous\ntrees, as they put forth their leaves in the spring or shed them in\nthe autumn, is related to the change of the season; instinctive,\nintelligent, and emotional behaviour are called forth in response\nto those circumstances which exercise a constraining influence at\nthe moment of action. Used in this comprehensive sense, the term\n\u201cbehaviour\u201d neither implies nor excludes the presence of consciousness.\nWe know from our own experience, however, that consciousness does in\nsome cases accompany behaviour, and we infer that in many other cases\nit may be present. But we need a criterion of its presence to guide\nour inferences, and this criterion we found in the ability of living\nbeings to profit by experience. In Dr. Stout\u2019s phraseology, if a thing\nseems to acquire meaning for such a being, and the behaviour is guided\nin accordance with such acquired meaning, we infer the presence of\nconsciousness as supplying conditions effective in determining its\ncourse. Still this does not exclude, nay, rather it presupposes the\npresence of sentience at a lower stage of evolution, a sentience which\nis as yet ineffective since the process of conscious coalescence has\nnot begun, or has not been carried far enough.\n\nIn foregoing chapters we have constantly held the problems of evolution\nin view, and in special sections directed attention to them. But the\nsubject is so central to modern thought and discussion, that some\nfurther consideration of certain aspects of the evolutionary process\nand products will fitly serve to bring our inquiry to a conclusion.\n\nWe must accept, as a datum from the physiological point of view, the\nfact that protoplasm does respond to stimuli,--that it possesses the\nfundamental property of irritability. It is a substance that is in a\nstate of unstable equilibrium. Its tendency to pass to a condition of\nmore stable equilibrium is that in and through which organic behaviour\nin its very simplest expression is possible. And this, with progressive\ncomplication, runs through the whole gamut of animal behaviour, and\neventually passes over into the sphere of consciousness. \u201cThe tendency\nto equilibrium,\u201d writes Dr. Stout,[187] \u201cis the physiological correlate\nof what on the psychical side we call conation,--the striving aspect of\nconsciousness.\u201d But, protoplasm at the outset--or as near the outset\nas we can get--is, in technical phrase, differentially responsive. The\nnature of the stimulus and the nature of the conditions decide what\nthe nature of the response shall be. And even in that jelly-like speck\nof living matter, the _Am\u0153ba_, the responses conspire to a biological\nend. If they did not so conspire, we should not have the phenomena of\nlife. The mere act of living, building up from food-stuff and oxygen an\nunstable substance which \u201cexplodes\u201d and contracts under stimulation,\nimplies that the processes which thus conspire are related in such\na manner as to fulfil and secure their end. In higher unicellular\nanimals, such as the _Paramecium_, the relations are less simple; but\nin them the continuance of that sum of organic behaviour which we\ncall life, is secured only on the condition that these less simple\nrelations are duly preserved, and that the vital processes conspire\nwith sufficient unity of biological purpose. And when we pass to the\nhigher creatures in which many cells unite to form one animal, the very\nword \u201cunite\u201d indicates that the vital processes of all must conspire\nwith sufficient _unity_ of biological purpose to insure the continued\nlife of the whole.\n\nNow, in all the higher and more active animals a nervous system is\ndeveloped, which has for its purpose and end the preservation and\nfurtherance of unity amid circumstances of progressively increasing\ndiversity. And in the course of its evolution an added means of\npreserving and furthering the essential unity is provided in\nconsciousness, which, through the coalescence of scattered units of\nsentience, leads behaviour to acquire a new and higher unanimity of\npurpose. Thus a mental evolution is engrafted on the organic evolution\nwhich precedes it. But every step in this mental evolution presupposes\na step in organic evolution. And such is the complexity of structure\nand process in all the higher animals that much of the business of\nbehaviour is relegated to quasi-independent nervous centres, which\nperform this business automatically, and will continue to perform it,\nwith much subsidiary unity of end, when they are left to themselves and\nall connection with the supremely unifying sensorium has been severed.\n\nBefore proceeding to give some examples of this fact, and to indicate\nits bearing on our interpretation of behaviour, it may be well to\nstate distinctly that no attempt is or will be here made to trace in\ndetail the course of the evolution of animal behaviour through the\nascending grades of life, nor, indeed, to prove that there has been any\nsuch evolution. Evolution by natural genesis is here assumed as the\nonly hypothesis with which science has any concern. If it be false,\nthen have the labours of workers and thinkers, since Darwin and Mr.\nHerbert Spencer worked and thought, been vain. Special creation is\nnot a scientific hypothesis, but a reference of biological and mental\nphenomena to an ultimate cause, which lies beyond and altogether apart\nfrom the scope of scientific inquiry. The fundamental assumption of\nthe man of science is, that any natural event he may select for\ndetailed study has natural conditions and antecedents. And it is only\nin such detailed study--taking this or that particular occurrence and\nendeavouring to ascertain what were its related antecedents--that\nadvance in the evolutionary interpretation of nature can be secured.\n\nSuch advance has been secured by the labours of those physiologists\nwho have established by careful experiment the quasi-independent\naction of subsidiary nerve-centres as constituents of the nervous\nsystem as a whole. In such animals as the crayfish and the lobster\nthe central nervous system consists of a chain of \u201cganglia,\u201d or\nnerve-knots, which are connected together by nerve-strands. If these\nstrands be cut between the thorax, which carries the walking limbs,\nand the abdomen or hinder portion of the body, the nerve-connection\nbetween these parts is severed. If the forepart be irritated through\nits sense-organs, the limbs of that part will respond; but, whereas\nan unmutilated crayfish, subjected to such irritation, would give a\nvigorous flap of the tail, this does not take place in the crippled\nanimal.[188] Still, if the abdomen be irritated, it will respond by a\nstrong and swift contraction. The two portions of the body are each\ncapable of acting independently with well co-ordinated movements, but\nno longer of working together with unity of purpose. In the hinder\nportion the abdominal limbs, or swimmerets, all swing backwards and\nforwards simultaneously with rhythmic strokes; they act in concert.\nSever now the connections between their ganglia, and each pair of\nlimbs will continue to swing rhythmically but not with concerted\nrhythm. We have isolated a number of quasi-independent centres, and\nrendered them really independent. Each is concerned with its own\nproper co-ordination, but can no longer combine with others in a\nwider co-ordination. Mr. Hyde[189] has shown that in the king-crab,\n_Limulus_, when the nerve-chain is severed just in front of the\nabdominal region, the rhythmic respiratory movements of the abdominal\nsegments still proceed regularly and co-ordinately. Even when only\na fraction of the nerve-cord, separated by severances in front and\nbehind, is left, corresponding with a single abdominal segment,\nthe rhythmic action of that segment continues; but it is no longer\nsynchronous with that of adjacent segments similarly isolated.\n\nIt will probably not be contended that the co-ordinated rhythm of\nthe isolated segment in crayfish or king-crab is anything but a bit\nof organic and physiological behaviour. Whether it be accompanied by\nconsciousness--a bit of consciousness isolated from other bits--we\ndo not know; but we have no grounds for supposing that the rhythmic\nbehaviour is guided by consciousness. And when, as Dr. Carpenter\npointed out half a century ago, a water-beetle, from which the \u201cbrain\u201d\nhas been removed, swims forwards if placed in water, we must surely\nregard the co-ordinated progression as organic behaviour, whatever view\nwe may hold with regard to a consciousness which in such a case is in\na very literal sense a divided consciousness.\n\nIn these invertebrates the central nervous system is obviously\nsegmented--one can distinguish the ganglia and their connecting\nnerve-strands. In the vertebrate the brain and spinal cord form a\ncontinuous mass of nerve-tissue without obvious segmentation. But the\npairs of spinal nerves, each nerve with its afferent and efferent\n\u201croot,\u201d indicate a really segmented condition, though in the cord\nitself the segments so run together and overlap that they cease to be\nexternally obvious. And there is a certain, though limited, amount of\noverlap in the distribution of these segmental nerves. Still, well\nco-ordinated responses occur when comparatively short portions of the\nspinal cord are isolated by severance from the rest. In the male frog,\nespecially during the breeding season, a clasping reflex is produced by\nstimulating the dark swollen pads on the inner side of the hand, and\nthis, as Goltz has shown, is exhibited when all the central nervous\nsystem has been destroyed save the segments to which the nerves for\nthe arms proceed. \u201cSimilarly,\u201d writes Dr. Sherrington,[190] \u201cin the\ncat and monkey, the reflex wagging of the tail persists when behind\nthe spinal transection only the sacral region of the cord is left\nintact.\u201d When the spinal cord of the dog is severed, so as to isolate\nthat portion which is concerned with movements of the hinder part of\nthe body, pressure on the pad of one hind-foot usually produces, not\nonly a lifting of that leg, but also an extension of its fellow--that\nis to say, a co-ordinated response of the two limbs. But in the case\nof the vertebrates, more than in that of the invertebrates, the\nco-ordinated response of an isolated part of the central nervous system\nseems to lack the furtherance of its action, which normally comes\nfrom the higher centres from which it has been severed. \u201cThe spinal\nreflexes significant of progression seem,\u201d says Dr. Sherrington,[191]\n\u201cto contribute chiefly towards preparatory posture in readiness for\nthe onset of action executed by the musculature under the driving of\nhigher centres. Thus the well-known reflex spinal posture of the frog\nis flexion of the hind limbs, the extensors of the joints being taut\nand ready for the jump. The spinal reflexes, which in their results\napproximate most closely to the normal reactions of the unmutilated\nindividual, are those connected with the pelvic and abdominal\nviscera,\u201d many of which \u201care executed as spinal reflexes in a manner\npresenting little or no physiological defect from the normal. And if\nthe bulb\u201d--the continuation of the spinal cord within the skull to form\nthe basal portion of the brain--\u201cbe included with the spinal cord, and\nthese together, including their nerves, be isolated from the rest of\nthe nervous system, the animal as regards its visceral life, including\nthat of the heart and lungs, is practically intact.\u201d\n\nHuxley graphically describes the actions of a frog from which the\ncerebral hemispheres have been removed. \u201cIf that operation,\u201d he\nsays,[192] \u201cis performed quickly and skilfully, the frog may be kept\nin a state of full bodily vigour for months, or it may be for years;\nbut it will sit unmoved. It sees nothing; it hears nothing. It will\nstarve sooner than feed itself, although food put into its mouth is\nswallowed. On irritation, it jumps or walks; if thrown into water it\nswims. If it be put on the hand it sits there, crouched, perfectly\nquiet, and would sit there for ever. If the hand be inclined very\ngently and slowly, so that the frog would naturally tend to slip off,\nthe creature\u2019s fore paws are shifted on to the edge of the hand, until\nhe can just prevent himself from falling. If the turning of the hand\nbe slowly continued, he mounts up with great care and deliberation,\nputting first one leg forward and then another, until he balances\nhimself with perfect precision on the edge; and if the turning of\nthe hand is continued, he goes through the needful set of muscular\noperations, until he comes to be seated in security on the back of the\nhand. The doing of all this requires a delicacy of co-ordination and a\nprecision of adjustment of the muscular apparatus of the body which are\nonly comparable to those of a rope-dancer.\u201d\n\nNow, why have we entered into these details? To reinforce, from a\nsomewhat different point of view, that which has again and again been\nurged in the preceding sections of this inquiry, that much of animal\nbehaviour is an organic legacy. A going mechanism of great delicacy,\nwith ready-made co-ordinations, the products of biological evolution,\naffords to consciousness a vast body of its primary data. As Dr.\nSherrington himself says,[193] \u201cco-ordination is abundantly shown\nto result from the independent power of the spinal arcs, altogether\napart from the influence of the great cranial sense-organs, and of\nthe cerebral arcs superposed upon them. These senses and the brain\nfind the elementary co-ordination of the skeletal musculature an\nachievement already provided and to hand in the spinal cord. And no\ndoubt the product of the instrument is, with the instrument itself,\ngiven over to their use in the reactions they elicit from the spinal\nmusculature.\u201d We have seen how instinctive behaviour, in those animals\nin which it is best studied, affords in hereditary biological outline,\na sketch which subsequent acquisition, under experience, serves only\nto elaborate by the filling in of details and of the more delicate\nshading in behaviour. But in the higher animals, in which a period of\nyouth is a time for the acquisition of experience--for experimentation\nand practice,--it might seem that the inherited biological legacy was\nof less importance. The \u201cspinal animal,\u201d as Dr. Sherrington calls\nit,--that is, the animal in which the spinal centres are isolated\nfrom the cerebral centres--goes far to disprove any such view. In\nthem the cerebral senses and the brain find elementary co-ordination\nof the bodily movements an achievement already provided and to hand\nin the spinal cord. But when different animals are compared--frog,\nbird, rabbit, dog, and monkey--the permanent effects of severance of\nbrain connection, the effects which remain when the temporary period\nof disturbing \u201cshock\u201d is over, are more marked in the higher than\nthe lower types. And concerning this, Dr. Sherrington says,[194]\n\u201cThe deeper depression of reaction into which the higher animal, as\ncontrasted with the lower, sinks when made spinal, appears to me\nsignificant of this, that in the higher types, more than in the lower,\nthe great cerebral senses actuate the motor organs, and impel the\nmotions of the individual.\u201d\n\nWhether in the animal in which all direct connection between the\nanterior and posterior portions of the central nervous system has been\nsevered there is a double consciousness--a cerebral consciousness and a\nspinal consciousness--we are not in a position accurately to determine.\nIf the generally accepted opinion, that the higher brain-centres\nconstitute the sensorium or seat of consciousness, be correct, we must\nsuppose that a maimed consciousness, with many avenues of experience\nclosed, is retained in the anterior moiety, while the posterior is\nrelegated to a condition of mere sentience at best. In any case all\nrelation between the two is prevented. The two--if two there be--are\nrendered quite independent through severance of the cord in the region\nof the neck. But there is a point of view indicated by Dr. Sherrington\nwhich is full of suggestion and interest.\n\n\u201cIt is significant in the evolution of animal form,\u201d he says,[195]\n\u201cthat the organ that exhibits most uninterrupted and harmonious\nincrease in development, as studied successively in passing from lowest\nto highest, is the brain. And it is significant that in the nervous\nsystem--segmental system as it is--the brain is developed, not in those\nsegments whose sense organs are ordinary cutaneous (tactual, etc.),\nmuscular and visceral, but in the segments connected with the visual,\nolfactory, and auditory sense-organs; in other words, the brain is\ndeveloped in the head. The head is, so to say, the individual; it has\nthe mouth, it takes the food, including air and water, and it has the\nmain sense organs providing data for both space and time. To this the\nbody, an elongated motor organ with a share of the viscera and the\nskin, is appended primarily as a machine for locomotion. This latter\nmust of necessity lie at the behest of the great sense organs of the\nhead.\u201d\n\nNow let us try and picture to ourselves a spinal animal, or one which\nretains only the lowest portion of the brain, the part known as the\nbulb or _medulla oblongata_; let us assume that it is conscious and\ncapable of acquiring experience through the association and coalescence\nof the data afforded by the senses that remain to it; and let us try\nto imagine the conscious situations which would arise, and their\nvalue in the guidance of behaviour. The senses that remain are touch\nand the temperature sense, the motor sense affording data from the\nmuscles, joints, and tendons, and those which supply certain visceral\nsensations. There is not one of much, if any, guiding value left. There\nis not one of what we may term anticipatory use. There is not one\nwhich could serve to infuse anything like definite meaning into the\nsituation. For, after all, meaning is expectation. There is an element\nof anticipation in all those senses which are of any real guiding value\nin the conscious situation. Sight, hearing, and, especially for some\nanimals, smell,--these are the senses which forewarn of something\nwhich may follow; of other sensations with which in the course of\nexperience they have coalesced. And they are all cut off from the\nsupposed spinal animal. A light touch might in some cases forewarn\nof the shock or severe pressure, which would perhaps follow. But the\nshocks would so often come suddenly that it is questionable whether the\nwarning would be of much avail. Still, touch is a warning and cognitive\nsense, and through it the environment would acquire a limited amount of\nmeaning.\n\nNow, the biological value of coalescent association lies in this\nvery element of warning. The anticipatory senses, sight, hearing,\nsmell, are in their several degrees the \u201cprojective\u201d senses, the\nsenses which carry with them the quantity of \u201coutness.\u201d And their\n\u201cprojective\u201d character is the necessary psychological expression of\ntheir distinctive biological end. They must be projective, must carry\nwith them \u201coutness,\u201d if they are to convey what we, following Dr.\nStout, have so often spoken of as meaning. But if the biological value\nof coalescent association lies in the expectation it renders possible;\nand if, in the spinal animal, there are no senses left save touch,\nwhich could receive from the environment preparatory warning of what\nis coming; it would seem exceedingly improbable that it should develop\nquasi-independent conscious situations of its own. In the unmutilated\nanimal, at any rate, tactual experience would most probably coalesce\nwith that derived from the senses which more distinctively take the\nlead in the acquisition of meaning. And we may therefore, on these\ngrounds, as well as on others, acquiesce in the current view that the\nquasi-independent functioning of the spinal cord and its constituent\nsegments is, at best, lit up with those flashes of mere sentience of\nwhich Sir Michael Foster speaks in the passage we quoted in an earlier\nsection.[196]\n\nIf from the consideration of the isolated spinal animal we turn for a\nmoment to that of the isolated cerebral animal, we find it in a very\ndifferent position. It is possessed of the warning senses--those which\nfrom several points of view are the leading senses--but they are\nleaders without a following; they have only a very limited company to\nconduct into action. The company is there, on the further side of the\nseverance, but they have lost touch with it. They know not what it is\ndoing, and have therefore neither the data nor the executive power to\nguide its man\u0153uvres in the field of behaviour. They can form maimed\ncoalescent situations, but they are as impotent as a mere theorist\ndevoid of all power of practical application. We need not, however,\nfollow the theme further. We need only add that, could we isolate\ntracts of nervous tissue in the lower brain-centres of such a cerebral\nanimal, we should find that subsidiary co-ordinations would belong, as\na physiological heritage, to these isolated fragments.\n\nThe conclusions we may draw, then, with regard to the evolution of\nbehaviour, as viewed in its physiological aspect, are that it is,\nin its simplest expression and in its most complex, conditioned by\nsufficient unity of purpose to meet the biological end of survival;\nthat the complex unity of purpose may be analyzed into a multiplicity\nof subsidiary processes each with its subsidiary unity of purpose; and\nthat the psychological coalescence which gives unity to experience\nunder the guidance of the leading senses, is paralleled in a\nphysiological coalescence within the nexus of the nervous system.\n\n\nII.--THE BIOLOGICAL ASPECT\n\nThe biological aspect of behaviour--its relation to biological\nends--has so often come under our consideration in the foregoing\nchapters that little need be added in this section: and that little\nmay be most appropriately devoted, first to the question whether\nconsciousness does influence behaviour; and secondly, this being\naccepted, to the importance of the _r\u00f4le_ that is played by the\ndevelopment of conscious situations in securing, in the higher animals,\nthe biological end of racial preservation.\n\nThat this end is secured without the aid of consciousness in the\ncase of many organic species, in all those, for example, which we\nclassify as plants, must not be taken as presumptive evidence that in\nother species, for instance in the multitudinous host of insects, the\ndevelopment of conscious situations is of no biological value. The fact\nthat chlorophyll is not developed in any mammal does not show that the\npossession of this substance is of no service to the higher plants.\nIt would not be worth while to give expression to this very obvious\ntruth, were it not that critics of natural selection persistently\nargue that because one species gets on perfectly well without this\nor that particular character it can have played no part in securing\nthe survival of another species. When I described, at a meeting of\nnaturalists, how well young chicks could swim, such a critic drew me\naside after the meeting, and expressed his surprise that this did\nnot convince me that the webbed foot of the duck could not logically\nbe attributed to natural selection. This is an extreme case, and one\nobviously taken on peculiarly weak grounds. But even Huxley urged\nthat, because a frog, from which the cerebral hemispheres have been\nremoved, performs many co-ordinated actions without conscious guidance,\nconsciousness is, throughout nature, merely an accompaniment of certain\nmolecular changes in the brain. \u201cSuch a frog,\u201d he says,[197] \u201cwalks,\nhops, swims, and goes through his gymnastic performances quite as well\nwithout consciousness, and consequently without volition, as with it;\nand if a frog, in his natural state, possesses anything corresponding\nwith what we call volition, there is no reason to think that it is\nanything but a concomitant of the molecular changes in the brain which\nform part of the series involved in the production of motion.\n\n\u201cThe consciousness of brutes,\u201d he continues, \u201cwould appear to be\nrelated to the mechanism of their body simply as a collateral product\nof its working, and to be as completely without any power of modifying\nthat working as the steam-whistle which accompanies the work of\na locomotive engine is without influence on its machinery. Their\nvolition, if they have any, is an emotion indicative of physical\nchanges, not a cause of such changes. It does not enter into the chain\nof causation of their actions at all.\u201d\n\nIf the literal truth of this contention--the logical soundness of this\nconclusion--be admitted, it seems absurd to speak of the biological\nvalue of consciousness in behaviour or to discuss the importance of the\n_r\u00f4le_ that is played by the development of conscious situations in\nsecuring the biological end of racial preservation.\n\nNow, consciousness is regarded by an influential school of thinkers as\na sort of _deus ex machina_, which, sitting enthroned, and crowned with\na capital letter as Will, directs, like a being from another sphere,\nthe doings of the body. It was against the doctrines of this school\nthat Huxley took up arms. They do not concern us here. The will, or\nvolition, as an underlying cause, stands outside the pale of scientific\ninquiry. It belongs to the wide realm of metaphysics; its plea must be\nheard in another court. In this part of his contention Huxley was, we\nbelieve, unquestionably right from the scientific standpoint. Neither\nwill, nor impulse, nor instinct, nor consciousness itself, should be\nintroduced into any scientific description or explanation of phenomena\nas a cause of their existence or being, for as such it does not enter\ninto the sequence of events; it is that which metaphysics claims as\ntheir _raison d\u2019\u00eatre_--that which gives them being. Science in this\nmatter should be frankly agnostic--neither affirming nor denying\naught. This, of course, is not equivalent to saying that the agnostic\nposition is the true end of human reason. That would only be so on the\nassumption that the problems of science are the only problems with\nwhich that reason can deal. To exclude metaphysics from science is not\nto exclude it from human thought. As a matter of fact such exclusion\nis neither possible nor reasonable. But to clearly distinguish the\nproblems of science from those of metaphysics is absolutely necessary,\nif we are to prevent hopeless confusion of issues.\n\nIn contending, however, against the introduction of metaphysical\ndoctrines into the region of scientific explanation, Huxley seems\nto have been carried too far by the force of his own attack. So long\nas he held to the position that every conscious state has, as its\nconcomitant, a molecular change in the brain, he had all the forces\nof evolution on his side. But when he said that consciousness is\nmerely the steam-whistle of life\u2019s locomotive, or merely answers to\nthe sound which the animal-bell gives out when it is struck, he takes\nup another position of far less strategical strength. For whereas\nthe frog from which the physical centres of consciousness have been\nremoved sits crouched and motionless, and \u201cwill starve sooner than\nfeed itself, although food put into its mouth is swallowed;\u201d the frog\nin which conscious situations can take form in unmutilated cerebral\nhemispheres behaves in a very different manner. It is nothing less\nthan pure assumption to say that the consciousness, which is admitted\nto be present, has practically no effect whatever upon the behaviour.\nAnd we must ask any evolutionist who accepts this conclusion, how he\naccounts on evolutionary grounds for the existence of a useless adjunct\nto neural processes.\n\n\u201cIt is,\u201d says Huxley,[198] \u201cexperimentally demonstrable--any one who\ncares to run a pin into himself may perform a sufficient demonstration\nof the fact--that a mode of motion of the nervous system is the\nimmediate antecedent of a state of consciousness. We have as much\nreason for regarding the mode of motion as the cause of the state of\nconsciousness, as we have for regarding any event as the cause of\nanother. How the one phenomenon causes the other we know as much, or as\nlittle, as in any other case of causation; but we have as much right\nto believe that the sensation is an effect of the molecular change, as\nwe have to believe that motion is an effect of impact; and there is as\nmuch propriety in saying that the brain evolves sensation, as there is\nin saying that an iron rod, when hammered, evolves heat.\u201d But if we\nspeak of the related antecedent as the cause, it is not obvious why we\nshould not describe the desire to demonstrate the supposed fact as the\ncause of running in the pin. We seem to have just as much reason for\ncalling this antecedent state of consciousness the cause of certain\nmovements and behaviour, as of calling a mode of motion in the brain\nthe cause of a further state of consciousness. It is true that we\nhave not the least idea how the desire can cause the act; but Huxley\npractically admits that we have no idea how molecular change can be the\ncause of consciousness. In the one case we are no worse off than we\nare in the other. Neither position is logically defensible; since each\nassumes that physical events and states of consciousness can constitute\nlinks in the same causal chain.\n\nThe philosophical hypothesis known as monism regards the molecular\nchange, not as the antecedent of a conscious state, but as its\nconcomitant. That which from a physical and physiological point of\nview is a complex molecular disturbance is, at the same time, from a\npsychological point of view, a state of consciousness. The two are\ndifferent aspects of one natural occurrence. Why such an occurrence\nshould have two so different aspects we have not the faintest idea; but\nhere we are not one whit worse off than we were before. The hypothesis\ndoes, however, help us to get over our difficulty. An essential\nfeature of Huxley\u2019s contention is that the physical and physiological\nchain of causation is complete in itself, which may be granted; and\nfurther, that if consciousness does arise it is merely an adjunct\nwithout influence on the sequence of events--what is influential is\nthe molecular disturbance, not the consciousness which accompanies it.\nBut according to monism the state of consciousness actually is that\nvery same something which the physiologist calls, in the language of\nphysics, a molecular disturbance. And in saying that consciousness\ninfluences behaviour one who accepts this hypothesis is merely avoiding\na cumbrous form of circumlocution. He puts it in this way instead\nof saying that the nerve-changes in the cerebral hemispheres, or\nelsewhere, which from a psychological point of view _are_ a conscious\nsituation, influence and determine the course of behaviour. But from\nthis point of view it is absurd to say that the consciousness is merely\nan adjunct--absurd to say that were there no conscious situation the\nneural situation would remain unchanged. They are the very same thing\nfrom different points of view; and to say there is no influential\nconscious situation is simply equivalent to saying that there is not\nthis determining neural situation.\n\nHowever we explain the fact, there are few who hesitate to accept it\nfor the purposes of scientific explanation. The conscious situation,\nhaving no doubt for the physiologist a neural aspect if he could only\nget at it as a whole, does practically determine the behaviour of the\nanimal which has gained the requisite experience. If we accept the\nfact, we may pass on to its importance in securing the biological end\nof race preservation.\n\nIt is a commonplace of evolutionary doctrine that, other things being\nequal, those races will survive, in the constituent members of which\nintelligent behaviour enables them to deal most effectually with an\nenvironment of increasing complexity. And it is a matter of familiar\nobservation that such behaviour is closely connected with delicacy\nand refinement of development in those senses which take the lead in\ncognitional process, and with rapidity and precision in the motor\nco-ordination through which prompt and skilful advantage is taken of\nthe situation which has, through experience, acquired meaning.\n\nBut though the importance of intelligent adjustment to the\ncircumstances of life is widely admitted as a general principle, it\nis perhaps through a study of animal behaviour that we are best able\nto realize its full range and extent. Biologists are so largely, and\nquite wisely, occupied in the study of morphological and physiological\nproblems, which admit of a treatment more exact than the most ardent\nadvocate of the investigation of behaviour, under natural or even\nunder experimental conditions, can claim; they devote, again quite\nrightly, so large a share of attention to the variation and natural\nselection of adaptive structure in its adult condition and embryonic\nstages; the pendulum of opinion has, under the teaching of Professor\nWeismann, swung so far in the direction of the non-acceptance of\nthe hereditary transmission of characters individually acquired\nthrough intelligent adjustment or otherwise; that the part played by\nconsciousness in the evolution of the higher and more active animals is\napt to pass unnoticed or unrecorded. It is well, therefore, to put in\na reminder that a great number of animals would never reach the adult\nstate in which they pass into the hands of the comparative anatomist\nsave for the acquisition of experience, and the effective use of the\nconsciousness to which they are heirs; that their survival is due,\nnot only to their possession of certain structures and organs, but,\nevery whit as much, to the practical use to which these possessions\nare put in the give and take of active life; and that many interesting\nproblems which are keenly discussed by evolutionists in the light of\nnatural selection presuppose conscious situations which are more or\nless tacitly taken for granted.\n\nLet us cast a rapid glance over some of these topics of biological\ndiscussion. The fascinating subject of mimicry, involving as it\nnecessarily does the discussion of the value of warning colours and\nbehaviour, a subject opening up an extensive group of problems so\nbrilliantly studied by Professor Poulton, is meaningless save in so\nfar as there is implied a conscious reaction to colour and form on the\npart of animals which can learn from experience. The warning colours\nreinstate a conscious situation, so that, misled by appearances, a bird\nmistakes the mimicking insect for its nauseous \u201cmodel.\u201d\n\nThe whole range of behaviour, included under play, experimentation, and\npractice, on the importance of which, following the lead so ably given\nby Professor Groos, we have insisted, is equally meaningless, save as a\nmeans to the acquisition of serviceable experience for use in the more\nserious business of after-life; and experience is the establishment,\nthrough association and coalescence, of conscious situations which\npossess guiding value. And if, as we shall hereafter see, they may\nalso be regarded as a means of securing pleasure, as a psychological\nend of behaviour, it is not less obvious that it is only through the\ndevelopment of consciousness that such a psychological end can have any\nexistence.\n\nIt matters not if the particular form assumed by play and\nexperimentation be largely dependent on instinctive tendencies. For\nall the phenomena of instinct, profoundly organic as are the modes of\nbehaviour comprised under this head, definite as are the inherited\nco-ordinations in the most typical examples of its occurrence, have\nalso, except in some doubtful cases, a conscious aspect. At any rate\nthis is the case in so far as instinctive response forms the hereditary\nbasis on which is reared a more nicely adjusted intelligent edifice,\nin so far as instinctive procedure is subsequently modified and guided\nby acquired experience, in so far as there creeps in that \u201clittle dose\nof judgment\u201d which Huber found in bees, Lord Avebury attributes to\nants, Dr. Peckham sees in spiders and solitary wasps, and all observers\nfind in birds and mammals. For if in these cases instinctive behaviour\nwere unconscious, it would, as such, remain outside experience; and if\noutside experience, there could be no data on which consciousness could\nbase any modification of inherited behaviour, no opportunity of taking\nup the ready-formed responses into the mental synthesis and utilizing\nthem for the wider ends of intelligent purpose.\n\nIn social behaviour there is a reciprocity of suggestion between the\nmembers of the community. And such suggestion is operative through an\nappeal to consciousness. However instinctive the forms of procedure\nmay be in social insects, there remains much beyond which is hard to\nexplain on the hypothesis that there is, in them, nothing analogous to\na conscious situation; while in such vertebrates as birds and mammals\nwe cannot but believe that consciousness is the main determinant of\nmuch behaviour which seems to imply the germs, or more than the germs,\nof sympathy. The little monkey I saw in Hamburg cuddling up caressingly\nto a wounded companion, must surely have experienced a conscious\nsituation analogous to that which prompts a child to nestle alongside\nher companion in distress. And he who has seen no signs of sympathy in\ndogs, has either watched their behaviour in vain, or is himself lacking\nin sympathy.\n\nIn sexual selection by preferential mating, even if we follow Professor\nGroos in believing that it is a special mode of natural selection,\nthe conscious situation is essential. If we accept the theory in any\nform, we must regard the adornments, antics, and display of the male\nas an appeal in some way to the consciousness of the female, whatever\nparticular form the effects in that consciousness may take, whether the\nappeal evoke a sense of beauty, or simply be a means of exciting to the\nconsummation of the natural end of courtship. Even if we follow Mr.\nWallace in regarding plume and song as \u201crecognition marks,\u201d it is only\nby their appeal to consciousness in this way, if in no other, that they\nare of any biological value. And this, of course, applies equally to\nthe whole range of his theory of recognition marks--their sole utility\nlies in their being a stimulus to consciousness through which the end\nof recognition is secured. So, too, not only the specialized behaviour\nwhich we dignify by the name of \u201ccourtship,\u201d but every case in which\nmate is drawn to mate through sight, smell, hearing--any of the leading\nsenses--testifies to the importance of consciousness in furthering an\nend of supreme biological importance.\n\nAnd if, as Darwin urged, the \u201claw of battle\u201d among the males\nco-operates with preferential mating, as we can hardly deny, in\nsecuring strong, vigorous, and healthy fathers of the generation they\nbeget, here, too, consciousness is an important factor. Can we conceive\na \u201claw of battle\u201d among unconscious beings? If success in the combat\nwere a mere matter of brute strength, it would imply some consciousness\nin its dull exercise. But it is more. It is also a trial of skill.\nWere it not so our forefathers would not have spent hours in watching\na cock-fight, or laid heavy odds on their particular \u201cfancy.\u201d\n\nWe need not labour the theme. In the search for food or a nesting\nsite, in the capture of prey and escape from enemies, in all that\ndemands attention, and in all that necessitates practice, in what\nM. Houssay calls \u201cthe industries of animals,\u201d and in that which Mr.\nHudson calls \u201ctradition,\u201d consciousness has a part to play. Even\nplants unconsciously appeal to the consciousness of insects, birds,\nand mammals. Their bright, scented, nectar-bearing flowers, and their\nsweet, coloured fruits are means of effecting the biological ends of\nfertilization and the dissemination of seeds, but only on condition\nthat their colours stimulate the sense of sight, and their scent and\nsweetness the senses of smell and taste. It is, perhaps, going too far\nto claim that, wherever sense-organs exist they imply at least some\ndim and rudimentary form of conscious situation of guiding value so\nfar as it goes; for it is possible that in some cases the coalescence\nof elementary items of sentience has not been carried far enough to\njustify us in speaking of experience by which the animal can profit.\nBut it is surely not going too far to claim that, wherever two or three\nsuch sense-organs are gathered together in any living being, there is\nconsciousness in the midst of them, beginning to exercise that guidance\nwhich serves so markedly to differentiate the typical animal from the\ntypical plant.\n\nBut throughout the animal kingdom, until we reach its highest\ndevelopment in man, the guidance of consciousness, important as it\nis, seems to be almost wholly subservient to a biological end, that\nof the preservation of the race, and for the race of the individual.\nPractical utility is the touchstone of animal intelligence, and of the\nwhole range of feeling and emotion in beings still under examination in\nthe stern school of natural selection. By this we mean that practical\nutility has determined what degree and complexity of intelligence,\nfeeling, and emotion shall be attained. If the requisite level be not\nattained--elimination. Higher levels no doubt bring advantage--so long\nas they are practically useful. But in the school of natural selection\nuseless accomplishments are not much taught. Although its examinations\nare in a sense competitive, all are allowed to pass who qualify for\nsurvival. But the competitors become more numerous and the standard\nfor a pass rises. As the school increases in size higher classes with\nharder problems to solve are established. Progress is an incident of\nthe constant survival of the fittest when there are variations in\nfitness.\n\n\nIII.--THE PSYCHOLOGICAL ASPECT\n\nOn the hypothesis of monism, the nature of which, so far as it bears\non our inquiry, was briefly indicated in the foregoing section, the\nconscious situation is the psychical or mental expression of that\nwhich for the physiologist is what we may term a neural situation. As\nsuch it does not enter into the chain of physical causation; nor do\nphysical events as such--that is to say, save as experienced--enter\ninto the chain of mental causation. For mental development they have\nno independent existence, and are negligible except in so far as they\nenter as items of experience into the conscious situation.\n\nBut altogether apart from the way or ways in which we may attempt to\nexplain the fact, most of us believe, with unquestioning confidence,\nthat the growth of practical experience, somehow associated with\nnervous changes in the brain or sensorium, is of real value in the\nguidance of behaviour in such manner as to secure biological ends.\nConscious experience must therefore, in the animal world, serve its\nbiological purpose, or it will be of no avail. If there be not a\npre-established harmony, there must be an evolved harmony; and how such\na harmony could be evolved if consciousness be not by some means in\nvital touch with behaviour, influenced by and in turn influencing it,\nwe cannot conceive. The steam-whistle theory of consciousness leaves\nthe matter, for the evolutionist, in this inconceivable position.\n\nWe need not, however, flog a dead horse. We need not ask how, on the\nsteam-whistle theory, those states of feeling which we broadly classify\nas pleasurable could become associated with behaviour conducing to\nwelfare, and those which we group as hurtful with behaviour which\nis biologically harmful. It is more important, again, to notice\nthat, associated and consonant with the biological end, there\narises a psychological end of behaviour--what we may term, with the\nqualifications before considered,[199] the getting of pleasure and the\navoidance of pain. This is the purpose of behaviour as viewed from the\npsychological aspect. The biological end of animal conation is racial\nsurvival; its psychological end is individual satisfaction. And the two\nends are, in the main and broadly speaking, consonant--a result which\nwould unquestionably be secured by natural selection, but is on any\nother naturalistic hypothesis difficult of explanation.\n\nBut the two ends are not only consonant; they are supplementary one\nto the other. During much of the life of the higher animals there is\nno need, immediately present and pressing, for the output of action\nto meet biological ends. There are periods of life and intervals of\ntime when the sharp incidence of the struggle for existence does not\ncall for the serious business of behaviour. But at these periods and\nin these intervals the animal is not inactive; indeed, it is restless\nin its activity. Unless it be weary with unwonted exertion, or basking\nin the psychical sunshine of content, due to the unsought advent of\npleasant stimulation or the after-effects of previous behaviour (for\nexample, when hunger has been relieved), the healthy animal must be up\nand doing. This familiar fact no doubt affords the basis in observation\nof the surplus-energy theory of play. But is it necessarily surplus\nenergy? Is it not rather normal energy which expends itself in this way\nwhen there is no immediate and serious biological business on hand?\nAnd, as Professor Groos has pointed out, play is seen when we have\nevery reason to suppose there is no surplus energy, nay, even when the\nnormal energy is at a low ebb. There is no more pathetic sight than a\nsick kitten, with energy obviously much below par, utilizing its little\nremaining strength in feeble attempts to play.\n\nIt is unnecessary to do more than remind the reader of the theory\nelaborated with so much skill and care by Professor Groos, that the\nforms assumed by play--in which, it will be remembered, he includes a\nvery wide range of behaviour--have a very important indirect biological\nend in practice and experimentation. Our present point is, that its\ndirect psychological end is the satisfaction it affords. Without\nthis the individual would not be impelled to the continuance of\nperformances which occupy a wide space in the field of animal behaviour\nin which the biological end has reference, not to present requirements,\nbut to future needs.\n\nNo one has given better expression to the sway of this psychological\nend than Mr. W. H. Hudson. \u201cWe see,\u201d he says,[200] \u201cthat the inferior\nanimals, when the conditions of life are favourable, are subject to\nperiodical fits of gladness, affecting them powerfully and standing\nout in vivid contrast to their ordinary temper. And we know what\nthis feeling is--this periodic intense elation which even civilized\nman occasionally experiences when in perfect health, more especially\nwhen young. There are moments when he is mad with joy, when he cannot\nkeep still, when his impulse is to sing and shout aloud and laugh at\nnothing, to run and leap and exert himself in some extravagant way.\nAmong the heavier mammalians the feeling is manifested in loud noises,\nbellowings, and screamings, and in lumbering, uncouth motions--throwing\nup the heels, pretended panics, and ponderous mock battles.\n\n\u201cIn smaller and livelier animals, with greater celerity and certitude\nin their motions, the feeling shows itself in more regular and often in\nmore complex ways. Thus Felid\u00e6, when young, and in very agile sprightly\nspecies, like the puma, throughout life, simulate all the actions of\nan animal hunting its prey--sudden, intense excitement of discovery,\nconcealment, gradual advance, masked by intervening objects, with\nintervals of watching, when they crouch motionless, the eyes flashing\nand tail waved from side to side; finally, the rush and spring, when\nthe playfellow is captured, rolled over on his back, and worried to\nimaginary death. Other species of the most diverse kinds, in which\nvoice is greatly developed, join in noisy concerts and choruses; many\nof the cats may be mentioned, also dogs and foxes, capybaras and other\nloquacious rodents; and in the howling monkeys this kind of performance\nrises to the sublime uproar of the tropical forest at eventide.\n\n\u201cBirds are more subject to this universal joyous instinct than mammals,\nand there are times when some species are constantly overflowing with\nit; and as they are so much freer than mammals, more buoyant and\ngraceful in action, more loquacious, and have voices so much finer,\ntheir gladness shows itself in a greater variety of ways, with more\nregular and beautiful motions, and with melody. But every species or\ngroup of species has its own inherited form or style of performance;\nand however rude and irregular this may be, as in the case of the\npretended stampedes and fights of wild cattle, that is the form in\nwhich the feeling will always be expressed.\u201d\n\nThat all this, which Mr. Hudson so graphically describes, belongs to\nthe psychological aspect of animal behaviour and is directly prompted\nby conative tendencies whose immediate end is conscious satisfaction,\nthe mere joy of unrestrained and healthy activity, may be freely\nadmitted, without denying that all this exuberant psychical life\nowes its evolution to the fact that it is in consonance with and\nsupplemental to biological ends which secure survival. It is with\nanimals as it is with man; play is the preparation for earnest. As I\nhave elsewhere said,[201] what our national games have done for the\nEnglish race it is difficult to overestimate. They train us to use our\nbodies and expend our energies to the best advantage. An old soldier,\nwatching a football match, said, \u201cThat\u2019s the training for our future\nsoldiers and sailors.\u201d The playing fields are the finest school of\norganized co-operation in the world. But, apart from compulsion, a\nboy will not enter into the game with that zest through which alone\nit acquires real value for training, unless there be an immediate\npsychological end in the satisfaction he derives. And with animals\npractice and preparation for the business of life could not occur if\nthe ultimate biological purpose of it all were not supplemented by the\nenjoyment it brings for its own sake.\n\nBut in animal play, as indeed in that of human youth, we are perhaps\na little apt, in laying stress on the bodily skill and readiness\nof response to which it so effectually ministers, to forget that it\nis also a psychological training. In technical phraseology, we are\ndisposed to fix our attention on the acquired co-ordination of act\nand movement rather than on the correlation of conscious data, which\nrenders possible the skilful performance. And yet, rightly considered,\nthe behaviour itself is simply the outcome of a conscious situation,\nduly elaborated, and knit together through the association and\ncoalescence of its constituent data. It is a means to the unification\nof consciousness by bringing into relation scattered and, at first,\nquasi-independent sensory and emotional elements. Success is only\nattained through the concentration of attention and effort on that\nwhich is the centre of interest and also the focus of endeavour. And\nthis close attention and well-directed effort, which are trained in\nthe playful output of energy, are just the mental qualities which\nwill stand the animal in good stead when the real incidence of life\u2019s\nstruggle comes upon it, when the reward of success is survival and\nthe penalty of failure elimination. For they are not merely physical\nqualities, though their effects are bodily movements of attack and\ndefence, of active escape, or merely \u201clying low.\u201d They are essential\npsychological features of a unified and well-directed conative process.\n\nIn the fairly abundant play-time of animal life, this unification and\ndirection of conative process can take form under conditions wherein\nthe preliminary failures which accompany all forms of learning do\nnot entail the severe penalty of elimination. If we may so put it,\nand so apply a deeply instructive parable, Natural Selection says\nto her more favoured children, in which conscious situations can be\ndeveloped, \u201cHere are the talents with which I have endowed you; make\nuse of them till I come, as come I shall in due time.\u201d This animal\nputs them out to usury in play; that animal keeps them laid up in the\nnapkin of inactivity. Then Natural Selection, the austere one, comes;\ngives the commendation of survival to the animal that had learnt to\nput its talents to use in the period of preparation, and condemns to\nelimination that which had not traded with his talents at the bank of\nplay. In animal life, on the perceptual plane, we have the same need\nfor training in little things and seemingly unimportant matters in\npreparation for the stress and storm which may, nay must, come upon\nthem, that we find in men and women on the higher ethical plane. To\nthose who think that the play of animals is too trifling a thing to\naffect the question of survival, we would suggest the application, with\na necessary difference, of the thought which Miss Edith Simcox puts\ninto the following words: \u201cDoes it,\u201d she says, \u201cseem a trifling thing\nto say that in the hours of passionate trial and temptation a man can\nhave no better help than his own past? Every generous feeling that has\nnot been crushed, every wholesome impulse that has been followed, every\njust perception, every habit of unselfish action, will be present in\nthe background to guide or to sustain. It is too late, when the storm\nhas burst, to provide our craft with rigging fit to weather it; but we\nmay find a purpose for the years that oppress us by their dull calm, if\nwe elect to spend them in laying up stores of strength and wisdom and\nemotional prejudices of a goodly human kind, whereby, if need arises,\nwe may be able to resist hereafter the gusts of passion that might else\nbear us out of the straightforward course.\u201d To apply the thought, the\ntrifles of play supply the psychological rigging which alone can save\nthe animal craft in the coming storm of the struggle for existence. And\nthe point on which we have to lay special stress in this section is,\nthat it is psychological rigging--or, if this seems to lay too much\nemphasis on the genesis of conscious situations, we may at least urge\nthat the psychological ropes are of co-ordinate importance with the\nbiological spars.\n\nSo far, then, we reach the following conclusion: that if we classify\nthe behaviour of the higher and more intelligent animals under two\nheads, the one comprising all those acts which are of direct biological\nvalue in enabling the animal to escape elimination under the immediate\nstress of the struggle for existence, and the other including all those\nacts which are of indirect preparatory or educative value, the latter,\nwhich are under their biological aspect not less important than the\nformer, are under their psychological aspect of perhaps even greater\nimportance. For the conditions of actual struggle are not those under\nwhich mental development could most easily be furthered, though they\nare those in which it is most effectually tested. Hence, the more\nintelligent animals pass through a period during which they are more\nor less shielded from the incidence of natural selection by their\nparents, and this is the period of play and of psychological education.\nAnd the tendency to play is so far organic, in that it is dependent on\ninherited instinctive propensities, and so far psychological in that\nit is accompanied by a felt want, which constitutes a conative impulse\nfinding its appropriate end in the consciousness of satisfaction. But\nplay--if we accept the term as the group-name for all these modes\nof behaviour which fall under our second class, those of indirect\nbiological value--does not cease with the period of youth; it occupies\nall the intervals in the more serious business of animal life. And no\ndiscussion of animal behaviour can be adequate which does not assign\nto this class its due place, alike in biological and in psychological\nevolution.\n\nThe whole value of experience lies in the linkage and coalescence\nof the data afforded to consciousness. It is true that an inherited\nnervous system supplies the organic conditions of that physiological\nlinkage and functional coalescence of which experience is the\npsychological expression. It is true that this physical integration\nsecures a ready-made grouping of the conscious data which are the\nconcomitants of orderly molecular changes in the brain or analogous\nsensorium. Still, it also remains true that the value of experience\nlies in the further linkage and coalescence that is acquired by the\nindividual in the course of what we may fitly call its education. Every\nstep in this education gets its psychological sanction through the\nsatisfaction it affords in consciousness; and the time of acquisition\nis not during the stress of examination in the actual struggle for\nexistence, but rather in the youthful period and in the subsequent\nintervals of preparation and practice during the play-time of animal\nlife.\n\nThe examination analogy--if, indeed, it may not be rightly regarded\nas something more than an analogy--may be pressed a little further\nas a means of fixing our attention on two points which are worthy\nof consideration. The first is that, in the preparation for the\nexamination, specific practice as much of it is, cramming is not\nthe system exemplified by the higher animals. A good all-round\neducation in the acquisition of conscious situations more or less\ncoalescent into a unified system of experience, and in their effective\nutilization without unnecessary delay and bungling along more or\nless converging lines of practical behaviour; this is what secures a\n\u201cpass\u201d in survival, especially where the circumstances of life have\nreached a considerable degree of complexity. The instinctive act,\nwith its relatively definite response to a question which is almost\ncertain to be set to every candidate for survival, is that, which is\nthe analogue in behaviour to the result of a system of cram. Organic\nnature does employ this system in the lower classes of her school;\ndefinite responses are ground into merely instinctive types generation\nafter generation, and the right answers are given, automatically and\nunintelligently, whenever the oft-recurrent questions are set. But this\nwill not do when the questions require the exercise of intelligence,\nwhen they are of the nature of problems, with just those delicate but\nnot unimportant shades of difference which baffle the candidate who\nhas been drilled in a merely mechanical fashion. Hence the cramming\nof instinct does not suffice for animals whose environment presents\nproblems of greater variety and greater complexity. Intelligence\nis required to meet the particular combinations as they arise. The\ngreyhound, which is loosed on a hare, has never seen that hare run in\nexactly that way over that special tract of country. But he has been\ntrained in such situations, and is thus prepared to meet the special\nproblem in its details as they present themselves in the light of the\nexperience he has gained of other like problems. And his skill in\npursuit has not only been gained through education in coursing. In a\nthousand ways, as puppy and dog, he has learnt how to use well those\nsinewy limbs. The training of his whole life is brought to bear on the\nquestion immediately before him.\n\nThe general bearing of these facts is obvious. Play, as a means of\nanimal education, is varied, and has for its end all-round training\nof the animal mind in its sphere of operation. Although there are\nsome specific propensities, certain observable trends of behaviour,\nas in hunting-play, courtship-play, and the like, we must not expect,\nnor do we find, anything like stereotyped definiteness of conative\nactivity. We find that freedom and elasticity in animal education which\nis, perhaps, more often advocated than carried into practice in human\neducation.\n\nThe second point arising out of the examination analogy is, that its\nrange determines the level of preparation therefor. It is, for animals,\na practical examination, not a theoretical. Not a single question is\nset demanding an explanation. The problems are such as can be solved by\nintelligence, not such as require the exercise of reason, as we have\nused the term in foregoing pages. These higher problems are only set\nwhen the sixth form is reached, and there is no conclusive evidence\nthat any animals get into the sixth. This, however, is entirely a\nquestion of evidence, and many of us will be glad to welcome them\nthere, if proved ability to deal reflectively with ideational questions\njustifies their promotion.\n\nIf any of them do belong to this form, they have probably got there\nthrough play. For in the stress of the actual examination there is not\nmuch time for reflection. Or perhaps we may rather say that, not in\nactual struggle, and not in active preparation for it in play-time,\nbut in intervals of leisure between both, when the animal lies quietly\nturning over in his mind we know not what, will experience be reviewed,\nand generalizations drawn as to the why of events in this strange\nworld. Probably the animal accepts things as they are, and does not\ntrouble about their explanation. But it may not be so. At any rate,\nif animals lack the means of descriptive inter-communication, and\nhave no words as concrete pegs on which to hang abstract ideas, their\nexplanations cannot be carried far. Theories without the power of\ndisputation would be a poor solace in leisure moments.\n\nOne more point may be noticed with regard to the psychological aspect\nof the evolution of behaviour--the reciprocal action of intelligence.\nIt is the intelligence of others that introduces so much variety and\ncomplexity into the environment. Hunters and hunted, combatants,\nrivals, mate and mate, enemies or companions in their varied aspects,\nintroduce through their intelligence complications which only\nintelligence can meet. And, as intelligence begets intelligence, so do\nemotional attitudes beget answering emotional states. Psychological\nevolution translated into practical behaviour gives rise to situations\nof reciprocal complexity. This point of view is, however, so familiar,\nthat nothing need be said in its further elucidation. The behaviour\nof any given animal does not stand alone, but is closely related with\nthe behaviour of others. Among social animals the relationships are\npeculiarly close, and it is among them that the psychological aspect of\nbehaviour reaches its highest expression.\n\n\nIV.--CONTINUITY IN EVOLUTION\n\nUnder the head of organic behaviour, in the widest acceptation of\nthe term, fall the whole of physiology, the whole of embryological\ndevelopment, nay, more, the whole of organic evolution; while mental\nevolution, in all its stages, may be regarded as the psychological\naspect of that which, from the physiological aspect, is the evolution\nof nervous systems. Life itself is the behaviour of a particular kind\nof substance which is found more or less abundantly under natural\nconditions. No other known substance behaves in this way, and so\nignorant are we as to the conditions of its natural origin, that it is\nuseless to guess at a scientific explanation. And even if we knew all\nthe antecedents and conditions of its origin we should be no nearer a\ncomprehension of why protoplasm has the peculiar properties which we\nfind it to possess. That is a question to which science can give no\nanswer. Who knows why a certain compound of oxygen and hydrogen in\ncertain proportions has the properties of that which we call water?\n\nLet us note the distinction between saying, as we said above, that life\nis the behaviour of protoplasm, and asserting that life is the cause\nof this behaviour. The one is a scientific statement of observed fact,\nthe other an explanation of the fact in metaphysical terms, a reference\nof the fact to its underlying cause. So long as we quite clearly\nunderstand that we are talking the language of metaphysics, we may\nspeak of life as a cause of organic behaviour; but let us be careful\nto remember that the statement has no more value for science than the\nassertion that aqueosity is the cause of the behaviour of water.\n\nLeaving on one side, then, the natural origin of protoplasm, the\nconditions of which are unknown, we find that, as a matter of\nobservation, every bit of living substance, the history of which has\nbeen traced, is a fragment detached from some other bit which behaved\nin the same way. This is the basal fact of the continuity of organic\nevolution. But such a detached fragment has the property of increasing\nby taking up from the environment more of those elementary materials\nfrom which it is itself compounded in subtle synthesis. Nay, further,\nevery fragment of which we know the history is found to increase in\nsuch a way as to reach, in form, structure, and idiosyncracies of\nbehaviour, the likeness of the organism--plant or animal--from which it\nwas derived. In the higher plants and animals the separated fragments\nor cells are the ova and sperms, or their equivalents, which unite,\nwith fusion or coalescence of their nuclear matter, and thus give rise\nto a new individual in the course of embryological development.\n\nNow, as we have already seen, much modern biological discussion centres\nround the question whether the detached reproductive fragment, ovum or\nsperm as the case may be, is derived from the whole body of the parent,\nby what Darwin termed pangenesis or in some other way, or only from\ngerminal substance set apart in development for this end. And we have\nprovisionally accepted the hypothesis that it is the direct descendant\nof other reproductive cells; and that, throughout a long ancestry,\nstretching back into the far past, there never occurs in the direct\nline of genealogical sequence, any highly differentiated cell, such as\na gland-cell, muscle-cell, nerve-cell; never, with certain reservations\ninto which we need not enter, is found the representative of any\ntissue save that to which the reproductive function is restricted. In\ntechnical phraseology, the continuity of organic evolution is due to\nthe continuity of the germinal substance.\n\nDuring embryological development the fertilized ovum--consisting\nof two fused fragments of this germinal substance--gives rise to a\nhost of ordered and marshalled cells, which are divisible into two\ngroups: the one forms the body with its muscles, bones, glands,\ndigestive system, skin, sense-organs, nerve-centres, and so forth;\nthe other forms a reserve store of germinal substance, from which\nare derived the ova and sperms. The former take no direct share in\nreproduction; they are off the line of continuous descent; they die\nwithout issue. But they protect and minister to the reproductive\nfunction of the second group--the potential ancestors of the races to\nfollow. But all instinctive and intelligent behaviour is the outcome\nof the orderly working of the nervous system, is initiated through\nsensory stimulation, and is executed by the motor organs; and all the\nstructural parts, through which such behaviour is possible, belong\nto the body--that which dies without issue. How, then, can instinct\nand intelligence be inherited? In a sense they are not inherited. The\nnervous system which is their organic basis begets no heirs. But it is\nbegotten of germinal substance, which not only produced the body of\nwhich the nervous system is a part, but also handed on, with that body,\nsamples of the same germinal substance capable of reproducing a similar\nbody and a like nervous system. Herein lies the basis of heredity.\n\nThe stress of the struggle for existence falls upon the body; and\ninstinctive or intelligent behaviour is a means to its preservation\nin the struggle for existence. According as it survives or not, will\nthe samples of germinal substance it contains fulfil their biological\nend or perish with it. Natural selection secures the survival of those\nanimals which bear the seed from which their like will be developed.\n\nOn this view all variation arises within the germinal substance, but it\nis manifested in the body which is its product. How variations arise we\ndo not know with any exactness of detail. That the germinal substance\nis influenced in its nutrition and in other ways by the surrounding\ntissues is highly probable; and this influence may lead to changes\nwhich are the source of variations; but it is very doubtful whether\nsuch influence can be what we before termed \u201chom\u0153opathic.\u201d[202] It is\nimprobable that the formation of the nerve-connections involved in\nintelligent behaviour which has grown habitual through repetition,\ncan so influence the germinal cells as to give rise to variations of\nlike nature. In other words, acquired habit is probably not a direct\ndeterminant of an inherited variation of like nature in instinctive\nbehaviour. Apart from such influence the only source of variations\nwhich can be assigned is either the differential division of nuclei\nin preparation for the process of fertilization,[203] or the process\nof fertilization itself. The union of perhaps differentiated germinal\nsubstance from two distinct parents affords the opportunities for the\nadmixture and compounding of hereditary qualities in the two samples,\nfrom which variations favourable or the reverse may arise.\n\nIt is now generally recognized, however, that the origin of variations\nis a problem quite distinct from that of the survival of those whose\ndirection is favourable to that end. The theory of natural selection,\nas such, does not pretend to offer any explanation of the manner in\nwhich variations arise; though of course a complete theory of organic\nevolution must assign the antecedents and conditions of organic\nprogress in all its varied phases. We know that variations do occur;\nwe know, too, that more individuals are born than survive to procreate\ntheir kind; and, on the theory of natural selection, we draw from these\ndata the conclusion that, on the average, the animals that escape\nelimination are those in which the variations are of such a nature as\nto conduce to this end.\n\nIt will be seen that, on the hypothesis of organic heredity, thus\nbriefly sketched, continuity can, in strictness and, as we may phrase\nit, in its first intent, only be predicated of the germinal substance;\nbut that this substance gives rise to products--active vigorous animals\nbehaving in certain ways, each after his kind--which hold similar\ngerminal substance in trust for future use. Natural selection deals\nwith the trustees; and if they succumb, that which they hold in trust\nis lost. To put the matter in another way: Nature says to the germinal\nsubstance, \u201cBy your products you must be judged in accordance with the\ncriterion of utility and efficiency.\u201d Practical use in the give and\ntake of active life is the touchstone of all behaviour which makes for\nsurvival. This being secured, there may be a balance of behaviour for\nother purposes. But in animals the balance is not of large amount, and\nother purposes have not taken form and direction. It should be clearly\nnoticed that, on the hypothesis we are considering, use is the test\nof survival, and though it is not the direct cause of variations, it\naffords their sanction in survival. That animal escapes elimination\nwhose behaviour is of practical use; and it holds in trust for the\nfuture a store of germinal substance from which is produced a successor\ncapable of behaving in like manner.\n\nThe whole drama of organic evolution may be regarded as the realization\nin a succession of individuals of the evolving potentiality of\ncontinuous lines of germinal substance. The successive individuals\ndie--but the germinal substance lives on in their heirs, if they have\nany. In virtue of what intimate and hidden structure or disposition of\nparts the germ possesses this potentiality we do not know. The ovum\nof a dog is a microscopic speck less than one-hundredth of an inch in\ndiameter; the sperm is far more minute. They unite, and their nuclei\ncoalesce. The cellular product divides and subdivides. The cell colony\nabsorbs nutriment from the maternal tissues. Division proceeds apace,\nand the cells are marshalled and ordered in embryological development;\ndefinite tissues are formed; the stages of their genesis can be\npredicted with accuracy; and in due time a puppy is born which shall\ngrow to the likeness of its parents and behave as they behaved. We can\ntrace the succession of events; we see that they form a related series;\nwe have good reason for believing that the state of matters at any\none moment is the antecedent condition of the state of matters at the\nsucceeding moment. More than this science cannot say. The underlying\ncause is, for science, hidden in the mists of the unknown. Even for\nmetaphysics it is but part of the force that beats through the universe\nand makes it not a chaos but a cosmos--a force known to us only in its\neffects.\n\nIt will thus be seen that the conception of continuity in organic\nevolution has, broadly considered, a threefold aspect. First,\nthere is the continuity of the germinal substance through whose\nreproductive behaviour under the appropriate conditions embryological\ndevelopment occurs; secondly, there is continuity in this embryological\ndevelopment, stage by stage, from the fertilized ovum to the adult\nwhich is its final product and expression; thirdly, there is continuity\nin these final products, in the animals whose organic, instinctive,\nand intelligent behaviour lie open to our study and investigation. The\nfirst is germinal, the second developmental, the third evolutional\ncontinuity.\n\nBefore attempting to summarize some of the contributions afforded by\nour inquiry towards the doctrine of continuity in the last of these\nthree aspects, we must pause for a moment to consider how far and in\nwhat sense continuity can be predicated of mental development.\n\nWe have regarded the conscious situation as the psychical aspect of a\nnerve-situation in the sensorium; and the nervous system, capable of\nbehaving in this way, is in developmental continuity with the germinal\nsubstance of the fertilized ovum. But what shall we say with regard to\nthe psychical aspect? Two hypotheses seem open to us, each of which\npresents difficulties, but of different kinds. The first is, that when\nthe organic development of the nervous system reaches a certain level\nand order of complexity consciousness emerges, how and whence we know\nnot. The second is, that consciousness is developed from sentience,\nwhich is the concomitant of all organic behaviour; which accompanies\nlife wherever it occurs and therefore shares the continuity of the\ngerminal substance.\n\nThe difficulty inseparable from the first hypothesis, is that it\nis contrary to the analogy of all that we know or infer elsewhere\nthroughout the realm of nature. Huxley[204] likened its emergence to\nthe production of heat when an iron bar is struck by repeated blows\nof the hammer. But this analogy will not hold; for heat is a mode\nof energy, and only emerges through the transformation of other and\npre-existing modes of energy. A certain amount of the energy of motion\nin the massive hammer-head is transferred to the iron rod, and assumes\nthe form of that molecular vibration which we call heat. And by what\namount the one is the gainer, by that amount is the other the loser.\nBut we have no reason to suppose that the like takes place in the\norigin of the mental concomitants of neural changes. No portion of the\nbrain\u2019s store of physical energy is drained off to form the rivulet\nof consciousness. Now, whenever we speak of a product elsewhere in\nnature, we mean a specialized bit of something pre-existent. Water is\nthe product of pre-existing oxygen and hydrogen. Heat is the product\nof other forms of energy. But this is not so on the first hypothesis,\naccording to which consciousness emerges when the functional activity\nof the nervous system reaches a certain level and order of complexity.\nThe mental concomitants are not \u201cproducts,\u201d in the recognized sense\nof the term. Furthermore, although on this hypothesis we may still\nspeak of what was termed above evolutional continuity in the mental\nconcomitants, there is nothing analogous to either developmental or\ngerminal continuity.\n\nOn the second hypothesis, according to which sentience is the\nconcomitant of all organic behaviour, such developmental and germinal\ncontinuity, or their analogues in the psychical order of being, are\nrendered conceivable. Consciousness is regarded as a developed form\nof sentience. But the sentience is wholly hypothetical. It is at best\na \u201cmay be,\u201d and its existence is incapable of proof. And science is\nrightly impatient of hypotheses the validity of which cannot in any way\nbe verified. Our safest course, therefore, is to accept that which is\ncommon to both hypotheses, evolutional continuity, and for the rest to\nbe content with a confession of ignorance.\n\nWe have already drawn attention to the fact that mere sentience,\nif it exists, has no power of guidance over organic behaviour; but\nconsciousness, when it emerges, is a concomitant of nervous processes\nwhich determine the nature and direction of such nerve-changes as are\nthe antecedents of intelligent behaviour. The steps by which this\ncontrol is established are unknown. It is, indeed, probable that\nconscious guidance arises as an accompaniment of the differentiation\nof controlling centres from the automatic centres of the nervous\nsystem; but of how this takes place we are as ignorant as we are of\nmany other differentiations in the course of embryological development\nand evolutional progress. Of those nervous arrangements within the\nbrain which are the physiological concomitants of the far later mental\nprocesses of reflection, abstraction, generalization, and the formation\nof ideals, we are, if it be possible, even yet more profoundly\nignorant. Nor would it serve any good purpose to indulge in speculation\nwhere there are not even the data to enable us so much as to hazard\na probable guess. The utmost we are justified in attempting is to\nshow how organic behaviour leads up to and affords the requisite data\nfor the exercise of intelligence, and how both supply the necessary\npreliminary stages in the development and evolution of what, following\nDr. Stout, we have termed ideational process. This we have endeavoured\nto do in preceding pages; and all that is now required is to conclude\nour inquiry with a brief summary by which the results, as affording\nsome basis for evolutional continuity, may be focussed.\n\nWe regard reflex action and instinctive behaviour, broadly considered,\nas genetically prior to that which is intelligent. Their development\nin the individual and their evolution in the race are reached by the\ndifferentiation and integration of nerve-centres. In the abdominal\nregion of the crayfish, for example, special centres are differentiated\nfor the behaviour of each pair of swimmerets; but these are so\nintegrated that the whole series of like abdominal appendages swing\nrhythmically with co-ordinated movements. Now, when a sensorium is\ndeveloped, it does not have to group by an act of conscious selection\nand deliberate arrangement the multiplicity of scattered sensory\ndata which it receives; it does not have to organize from diverse\nand hitherto unrelated elements some sort of system in experience:\nit receives them as a physiological heritage already grouped, and to\nsome extent organized. Stimulus and response are organically linked;\nand within the response inherited co-ordinations, often exceedingly\ncomplex, afford a correlated group of sensory data. Just in so far\nas organic heredity has provided a working system of bodily parts,\ndoes consciousness receive systematic information of their orderly\nworking. No doubt it is true that the development and evolution of the\nsensorium proceeds _pari passu_ with the development and evolution of\nreflex actions compounded and co-ordinated to give rise to instinctive\nbehaviour. No doubt the progress of the one is in close touch and\nrelation with the progress of the other; for such relation receives\nthe emphatic sanction of utility. Still it is none the less true that\nin individual development, as in racial evolution, the organic takes\nthe lead. What is intelligently acquired is something added to that\nwhich has been engrained, through natural selection or otherwise,\nas a potentiality of the germinal substance. What we have first to\nnote, then, is that organic evolution provides ready-grouped data to\nconsciousness.\n\nThe second point is, that the germs of abstraction and generalization,\nor rather processes which are the precursors of abstraction and\ngeneralization, arise, and cannot fail to arise, in the genesis of\nexperience from the performance of inherited responses, and from\nthe coalescence of their results into a conscious situation. To a\nquite young chick I gave pieces of yellow orange peel, which were\nfound to be distasteful and rejected. In Dr. Stout\u2019s phraseology,\nthey acquired meaning in experience. Can one doubt that the colour\nand taste were thus rendered predominant, and that the shape, size,\nand other qualities of the bits of orange peel remained practically\nunnoticed? Shortly afterwards the chick was given chopped and\ncrumbled egg; the fragments of \u201cwhite\u201d were eaten, but the bits of\nhard-boiled yolk were untouched. They possessed a sufficient general\nresemblance to the orange peel to carry the same meaning. In many\nways particular qualities of objects are emphasized in so far as\nthey incite to behaviour; they form centres of biological interest,\njust as the abstract quality of ideational thought is the centre of\nrational interest on a higher plane of mental development. And in\nmany ways objects presenting certain salient features in common,\namid differences which remain unnoticed, are unconsciously grouped\nas the starting-points of similar perceptual situations, just as\nin the generalization of ideational thought similar relationships\nare deliberately grouped as the starting-points of like conceptual\nsituations. Both are purposive and have an end, which we as\ninvestigators are able to assign; but only for reflection and\nconceptual thought are they also purposeful--the end being foreseen and\nrealized, not only by the investigators, but by the agent concerned.\nAnd the purpose or end itself is in the two cases different. In the one\ncase it is the biological end of practical behaviour; in the other case\nit is the rational end of explanation--abstraction and generalization\nbeing deliberately used as a means to this latter end. The question\nhas again and again been asked: Do animals reason? And different\nanswers are given by those who are substantially in agreement as to\nthe facts and their interpretation, but are not in agreement as to\ntheir use of the word \u201creason.\u201d Perhaps, if the question assume the\nform--Are animals capable of explaining their own acts and the causes\nof phenomena?--the position of those who find the evidence of their\ndoing so insufficient may be placed in a clearer light. This is what\nis generally meant by the statement that animals have probably not\nreached the level of rational beings.\n\nBut even if they have not reached this level, their perceptual\nprocesses supply the antecedent conditions which are necessary if this\nlevel is to be attained in the course of further evolution. We have\nseen that, even in relatively simple cases, where conscious situations\nmark only the beginnings of intelligence, there is a biological\nemphasis of some, rather than others, among what we call the qualities\nof objects, and there is a grouping, on biological grounds, of certain\nthings which have some quality in common--such, for example, as being\nfit for food. Here we have at the outset of perceptual development the\ngerms of processes which are the precursors of the abstraction and\ngeneralization of ideational thought. And in the more complex conscious\nsituations of the higher animals these processes attain to such degree\nof development as is necessary to secure more difficult and more remote\nbiological ends, until all that is necessary, for their rational use,\nis the quickening touch of a new purpose, that of explanation.\n\nWe have seen that, through what Dr. Stout terms \u201cmanipulation,\u201d and\nProfessor Groos \u201cexperimentation\u201d--names applied to a type of behaviour\nwidely exemplified among the higher animals,--things, as the nuclei of\nconscious situations, become differentiated from the environment. One\ncan hardly question that a fly to the trout, a ball to the kitten, a\nbone to the puppy are things distinguished from their surroundings, and\nthat they become marked off as special centres of interest. Here on the\nperceptual plane is a process which is the antecedent of the conception\nof quasi-independent objects on the ideational plane. For rational\nthought the thing, as object, is not only the centre of a practical\nsituation leading to behaviour of direct or indirect biological value,\nbut is the nucleus around which we build all the qualities which\nare ascertained by more elaborate manipulation and experimentation\ncarried out deliberately and of set purpose for rational ends. It\nbecomes capable of definition with the aim of explaining what are its\ncharacteristics as an object.\n\nThere can be little doubt that the higher animals become intimately and\npractically acquainted with their environment. The dog who accompanies\nhis master in many a ramble, the horse who carries him again and again\nover all the surrounding country, has a good perceptual knowledge of\na somewhat extended environment. And this, again, is the precursor\nof the far more extended conceptual knowledge which leads up at last\nto a rational conception of the universe of objects in their varied\nrelationships. But only through the concentration of thought rendered\npossible by much true abstraction and generalization,--only through\ndisentangling the relationships and regrouping them for the purpose of\nframing an ideal scheme,--only, in short, by explanation and for the\nsake of explanation is this difficult process brought to a more or less\nsuccessful issue.\n\nAgain, there can be little doubt that the higher animals, in the course\nof experience begotten of behaviour, reach a perceptual sensing of\nthe bodily self, through experience derived from the non-projecting\nsenses, in pain and sickness, and often, we may hope, in the sense of\nwell-being, and the joy of existence. They do not probably set this\nself in antithesis to the not-self. That comes with reflection, and is\nthe result of ideal construction based on the analysis of experience,\nwith a view to reaching some explanation of the genesis of experience.\nBut in their perceptual awareness of the embodied self, they have\nthat kind of consciousness which affords the necessary data, for\nthe later conception of the self--when experience is polarized into\nits subjective and objective aspects and thus is explained, so far\nas science can explain it; suggesting, indeed, long ere science has\nattained this end, metaphysical explanations by reference to underlying\ncauses--too often accepted as an easy substitute for the difficult\ntracing out of the antecedent conditions which science endeavours\npainfully and by slow steps to formulate.\n\nIt is unnecessary to do more than remind the reader that we have found\nthat such processes as attention and imitation pass through instinctive\nand intelligent stages which are the precursors of the ideational\nstage, where they reach a higher expression as deliberately conscious\nacts. In the young bird that instinctively pecks at some small, perhaps\nmoving, thing, which forms the starting point of a piece of responsive\nbehaviour, we have attention in the germ. When experience has caused\nthe thing to acquire meaning, attention passes into a succeeding\nintelligent phase; but only when we desire to explain this meaning,\nand attention thus has a deliberate purpose, do we find it entering\nupon its higher ideational career. So, too, as we have seen, imitation\nis at first a specialized form of instinctive behaviour, where the\nresponse is seen to resemble that which stimulates it. Later it becomes\nintelligent when the repetition of the imitative behaviour is due to\nthe satisfaction it introduces into the conscious situation. Then, at\nlast, it reaches the ideational stage, where reflection gives rise to\nan ideal, which is to be realized in conduct. The imitation by the\nchild of its older companions is at first probably intelligent; but\nwhen the child begins to consider why it imitates these and not those\namong its companions, he is passing to the ideal stage, and imitation\nbecomes the sincerest form of hero-worship. The boy who merely imitates\nhis elder brothers playing at soldiers because he gets satisfaction\nfrom so doing, becomes the subaltern who has his ideal soldier, and\nwill face death firmly rather than fall below his conception of how\nsuch a soldier should behave.\n\nWe need not again attempt to indicate how among animals we have the\nperceptual precursors of the \u00e6sthetic and ethical concepts. But we may\nremind the reader that we endeavoured to show that intercommunication\nhad its foundation in instinctive sounds; and that it passed into the\nintelligent stage in the perceptual life, when these sounds acquired\nmeaning, and hence became guides to behaviour. This is especially\ninstructive from our present standpoint, since it is probable that the\npassage of communication from the indicating to the descriptive stage\nafforded the conditions under which rational thought was evolved.\nFor such thought it is essential that attention should be focussed on\nthe relationships of things. And no description is possible without\nmaking distinctly present to consciousness these relationships,\nin time and space, the data for which are abundantly present in\nthe perceptual life, though lurking in the background, and needing\nsomething to fix them and to aid consciousness in distinguishing them\nclearly. In descriptive communication parts of speech, or their initial\nequivalents, afford fixation points for these relationships, and serve\nto render them distinct. If the reader will try to describe even the\nsimplest occurrence without introducing the symbols for the relations\nwhich the events bear to each other, his failure will serve to bring\nhome how essential a feature this is. In social communication, then,\nwe probably have the key to the passage from perceptual to ideational\nprocess; and in this passage description is the antecedent of, and\naffords the conditions to, explanation. Words, moreover, as we have\nalready said, form the pegs upon which we can hang up, for ready\nreference, the products of abstraction and generalization, or, to\nmodify the analogy, they form the bodies of which these products are\nthe rational soul.\n\nIf we are ever to trace the passage from the instinctive through\nthe indicating stage of communication, and so onwards through the\nbeginnings of description to its higher levels, and thus to the use of\nlanguage as a medium of explanation, it must be through child-study.\nIn every normal human child the passage does actually take place,\nthough, no doubt, in a condensed and abbreviated form as an epitomized\nrecapitulation in individual development, of the steps of evolutional\nprogress. Thus we may obtain a key to the solution of one of the most\ndifficult problems in evolution by continuous process--that of the\ntransition from animal behaviour to human conduct.\n\n\n\n\nINDEX\n\n\n A\n\n Abstract and general ideas, 57\n\n Abstraction, 166;\n germs of, 332 ff.\n\n Acceleration, 250\n\n Accommodation defined, 36\n\n Acquired characters, inheritance of, 35, 110\n\n Acquired instincts (Wundt), 66, 106\n\n Acquisition defined, 36;\n ultimately dependent on natural selection, 289\n\n Adaptation defined, 37\n\n ADDISON on instinct, 63\n\n \u00c6sthetics, animal, 270\n\n Afferent and efferent impulses, 32, 101\n\n Aid, mutual, among animals, 227\n\n _Ammophila_ mode of stinging prey, 75;\n of carrying prey, 76;\n deposition of egg, 77;\n intelligent behaviour of, 127\n\n _Am\u0153ba_, 296\n\n Antlers of deer, 15\n\n Ants, behaviour of, 123;\n intercommunication of, 198;\n social communities of, 205\n\n _Aporus_, intelligent behaviour of, 126\n\n Appreciation, germs of, 273\n\n Ardour of male in courtship, 269\n\n _Argyrom\u0153ba_, instincts of, 79\n\n Arrest of development in egg, 14\n\n Association in coalescent situation, 46\n\n Attention, 242\n\n AUDUBON on American night-hawks, 261\n\n AVEBURY, Lord, on ants, 198;\n on Van, 200;\n on aphides and ants, 214;\n on slave ants, 215;\n on intelligence of ants, 218\n\n\n B\n\n BALDWIN, Prof. Mark, on organic selection, 37 (note), 115;\n on functional selection, 163;\n on imitation, 179 ff.;\n on projective stage of development, 275\n\n Batesian mimicry, 165\n\n BECHSTEIN on canaries, 262\n\n Bees, homing of, 131;\n social communities of, 205\n\n Beetle soliciting food from ant, 213\n\n _Bembex_ mode of carrying prey, 76\n\n BETHE, Dr., on instinctive behaviour of ants, 217\n\n BINET, M., on infusoria, 6\n\n Biological value of play, 250;\n purpose, 294;\n aspect of animal behaviour, 305\n\n Birch-weevil, leaf-case of, 121\n\n Birds, instinct of, 84\n\n Bison, behaviour of the, 226\n\n BLACKBURN, Mrs. Hugh, on instinct of cuckoo, 90\n\n BLOCKMANN, Dr., on _componotus_, 210\n\n BOLTON on goldfinches\u2019 nests, 136\n\n Bower-bird, observations on, 261, 273\n\n BUCKMAN, Mr. S. S., on speech of children, 203\n\n BUDGETT, Mr. John S., on nest-building, 135\n\n Bullfinch, nest of, 135\n\n\n C\n\n CAMERON, Mr., on mimetic insects in ants\u2019 nest, 212\n\n Canaries\u2019 nest, building of, 135\n\n Canon of interpretation, 270\n\n Capacity, innate, 176\n\n Capuchin monkey, imitation in, 188, 278\n\n CARPENTER, W. B., on water-beetle, 299\n\n Catasetum, fertilization of, 29\n\n Cats, Prof. Thorndike\u2019s experiments on, 147, 184\n\n Causation, idea of, 257\n\n Cell-division in egg, 14\n\n _Cerceris_, instincts of, 74;\n locality studies of, 129\n\n _Chalicodoma_, parasites of, 78;\n Fabre\u2019s observations on, 130\n\n Chick swimming, 85;\n instincts of, 85 ff.;\n imitation in, 183\n\n Child-study, desirability of, 155, 337\n\n Choice, apparent in Paramecia, 9;\n in the pairing situation, 266\n\n Ciliary action in Paramecium, 4-10\n\n Circular process (Baldwin), 181\n\n _Clepsine_, behaviour of, 159\n\n Coalescence in conscious situation, 46\n\n Coincident variations defined, 37;\n survival of, 115, 174\n\n Communities, social, of bees and ants, 205\n\n Companion as centre of special interest, 244\n\n _Componotus_, communities of, 210\n\n Conation and impulse, 187, 235\n\n Concept, nature of, 167\n\n Condensation of experience, 163\n\n Conduct implies motive, 60;\n and ideal, 278\n\n Congenital responses, 41\n\n Conjugation in Paramecium, 4\n\n Connate instincts, 66, 69\n\n Conscience, ambiguity of word, 281\n\n Conscious accompaniments of certain organic changes, 42;\n aspect of instructive behaviour, 99\n\n Consciousness, as accompaniment and as guide, 34;\n effective, defined, 43;\n as heir to organic estate, 52;\n as epiphenomenon, 306\n\n Consentience, 53, 62\n\n Consonance of biological and psychological end, 286, 316\n\n Constancy of environment leads to stereotyped behaviour, 173\n\n Continuity in evolution, 324;\n threefold aspect of, 329\n\n Control, the sign of effective consciousness, 43\n\n Co-ordinated acts, 69, 100;\n inherited, 94, 95\n\n Corporate behaviour, 14\n\n Courtship in animals, 259\n\n Coyness of female birds, 264 ff.\n\n Cranial sense-organs, 301\n\n Crayfish, reflex action in, 298\n\n Creation, special, 297\n\n Criteria of effective consciousness, 43;\n of intelligence, 120\n\n Cruelty in cat, 277\n\n Cuckoo, instinct of nestling, 90\n\n\n D\n\n DARWIN, Charles, fig. of sun-dew leaf, 26;\n of Venus\u2019s fly-trap, 27;\n of catasetum, 31;\n on earthworms, 158;\n on social life of animals, 225;\n on human ancestry, 229;\n on play and practise, 259;\n on sexual selection, 262 ff.;\n on law of battle, 313\n\n DAVIS, Prof. Ainsworth, on limpets, 156\n\n DEAN, Dr. Bashford, on chick swimming, 85\n\n Deceit in animals, 280\n\n Deferred instincts, 70\n\n Definiteness of instinctive behaviour, 66\n\n Description, involves relational terms, 202\n\n _Didunculus_, changed habits in, 221\n\n Differentiation and integration of nerve-centres, 167\n\n Disintegration of instincts, 176\n\n Diving, instinctive, 86\n\n Dog, observations on, intelligence of, 141 ff., 152, 200, 271, 322\n\n Duckling, inherited co-ordination in, 96\n\n _Dytiscus_, instinct of, 104\n\n\n E\n\n Earthworms, Darwin\u2019s observations on, 158 ff.\n\n Education in play, 255, 320 ff.\n\n Effective consciousness defined, 43\n\n Efferent and afferent impulses, 32, 101\n\n Egg, cell-division in, 14\n\n EIMER, Th., on instincts of solitary wasps, 73;\n on origin of instincts, 108\n\n Emotions, and feelings, 235 ff.;\n psychological nature of, 246;\n evolution of, 282\n\n Energy stored in cell, 23\n\n Equilibrium, tendency to, 296\n\n _Eristalis_, mimicry of, 164\n\n ESPINAS, Prof., on social life of animals, 230\n\n Ethics, animal, 270\n\n Evolution of organic behaviour, 35;\n of consciousness, 61;\n of instinctive behaviour, 106;\n of intelligent behaviour, 155;\n of social behaviour, 225;\n of feeling and emotion, 282;\n of animal behaviour, 295;\n as continuous, 324 ff.\n\n Experience, of value for future guidance, 44;\n is it inherited? 48, 97;\n condensation of, 163\n\n Experimentation, 251, 253\n\n Explanation, characteristic of later phases of mental development,\n 58, 257\n\n Explosive nature of cell, 21\n\n Expression of emotions, 247\n\n External stimuli to instinctive behaviour, 102\n\n\n F\n\n FABRE on behaviour of _Sphex_, 77, 172;\n of _Chalicodoma_, 78, 129;\n of _Leucopsis_, 79;\n of _Pompilus_, 129\n\n Faculty, instinctive, 64\n\n Falcons, training of, 137\n\n Fear in birds not inherited in specific direction, 49, 110\n\n Feelings and emotion, 235 ff.;\n evolution of, 282;\n feeling-tone, 240\n\n Ferns, fertilization of, 24\n\n Fertilization of ferns, 24;\n of _Valisneria_, 28;\n of orchids, 29\n\n FINN, Mr. Frank, on the acquisition of experience by young birds, 50\n\n Fission, reproduction of Paramecium by, 4\n\n Flight, instinctive, 86\n\n FOREL on _Componotus_, 211\n\n FOSTER, Sir Michael, on consciousness accompanying reflex action in\n pithed frog, 33\n\n Frog, reflex action in, 33, 299, 300\n\n Functional selection, 163\n\n Fungus garden of ants, 216\n\n\n G\n\n GARNER, Mr. R. L., \u201cThe Speech of Monkeys,\u201d 198\n\n Gas-engine, analogy of, 20\n\n General and abstract ideas, 57;\n generalization, 167;\n germs of, 332 ff.\n\n Generic image, 162;\n situations, 163\n\n Germinal substance, continuity of, 328\n\n GOULD, Dr., on humming-birds, 273\n\n GREEN, Mr. E. G., on ants, 210\n\n Greenfinch, nest of, 135\n\n GROOS, Prof., on instinct, 64;\n origin of, 116;\n on imitation, 187;\n on animal play, 248 ff.;\n on \u201cLove Play,\u201d 259;\n on coyness of female birds, 264;\n on choice in mating, 267;\n on make-believe, 280\n\n\n H\n\n Habits and habitual acts, 107, 177\n\n HAGUE on ants, 199\n\n HAMERTON, P. G., on trained dog, 152\n\n HANCOCK, Dr. John, on cuckoo, 92\n\n Heredity and circumstance, 39;\n twofold aspect of, 40;\n relation of to use, 170, 177;\n in evolution as continuous, 326\n\n Homing of bees, 131\n\n Hom\u0153opathic influence defined, 36\n\n Honey-pot ant, 215\n\n House-martin, nest-building of, 113\n\n HUDSON, Mr. W. H., on fear in birds, 49, 50, 110;\n on animal gladness, 317\n\n Hunting play, 254\n\n HUXLEY, T. H., on reflex action in frog, 300;\n on consciousness as epiphenomenon, 306 ff.;\n on consciousness as product of nervous changes, 330\n\n HYDE, Mr., on king-crab, 298\n\n _Hydractinia_, colonial polype, 206\n\n\n I\n\n Ideals, distinguish ethics, 278\n\n Ideational stage of mental development, 59\n\n Imitation, 179 ff.;\n three stages of in child, 192\n\n Impulse in intelligent behaviour, 60;\n Prof. Thorndike\u2019s use of the term, 186;\n connection of with conative process, 235\n\n Independence of automatic and controlling centres, 43\n\n Infant, congenital responses in, 54\n\n Influence of intelligence on instinct, 169\n\n Inheritance of acquisitiveness, 40\n\n Innate capacity, 176;\n likes and dislikes, 119\n\n Insects, instinctive behaviour in, 71;\n intelligent behaviour in, 123\n\n Instinct, broader and narrower view of, 99;\n primary and secondary, 108, 109;\n influence of intelligence on, 169;\n priority of, to intelligence, 173;\n disintegration of, 175\n\n Instinctive behaviour defined, 63;\n in insects, 71;\n in birds, 84;\n conscious aspect of, 98\n\n Integration and differentiation of nerve-centres, 167\n\n Intelligence lapsed, 107;\n influence of, on instinct, 169;\n of ants, Lord Avebury on, 218;\n biological importance of, 310\n\n Intelligent behaviour, 117;\n evolution of, 155\n\n Intelligent process distinguished from rational, 59, 138\n\n Intercommunication, 193, 336\n\n Interest, 243\n\n Internal factors in instinctive behaviour, 102\n\n Irritability, fundamental, property of protoplasm, 240, 296\n\n\n J\n\n JAMES, Prof. Wm., theory of emotions, 246, 292\n\n Jays, bathing of, 89;\n mode of taking food, 94\n\n JENNER on cuckoo, 92\n\n JENNINGS, Dr. H. S., on behaviour of Paramecia, 5\n\n\n K\n\n KERNER, Dr., on sun-dew, 26;\n on sensitive Oxalis, 27;\n on Valisneria, 29\n\n King-crab, reflex action in, 298\n\n KNIGHT, Andrew, on Norwegian ponies, 110\n\n KROPOTKINE, Prince, on mutual aid among animals, 227\n\n\n L\n\n Lamarckian hypothesis, 169, 171, 177\n\n Language, nature of, 195\n\n LANKESTER, Prof. E. Ray, on small-brained mammal, 168\n\n Lapwing, instinctive behaviour of, 113\n\n Law of battle, 313\n\n Leech, observation on, 159\n\n _Leucopsis_, instincts of, 79\n\n LEWES, G. H., on lapsed intelligence, 107\n\n Limpets, observations on, 156\n\n LINDLEY, Dr., on children, 141\n\n Locality, studies by wasps, 128\n\n LOCKE, John, limitations of animals, 167\n\n\n M\n\n MACKENZIE, Prof. J. S., on ethics, 278;\n on conscience, 281;\n on ambiguity of word \u201cpleasure,\u201d 285\n\n Make-believe, 280\n\n Mammals, early small-brained, 168\n\n Manipulation (Stout), 251\n\n MARCHAL, Prof., on instincts of _Cerceris_, 74\n\n MARSHALL, Mr. H. R., on instinct, 66\n\n Martin, nest-building of, 113\n\n MARTINEAU, James, on pleasure and pain, 284\n\n MAUPAS, M., observations on infusoria, 4\n\n MAYER, Dr. A. G., on mating instinct of moths, 83\n\n MCCOOK, Dr., on ants, 214\n\n Meaning, Dr. Stout\u2019s use of term, 46, 243, 268\n\n MEDLICOTT, Mr. H. B., on behaviour of wild pigs, 196\n\n Megapodes, instinctive flight of, 87\n\n _Melo\u00eb_, instincts of, 81\n\n Mental development, stages of, 48, 56\n\n MERCIER, Dr. Charles, on criteria of intelligence, 120\n\n Metaphysical explanations, 19;\n aspect of instinct, 64;\n of impulse, 237;\n of purpose, 294;\n of will, 307;\n of life, 325\n\n MILLS, Prof. Wesley, on social influence on puppy, 220\n\n _Miltogramma_, parasitic fly, 134\n\n Mimicry, Batesian and M\u00fcllerian, 165;\n intelligent aspect of, 311\n\n Modifiability, 171\n\n Modification, defined, 36;\n relation of, to hereditary characters, 170\n\n M\u00d6LLER, Herr, on fungus garden of ants, 216\n\n Monistic hypothesis, 309, 315\n\n Monkey, capuchin, imitation in, 188\n\n _Monodontomerus_, instincts of, 79\n\n Moor-hen, diving of, 89\n\n Moths mating, instinct of, 83\n\n Motive in rational conduct, 60\n\n Movement plays, 251\n\n M\u00dcLLER, Prof. Max, on barrier between brute and man, 204\n\n M\u00fcllerian mimicry, 165, 166\n\n Mystery of life, 18\n\n\n N\n\n Natural selection, shielding of chicks from, 111;\n under uniform and variable circumstances, 175;\n in playtime of life, 319\n\n Nervous arc, 33;\n system of higher animals, 297\n\n Nest-building, observations on, 135\n\n NOIR\u00c9 on concept, 167\n\n Norwegian ponies, 109\n\n Nucleus division, 12\n\n\n O\n\n Object and subject, 245, 276\n\n Octopus, intelligence of, 158\n\n _\u0152cophylla_, behaviour of, 210\n\n Orchids, fertilization of, 29\n\n Organic basis of differentiation of consciousness, 53\n\n Organic behaviour in development, 15\n\n Organic selection, 37 (note), 115\n\n Overproduction of movements, 164\n\n Oxalis, sensitive, behaviour of, 27\n\n _Oxybelus_, mode of carrying prey, 76\n\n\n P\n\n PALEY, definition of instinct, 64\n\n Paramecium, behaviour of, 3, 296\n\n Partridge, note of young, 93\n\n PECKHAM, Dr. G. W., on instinct, 65;\n on solitary wasps, 72 ff., 126 ff.\n\n Pecking instinct of chicks, 93\n\n Peewit, note of young, 93\n\n _Pelop\u0153us_, instincts of, 72\n\n Perceptual stage of mental development, 59\n\n Personality, 245, 257\n\n Pheasants, note of young, 92;\n inherited co-ordination in, 95;\n plumage of Argus, 262\n\n _Philanthus_, prey of, 73;\n mode of stinging prey, 74\n\n Physiological aspect of animal behaviour, 295\n\n Pigeons, nests of, 136\n\n Pigs, wild, behaviour of, 196\n\n Plants, behaviour of, 24\n\n Plastic period of life, 168\n\n Plasticity of tissues, 40;\n of behaviour, 172\n\n Play of animals, 248 ff.;\n biological value of, 250;\n psychological aspect of, 256, 311, 316\n\n PLAYNE, Mr. H. C., on pigeons\u2019 nests, 136\n\n Pleasure, 241;\n ambiguity in word, 285\n\n _Polistes_, locality studies of, 131\n\n _Pompilus_, mode of carrying prey, 76;\n Fabre\u2019s observation on, 129\n\n Presentative elements distinguished from re-presentative, 46\n\n Primary instincts (Romanes), 108\n\n Projective stage of mental development, 275;\n senses, 304\n\n _Pronuba_, instinct of, 82\n\n Propensity, instincts as, 64;\n congenital, 176\n\n Protoplasm, fundamental properties of, 296\n\n Psychological aspect of play, 256;\n purpose, 294;\n aspect of animal behaviour, 315\n\n\n R\n\n Rational process distinguished from intelligent, 59, 138\n\n Reflex action, 31, 35, 298 ff.;\n relation of instinct to, 70\n\n Relationships, importance of, 202\n\n Re-presentative elements distinguished from presentative, 46\n\n _Rhynchites_, instinct of, 121\n\n ROMANES, G. J., on \u201cdiscrimination\u201d and \u201cperception\u201d in plants, 32;\n on instincts of solitary wasps, 73;\n definition of instinct, 99;\n on primary and secondary instincts, 108, 109;\n on ants, 126;\n on general ideas, 166;\n on animal communication, 201;\n on cruelty in cat, 277\n\n ROMANES, Miss, observations on capuchin monkey, 188, 278\n\n Roots of spinal nerves, 299\n\n ROTHNEY, Mr. G. A. G., on Indian ants, 212\n\n\n S\n\n SCHNEIDER, on octopus, 158\n\n SCOTT, Dr. D. H., on fern fertilization, 25\n\n Scratching in duckling, 96\n\n Sea anemone, diffused nervous system of, 32\n\n Secondary instincts (Romanes), 108, 109\n\n Segmental nature of central nervous system, 299\n\n Selection, functional, 163;\n natural, shielding of chicks from, 111;\n under uniform and variable circumstances, 175;\n in playtime of life, 319;\n sexual, 261 ff., 313\n\n Self, as ideal construction, 239\n\n Sentience, 62;\n origin of, 330\n\n Sexual selection, 261 ff., 313\n\n SHARP, Dr. D., on birch-weevil, 121;\n on _\u0152cophylla_, 210\n\n SHELLARD, Mr. E. J., observations on staghound, 144\n\n SHERRINGTON, Prof., on emotion, 292;\n on spinal animal, 298 ff.\n\n Shock, effects of physiological, 302\n\n SIMCOX, Miss Edith, quoted, 320\n\n _Sitaris_, instincts of, 82\n\n Slave ants, 215\n\n Snails, observations on, 157\n\n Social behaviour, 179;\n evolution of, 225\n\n Solitary wasps, instincts of, 72 ff.;\n intelligence of, 126 ff.\n\n Solomon Islands, rats of, 222\n\n Sounds emitted by young birds, 92\n\n SPALDING, Douglas, on newly hatched turkeys, 49;\n on instinct, 99\n\n Special creation, 297\n\n Speech, connection of, with rational process, 58, 233;\n so-called, of monkeys, 198;\n of children, 203;\n aids passage from perceptual to ideational process, 337\n\n SPENCE, on instinct, 63\n\n SPENCER, Mr. Herbert, on instinct and reflex action, 70;\n on play due to surplus vigour, 248;\n on pleasure and pain, 284, 287;\n on survival, 288\n\n _Sphex_, mode of carrying prey to nest, 77, 172\n\n Spiders placed in crotch by wasps, 133\n\n Stereotyped behaviour, 172\n\n Sticklebacks, observations on, 130\n\n STOUT, Dr. G. F., on \u201cmeaning\u201d for consciousness, 46, 243, 268;\n on ideational and perceptual stages of mental development, 59, 271;\n on octopus, 158;\n on conative process, 235;\n on the self, 239;\n on manipulation, 251;\n on emotion, 293\n\n STRANGE, Mr., on bower-bird, 261\n\n Subject and object, 245, 276\n\n Sun-dew leaf, behaviour of, 25\n\n Swimming, instinctive, 85\n\n\n T\n\n TAIT, Lawson, on begging-cat, 110\n\n TARDE, M., on imitation as a social factor, 179\n\n Tendencies, congenital, 176\n\n THOMAS, Mr. Oldfield, on rats of Solomon Islands, 222\n\n THORNDIKE, Dr., on swimming of chick, 85;\n experiments on intelligence, 147 ff.;\n experiments on imitation, 179, 183 ff.\n\n Tradition, animal, 220\n\n Trial and error, method of, 139\n\n\n U\n\n Unity of perceptual process, 240;\n of biological purpose, 297\n\n Use, super-normal, 170;\n relation of, to heredity, 171, 177\n\n\n V\n\n VALISNERIA, fertilization of, 28\n\n Variation defined, 36;\n origin of, 327\n\n Venus\u2019s fly-trap, behaviour of, 26\n\n Vigour, play due to surplus, 248\n\n Volition as conative, 238\n\n\n W\n\n WALLACE, Dr. A. R., on sexual selection, 264\n\n WALLASCHEK, Mr., on play as surplus vigour, 248\n\n Wapiti, antlers of, 16\n\n WASMANN, Dr., on insects associated with ants, 213\n\n Wasps, solitary, instincts of, 72 ff.;\n intelligence of, 126 ff.\n\n WEIR, Mr. Jenner, on canaries, 135\n\n WEISMANN, Prof., on origin of instinct, 109\n\n WHITMAN, Prof., on _Clepsine_, 159\n\n WHITMEE, Rev. S. J., on tooth-billed pigeon, 221\n\n Will, metaphysics of, 307\n\n WILLISTON, Dr. S. W., observation on _Ammophila_, 127\n\n WOOD, Mr. Foster, on hen-swimming, 86\n\n WORCESTER, Dr., on megapode, 87\n\n WUNDT, Prof., on instinct, 65, 99, 106\n\n\n Y\n\n Youth, plasticity of, 168\n\n Yucca moth, instincts of, 82\n\n\n\n\nTHE END\n\n\n\n\nPRINTED BY WILLIAM CLOWES AND SONS, LIMITED, LONDON AND BECCLES\n\n\n\n\nFOOTNOTES\n\n\n[1] See \u201cThe Psychology of a Protozoon,\u201d in the _Amer. Jour. of\nPsychology_, vol. X., No. 4, July, 1899, and the fuller papers there\nquoted.\n\n[2] \u201cThe Psychic Life of Micro-Organisms,\u201d 1889, p. 61.\n\n[3] This paragraph is taken from \u201cAnimal Life and Intelligence,\u201d p. 28.\n\n[4] The following paragraphs are taken with some slight changes from\n\u201cAnimal Life and Intelligence,\u201d pp. 30-35.\n\n[5] D. H. Scott, \u201cAn Introduction to Structural Botany,\u201d part ii.,\n\u201cFlowerless Plants,\u201d pp. 70, 71.\n\n[6] _Ibid._, p. 71.\n\n[7] Kerner, \u201cNatural History of Plants,\u201d translated by F. W. Oliver,\nvol. i., p. 145.\n\n[8] Kerner, \u201cNatural History of Plants,\u201d vol. i., p. 536.\n\n[9] Kerner, \u201cNatural History of Plants,\u201d vol. ii., p. 132.\n\n[10] Darwin, \u201cFertilization of Orchids,\u201d 2nd edit., pp. 191, 192.\n\n[11] \u201cMental Evolution in Animals,\u201d p. 50.\n\n[12] _Ibid._, p. 51.\n\n[13] \u201cA Text-book of Physiology,\u201d 5th edit., part iii., p. 909.\n\n[14] \u201cA Text-book of Physiology,\u201d 5th edit., part iii., pp. 911, 912.\n\n[15] Professor Mark Baldwin has applied the term \u201corganic selection\u201d\nto the result of this interaction (_American Naturalist_ for June and\nJuly, 1896). Cf. also H. F. Osborn (_Science_, Nov. 27, 1896); August\nWeismann (Romanes Lecture on \u201cThe Effects of External Influences on\nDevelopment,\u201d 1894), and \u201cGerminal Selection,\u201d _Monist_, Jan., 1896;\nand the author\u2019s \u201cHabit and Instinct,\u201d ch. xiv., 1896.\n\n[16] \u201cHabit and Instinct,\u201d p. 26.\n\n[17] _American Journal of Psychology_, vol. ix., No. 1.\n\n[18] _Psychological Review_, vol. vi., No. 3.\n\n[19] \u201cNaturalist in La Plata,\u201d p. 88.\n\n[20] _Journal Asiatic Society of Bengal_, lxvii., part ii., 1897, p.\n614.\n\n[21] _Spectator_, No. 120.\n\n[22] Kirby and Spence, \u201cIntroduction to Entomology,\u201d Letter xxvii. p.\n537 (7th Edit., 1858).\n\n[23] Cf. supra, p. 18.\n\n[24] \u201cThe Play of Animals,\u201d translated by Elizabeth L. Baldwin, p. 62.\n\n[25] George W. and Elizabeth G. Peckham, \u201cOn the Instincts and Habits\nof the Solitary Wasps,\u201d p. 231.\n\n[26] \u201cLectures on Human and Animal Psychology,\u201d pp. 388, 397, 399.\n\n[27] \u201cInstinct and Reason,\u201d pp. 90, 92.\n\n[28] \u201cInstinct and Reason,\u201d p. 91.\n\n[29] Chapter I., Section V.\n\n[30] \u201cOn the Habits and Instincts of the Solitary Wasps,\u201d by George W.\nand Elizabeth G. Peckham (1898).\n\n[31] \u201cMental Evolution in Animals,\u201d p. 299.\n\n[32] \u201cOrganic Evolution,\u201d translated by J. T. Cunningham, p. 280.\n\n[33] See A. G. Mayer \u201cOn the Mating Instinct of Moths.\u201d _Ann. and Mag.\nof Nat. Hist._, ser. 7, vol. v., Feb., 1900, p. 183.\n\n[34] Some of the observations on which the summary of results given in\nthis section are founded are presented in some detail in \u201cHabit and\nInstinct,\u201d pp. 29-100.\n\n[35] _Psychological Review_, May, 1899, p. 286.\n\n[36] \u201cBirds from Moidart and Elsewhere,\u201d p. 107. Edinburgh: Douglas.\n\n[37] _Transactions of Northumberland and Durham Natural History\nSociety_, vol. viii., p. 213.\n\n[38] \u201cMental Evolution in Animals,\u201d p. 159.\n\n[39] \u201cLectures on Human and Animal Psychology,\u201d p. 401.\n\n[40] \u201cInstinct and Acquisition,\u201d _Nature_, vol. xii., p. 507.\n\n[41] On the nature of impulse, see _infra_, p. 235.\n\n[42] \u201cLectures on Human and Animal Psychology,\u201d p. 405.\n\n[43] \u201cOrganic Evolution,\u201d pp. 223, 263, 258, 279, 276, 298.\n\n[44] \u201cEssays on Heredity\u201d (1889), p. 91.\n\n[45] _Op. cit._, pp. 196-198.\n\n[46] Professor Henry Osborn has also indicated the relationship\nreferred to.\n\n[47] \u201cThe Play of Animals,\u201d p. 64.\n\n[48] \u201cSolitary Wasps,\u201d p. 236.\n\n[49] See D. Sharp, \u201cCambridge Natural History,\u201d \u201cInsects,\u201d part ii., p.\n293, and the original authorities cited on p. 294.\n\n[50] This and the three succeeding paragraphs are taken from \u201cAnimal\nLife and Intelligence,\u201d p. 425.\n\n[51] \u201cAnimal Intelligence,\u201d p. 59.\n\n[52] \u201cInstincts and Habits of the Solitary Wasps,\u201d p. 55.\n\n[53] _Op. cit._, p. 22.\n\n[54] _Op. cit._, p. 215.\n\n[55] \u201cD\u00fcrfen wir den Ameisen und Bienen psychische Qualit\u00e4ten\nZuschreiben.\u201d _Pfl\u00fcger\u2019s Archiv._, lxx., 1898.\n\n[56] \u201cSolitary Wasps,\u201d p. 219.\n\n[57] _Op. cit._, pp. 131, 132.\n\n[58] In a letter to Darwin, quoted by Romanes, \u201cMental Evolution in\nAnimals,\u201d p. 226.\n\n[59] \u201cThe Structure and Life of Birds,\u201d p. 335.\n\n[60] Preface to \u201cHarmonia Ruralis,\u201d quoted by Yarrell, \u201cBritish Birds,\u201d\nvol. i., p. 541.\n\n[61] _American Journal of Psychology_, vol. viii., no. 4, pp. 431-493.\n\n[62] \u201cIntroduction to Comparative Psychology,\u201d p. 255.\n\n[63] \u201cIntroduction to Comparative Psychology,\u201d p. 290.\n\n[64] _The Portfolio_ (1873), p. 27, \u201cCanine Guests.\u201d\n\n[65] \u201cAnimal Intelligence,\u201d pp. 28, 29.\n\n[66] _Nature_, vol. xxxi., p. 200.\n\n[67] _Ibid._, vol. li., p. 127.\n\n[68] \u201cManual of Psychology,\u201d p. 257.\n\n[69] \u201cVegetable Mould and Earthworms,\u201d p. 95.\n\n[70] _Wood\u2019s Holl Biological Lectures_ (1898), p. 287.\n\n[71] _Supra_, p. 44.\n\n[72] \u201cMental Evolution in Man,\u201d p. 27.\n\n[73] \u201cIntelligence of Animals,\u201d p. 121.\n\n[74] \u201cMental Development in the Child and the Race--Methods and\nProcesses,\u201d p. 278.\n\n[75] \u201cAnimal Intelligence:\u201d monograph supplement to _Psychological\nReview_, 1898, p. 61.\n\n[76] _Op. cit._, pp. 263, 172, 201, 132, and 248 (note).\n\n[77] \u201cAnimal Intelligence,\u201d pp. 47-64.\n\n[78] _Op. cit._, pp. 66, 14, 15.\n\n[79] Cf. _infra_, p. 235.\n\n[80] \u201cThe Play of Animals,\u201d Eng. trans., p. 79.\n\n[81] \u201cHabit and Instinct,\u201d pp. 174-180.\n\n[82] \u201cThe Evolution of Mind in Man,\u201d footnote, pp. 25, 26. Quoted in\n\u201cIntroduction to Comparative Psychology,\u201d from which the comments on it\nare extracted.\n\n[83] \u201cThe Speech of Monkeys.\u201d\n\n[84] \u201cScientific Lectures,\u201d pp. 112, 118.\n\n[85] _Nature_, vol. vii., p. 443.\n\n[86] \u201cThe Senses of Animals,\u201d p. 277.\n\n[87] \u201cMental Evolution in Man,\u201d p. 100.\n\n[88] _Op. cit._, p. 175.\n\n[89] Compare chap. xiii., on \u201cThe Perception of Relations,\u201d in my\n\u201cIntroduction to Comparative Psychology.\u201d\n\n[90] _Nineteenth Century_, May, 1897, pp. 793-807.\n\n[91] Sharp, \u201cInsects,\u201d part ii., p. 147.\n\n[92] _Nature_, vol. lxii., p. 253 (July 12, 1900).\n\n[93] The quotation is from \u201cThe Cambridge Natural History,\u201d vol. vi.,\n\u201cInsects,\u201d part ii., by David Sharp, F.R.S.; see pp. 145, 146.\n\n[94] Sharp, _op. cit._, p. 147.\n\n[95] G. A. J. Rothney, \u201cNotes on Indian Ants,\u201d _Trans. Ent. Soc._,\n1889, p. 354.\n\n[96] Sharp, _op. cit._, p. 226.\n\n[97] Lord Avebury (Sir John Lubbock), quoted in Romanes\u2019 \u201cAnimal\nIntelligence,\u201d pp. 62, 63.\n\n[98] Lord Avebury (Sir John Lubbock), \u201cScientific Lectures,\u201d pp. 78, 79.\n\n[99] _Nature_, vol. xlvii., p. 393 (Aug., 1893), where A. M\u00f6ller\u2019s\ninvestigations are described by J. C. Willis.\n\n[100] A. Bethe, \u201cD\u00fcrfen wir den Ameisen und Bienen psychische\nQualit\u00e4ten Zuschreiben,\u201d _Pfl\u00fcger\u2019s Archiv._, lxx., 1898.\n\n[101] See p. 37.\n\n[102] _Supra_, p. 138.\n\n[103] \u201cScientific Lectures,\u201d pp. 80-82.\n\n[104] _Proceedings of the Zoological Society_, 1874, p. 184.\n\n[105] \u201cScientific Lectures,\u201d 2nd edit., p. 140.\n\n[106] Weismann, \u201cEssays,\u201d vol. ii., p. 50.\n\n[107] Huxley, \u201cCollected Essays,\u201d vol. vii., p. 155.\n\n[108] \u201cThe Descent of Man,\u201d vol. i. p. 853, 2nd Ed., 1888. The\nquotations from Darwin in this paragraph and that which follows are\nsomewhat condensed by a few omissions.\n\n[109] Vol. xxviii., Sept. and Nov., 1890, pp. 337-354, 699-719.\n\n[110] _Nineteenth Century_, Feb., 1888, p. 165. \u201cCollected Essays,\u201d\nvol. ix., p. 204.\n\n[111] _Op. cit._, pp. 709, 710.\n\n[112] Page 711.\n\n[113] \u201cMutual Aid among Savages.\u201d _Nineteenth Century_, vol. xxix.\nApril, 1891, p. 538.\n\n[114] \u201cDescent of Man,\u201d vol. i., p. 96.\n\n[115] \u201cDes Soci\u00e9t\u00e9s Animales: \u00c9tude de Psychologie Compar\u00e9e\u201d (Paris,\n1877).\n\n[116] \u201cMutual Aid among Savages,\u201d _Nineteenth Century_, April, 1891,\npp. 539, 540.\n\n[117] Page 63.\n\n[118] _Op. cit._, p. 267; _cf. supra_, p. 138.\n\n[119] G. F. Stout, \u201cManual of Psychology,\u201d p. 268.\n\n[120] _Ibid._, p. 318.\n\n[121] \u201cManual of Psychology,\u201d p. 84.\n\n[122] \u201cHabit and Instinct,\u201d ch. ix., p. 186.\n\n[123] \u201cLetters on the \u00c6sthetic Education of Mankind,\u201d xxvii.\n\n[124] \u201cPrinciples of Psychology,\u201d \u00a7 533.\n\n[125] \u201cOn the Origin of Music,\u201d pp. 231, 232.\n\n[126] \u201cThe Play of Animals,\u201d Eng. trans., p. 12.\n\n[127] _Op. cit._, p. 7.\n\n[128] _Op. cit._, p. 19.\n\n[129] _Op. cit._, pp. 75, 76.\n\n[130] \u201cManual of Psychology,\u201d p. 327.\n\n[131] _Op. cit._, pref., p. xx.\n\n[132] _Op. cit._, p. 290.\n\n[133] \u201cManual of Psychology,\u201d p. 266.\n\n[134] _Op. cit._, p. 314.\n\n[135] \u201cDescent of Man,\u201d vol. ii., p. 60, 2nd edit. 1888.\n\n[136] \u201cThe Play of Animals,\u201d Eng. trans., p. 229.\n\n[137] Quoted by Groos, _op. cit._, p. 259.\n\n[138] \u201cDescent of Man,\u201d vol. ii., p. 77.\n\n[139] Darwin, _op. cit._, p. 99.\n\n[140] Quoted by Darwin, \u201cDescent of Man,\u201d vol. ii., p. 58.\n\n[141] \u201cDescent of Man,\u201d vol. ii., p. 56.\n\n[142] \u201cHabit and Instinct,\u201d p. 217.\n\n[143] \u201cDescent of Man,\u201d vol. ii., p. 251.\n\n[144] _Op. cit._, p. 137.\n\n[145] \u201cDarwinism,\u201d p. 285.\n\n[146] _Op. cit._, p. 293.\n\n[147] _Op. cit._, p. 172.\n\n[148] _Op. cit._, pp. 285, 286.\n\n[149] _Op. cit._, p. 283.\n\n[150] _Op. cit._, p. 243.\n\n[151] _Op. cit._, p. 242.\n\n[152] _Op. cit._, pref., p. xxii.\n\n[153] _Op. cit._, p. 240.\n\n[154] _Op. cit._, p. 244.\n\n[155] \u201cManual of Psychology,\u201d p. 85.\n\n[156] \u201cManual of Psychology,\u201d p. 23.\n\n[157] _Op. cit._, p. 22.\n\n[158] \u201cIntroduction to Comparative Psychology,\u201d p. 53.\n\n[159] \u201cManual of Psychology,\u201d p. 266.\n\n[160] \u201cAnimal Life and Intelligence,\u201d p. 340.\n\n[161] \u201cMutual Development in the Child and the Race,\u201d p. 19.\n\n[162] _Supra_, p. 270.\n\n[163] \u201cAnimal Intelligence,\u201d p. 413.\n\n[164] _Atalanta_, Jan., 1889. Reprinted in \u201cAnimal Sketches,\u201d p. 17.\n\n[165] \u201cThe Play of Animals,\u201d p. 122.\n\n[166] Appendix to \u201cAnimal Intelligence,\u201d p. 486.\n\n[167] \u201cManual of Ethics,\u201d p. 1.\n\n[168] \u201cAnimal Life and Intelligence,\u201d p. 404.\n\n[169] \u201cAnimal Life and Intelligence,\u201d p. 400. \u201cIntroduction to\nComparative Psychology,\u201d p. 369.\n\n[170] \u201cAnimal Intelligence,\u201d p. 444.\n\n[171] \u201cThe Play of Animals,\u201d p. 299.\n\n[172] _Op. cit._, p. 145.\n\n[173] \u201cManual of Ethics,\u201d pp. 285, 286.\n\n[174] Starcke, _International Journal of Ethics_, vol. ii., no. 3\n(April, 1892), p. 348.\n\n[175] \u201cManual of Psychology,\u201d p. 234. \u201cDispleasure\u201d here means the\nfeeling attitude antithetical to \u201cpleasure.\u201d\n\n[176] _Op. cit._, p. 65.\n\n[177] \u201cTypes of Ethical Theory,\u201d vol. ii., f. 350.\n\n[178] \u201cManual of Ethics,\u201d p. 85.\n\n[179] \u201cPrinciples of Psychology,\u201d vol. i., pt. ii., ch. ix. \u00a7 125.\n\n[180] \u201cManual of Ethics,\u201d p. 72.\n\n[181] \u201cLife and Letters,\u201d vol. i., p. 310.\n\n[182] Vol. i., pt. ii., ch. ix., \u00a7 124. I quote from the valuable\n\u201cEpitome\u201d prepared by Mr. Howard Collins, p. 214.\n\n[183] \u201cPrinciples of Biology,\u201d revised and enlarged edit. (1898), p.\n560.\n\n[184] From \u201cAnimal Life and Intelligence,\u201d p. 382.\n\n[185] \u201cExperiments on the Value of Vascular and Visceral Factors for\nthe Genesis of Emotion,\u201d _Proc. Roy. Soc._, vol. lxvi., pp. 390-403\n(1900).\n\n[186] \u201cManual of Psychology,\u201d p. 288.\n\n[187] \u201cManual of Psychology,\u201d p. 132.\n\n[188] See Huxley\u2019s book on \u201cThe Crayfish,\u201d in the International Science\nSeries, p. 108.\n\n[189] _Journal of Morphology_, vol. ix. Quoted by Professor C. S.\nSherrington in The Marshall Hall Address, \u201cOn the Spinal Animal\u201d\n(reprinted from _Medico-Chirurgical Transactions_, vol. 82), p. 4.\n\n[190] \u201cThe Spinal Animal,\u201d p. 5.\n\n[191] _Op. cit._, p. 23.\n\n[192] \u201cCollected Essays,\u201d vol. i., essay on \u201cAnimal Automatism,\u201d p. 224.\n\n[193] _Op. cit._, pp. 20, 21.\n\n[194] _Op. cit._, p. 29.\n\n[195] _Op. cit._, p. 18.\n\n[196] _Vide supra_, p. 33.\n\n[197] \u201cCollected Essays,\u201d vol. i., p. 240.\n\n[198] _Op. cit._, pp. 238, 239.\n\n[199] _Vide supra_, p. 285.\n\n[200] \u201cNaturalist in La Plata,\u201d pp. 280, 281.\n\n[201] \u201cPsychology for Teachers,\u201d p. 70.\n\n[202] _Supra_, p. 36.\n\n[203] _Supra_, p. 13.\n\n[204] \u201cCollected Essays,\u201d vol. i., p. 239.\n\n\n\n\nTranscriber's Note\n\n\nIllustrations have been moved alongside the text which they\nillustrate, and may no longer match the locations given in the List of\nIllustrations.\n\n\nThe following apparent errors have been corrected:\n\np. vii \"FIG\" changed to \"FIG.\"\n\np. viii \"Mr\" changed to \"Mr.\"\n\np. 29 \"Figs. 9\" changed to \"Fig. 9\"\n\np. 34 (note) \"on\" changed to \"of\"\n\np. 50 (footnote) \"p 88\" changed to \"p. 88\"\n\np. 72 (note) \"(1898)\" changed to \"(1898).\"\n\np. 107 (note) \"405\" changed to \"405.\"\n\np. 131 \"219\" changed to \"219.\"\n\np. 131 (note) \">Pfluger\u2019s\" changed to \"Pfl\u00fcger\u2019s\"\n\np. 162 (note) \"p 44\" changed to \"p. 44\"\n\np. 165 \"Mullerian\" changed to \"M\u00fcllerian\"\n\np. 212 \"Where-ever\" changed to \"Wherever\"\n\np. 216 \"79\" changed to \"79.\"\n\np. 226 \"drives\" changed to \"drive\"\n\np. 239 (note) \"G. F\" changed to \"G. F.\"\n\np. 256 \"objects\" changed to \"objects.\"\n\np. 267 \"woes\" changed to \"woos\"\n\np. 330 (note) \"239\" changed to \"239.\"\n\np. 332 \"co ordinated\" changed to \"co-ordinated\"\n\np. 338 \"106.\" changed to \"106\"\n\np. 338 \"BECKSTEIN\" changed to \"BECHSTEIN\"\n\np. 338 \"leafcase\" changed to \"leaf-case\"\n\np. 339 \"nerve centres\" changed to \"nerve-centres\"\n\np. 341 \"nerve centres\" changed to \"nerve-centres\"\n\np. 341 \"king crab\" changed to \"king-crab\"\n\np. 341 \"of, intelligence\" changed to \"of intelligence\"\n\np. 342 \"on, infusoria\" changed to \"on infusoria\"\n\np. 342 \"mating, instinct\" changed to \"mating instinct\"\n\np. 343 \"SCHNEIDER on\" changed to \"SCHNEIDER, on\"\n\np. 343 \"Shock effects\" changed to \"Shock, effects\"\n\np. 343 \"SPENCE on\" changed to \"SPENCE, on\"\n\np. 344 \"106.\" changed to \"106\"\n\np. 344 \"of 327\" changed to \"of, 327\"\n\np. 344 \"72 ff.,\" changed to \"72 ff.;\"\n\n\nPunctuation and spelling have otherwise been kept as printed.\n\n\nThe following are used inconsistently in the text:\n\nalarm-note and alarm note\n\nco-existed and coexists\n\nco-incident and coincident\n\ndanger-note and danger note\n\nfirst-hand and firsthand\n\nfox-terrier and fox terrier\n\nground-work and groundwork\n\ninter-communication and intercommunication\n\nnewly-hatched and newly hatched\n\nnon-plussed and nonplussed\n\nplay-time and playtime\n\npre-requisite and prerequisite\n\nre-presentations and representations\n\nre-presentative and representative\n\nRomanes\u2019s and Romanes\u2019\n\nsupra and _supra_\n\nVenus\u2019s Fly-trap, Venus\u2019s Fly Trap and Venus\u2019s fly-trap","title":"Animal Behaviour","tradition":"philosophy-ethics","translated_text":null,"word_count":119376}