In the first place, it is probable that, as in other modes of animal behaviour, traditional procedure is founded on an instinctive basis. This must be an imitative tendency of the broad follow-my-leader type indicated in the first section of this chapter. And this would afford wide instinctive foundations, which would owe their hereditary character to the fact that, under natural selection, those individuals in the community would survive which fell into line with the adaptive behaviour of their companions, while those which failed in this respect would be eliminated as more or less isolated outsiders, standing apart from the social life. In illustration we may take a hypothetical case, founded, however, upon observation. The Rev. S. J. Whitmee, a missionary in Samoa, believes that the tooth-billed pigeon of these islands (Didunculus strigirostris) “has probably been frightened when roosting, or during incubation, by attacks of cats, and has sought safety in the trees. Learning, from frequent repetition of the fright, that the ground is a dangerous place, it has acquired the habit of building, roosting, and feeding on the high trees; and this habit is now operating for the preservation of this interesting bird, which a few years ago was almost extinct.”[104] Now, in this case, the young birds which followed the lead of those who, under experience, had acquired the habit, would stand a better chance of survival than those who, failing to do so, were caught napping on the ground. In further illustration, we may take the case of two species of rats found by Mr. C. M. Woodford on one of the Solomon Islands. These two species are regarded by Mr. Oldfield Thomas as slightly altered descendants of one parent species, with adaptations due to the fact that, of this original species, some have adopted a terrestrial, others an arboreal life. Thus Mus rex lives in trees, has broad footpads, and a long rasp-like, probably semi-prehensile tail; while Mus imperator lives on the ground, has smaller pads, and a short smooth tail. How far the different modes of behaviour in the two species may have been fostered by the influence of tradition we do not know; but it is not improbable that such an influence would be a co-operating factor in the process of segregation, and that in the course of time each form has been adapted to its special environment through the elimination of those individuals which were not in harmony with the conditions of their life.
Such a case—admittedly hypothetical in the interpretation put upon the facts—may help us to see how the general instinctive follow-my-leader tendency might become specialized in certain essential lines of racial behaviour, and how, under natural selection, coincident variations in the line of traditional acts might become more and more definitely inherited as, at first, strong instinctive tendencies, and eventually more stereotyped modes of instinctive behaviour. This, indeed, may have been the mode of origin of some of the social instincts.
Reverting, however, to the stage where the general instinctive follow-my-leader tendency is only partly or incompletely specialized along particular lines of behaviour, we should have at this stage certain hereditary trends of action, dependent on stimuli afforded by the behaviour of others, but needing, for their guidance to finer issues and more adequate and highly perfected performance, the play of intelligence and the satisfaction of nascent social impulses. In the economy of the hive or the nest there are, no doubt, instinctive tendencies and predispositions; but there is also something more than organic heredity with its transmitted modes of behaviour analogous to the inherited form and structure of the body or its parts. Consciousness exerts a guiding influence. The insect is not independent of experience, but is capable of profiting by the teachings of that fertile mother of all intelligent behaviour. It is unnecessary, however, to insist on the fact that such insects are something more than instinctive automata, but are guided in their behaviour by the results of experience. Many careful observers lay stress upon this; if, indeed, they do not go further and claim for the social insect the higher rational faculty. “When we see,” says Lord Avebury,[105] “an ant-hill tenanted by thousands of industrious inhabitants, excavating chambers, forming tunnels, making roads, guarding their home, gathering food, feeding the young, tending their domestic animals—each one fulfilling its duties industriously, and without confusion—it is difficult altogether to deny to them the gift of reason; and the preceding observations tend to confirm the opinion that their mental powers differ from those of man, not so much in kind as in degree.”
If the term “reason” be here accepted in the broad sense, and not in the narrower sense before indicated, this passage will probably be endorsed by the majority of those who have paid any attention to the subject. Even those who regard “reason,” in the more restricted acceptation of the term, as outside any scheme of evolution, since it differs in kind and not merely in degree, would probably deny this faculty to ants. In any case the passage expresses the conviction of a close and singularly unprejudiced observer, that the doings of ants involve conscious guidance in the light of experience individually acquired.
And yet the behaviour of different species of ants, each after its kind, is remarkably constant—so constant that, to use the words of Dr. Peckham in another connection, it is characteristic of the species, and would be an important part of any definition of the insect based upon its habits. And some part of this constancy may be due to tradition, though much of it may result from strong instinctive tendencies which intelligence guides to similar ends, because the conditions are similar in successive generations of social insects.
From the point of view of observation, however, it is particularly difficult to distinguish the part played by tradition as a psychological influence from that played by what we have above described as instinctive imitation. In our study of other modes of instinctive behaviour we can isolate an individual, or group of young individuals, and observe how far certain acts are performed prior to any experience. Thus chicks behave in certain instinctive ways under conditions which preclude their learning from the hen or other older birds—so that tradition cannot be operative. But where social behaviour is concerned, such methods of observation are necessarily excluded, since isolation involves the absence of the social factor. And if certain instinctive acts require for their due performance the stimulus of the like performance in others, what is this but a form of instinctive tradition; and how are we to distinguish it from intelligent tradition, where a psychological factor has freer play and exercises guidance over the performance? In the present state of our knowledge we can do no more than suggest, as not improbable, that tradition passes through three phases: the first in which it is instinctive; the second in which it becomes intelligent through the satisfaction which the due performance of traditional acts arouses in consciousness; and the third in which, at any rate in man, it takes on a rational form, and is made to accord with an ideal scheme, the product of conceptual thought and of reflection on data which have been generalized and considered in their due relationships to the scheme which takes definite form in the mind. Whether in the social communities of insects or those of beavers, among mammals, or rooks among birds, tradition has begun to pass into the third or rational stage, we do not know. It may be so, but probably the development along these lines has not been carried far. Presumably in the ant, rook, and beaver anything like an ideal scheme of thought based on reflection, if it exist, is as yet exceedingly indefinite.
But even supposing that no animal has yet risen beyond the second or intelligent stage, it is none the less important to realize that we have here, in animal life, the foundations on which may be raised what may, perhaps, be regarded as one of the characteristic features of human progress. This characteristic is the transference of evolution from the organism to the environment handed on from generation to generation. Thus man, “availing himself of tradition, is able to seize upon the acquirements of his ancestors at the point where they left them.”[106] Thus “he has slowly accumulated and organized the experience which is almost wholly lost with the cessation of individual life in other animals.”[107] But he is able to do so through the extension, refining, and fixing of that instinctive and intelligent tradition which begins to take form in animal communities.
V.—The Evolution of Social Behaviour
“Animals of many kinds,” said Darwin,[108] “are social; every one must have noticed how miserable horses, dogs, sheep, etc., are when separated from their companions. The most common mutual service in the higher animals is to warn one another of danger. Every sportsman knows how difficult it is to approach animals in a herd or troop. Wild horses and cattle do not, I believe, make any danger-signal; but the attitude of any one of them who first discovers an enemy warns the others. Rabbits stamp loudly on the ground with their hind feet as a signal; sheep and chamois do the same with their fore feet, uttering likewise a whistle. Many birds and some mammals post sentinels. The leader of a troop of monkeys acts as such, and utters cries expressive both of danger and of safety. Social animals perform many little services for each other: horses nibble, and cows lick each other; monkeys search each other for external parasites, and are said to remove thorns and burrs. Social animals mutually defend each other. Bull bisons in North America, when there is danger drive the cows and calves into the middle of the herd, whilst they defend the outside. Among baboons the old males come forward to the attack. Wolves hunt in packs; and pelicans fish in concert.
“It has often been assumed,” continues Darwin, “that animals were in the first place rendered social, and that they feel as a consequence uncomfortable when separated from each other, and comfortable whilst together; but it is a more probable view that these sensations were first developed, in order that those animals which would profit by living in society should be induced to live together, in the same manner as the sense of hunger and the pleasure of eating were, no doubt, first acquired in order to induce animals to eat. The feeling of pleasure from society is probably an extension of the parental and filial affections, since the social instinct seems to be developed by the young remaining long with their parents; and this extension may be attributed in part to habit, but chiefly to natural selection. With those animals which were benefited by living in close association, the individuals which took the greatest pleasure in society would best escape various dangers; while those which cared least for their comrades, and lived solitary, would perish in greater numbers. In however complex a manner the feeling of sympathy may have originated, as it is one of high importance to all those animals which aid and defend one another, it will have been increased through natural selection; for those communities which included the greatest number of the most sympathetic members would flourish best, and rear the greatest number of offspring.”