There is some little difficulty in distinguishing between instinctive activities and reflex actions. Mr. Herbert Spencer defines or describes instinct as compound reflex action. Mr. Romanes defines instinct as reflex action into which there is imported the element of consciousness. But, on the one hand, many instincts involve something more than compound reflex action, since there is an organized sequence of activities; and, on the other hand, the difficulty (which Mr. Romanes admits) or impossibility (as I contend) of applying the criterion of consciousness renders unsatisfactory the introduction of the mental element as distinctive. I would say, therefore, that (1) reflex actions are those comparatively isolated activities which are of the nature of organic or physiological responses to more or less definite stimuli, and which involve rather the several organs of the organism than the activities of the organism as a whole; and that (2) instinctive activities are those organized trains or sequences of co-ordinated activities which are performed by the individual in common with all the members of the same more or less restricted group, in adaptation to certain circumstances, oft-recurring or essential to the continuance of the species.
These instinctive activities may, as I have said, be performed at once and without practice (perfect instincts) or by self-suggested trial and practice (incomplete instincts). Most young mammals require some little practice in the use of their limbs before they are able to walk or run. But young pigs run about instinctively so soon as they are born. Thunberg, the South African traveller, relates, on the testimony of an experienced hunter, the case of a female hippopotamus which was shot the moment she had given birth to a calf. "The Hottentots," he said, "who imagined that after this they could catch the calf alive, immediately rushed out of their hiding-place to lay hold of it; but, though there were several of them, the new-born calf got away from them, and at once made the best of its way to the river."
Even in cases where some practice is apparently necessary, the activities may be, and often are, perfectly instinctive. They cannot, however, be performed immediately on birth, because the nervous and muscular mechanism is not at that time sufficiently developed. They might, perhaps, with advantage be termed "deferred instincts." If time be given for this development, the activities are carried out at once and without practice. Throw a new-born puppy into the river, and, after some helpless floundering, he will be drowned. Throw his brother when fully grown into the river, and, though he may never have been in the water in his life, he will swim to shore. He has not to learn to swim; this is with him an instinctive activity. The dog inherits the power which the boy must with some little difficulty acquire. He probably has to pay no special attention to the muscular adjustments involved. The act is accompanied by consciousness, but not that directed consciousness we call "attention." When the boy has acquired the habit, he is scarcely conscious of the special muscular co-ordinations as he swims across the river; he is only conscious of a desire to pick the water-lilies near the further bank.
Birds, especially those which are called prœcoces, in contradistinction from the altrices, which are hatched in a helpless, callow condition, come into the world prepared at once to perform complex activities. Mr. Spalding writes,[IO] "A chicken that had been made the subject of experiments on hearing [having been blindfolded at birth] was unhooded when nearly three days old. For six minutes it sat chirping and looking about it; at the end of that time it followed with its head and eyes the movements of a fly twelve inches distant; at ten minutes it made a peck at its own toes, and the next instant it made a vigorous dart at the fly, which had come within reach of its neck, and seized and swallowed it at the first stroke; for seven minutes more it sat calling and looking about it, when a hive-bee, coming sufficiently near, was seized at a dart, and thrown some distance much disabled. For twenty minutes it sat on the spot where its eyes had been unveiled without attempting to walk a step. It was then placed on rough ground, within sight and call of a hen with a brood of its own age. After standing chirping for about a minute, it started off towards the hen, displaying as keen a perception of the qualities of the outer world as it was ever likely to possess in after-life. It never required to knock its head against a stone to discover that there was 'no road that way.' It leaped over the smaller obstacles that lay in its path, and ran round the larger, reaching the mother in as nearly straight a line as the nature of the ground would permit. This, let it be remembered, was the first time it had ever walked by sight."[IP]
Mr. Spalding's experiments also proved that, even among the altrices, young birds do not require to be taught to fly, but fly instinctively so soon as the bodily organization is sufficiently developed to render this activity possible. He kept young swallows caged until they were fully fledged, and then allowed them to escape. They flew straight off at the first attempt. They exhibited the instinctive power of flight in a perfect but deferred form.
It is, however, among the higher invertebrates—especially among the insects, and of them pre-eminently in the social hymenoptera, ants and bees, that the most remarkable and complete instincts are seen. There is, however, a tendency to ascribe all the habits of ants and bees to instinct, often, as it seems to me, without sufficient evidence that they are performed without instruction, and through no imitation or intelligent adjustment. This is, perhaps, a survival of the old-fashioned view that all the mental activities of the lower animals are performed from instinct, whereas all the activities of human beings are to be regarded as rational or intelligent. In popular writings and lectures, for example, we frequently find some or all of the following activities of ant-life ascribed to instinct: recognition of members of the same nest; powers of communication; keeping aphides for the sake of their sweet secretion; collection of aphid eggs in October, hatching them out in the nest, and taking them in the spring to the daisies, on which they feed, for pasture; slave-making and slave-keeping, which, in some cases, is so ancient a habit that the enslavers are unable even to feed themselves; keeping insects as beasts of burden, e.g. a kind of plant-bug to carry leaves; keeping beetles, etc., as domestic pets; habits of personal cleanliness, one ant giving another a brush-up, and being brushed-up in return; habits of play and recreation; habits of burying the dead; the storage of grain and nipping the budding rootlet to prevent further germination; the habits described by Dr. Lincecum, and to a large extent confirmed by Dr. McCook,[IQ] that Texan ants go forth into the prairie to seek for the seeds of a kind of grass of which they are particularly fond, and that they take these seeds to a clearing which they have prepared, and then sow them for the purpose, six months afterwards, of reaping the grain which is the produce of their agriculture; the collection by other ants of grass to form a kind of soil on which there subsequently grows a species of fungus upon which they feed; the military organization of the ecitons of Central America; and so forth. Now, the description of the habits of ants forms one of the most interesting chapters in natural history. But to lump them together in this way, as illustrations of instinct, is a survival of an old-fashioned method of treatment. That they have to a very large extent an innate basis may be readily admitted. But at present we are hardly in a position to say how far they are instinctive, that is, performed by each individual straight off, and without imitation, instruction, or intelligence; how far habitual, that is, performed after some little training and practice; how far there is the intelligent element of special adaptation to special circumstances; how far they are the result of imitation; to what extent, if any, individual training and instruction are factors in the process.
To put the matter in another way. Suppose that an intelligent ant were to make observations on human activities as displayed in one of our great cities or in an agricultural district. Seeing so great an amount of routine work going on around him, might he not be in danger of regarding all this as evidence of blind instinct? Might he not find it difficult to obtain satisfactory evidence of the establishment of our habits, of the fact that this routine work has to some extent to be learnt? Might he not say (perhaps not wholly without truth), "I can see nothing whatever in the training of the children of these men to fit them for their life-activities. The training of their children has no more apparent bearing upon the activities of their after-life than the feeding of our grubs has on the duties of ant-life. And although we must remember," he might continue, "that these large animals do not have the advantage which we possess of awaking suddenly, as by a new birth, to their full faculties, still, as they grow older, now one and now another of their instinctive activities are unfolded and manifested. They fall into the routine of life with little or no training as the period proper to the various instincts arrives. If learning thereof there be, it has at present escaped our observation. And such intelligence as their activities evince (and many of them do show remarkable adaptation to uniform conditions of life) would seem to be rather ancestral than of the present time; as is shown by the fact that many of the adaptations are directed rather to past conditions of life than to those which now hold good. In the presence of new emergencies to which their instincts have not fitted them, these poor men are often completely at a loss. We cannot but conclude, therefore, that, although shown under somewhat different and less favourable conditions, instinct occupies fully as large a space in the psychology of man as it does in that of the ant, while their intelligence is far less unerring and, therefore, markedly inferior to our own."
Of course, the views here attributed to the ant are very absurd. But are they much more absurd than the views of those who, on the evidence which we at present possess, attribute all the varied activities of ant-life to instinct? Take the case of the ecitons, or military ants, or the harvesting ants, or the ants that keep draught-bugs as beasts of burden: have we sufficient evidence to enable us to affirm that these activities are purely instinctive and not habitual? That they are to a large extent innate, few are likely to deny; but then our own habitual acts have a basis that is, to a very large extent, innate. The question is not whether they have an innate basis, but whether all the varied manœuvres of the military ants, for example, are displayed to the full without any learning or imitation, without teaching and without intelligence on the part of every individual in the army.[IR]
That in some cases there is something very like a training or education of the ant when it emerges from the pupa condition is rendered probable by the observations of M. Forel. As Mr. Romanes says,[IS] "The young ant does not appear to come into the world with a full instinctive knowledge of all its duties as a member of a social community. It is led about the nest and 'trained to a knowledge of domestic duties, especially in the case of larvæ.' Later on, the young ants are taught to distinguish between friends and foes. When an ants' nest is attacked by foreign ants, the young ones never join in the fight, but confine themselves to removing the pupæ; and that the knowledge of hereditary enemies is not wholly instinctive in ants is proved by the following experiment, which we owe to Forel. He put young ants belonging to three different species into a glass case with pupæ of six other species—all the species being naturally hostile to one another. The young ants did not quarrel, but worked together to tend the pupæ. When the latter hatched out, an artificial colony was formed of a number of naturally hostile species, all living together after the manner of the 'happy families' of the showmen."
I have said that the varied activities of ants, though they may not in all cases be truly instinctive, are nevertheless the outcome of certain innate capacities. It seems to me necessary to distinguish carefully between innate capacity and instinct. Every animal comes into the world with an innate capacity to perform the activities which have been necessary for the maintenance of the normal existence of its ancestors. This is part of its inherited organization. Only when these activities are performed at the bidding of impulse, through no instruction and from no tendency to imitation, can they, strictly speaking, be termed instinctive. The more uniform the conditions of ancestral life, and the more highly developed the organism when it enters upon the scene of active existence, the more likely are the innate capacities to manifest themselves at once and without training as perfect instincts. Among birds, the prœcoces, which reach a high state of development within the egg, and among insects, those which undergo complete metamorphosis, and emerge from the pupa or chrysalis condition fully formed and fully equipped for life, display the greatest tendency to exhibit activities which are truly and perfectly instinctive. But man, whose ancestors have lived and worked under such complex conditions, and who comes into the world in so helpless and immature a state, though his innate capacities are enormous, exhibits but few and rudimentary instincts.