One marked characteristic of many of the habits and instincts of the lower animals is the large amount of blind prevision (if one may be allowed the expression) which they display. By blind prevision I mean that preparation for the future which, if performed through intelligence or reason, we should term "foresight," but which, since it is performed prior to any individual experience of the results, is done, we must suppose, in blind obedience to the internal impulse. The sphex, a kind of wasp-like insect, forms a little mud chamber in which she lays her eggs. She goes forth, finds a spider, stings it in such a way that it is paralyzed but not killed, and places it in the chamber for her unborn young, which she will never see. The hen incubates her eggs, though she may never have seen a chicken in her life. The caterpillars of an African moth weave a collective cocoon as large as a melon. All unite to weave the enveloping husk; each forms its separate cocoon within the shell, and all these separate cocoons are arranged round branch-passages or corridors, by which the moths, when they emerge from the chrysalis condition, may escape. Another caterpillar, that of a butterfly (Thekla) feeds within the pomegranate, but with silken threads attaches the fruit to the branch of the tree, lest, when withered, it should fall before the metamorphosis is complete. An ichneumon fly, mentioned by Kirby and Spence, "deposits its eggs in the body of a larva hidden between the scales of a fir-cone, which it can never have seen, and yet knows where to seek;" and thus provision is made for young which it will never know. Instances of such blind prevision might be quoted by the score. It is idle to speculate as to the accompaniments of consciousness of such acts. If it be asked—May there not be associated with the performance of the instinctive activity of incubation an inherited memory of a generalized chick? we can only answer that we do not know, but that we guess not.[IT]
There is, however, one association, in the case of these and other instincts, which we may fairly surmise to be frequent, though, for reasons to be specified hereafter, it is probably not invariable. Just as we saw to be the case with habits, so too with instinctive activities, their performance is not infrequently associated with pleasurable feeling, their non-performance with pain and discomfort and a sense of craving or want. The animal prevented from performing its instinctive activities is often apparently unquiet, uneasy, and distressed. Hence I said that the animals in our zoological gardens, even if born and reared in captivity, may exhibit a craving for freedom and a yearning to perform their instinctive activities. This craving may be regarded as a blind and vague impulse, prompting the animal to perform those activities which are for its own good and for the good of the race to which it belongs. The satisfaction of the craving, the gratification of the blind impulse, is accompanied by a feeling of relief and ease. Thus where a motive emerges at all into consciousness, that from which we may presume that instinctive activities are performed is not any foreknowledge of their end and purpose, but the gratification of an immediate and pressing need, the satisfaction of a felt want.
We have, so far, been concerned merely with the various kinds of activity presented by men and animals, and with some of their characteristics. The organism, in virtue of its organization, has an inherited groundwork of innate capacity. Surrounding circumstances and commerce with the world draw out and develop the activities which the innate capacity renders possible. First, there are automatic and reflex actions, which are comparatively isolated activities in response to definite stimuli, external or internal. Secondly, there 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 are the instinctive activities. But no hard-and-fast line can be drawn between them and reflex actions. The instinctive activities may be either perfect or relatively imperfect, according to the accuracy of their adaptation to the purpose for which the activity is performed; but in either case they are carried out without learning or practice. In some cases, however, they cannot be performed until the organization is more perfectly developed than it is at birth; but when the proper time arrives they are perfect, and require no practice; these may be termed "deferred instincts." Where some practice, but only a little, is required, the instinctive activities may be regarded as incomplete; and these pass into those activities which require at first a good deal of practice, learning, and attention, but eventually run off smoothly and without special attention, at times almost or quite unconsciously. These are habitual activities. Finally, we have those activities which are performed in special adaptation to special circumstances. These are intelligent activities.
All of these may be, and the last, the intelligent actions, invariably are, accompanied by consciousness. The habitual activities, and those which are incompletely instinctive, are also, we may presume, accompanied by consciousness during the process of their organization and establishment. It is possible, however, that some of the perfectly instinctive activities may be performed unconsciously. When we consider how perfectly organized such activities are, and when we also remember that perfectly organized habitual activities are frequently in us unconscious, we shall see cause for suspecting that instinctive activities may, at any rate in some cases, be unconscious. No doubt the conditions of consciousness are not well understood. But let us accept Mr. Romanes's suggestion, that a physiological concomitant is ganglionic delay. "Now what," he asks,[IU] "does this greater consumption of time imply? It clearly implies," he answers, "that the nervous mechanism concerned has not been fully habituated to the performance of the response required, and therefore that, instead of the stimulus merely needing to touch the trigger of a ready-formed apparatus of response (however complex this may be), it has to give rise in the nerve-centre to a play of stimuli before the appropriate response is yielded. In the higher planes of conscious life this play of stimuli in the presence of difficult circumstances is known as indecision; but even in a simple act of consciousness—such as signalling a perception—more time is required by the cerebral hemispheres in supplying an appropriate response to a non-habitual experience, than is required by the lower nerve-centres for performing the most complicated of reflex actions by way of response to their habitual experience. In the latter case the routes of nervous discharge have been well worn by use; in the former case these routes have to be determined by a complex play of forces amid the cells and fibres of the cerebral hemispheres. And this complex play of forces, which finds its physiological expression in a lengthening of the time of latency, finds also a psychological expression in the rise of consciousness." Now, since in many instinctive activities the stimulus "merely needs to touch the trigger of a ready-formed apparatus of response," I think that they may be unconscious. And Mr. Romanes thus himself supplies the reason for rejecting his own definition of instinct as "reflex action into which there is imported the element of consciousness." Of course, logically, Mr. Romanes can reply, "It is merely a question of where we draw the line; if the activity is unconscious, it is a reflex action; if conscious, it is an instinct." I think this unsatisfactory, (1) because the criterion of consciousness, from its purely inferential nature, is practically impossible of application with accuracy; (2) because the same series of activities may probably at one time be unconscious and at another time conscious; and (3) because many actions which are almost universally regarded as reflex actions may at times be accompanied by consciousness, and would then have, on Mr. Romanes's view, to be regarded as instincts.
Having made this initial criticism, I may now state that I regard Mr. Romanes's treatment of instinct as most admirable and masterly. Building upon the foundation laid by Charles Darwin, he has worked out the theory of instinct in a manner at once broad and yet minute, lucid and yet close, definite in doctrine and yet not blind to difficulties. If I say that it is a piece of work worthy of the great master whose devoted disciple Mr. Romanes has proved himself, I am according it the highest praise in my power. I have ventured in this volume to criticize some of Mr. Romanes's conclusions in the field of animal intelligence. And lest I should seem to undervalue his work, lest our few divergences should seem to hide our many parallelisms, I take this opportunity of testifying to my great and sincere admiration of the results of his careful and exact observations, his patient and thoughtful inferences, and his lucid and often luminous exposition.
I do not propose to go over the ground so exhaustively covered by Mr. Romanes in his discussion of instinct. I shall first endeavour shortly to set forth his conclusions, and then review the subject in the light of modern views of heredity.
Admitting that some instincts may have arisen from the growth, extension, and co-ordination of reflex actions, Mr. Romanes regards the majority of instincts as of two-fold origin—first, from the natural selection of fortuitous unintelligent activities which chanced to be profitable to the agent (primary instincts); and, secondly, from the inheritance of habitual activities intelligently acquired. These are the secondary instincts, comprising activities which have become instinctive through lapsed intelligence. In illustration of primary instincts, Mr. Romanes cites the instinct of incubation. "It is quite impossible," he says,[IV] "that any animal can ever have kept its eggs warm with the intelligent purpose of hatching out their contents, so that we can only suppose that the incubating instinct began by warm-blooded animals showing that kind of attention to their eggs which we find to be frequently shown by cold-blooded animals.... Those individuals which most constantly cuddled or brooded over their eggs would, other things equal, have been most successful in rearing progeny; and so the incubating instinct would be developed without there ever having been any intelligence in the matter."
Many of the instincts which exhibit what I have termed above "blind prevision" must, it would seem, belong completely or in the main to this class. The instincts of female insects, which lead them to anticipate by blind prevision the wants of offspring they will never see; the instincts of the caterpillars, which lead them to make provision for the chrysalis or imago condition of which they can have no experience; the instinct of a copepod crustacean, which lays its eggs in a brittle-star, that they may therein develop, probably in the brood-sac, and may even destroy the reproductive powers of the host for the future good of her own offspring—these and many others would seem to have no basis in individual experience.
In illustration of the second class of instincts, those due to lapsed intelligence, Mr. Romanes cites the case of birds living on oceanic islands, which at first show no fear of man, but which acquire in a few generations an instinctive dread of him—for the wildness or tameness may become truly instinctive. "If," says Dr. Rae,[IW] "the eggs of a wild duck are placed with those of a tame one under a hen to be hatched, the ducklings from the former, on the very day they leave the egg, will immediately endeavour to hide themselves, or take to the water if there is any water, should any person approach, whilst the young from the tame duck's eggs will show little or no alarm, indicating in both cases a clear instance of instinct or 'inherited memory.'"