The Atlantic Monthly, Volume 05, No. 31, May, 1860

INSTINCT

"Instinct is a great matter," quoth Falstaff, when called upon to find out a device, a "starting-hole," to hide himself from the open and apparent shame of having run away from the fight and hacked his sword like a handsaw with his own dagger. Like a valiant lion, he would not turn upon the true prince, but ran away upon instinct. Although the peculiar circumstances of the occasion upon which the subject was presented to Falstaff's mind were not very favorable to a calm consideration of it, he was undoubtedly correct in saying that instinct is a great matter. "If, then, the tree may be known by the fruit," says Falstaff, "as the fruit by the tree, then, peremptorily I speak it, there is virtue in that Falstaff"; and it is proper that his authority should be quoted, even upon a question of metaphysical science.

That psychological endowment of animals which we denominate instinct has in every age been a matter full of wonder; and men of thought have found few more interesting subjects of inquiry. But it is confessed that little has been satisfactorily made out concerning the nature and limitations of instinct. In former times the habits and mental characteristics of those orders of animated being which are inferior to man were observed with but a careless eye; and it was late before the phenomena of animal life received a careful and reverent examination. It is vain to inquire what instinct is, before there has been an accurate observation of its manifestations. It is only from its outward manifestations that we can know anything of that marvellous inward nature which is given to animals. We cannot know anything of the essential constitution of mind, but can know only its properties. This is all we know even of matter. "If material existence," says Sir William Hamilton, "could exhibit ten thousand phenomena, and if we possessed ten thousand senses to apprehend these ten thousand phenomena of material existence, of existence absolutely and in itself we should be then as ignorant as we are at present." But this limitation of human knowledge has not always been kept in view. Men have been solicitous to penetrate into the higher mysteries of absolute and essential existence. But in thus reaching out after the unattainable, we have often passed by the only knowledge which it was possible for us to gain. Much vague speculation concerning instinct has arisen from the attempt to resolve the problem of its ultimate nature; and perhaps much more might have been made out with certainty about it, if no greater task had been attempted than to classify the phenomena which it exhibits and determine the nature of its manifestations. In regard to instinct, as well as everything else, we must be content with finding out what it seems to us to be, rather than what it is. Even with this limitation, the inquiry will prove sufficiently difficult. The properties of instinct are a little more inscrutable than those of the human mind, inasmuch as we have our own consciousness to assist us in this case, while we are left to infer the peculiarities of instinct from its outward manifestations only. And moreover, the inquiry involves an understanding of the workings of the human mind; for it is only when viewed in contrast with the rational endowments of man that the character of instinct is best known. All other questions connected with the subject are subordinate to this one of the apparent difference between instinct and reason.

Many definitions have been given of instinctive actions. These differ widely in their extent, and are for the most part quite inadequate. Some writers have ranged under this term all those customary habits and actions which are common to all the individuals of a species. According to this definition, almost every action of animated life is instinctive. But the general idea of an instinctive action is much more restricted; it is one that is performed without instruction and prior to experience,—and not for the immediate gratification of the agent, but only as the means for the attainment of some ulterior end. To apply the term instinct to the regular and involuntary movements of the bodily organs, such as the beating of the heart and the action of the organs of respiration, is manifestly an extension of the ordinary acceptation of the term. Organic actions of a similar character are also performed by plants, and are purely mechanical. "In the lowest and simplest class of excited movements," says Müller, "the nervous system would not appear to be concerned. They result from stimuli directly applied to the muscles, which immediately excite their contractility; and they are evidently of the same character with the motions of plants." Thus, the heart is excited to pulsation by the direct contact of the blood with the muscle. The hand of a sleeping child closes upon any object which gently touches the palm. And it is in this way, doubtless, that the Sea Anemone entraps its prey, or anything else that may come in contact with its tentacles. But so far are these movements from indicating of themselves the action of any instinctive principle, that they are no proof of animality; for a precisely analogous power is possessed by the sensitive plant known as the Fly-Trap of Venus (Dionoea muscipula): "any insect touching the sensitive hairs on the surface of its leaf instantly causes the leaf to shut up and enclose the insect, as in a trap; nor is this all; a mucilaginous secretion acts like a gastric juice on the captive, digests it, and renders it assimilable by the plant, which thus feeds on the victim, as the Actinea feeds on the Annelid or Crustacean it may entrap." In the animal organization a large class of reflex actions are excited, not by a direct influence, but indirectly by the agency of the nerves and spinal cord. Such actions are essentially independent of the brain; for they occur in animals which have no brain, and in those whose brain has been removed. However marvellous these functions of organic life may be, there is nothing in them at all resembling that agency properly called instinct, which may be said to take the place in the inferior tribes of reason in man. To refer these operations to the same source as the wonderful instinct that guides the bird in its long migratory flight, or in the construction of its nest, would be to make the bird a curiously constructed machine which is operated by impressions from without upon its sentient nerves.

Those actions have sometimes been called instinctive which arise from the appetites and passions; and they have been referred to instinct, doubtless, because they have one characteristic of instinct,—that they are not acquired by experience or instruction. "But they differ," says Professor Bowen, "at least in one important respect from those instincts of the lower animals which are usually contrasted with human reason. The objects towards which they are directed are prized for their own sake; they are sought as ends; while instinct teaches brutes to do many things which are needed only as means for the attainment of some ulterior purpose." When the butterfly extracts the nectar from the flowers which she loves most, she meets a want of her physical nature which demands satisfaction at the moment; but when, in opposition to her appetite, she proceeds to the flowerless shrub to deposit her eggs upon the leaves best suited to support her unthought-of progeny, she is not influenced by any desire for the immediate gratification of her senses, but is led to the act by some dim impulse, in order that an ultimate object may be provided for to which she has no reference at the time. We are surprised to find it declared, in the very interesting "Psychological Inquiries" of Sir B.C. Brodie, that the desire for food is the simplest form of an instinct, and that such an instinct goes far towards explaining others which are more complicated. It is true that the appetites and passions of animals have an ultimate object, but they are impelled to action by a desire for immediate gratification only; but when we speak of an instinct, we mean something more than a mere want or desire,—we have chiefly in view the end beyond the blind instrumentality by which it is reached.

When we watch the movements of a young bee, as it first goes forth from its waxen cradle, we are forced to recognize an influence at work which is unlike reason, and which is neither appetite nor any mechanical principle of organic life. Rising upon the comb, and holding steadily with its tiny feet, with admirable adroitness the young bee smooths its wings for its first flight, and rubs its body with its fore legs and antennae; then walking along the comb to the mouth of the hive, it mounts into the air, flies forth into the fields, alights upon the proper flowers, extracts their juices, collects their pollen, and, kneading it into little balls, deposits them in the sacks upon its feet; and then returning to its hive, it delivers up the honey and the wax and the bread which it has gathered and elaborated. In the hive it works the wax with its paws and feelers into an hexagonal cell with a rhomboidal bottom, the three plates of which form such angles with each other as require the least wax and space in the construction of the cell. All these complex operations the bee performs as adroitly, on the first morning of its life, as the most experienced workman in the hive. The tyro gatherer sought the flowery fields upon untried wings, and returned to its home from this first expedition with unerring flight by the most direct course through the trackless air.

This is one instance of that great class of actions which are allowed on all hands to be strictly instinctive. In the fact, that the occult faculties which urge the bee to make honey and construct geometrical cells are in complete development when it first emerges from its cell, we recognize one of the most striking characteristics of instinct,—its existence prior to all experience or instruction. The insect tribes furnish us with many instances in which the young being never sees its parents, and therefore all possibility of its profiting from their instructions or of its imitating their actions is cut off. The solitary wasp, for example, is accustomed to construct a tunnelled nest in which she deposits her eggs and then brings a number of living caterpillars and places them in a hole which she has made above each egg; being very careful to furnish just caterpillars enough to maintain the young worm from the time of its exclusion from the egg till it can provide for itself, and to place them so as to be readily accessible the moment food is required. But what is most curious of all is the fact that the wasp does not deposit the caterpillars unhurt, for thus they would disturb or perhaps destroy the young; nor does she sting them to death, for thus they would soon be in no state of proper preservation; but, as if understanding these contingencies, she inflicts a disabling wound. Yet the wasp does not feed upon caterpillars herself, nor has she ever seen a wasp provide them for her future offspring. She has never seen a worm such as will spring from her egg, nor can she know that her egg will produce a worm; and besides, she herself will be dead long before the unknown worm can be in existence. Therefore she works blindly; without knowing that her work is to subserve any useful purpose, she works to a purpose both definite and important; and her acts are uniform with those of all solitary wasps that have lived before her or that will live after her; so that we are compelled to refer these untaught actions to some constant impulse connected with the special organization of the wasp,—an innate tact, uniform throughout the species, of which we, not possessing anything of the kind, can form only a poor conception, but which we call instinct.

There have been some philosophers, however, who have exercised their ingenuity in tracing so-called instinctive actions to the operation of experience. The celebrated Doctor Erasmus Darwin gave, as an illustration of this view, his opinion that the young of animals know how to swallow from their experience of swallowing in utero. Without going into any refutation of this position, we would only remark, in passing, that the act of swallowing is not an instinctive action at all, but a purely mechanical one. Would not Doctor Darwin have rejoiced greatly, if he could have brought to the support of his theory the observation of our own great naturalist, Agassiz, who, knowing the savage snap of one of the large, full-grown Testudinata, is said to have asserted, that, under the microscope, he has seen the juvenile turtle snapping precociously in embryo?

But not only is instinct prior to all experience, it is even superior to it, and often leads animals to disregard it,—the spontaneous impulse which Nature has given them being their best guide. The carrier-pigeon or the bird of passage, taken a long distance from home by a circuitous route, trusting to this "pilot-sense," flies back in a straight course; and the hound takes the shortest way home through fields where he has never previously set foot.

The existence of instinct prior to all experience or instruction, and its perfection in the beginning, render cultivation and improvement not only unnecessary, but impossible. As it is with the individual, so it is with the race. One generation of the irrational tribes does not improve upon the preceding or educate its successor. The web which you watched the spider weaving in your open window last summer, carefully measuring off each radius of her wheel and each circular mesh by one of her legs, was just such a web as the spider wove of old when she was pronounced to be "little upon the earth, yet exceeding wise."

This incapacity for education is what so widely separates instinct from the rational powers of man. Man gathers knowledge and transmits it from generation to generation. He is not born with a ready skill, but with a capacity for it. His mind is formed destitute of all connate knowledge, that it may acquire the knowledge of all things. "Man's imperfection at his nativity is his perfection; while the perfection of brutes at their nativity is their imperfection." No rational being has ever arrived at such perfection that he cannot still improve; he can travel on from one attainment to another in a perpetual progress of improvement. He is, moreover, free to choose his own path of action; while the being of instinct is governed by a power which is not subject to his will, and which confines him to a narrow path which he cannot leave. But instinct, within its narrow limits, in many cases quite transcends reason in its achievements.

Perhaps man has never made a structure as perfect in all its adaptations as the honeycomb. Yet when Virgil spoke of the belief that bees have a portion of the mind divine, nothing was known of the wonderful mathematical properties of this beautiful fabric; and the demonstration of them which has been made within the present century is beyond the comprehension of far the larger part of mankind. If the bee comprehended the problem which it has been working out for these many ages before man was able to solve it, would its intellectual powers be inferior to his in degree, if they were the same in kind? The water-spider weaves for herself a cocoon, makes it impervious to water, and fastens it by loose threads to the leaves of plants growing at the bottom of a still pool. She carries down air in a bag made for this purpose, till the water is expelled from the cell through the opening below. The spider lived quite dry in her little air-chamber beneath the water ages before the diving-bell was invented; but that she understood anything of the doctrines of space and gravity, no one would venture to assert.

It has been the belief of some philosophers, and poets as well, that man has taken the hint for some of the arts he now practises from the brute creation. Democritus represents him as having derived the arts of weaving and sewing from the spider, and the art of building of tempered clay from the swallow; and we also read in Pliny's "Natural History," that the nest of the swallow suggested to Toxius, the son of Coelus, the invention of mortar. According to Lucretius, men learned music from the song of birds, and Pope describes them as learning from the mole to plough, from the nautilus to sail, and from bees and ants to form a political community. Perhaps we were behind the beaver in felling timber, in leading dams across rivers, and in building cabin villages,—behind the wasp in making paper, and behind the squirrel and spider in crossing streams upon rafts. So, if man had needed any example of war and violence and wrong, he had only to go to the ant-hill and see the red ants invade the camps of the black and bear off their little negro prisoners into slavery.

Whatever truth there may be in these ideas, it is at least conceivable that man may have profited from the example of these animals. He has copied from patterns set by Nature in tree and leaf and flower and plant; he has formed the Gothic arch and column from the trunks and interlacing boughs of the lofty avenue, the Corinthian capital from the acanthus foliage embracing a basket, and classic urns and vases from flowers. But no one could describe one species of the brute world as having derived a similar lesson from another, and much less from trees and plants. No species of animals has learnt anything new even from man, except within the narrow sphere of domestication.

It is only in particulars that instinct appears superior to reason in the works it achieves. When an animal is taken, ever so little, out of the ordinary circumstances in which its instincts act, it is apt to behave very foolishly. If a woodpecker's egg is hatched by a bird which builds an open nest upon the branches of a tree, when the young bird is grown large enough to shuffle about in the nest, induced by its instinct to suppose that its nest is in a hole walled round on all sides by the tree, with a long, narrow entrance down from above, it does not see that it has been inducted into the open nest of another bird, and is sure to tumble out. The bee and the ant, in a few particulars, show wonderful sagacity; but remove them from the narrow compass of their instincts, and all their wisdom is at an end. That animals are so wise in a few things and so wanting in wisdom in all others shows that they are endowed with a mental principle essentially of a different nature from that of the human race. "They do many things even better than ourselves," says Descartes; "but this does not prove them to be endowed with reason, for this would prove them to have more reason than we have, and that they should excel us in all other things also"; for reason can act not only in one direction, but in all.

But it will be said that instinct is not invariable,—that it often displays a capacity of accommodating itself, like reason, to circumstances, and is therefore a principle the same in kind with it,—or else that the animal has something of the rational faculty superadded to the instinctive. But does the animal make these variations in its conduct from a true perception of their meaning and purpose?

It is very natural for us to ascribe to reason those actions of other animals which would be ascribable to reason, if performed by man. "If," says Keller, (an old German writer,) "the fly be enabled to choose the place which suits her best for the deposition of her eggs, (as, for instance, in my sugar-basin, in which I placed a quantity of decaying wheat,) she takes a correct survey of every part and selects that in which she believes her ova will be the best preserved and her young ones well cared for." The fly, in this instance, apparently exercises an intelligent choice; but does any one doubt that the selection she makes is determined wholly by a blind, uncalculating instinct? The beaver selects a site for his dam at a place where the depth, width, and rapidity of the stream are most fit. There is a tree upon the bank, and food and materials for his work in the vicinity. If a man should attempt to build a beaver's dam, he would abstractly consider all these elements of fitness. The outward manifestations of the quality of abstraction are equally observable in either case. But we must not hastily conclude, because the beaver in one instance acts in a manner apparently reasonable, that he has any reason of his own; for, when we come to study the habits of this animal, we find that he displays all the characteristics of the instinctive principle. If animals are endowed with instincts which apparently act so much like reason in the ordinary course of their operations, we should not at once conclude that there is any need of endowing them with a modicum of reason to account for their deviations from this course, which do not outwardly resemble the acts of reason any more strongly. And besides, it is said, that, if we refer the variations to an intelligent principle, we must refer the ordinary conduct to the same principle. To use an old illustration,—if a bird is reasonable and intelligent, when, on perceiving the swollen waters of the stream approach her half-finished nest, she builds higher up the bank, she was intelligent while making her first nest, and was always intelligent; for how otherwise, it is asked, could she know when to lay down instinct and take up reason?

Instinct aims at certain definite ends; but these ends cannot always be reached by the same means, especially when places and circumstances are not the same. Accommodation is necessary, or it could not always produce the effects for which it is intended. Would the instinct of the spider be complete, if, after it has guided her to spin a web so neat and trim and regular, it did not also lead her to repair her broken snare, when the cords have been sundered by the struggles of some powerful captive? But this pliancy of the spider's instinct is no more remarkable than the contingent operation of the instincts of many species of animals. "It is remarkable," says Kirby, "that many of the insects which are occasionally observed to emigrate are not usually social animals, but seem to congregate, like swallows, merely for the purpose of emigration." When certain rare emergencies occur, which render it necessary for the insects to migrate, a contingent instinct develops itself, and renders an unsocial species gregarious.

It is probable that most of our domesticated species, exhibiting as they do in that condition attainments foreign to their natural habits and faculties in a wild state, were endowed with provisional instincts with a view to their association with man. But generally the docility of animals does not extend to attainments which are radically different from their habits and faculties in a wild state. Casual acquirements, which have no relation to their exigencies in their natural condition, never become hereditary, and are not, therefore, instinctive. A young pointer-dog, which has never been in the fields before, will not only point at a covey of partridges, but will remain motionless, like a well-trained dog. The fact that the sagacity of the pointer is hereditary shows that it is the development of an instinctive propensity; for simple knowledge is not transmitted by blood from one generation to another. We have heard of a pig that pointed game, and of another that was learned in letters; but we ascertain in every such instance that their foreign acquirements do not reappear in their progeny, but end with the pupils of the time being. The pig's peculiarity of pointing did not arise from the development of a provisional instinct, because it does not become hereditary; but the same act in the pointer-dog is instinctive,—for, when once brought out by associating with man, it has remained with the breed, being a part of the animal's nature, which existed in embryo till it was developed by a companionship with man, for whose use this faculty was alone intended.

Although the animals which especially display these exceptional or contingent instincts are those which are fitted for the use and comfort of man and may be domesticated, it is doubtless true that many other species are in some degree provided with them, and that they thus have a plasticity in their nature which enables them to exercise, under particular circumstances, unlooked-for attention, foresight, and caution. And besides, it is only in analogy with the laws of the physical world that instinct should admit of a slightly diversified application.