Part 2 (1/2)
This theory has much to commend it. It certainly meets the objection to the reflex theory which was stated just above--the objection that some of the instincts could not have arisen by gradual reflex adaptations. It also accounts for the extremely intelligent appearance which many instincts have.
But this view in turn is liable to a criticism which has grown in force with the progress of biological knowledge in recent years. This criticism is based on the fact that the theory of lapsed intelligence demands that the actions which the animals of one generation have acquired by their intelligence should be handed down through heredity to the next generation, and so on. It is evident that unless this be true it does no good to the species for one generation to do things intelligently, seeing that if the effects on the nervous system are not transmitted to their children, then the next and later generations will have to start exactly where their fathers did, and the actions in question will never become ingrained in the nervous system at all.
Now, the force of this criticism is overwhelming to those who believe--as the great majority of biologists now do[1]--that none of the modifications or so-called ”characters” acquired by the parents, none of the effects of use or disuse of their limbs, none of the tendencies or habits of action, in short, none of the changes wrought in body or mind of the parents during their lifetime, are inherited by their children. The only sorts of modification which show themselves in subsequent generations are the deep-seated effects of disease, poison, starvation, and other causes which concern the system as a whole, but which show no tendency to reproduce by heredity any of the special actions or functions which the fathers and mothers may have learned and practised. If this difficulty could be met, the theory that intelligence has been at work in the origination of the complex instincts would be altogether the preferable one of the two; but if not, then the ”lapsed intelligence” view must be thrown overboard.
[Footnote 1: The matter is still under discussion, however, and I do not mean in any way to deny the authority of those who still accept the ”inheritance of acquired characters.”]
Recent discussion of evolution has brought out a point of view under the name of Organic Selection which has a very fruitful application to this controversy over the origin of instincts. This point of view is one which in a measure reconciles the two theories. It claims that it is possible for the intelligent adaptations, or any sort of ”accommodations,” made by the individuals of one generation, to set the direction of subsequent evolution, even though there be no direct inheritance of acquired characters from father to son. It proceeds in the case of instinct somewhat thus:
Suppose we say, with the first theory given above, that the organism has certain reflexes which show some degree of adaptation to the environment; then suppose we admit the point, urged by the advocates of the lapsed intelligence theory, that the gradual improvement of these reflexes by variations in the endowment of successive generations would not suffice for the origin of instinct, seeing that partial instincts would not be useful; and, further, suppose we agree that many of the complex instincts really involved intelligent adaptation in their acquisition. These points carefully understood, then one new and further principle will enable us to complete a theory which will avoid the objections to both the others. This principle is nothing else than what we have seen already--namely, that the intelligence supplements the partial instincts in each generation and makes them useful in the respects in which they are inadequate, and so keeps the young alive in successive generations as long as the instinct is imperfect. This gives the species time gradually to supplement its instinctive endowment, in the course of many generations each of which uses its intelligence in the same way: time to acc.u.mulate, by the occurrence of variations among the offspring, the changes in the nervous system which the perfect instinct requires.
Thus as time goes on the dependence of each generation upon the aid of intelligence is less and less, until the nervous system becomes capable of performing the function quite alone. The result then will be the same as if the acquisitions made by each generation had been inherited, while in reality they have not. All that this theory requires in addition to what is admitted by both the historical views is that the species be kept alive long enough by the aid of its intelligence, which supplements imperfect instincts, to give it time to produce sufficient variations in the right direction. The instinct then achieves its independence, and intelligent supervision of it is no longer necessary (see Fig. 1).
[Ill.u.s.tration: FIG. 1,--Origin of instinct by Organic Selection: _A n_, perfect instinct. 1, 2 ... _n_, successive generations. Solid lines, nervous equipment in the direction of the instinct. Dotted lines, intelligence supplementing the nervous equipment. The intelligence is relied upon to keep the species alive until by congenital variations the nervous equipment becomes ”perfect.”]
This theory is directly confirmed by the facts, already spoken of, which show that many instincts are imperfect, but are pieced out and made effective by the intelligent imitations and acquisitions of the young creatures. The little chick, for example, does not know the value of water when he sees it, as essential as water is to his life; but he depends upon imitation of his mother's drinking, or upon the mere accident of wetting his bill, to stimulate his partial instinct of drinking in the peculiar fas.h.i.+on characteristic of fowls, by throwing back the head. So in other functions which are peculiar to a species and upon which their very lives depend, we find the delicate adjustment between intelligent adaptation by conscious action and the partially formed instincts which the creatures possess.
In the theory of Organic Selection, therefore, we seem to have a positive solution of the question of the origin of instinct. It is capable of a similar application in other cases where evolution has taken certain definite directions, seemingly guided by intelligence.
It shows us that mind has had a positive place in the evolution of organic nature.
_Animal Intelligence._--Coming to consider what further equipment the animals have, we light upon the fact just spoken of when we found it necessary to appeal in some measure to the animal's Intelligence to supplement his instincts. What is meant by Intelligence?
This word may be used in the broad sense of denoting all use of consciousness, or mind, considered as a thing in some way additional to the reflexes of the nervous system. In the life of the animal, as in that of man, wherever we find the individual doing anything with reference to a mental picture, using knowledge or experience in any form, then he is said to be acting intelligently.
The simplest form of intelligent action in the animal world and that from which most of the higher forms have arisen is ill.u.s.trated in the following example: a chick will peck at a strange worm, and, finding it unpalatable, will then in the future refuse to peck at worms of that sort. This refusal to do a second time what has once had a disagreeable result is intelligent. We now say that the chick ”knows”
that the worm is not good to eat. The instinctive action of pecking at all worms is replaced by a refusal to peck at certain worms. Again, taking the reverse case, we find that the chick which did not respond to the sight of drinking water instinctively, but had to see the mother drink first, acted intelligently, or through a state of consciousness, when it imitated the old hen, and afterward drank of its own accord. It now ”knows” that water is the thing to drink.
The further question which comes upon us here concerns the animal's acquisition of the action appropriate to carry out his knowledge. How does he learn the muscular combinations which supplement or replace the earlier instinctive ways of acting?
This question appears very clearly when we ask about the child's acquisition of new acts of skill. We find him constantly learning, modifying his habits, refining his ways of doing things, becoming possessed of quite new and complex functions, such as speech, handwriting, etc. All these are intelligent activities; they are learned very gradually and with much effort and pains. It is one of the most important and interesting questions of all psychology to ask how he manages to bring the nervous and muscular systems under greater and greater control by his mind. How can he modify and gradually improve his ”reactions”--as we call his responses to the things and situations about him--so as to act more and more intelligently?
The answer seems to be that he proceeds by what has been called Experimenting. He does not simply do things because he has intelligence,--simply that is, because he sees how to do them without first learning how; that is the older and probably quite erroneous view of intelligence. The mind can not move the body simply by its fiat. No man can do that. Man, like the little animal, has to try things and keep on trying things, in order to find out the way they work and what their possibilities are. And each animal, man, beast, or bird has to do it for himself. Apart from the instinctive actions which the child does without knowing their value at all, and apart from the equally instinctive imitative way of doing them without aiming at learning more by the imitations, he proceeds in all cases to make experiments. Generally his experiments work through acts of imitation. He imitates what he sees some other creature do; or he imitates his own instinctive actions by setting up before him in his mind the memories of the earlier performance; or, yet again, after he has struck a fortunate combination, he repeats that imitatively. Thus, by the principle already spoken of, he stores up a great ma.s.s of Kinaesthetic Equivalents, which linger in memory, and enable him to act appropriately when the proper circ.u.mstances come in his way. He also gets what we have called a.s.sociations established between the acts and the pleasure or pain which they give, and so avoids the painful and repeats the pleasurable ones.
The most fruitful field of this sort of imitative learning is in connection with the ”try-try-again” struggles of the young, especially children. This is called Persistent Imitation. The child sees before him some action to imitate--some complex act of manipulation with the hand, let us say. He tries to perform it in an experimental way, using the muscles of the hand and arm. With this he strains himself all over, twisting his tongue, bending his body, and grimacing from head to foot, so to speak. Thus he gets a certain way toward the correct result, but very crudely and inexactly. Then he tries again, proceeding now on the knowledge which the first effort gave him; and his trial is less uncouth because he now suppresses some of the hindering grimacing movements and retains the ones which he sees to be most nearly correct. Again he tries, and again, persistently but gradually reducing the blundering movements to the pattern of the copy, and so learning to perform the act of skill.
The ma.s.sive and diffused movements which he makes by wriggling and fussing are also of direct use to him. They increase remarkably the chances that among them all there will be some movements which will hit the mark, and so contribute to his stock of correct Equivalents.
Dogs and monkeys learn to unlock doors, let down fence rails, and perform relatively complex actions by experimenting; persistently with many varied movements until the successful ones are finally struck.
This is the type of all those acts of experimenting by which new complex movements are acquired. In children it proceeds largely without interference from others; the child persists of himself. He has greater ability than the animals to see the meaning of the completed act and to really desire to acquire it. With the animals the acquisitions do not extend very far, on account of their limitation in intelligent endowment; but in the training of the domestic animals and in the education of show-animals the trainer aids them and urges them on by making use of the a.s.sociations of pleasure and pain spoken of above. He supplements the animal's feelings of pain and pleasure with the whip and with rewards of food, etc., so that each step of the animal's success or failure has acute a.s.sociations with pain or pleasure. Thus the animal gradually gets a number of a.s.sociations formed, avoids the actions with which pain is a.s.sociated, repeats those which call up memories of pleasure all the way through an extended performance in regular steps; and in the result the performance so closely counterfeits the operations of high intelligence--such as counting, drawing cards, etc.--that the audience is excited to admiration.
This first glimpse of the animal's limitations when compared with man may suggest the general question, how far the brutes go in their intelligent endowment. The proper treatment of this much-debated point requires certain further explanations.
In the child we find a tendency to act in certain ways toward all objects, events, etc., which are in any respect alike. After learning to use the hands, for example, for a certain act, the same hand movements are afterward used for other similar acts which the child finds it well to perform. He thus tends, as psychologists say, to ”generalize,” that is, to take up certain general att.i.tudes which will answer for a great many details of experience. On the side of the reception of his items of knowledge this was called a.s.similation, as will be remembered. This saves him enormous trouble and risk; for as soon as an object or situation presents itself before him with certain general aspects, he can at once take up the att.i.tude appropriate to these general aspects without waiting to learn the particular features of the new. The ability to do this shows itself in two rather different ways which seem respectively to characterize man on the one hand and the lower animals on the other.
With the animals this tendency to generalize, to treat objects in cla.s.ses rather than as individuals, takes the form of a sort of composition or direct union of brain pathways. Different experiences are had, and then because they are alike they tend to issue in the same channels of action. The animal is tied down strictly to his experience; he does not antic.i.p.ate to any extent what is going to happen. He does not use one experience as a symbol and apply it beforehand to other things and events. He is in a sense pa.s.sive; stimulations rain down upon him, and force him into certain att.i.tudes and ways of action. As far as his knowledge is ”general” it is called a Recept. A dog has a Recept of the whip; so far as whips are not too different from one another, the dog will act in the same way toward all of them. In man, on the other hand, the development of mind has gone a decided step further. The child very quickly begins to use symbols, words being the symbols of first importance to him. He does not have, like the brute, to wait for successive experiences of like objects to impress themselves upon him; but he goes out toward the new, expecting it to be like the old, and so acting as to antic.i.p.ate it. He thus falls naturally into general ways of acting which it is the function of experience to refine and distinguish. He seems to have more of the higher sort of what was called above Apperception, as opposed to the more concrete and accidental a.s.sociations of Ideas. He gets Concepts, as opposed to the Recepts of the animals. With this goes the development of speech, which some psychologists consider the source of all the man's superiority over the animals. Words become symbols of a highly abstract sort for certain cla.s.ses of experiences; and, moreover, through speech a means of social communication is afforded by which the development of the individual is enormously advanced.
It is probable, in fact, that this difference--that between the Generalization which uses symbols, and mere a.s.sociation--is the root of all the differences that follow later on, and give man the magnificent advantage over the animals which he has. From it is developed the faculty of thinking, reasoning, etc., in which man stands practically alone. On the brain side, it requires special developments both through the preparation of certain brain centres given over to the speech function, and also through the greater organization of the gray matter of the cerebral cortex, to which we revert again in a later chapter. Indeed, looked at from the side of the development of the brain, we see that there is no break between man and the animals in the laws of organization, but that the difference is one of evolution.
Later on in the life of the child we find another contrast connected with the difference of social life and organization as between the animals and man. The animals probably do not have a highly organized sense of Self as man does; and the reason doubtless is that such a Self-consciousness is the outcome of life and experience in the very complex social relations in which the human child is brought up, and which he alone is fitted by his inherited gifts to sustain.
_The Play of Animals._--Another of the most interesting questions of animal life is that which concerns their plays. Most animals are given to play. Indeed that they indulge in a remarkable variety of sports is well known even to the novice in the study of their habits. Beginning when very young, they gambol, tussle, leap, and run together, chase one another, play with inanimate objects, as the kitten with the ball, join in the games of children and adults, as the dog which plays hide and seek with his little master, and all with a knowingness and zest which makes them the best of companions. The volumes devoted to the subject give full accounts of these plays of animals, and we need not repeat them; the psychologist is interested, however, mainly in the general function of play in the life of the individual animal and child, and in the psychological states and motives which it reveals.