The Fundamental Laws of Human Behavior
Imitation. Auditory and visual imitation at different stages of life. Kinesthetic imitation not inherited; of little importance even when acquired. Emotional reactions. Either contraction or relaxation prevailing in either organic or skeletal muscles. Emotional reactions inherited. Emotional reactions either of direct or of indirect value, for example, as signals for social interaction; especially in primitive man and in animals. Civilized man, deriving little benefit from his emotional reactions, practically unable to control them by experience.
WHILE discussing speech we had to mention the fact that certain activities of the speech organs occurring in response to auditory stimuli have the peculiarity of bringing about sounds very much like those which served as stimuli in. the first place. In any such case where the motor response repeats the stimulation we speak of imitation. "Imitation," therefore, is not the name of a force, but of a mode of reaction. Here the subject has imitated the sound beard. But imitation, of course, is not restricted to auditory stimulation. In auditory stimulation it makes its first appearance as one of the great factors of human education, during the second year of life. Visual imitation attains its maximum of importance about a year later. While auditory imitation plays a part of ever decreasing significance as life advances,
( 197) visual imitation determines our actions in all stages of life. The infant imitates the speech sounds which arc produced by children and older people in his presence. The eight or ten year old child has almost ceased to imitate the speech of others. How slight the tendency to imitate speech has become in grown people, all those know from experience, to their regret, who have ever learned or taught a foreign language. Grown people will do a hundred other things rather than repeat over and over again a phrase just heard, as small children do, — the secret of children's rapid success. It is quite natural, however, that auditory imitation is so strong during the second and the following few years and so weak later. The child must learn to speak early in life, and he learns by imitation. When this is once accomplished, imitation is no longer necessary. Aside from learning, auditory imitation has no value of its own. With visual imitation the case is quite different. It is true that a good many skillful movements may be and are learned by visual imitation; however, the imitative act itself, aside from all learning, has an enormous biological value all through life, in old age no less than in middle age and infancy. When we see a crowd gather on the street, we immediately run to the spot ourselves,—not because we still have to learn how to run to a point seen, but because it is of immense value for our social life to do at any time what we see other people do, exceptions notwithstanding.
There can hardly be any doubt that auditory imitation is largely the result of inheritance. All the elementary sounds are imitated because the necessary paths of small resistance are inherited. The apes, having practically the same vocal organs, do not, in our zoological gardens, acquire human speech, obviously because this factor of nervous inheritance is lacking. One might argue that
( 198) the existence of the so-called "baby talk" demonstrates the importance of experience in auditory imitation. It is true that baby talk is the result of the child's experience, not of his inheritance. But baby talk is not acquired by imitation on the child's part. The infant babbles in response to all kinds of stimulations, auditory or not auditory. The sounds thus produced are imitated by the parents and used by them in the baby's presence with reference to particular situations. The child then learns, by this experience, the meaning created by his parents for these sounds, which are in the main reduplications; that is, he learns to use these simple words in these particular situations,—by imitation on the part of his parents. Thus he acquires the talk peculiar to the nursery. It is clear, then, that the existence of baby talk is no argument in favor of any importance of experience in auditory imitation. Inheritance brings about adequately the imitation of all elementary speech sounds. To combine these elements into complicated groups composed of many successive elementary sounds, requires indeed both experience and reflex imitation on the child's part, —we have studied the process in a previous lecture. The imitation of the elementary sounds, however, is regulated by inherited reflexes.
In visual imitation, on the other hand, there seems to be little dependence on special inherited reflexes. Even the simplest movements which are executed by visual imitation seem to depend on experience. We have discussed in an earlier chapter the simplest reflex movements of the hands and feet. There is in them no imitation of any movement seen. Only when the child begins to make new movements by experience, can imitation be observed. And even in these earliest movements learned by experience there is hardly any imitation. The child
( 199) learns, for example, the upward movement of his hands which we make in order to take a thing from a shelf above, —but not by imitation, as we have found. He learns to creep, to stand, to walk, but not by imitation. It is only after he has acquired these skillful movements of his hands and. feet, that visual imitation becomes conspicuous. Now we observe that the little child, barely able to walk, joins us when we are standing with our back against the wall and takes his place at our side, leaning his back likewise against the wall. Now he puts his hat on when we put our hat on. Now lie places an open book on the music stand of the piano before he strikes the keys with his little fingers, because he has seen us open our music before striking the keys with our fingers. Visual imitation, therefore, depends altogether, or practically altogether, on experience; there is scarcely any inherited visual imitation.
We have discussed auditory imitation and visual imitation. Shall we add, as a third important class, kinesthetic imitation? If we apply the term imitation to every sensori-motor process which brings about directly a repetition of its stimulation, we might speak also of kinesthetic imitation. But whoever would restrict the term to cases where the stimulation results from an extra-corporeal (visible or audible) phenomenon, should not use this phrase, for kinesthetic stimuli are not external, but physiological phenomena. He might then, instead of adding a third class of imitation, speak of circular sensori-motor processes. In an earlier chapter we have already had occasion to mention that circular reactions are of much importance in the acquisition of skillful movements because they hasten, through repetition of the same nervous activity, the establishment of paths of low resistance. The question which interests us here is
( 200) this: Is kinesthetic imitation, if we are permitted to apply the term, largely inherited?
One might: think that the inheritance of kinesthetic imitation, of the occurrence of the motor response in the very muscles in which the sensory excitation occurred, is self-evident from the nature of the case, for two reasons. Did we not state the great importance of kinesthetic excitation for habits of temporally complex, that is, of serial, reactions? Secondly, should not nervous connections of low resistance be inherited between sensory points and motor points located side by side in the body, when many such connections are inherited between widely separated sensory points and motor points? Both these are false arguments. As to the latter, it is clear enough that in the lowest organisms, having no nervous system, the motor response occurs primarily at the point itself which has received the stimulation. It does not follow, however, that after differentiation of the tissues the sensory and motor points, because they are originally identical, must be closely connected by nervous paths. It is true that in the peripheral parts of the body the sensory and motor neurons of the same region usually run parallel in big bundles, the so-called nerves. But within the central nervous system they separate; and they are connected to form short reflex arches only where the functional needs of the organism unite them, as in the case of all other sensory and motor neurons. The former argument has no greater strength. Not everything of great importance is necessarily inherited. Further, in so far as kinesthetic excitation plays a part in the execution of habitual serial reactions, we have no imitation, for each kinesthetic stimulation in a serial reaction brings about a contraction of a new set of muscles, and a different kinesthetic stimulation. On the other hand, where we have repetition of
( 201) a truly inherited sensori-motor process, we have imitation, but it is not kinesthetic. For example, when a child learns to pile up blocks, (compare Lectures 11 and 12) there is a circular reaction,—imitation in so far as the child imitates a model (a block standing) by creating a thing like it ( a block or pile of blocks standing) ; but the stimulation of the circular process is visual, not kinesthetic.
Far from admitting, then, that kinesthetic imitation is largely inherited, we are led to deny almost its very existence, even as acquired by experience. Indeed, if it were inherited, it would greatly retard the acquisition of useful habits of reaction. For example, the child, instead of learning how to build a house of blocks, would continue, through the influence of such imitation, to move his hand up and down in the same manner without being influenced by the fact that blocks other than the one in his hand are lying about. Kinesthetic imitation, if inherited, would reduce man's biological significance to something like that of mechanical toys in a child's world, capable only of performing the same jump in endless repetition. There is little probability, then, that such a function should be acquired during life. Kinesthetic excitation as a biological factor seems to be confined to serial motor activity, consisting in a succession of different acts; there, indeed, kinesthetic excitation is indispensable.
While the larger part, of the motor activity of an animal consists of reactions upon the objects of the environment, brings about, indeed, in the case of visual or auditory imitation, a duplication of an environmental phenomenon, there are also motor activities which do not seem to affect the objects of the environment at all, and directly, most certainly, do not affect them; which are confined to the inner world of the organism. Motor responses of this class are often called emotional reactions. There is an
( 202) enormous literature debating the question what the emotions are aside from these internal reactions of the organism, what they are as purely introspective phenomena. Let us be satisfied with the simple statement that in most, if not all, conditions of animal life which are called emotional, internal reactions occur; and let us, without entering into a discussion of introspective "emotions, " give a broad classification of them and a brief discussion of their biological significance.
In order to understand these internal reactions properly, we have to discuss not only muscular contraction, but also muscular relaxation, and to regard the latter as a factor as positive as the former. Lacking space, we cannot here, and need not for our present purpose, enter into a discussion of the physiological mechanism by which relaxation as well as contraction is brought about. Let us regard either simply as the motor response to a proper excitation of sensory points. We have then at once two large classes of internal reactions, according as relaxation or contraction of the internal organs dominates,—we say "dominates" as it is entirely possible that relaxation of some organs be accompanied by contraction in others. A subdivision of each of these classes is found by reference to the two classes of muscles in our body, the "organic" muscles which perform the mechanical work of our internal organs, and the skeletal muscles which control the position of the members of the body, relative to each other, and their motion. The important fact that in the large majority of all cases of reaction in the organic muscles reactions in the skeletal muscles occur simultaneously, is comprehensible enough. In general, whenever the skeletal muscles tend more than ordinarily to relax, the motion of the body will be unusually weak; and whenever the skeletal muscles tend more than ordinarily to contract,
(203) the motion of the body will be unusually vigorous. Thus we should obtain among those motor responses with which we are at present concerned, four main classes: (1) Relaxation of organic muscles combined with vigorous motion. (2) Contraction of organic muscles combined with vigorous motion. (3) Relaxation of organic muscles combined with weak motion. (4) Contraction of organic muscles combined with weak motion. It is to be understood, however, that in no case do we include all the organic muscles or all the possible motion of the members of the body. Let us see, now, to what extent this classification aids us in characterizing familiar types of emotional reaction in animals and in man.
Unusual contraction or relaxation of the organic muscles becomes apparent chiefly in the blood vessels, the heart, the stomach, the intestine, the bladder, and the skin. If the ring-shaped muscles of the smaller blood vessels relax, the vessels take up a larger amount of blood forced into them by the heart. The skin, containing innumerable small blood vessels, then looks red. Our first class, therefore, is illustrated by a person who looks red, whose skin is warm owing to the presence of a large quantity of warm blood, and whose motion is very vigorous. We recognize in him what we commonly call the emotion of joy or the emotion of anger. Whether we apply the one or the other name, depends on the special situation, which may call forth—so far as the skeletal muscles are concerned—either movements of dancing, shouting, clapping the hands, and the like, or movements of attack. That the sensory excitation caused by the situation affects not only the skeletal muscles, but also such muscles as those in the walls of the blood vessels, is, by the way, a good illustration of the fact which we have previously emphasized, namely, that our nervous system is one, in spite of the
(204) special physiological and anatomical names applied for various reasons to its parts. This unity of the nervous system can also be demonstrated by such a simple experiment as this. Address a person suddenly with the question, "Why do you blush?" The response will consist, of course, in words spoken; but in addition, frequently, the person will be observed to blush, although ordinarily stimulation of the auditory organ is not capable of causing a relaxation of the muscles in the blood vessels of the face.
The situation in question, in which we find that person who looks red, etc., probably causes activities of the skeletal muscles which are of a direct objective purpose, for example, running. But it causes also activities of the skeletal muscles which are of no direct purpose, for example, the tension of the facial muscles, the grinning, of a person in joy or rage, often represented by caricatures like Figure 50. Since all the muscular functions with which we are concerned at present, are inherited, not acquired by experience, we may ask how we can understand the evolution of such seemingly useless reflexes. That in anger, where an animal attacks another animal, or in joy, where an animal applies to good use an object which he has succeeded in obtaining, vigorous motion is biologically of great value, is self-evident. But of what use is grinning?
One answer to the question is this. In anger, grinning may mean simply getting ready to bite, for the mouth is
( 206) an important weapon of attack of animals and of primitive man; and in joy, since the most important article applied to good use is an article of food, grinning may mean simply getting ready to bite off and chew. But it may have still another biological meaning. It may be of indirect value by helping to bring about social interaction—positive or negative, friendly or hostile—through rendering the situation quickly understood by other members of the animal species.
Let us give further examples to illustrate the indirect, purely social, value of movements or attitudes. In an infant the stimulation of hunger may cause reflex movements of the hands upwards, with the result that the fingers get into the mouth and are sucked, or that the finger nails, when the hands are withdrawn, scratch the face. Although these results are directly without any value to the child, they are indirectly of the very greatest value, for their sight stimulates the parents to definite activities, for instance, to providing the necessary food for the baby. A mother describing these reactions would surely say that the baby is "so hungry that he tries to put his hands into his mouth," or "so angry at the delay of his dinner that he scratches himself." This social value s not the least significant explanation of the evolution of reflexes which are directly of little value. There is still left to explain why in situations of joy or anger the blood should rush into the skin. Perhaps this is merely a symptom of the unusually strong circulation of the blood through the whole body, useful for continued activity of the muscles which, for physiological reasons, would soon be incapacitated for work without being washed out constantly by the blood current. But the redness of the skin, just as the tension of the facial muscles, the grinning, has also an indirect value of much importance, a value for social interaction. A red-faced man in a given situation
( 207) causes the situation to impress other men in a way by no means identical with the way in which they are affected by the situation while the man in its center looks pale.
The second chess of these peculiar motor responses was distinguished by contraction of organic muscles combined with vigorous motion. We recognize the symptoms of what is called the emotion of fear. That the stomach, the intestine, the bladder, and other internal organs contract in a fearful situation, that the heart beats with unusual force, is a familiar fact. Contraction of the smaller blood vessels causes the blood to disappear from the skin and the latter to become pale. Contraction of the minute muscle fibers distributed all through the skin, gives it the appearance ordinarily called "goose flesh"; and where the skin is hairy, this contraction causes the hair to "stand on end. " The skin, having lost its blood, cools off, and this cooling in turn calls forth reflexly shivering, the ordinary physiological response to cooling of the skin. The vigorous motion, adapted to the particular situation, shows itself in the individual's running faster than he is ordinarily able to. Vigorous motion, however, is only one external symptom of an extraordinary tendency to contract. Some degrees further, and this tendency results in a cataleptic state, a continuous contraction of all muscles, making all motion impossible. One person or animal responds to a dangerous situation by running, another is "turned into stone."
If we now ask of what biological value these inherited reactions are, we find the answer very readily so far as the extraordinary tendency of the skeletal muscles to contract in response to a dangerous situation is concerned. The faster the animal runs away from the dangerous situation, the safer it is. On the other hand, if the muscular contraction progresses up to the cataleptic, perfectly
( 208) motionless, state of the body, the animal is again relatively safe in case the danger comes from another animal being in the neighborhood, owing to the fact that a motionless body is less readily perceived by the eye — not to speak at all of the ear—than a moving body. Many species of birds and small mammals can be observed to assume this motionless attitude when surprised by a man or a hostile animal, especially when the dangerous being is not yet so near that the exposed animal is within direct reach. Many a hunted animal escapes the hunter by this mode of reflex reaction.
Why the organic muscles should tend to contract, however, is less clear. Apparently, their contraction in a dangerous situation can be of no direct value. A certain amount of indirect value, on the other hand, with respect to social interaction, is obvious, especially when the exposed animal is in the cataleptic state. The skin having lost its blood, the exposed animal resembles more nearly a dead animal; and this resemblance may save it. For example, it is reported that certain bears will leave a seemingly dead man's body unmolested; not to reiterate the anecdotes of hunters who gave no attention to an animal whose possession they felt sure of, because it was already dead, but who discovered suddenly that it had run away. Even an animal being chased by another may appear more formidable than it really is, on account of its fur or feathers standing on end, or may retard the enemy by the ejection of disgusting substances.
Our third class of responses was distinguished by relaxation of organic muscles combined with weak motion. This is of all the four classes the least important one. We experience it after having eaten a hearty dinner,—but this is not everyone's habitual occupation. Of vast importance is the fourth class, distinguished by contraction of organic
(208) muscles combined with weak motion. It is exactly the opposite of the first class (joy) and is, indeed, the reaction to any kind of disappointment,—what we most commonly call the emotion of sorrow. We can at once derive the symptoms and comprehend the biological value of this reaction if we recall that in animal life and in the life of primitive man the most ordinary kind of disappointment consists in the want of food. Imagine a winter month: every article which might serve as food covered by snow and impossible to find, for weeks or longer, until the weather changes. An animal which, under these circumstances, would continue to run about for food, would soon fall dead from exhaustion. However adverse the situation, the body can survive living on the substances stored away in its own tissues, if it only consumes this limited supply economically. For this the first requirement is that all muscular activity be reduced to a minimum. Thus we understand why the nervous system in a disappointing situation, tends to leave the skeletal' muscles in a state of relaxation. A person in great sorrow is so far from being master of his skeletal muscles that he drops as if he were completely paralyzed, like Romeo in Friar Laurence's cell:
"Wert thou as young as I, Juliet thy love,
An hour but married, Tybalt murdered,
Doting like me, and like me banished,
Then mightst thou speak, then mightst thou tear thy hair,
And fall upon the ground, as I do now,
Taking the measure of an unmade grave."
A disappointed person looks like Figure 51 (the opposite of Figure 50), since the relaxation of the facial muscles causes the angles of the mouth to be pulled down by the weight of the lower jaw.
Why should the nervous system, in a disappointing situation, tend to cause contraction of the organic muscles? Recall the animal just spoken of, disappointed in its food supply. If it does not exercise its muscles, little or no heat is produced, for the skeletal muscles are, physiologically, the very furnaces of the body. If little heat is produced, the loss of heat must be safeguarded against. Thus the biological value of the contraction of the muscles in the walls of the blood vessels becomes evident. The
contraction of the vessels prevents the blood from circulating much in the periphery of the body where cooling mainly takes place. The cooling by the conduction of heat through the tissues covering the body is little to be feared as long as the warm blood is kept in the inner parts of the body and prevented from circulating through the periphery. The actual cooling of the skin, exciting the sensory points of the skin, causes the reflex and habitual response of the animal's seeking shelter, again reducing the loss of heat, of physiological energy. Thus contraction of the organic muscles keeps the animal alive until a change of the external conditions enables it to resume its ordinary manner of life.
Less plain than these reflexes seems the fact that often a disappointed person weeps. From our statements thus far one should rather expect a person in joy to weep, provided we derive weeping from an unusual
( 210) blood pressure in the lacrimal glands, an unusual fulness of the blood vessels owing to the relaxation of the organic muscles. Indeed, people weep when joy reaches a high degree. That people weep in disappointment becomes plain when we recall the generally accepted notion that weeping gives relief from excessive sorrow. Only we should rather say: when the nervous system, through normal exhaustion, commences to respond to the disappointing situation less excessively, then weeping occurs. The tears here are actually not a cause, but an effect of relief. The organic muscles, excessively contracted for some time, at the moment when exhaustion of the nervous system commences, relax completely and the blood pressure in the lacrimal glands suddenly rises far beyond the normal.
All these responses of the organic muscles, with or without simultaneous activities of the skeletal muscles, of which we have discussed here only those which can be most easily classified, are the result of nervous connections between certain sensory and certain motor points and group formation among these connections, inherited by each individual of the species. The extent to which they can be modified by experience is slight., almost zero. This is, perhaps, to be regretted, since in the life of modern civilized man they have largely lost the biological usefulness attributable to them under primitive conditions of social life. Nevertheless, however advanced the present evolution of man's nervous system, in his inability to control these responses by experience, man practically shares the fate of the animals