The Fundamental Laws of Human Behavior
Control of the feet. The ability to walk equal to rising plus balancing. Reflex of straightening the leg. Reflex of squatting. Balancing with hand support preceding free balancing. Balancing on one leg preceded by balancing on both. Walking not a simple instinct, but a compound of reflexes united largely by experience. Balancing sideways preceding balancing fore and aft. Stretching the foot reflexly toward a thing which impresses the eye. Locomotion resulting from this reflex. Creeping. Creeping on two legs preceded by creeping on one. Influences of creeping on walking. Sitting up. Finger-sucking superceded by other habits. Free standing rarely preceded by walking. One-sidedness and general clumsiness of first walking. Encouraging a child to stand: a purely negative event. The so-called instincts of constructiveness and destructiveness: rather habits.
WHATEVER may be—practically and scientifically—the relative importance of arms and legs, hands and feet, the control of the feet, the acquisition of the ability of locomotion in the up-right position, has always attracted the chief interest of the amateur observers of child life, the parents and nurses. When the child can walk, their interest in observation almost ceases. And yet, most animals possess the ability of locomotion practically from birth, so that, in this res-
(139) -pect, the year old child merely attains the level of a newborn animal. The control of the hands when once fully attained, places the child on a level which no animal ever reaches. Nevertheless, walking attracts more attention than the control of the hands, probably because the change from the perfectly helpless condition of human infancy to an animal-like condition lessens the responsibility of the child's care-takers so much more suddenly than any of the changes which raise the child above the level of animal life.
The complete ability of locomotion in the upright position involves two distinct abilities of muscular action the ability to rise from a lying to a standing position and the ability to balance on either leg. The ability to rise is only imperfectly developed as long as holding on an object, a chair or the like, is necessary in order to rise. This imperfect ability usually precedes by several months the child's ability to rise to his feet from the floor without the aid of any supporting object. The ability to balance on (either) one leg is naturally preceded—as a rule by the ability to balance on both legs, which, on the whole, is more easily acquired.
The governing reflex of the whole group in question seems to be that of straightening the legs in response to pressure against the soles. A child about nine months old, or even considerably younger, may absolutely "refuse" to be held on anybody's arms in a sitting, flexible position. The reflex of straightening the legs causes a stiffening of the body. The mother then naturally places the child, no longer easily held in her arms when in this straight position, with his feet on her knees, or a table, or the floor. The child then stands, in a way, but retains this standing position only because he is kept from tumbling by his mother's arms. Soon the
( 140) child learns to use Isis own hands, in the control of which he has by [,his is Ii i n e already acquired considerable skill, in order to keep from tumbling. He grasps whatever is in sight and reach and thus learns to keep in a standing position. !Another reflex reaction is soon added to those of grasping the things which are seen and of straightening the legs when the soles are touched: that of changing from a standing to a squatting position, in response—probably to sensory excitations in the muscles and joints of the legs when supporting the body. The following periodic activity must then frequently take place. The child changes from a standing to a squatting position while having his mother's clothes or any other object in his grasp. Being in the squatting position he no longer receives the sensory excitations which caused squatting. Consequently the excitation of the soles of the feet regains its former relative power and straightening of the legs occurs. At the same time the touch of the objects in the child's hands causes a bending of the arms, an action derived perhaps from the reflex of putting things into the mouth, so that the whole action might be described by saying: the child gets up, pulling himself up by his hands. This may be followed again by squatting, again by raising himself, and so on. Since the squatting, when the body is held in the upright position by the hands having grasped an object, readily changes into kneeling, the periodic action may be: kneeling, standing, kneeling, standing, and so on. Further, when there are solid objects which the hands can grasp, the body is easily pulled up from a lying to a kneeling position, so that there may be a change from lying to standing, and the reverse, provided only that the grasping hands can come into play.
When the child stands before an object, holding on with both hands, it naturally happens that now and then one
( 141) of the hands loses its grasp. If this happens while his legs are perfectly straight, he is likely to tumble down toward the side of the other hand; and then he will get up again. But if it happens while the legs are in a slightly bent position, intermediate between standing and squatting, it means only that the weight of the body is thrown on one side and that the leg of this side is straightened in response to the increased pressure on the sole. Thus the body is again balanced and kept from tumbling. This ability to balance the body is then further improved in two ways. First, the resistance of the nervous path from the sensory points of the sole to the muscles straightening the leg is lessened, possibly by the mere maturing of the inherited reflex. Accordingly, sensory excitations of much smaller intensity, caused by much weaker pressure on the sole when the body is barely beginning to lose its balance, are capable of bringing about the motor response which restores the balance. Secondly, the nervous processes starting from the excitations of the sensory points in the muscles, tendons, and joints of both legs are, by motor condensation, caused to contribute to the motor response which restores the balance temporarily impaired. This second kind of improvement, when further developed in later years into an independent "variation of response ", becomes our ability to stand on one leg and to balance our body on one leg in dancing or skating. When the child has had a certain amount of practise in retaining its upright position, both hands may lose their grasp on the supporting object without causing any tumbling. The equilibrium of the body is then at any time restored by the newly acquired motor responses as soon as it is lost. We say that the child has "learned" to stand alone.
Let us return to the moment described in the beginning of the last paragraph. While the child is standing before
( 142) an object, holding on with both hands, one of the hands loses its grasp and consequently the leg on the other side is straightened. The body as a whole, perhaps, is thus somewhat raised, and with it that leg which remained slightly bent. But now this leg, hanging and subject to the effect. of gravity, straightens somewhat; and when the body regains its vertical position and the foot of this leg touches the ground, it straightens perfectly, owing to the reflex repeatedly mentioned. The weight of the body is thus thrown again—lightly upon the other leg. A swinging movement of the body may thus result, from the left to the right, from the right to the left. It is clear that this movement needs only a slight modification to become a regular walking movement. Children who are just beginning to walk, do indeed, usually, walk in this pendulum-like fashion, comparable to the walking of a sailor. One finds here and there in psychological literature the assertion that the walking of a child is the result of an instinct consisting in a tendency of the legs to swing fore and back in directions opposite to each other, and that these instinctive movements can be observed in a baby a few months old when held suspended. While such opposite fore and back swinging movements of the legs may sometimes be observed, it seems doubtful if they have much significance for the acquisition of the ability to walk, since one does not walk in suspension, but on a supporting surface. In any case, it is possible to derive the alternate movements of the legs in walking from the reflex of straightening each leg in response to pressure against the sole, without assuming any specific "instinct of walking."
We described how a child may learn to stand alone, balancing himself sideways. But in order to stand really alone he must also keep from losing his balance in the forward and backward directions.
( 143) From falling forward he may be kept by the very reflex of straightening mentioned before. When the body begins to move forward, less weight is placed on the heels and more on the soles. Accordingly the foot straightens, the heel is raised above the ground and the body is kept from moving forward since the centre of gravity is now behind the point of support. On the other hand, when the body begins to move backward, more and more weight is placed on the heels, the pressure on the soles vanishes, and the muscles which keep the legs straight relax. The knees then bend forward and thus a part of the weight of the body is thrown in front of the previous center of gravity, thus restoring the balance. Just as the swinging of the body to the left and right, so these kinds of movement have great significance for walking. In the walking movements of a grown person the raising of the heel of one foot may raise with the whole body the other foot from the floor and cause it by the mere force of gravity to swing forwards.
We have been trying to explain how a child learns to balance its body in the upright position without having to hold to an object. Before this accomplishment of standing free, the child usually begins to walk along by pieces of furniture, changing the hold of his hands as he walks on. What reflex is the basis of this locomotion? It seems that, in response to a visual stimulation, not only the hand but the foot, too, stretches toward the thing which impresses the eye. On the basis of such a reflex locomotion is easily explained. Imagine a child standing before a bench, holding on with both hands, and an object, say, a pencil, lying on the end of the bench to. the right. The effect of the stimulation of the eye by the pencil is a stretching of the right arm and the right leg to the right. The body then falls to the right until the right foot again
( 144) touches the ground. The body is now somewhat displaced to the right. The feet are farther apart than normally and are therefore, in consequence of special reflexes which we need not discuss, brought together to their normal position, but of course, without any essential change of the body sideways. Now the whole stretching of the right, hand and the right foot to the right may be repeated several times, until the hand grasps the object. This walking along the pieces of furniture or the walls of a room can therefore be very simply explained.
At about this time in a child's development another kind of locomotion is likely to make its appearance, creeping. As the baby happens to lie on his stomach, his eye is stimulated by an object and the arms are reflexly stretched forward, but not the arms alone, the legs too are stretched, these backward, of course; and later a drawing in of all the extremities simultaneously may occur as an alternative response to the visual stimulation. We can not apply here simply the term reflex, but must say that the baby possesses an instinct, since the simultaneous stretching of the arms forward and the legs backward, and alternately the simultaneous drawing in of all four extremities, are the result of selective grouping of nervous paths. That the alternation of stretching, drawing in, stretching, and so on, continues for some time can be explained by assuming that the sensory points of the muscles, tendons, and joints stimulated in either one position are by inheritance very closely connected with the motor points whose activity brings about the other position. The result of the simultaneous drawing in and simultaneous stretching of the arms and legs is not necessarily, but may be, locomotion, provided either the front or rear extremities find a better hold on the ground. At first, it happens not infrequently
( 145) that this is the case with the hands rather than the feet, and the somewhat ridiculous observation is then to be made of a baby pushing himself away from the object exciting the eye. Once now, when the arms and legs are being drawn in, it happens that in consequence of an unusually strong nervous process, one of the legs, drawn in with unusual force, gets under the body. When now, instinctively, the arms and legs are stretched, this leg, resting with the knee on the ground and bearing the weight of the body, can not slide over the ground, but pushes the body forward. The eyes are thus brought nearer the exciting object and, therefore, receive the same stimulation as before, only still stronger. The nervous process resulting from this stimulation now tends to take the path into the leg drawn under the body rather than into the other, because it is attracted in this direction. It is deflected by the flux resulting from the excitations of the sensory points of the knee and the muscles and tendons of the leg drawn under the body, whose corresponding motor points are, of course, in the muscles of the same leg. Thus the alternate stretching and drawing in occurs chiefly in this leg. The baby learns to creep on one leg.
Why does not the baby, one may ask, learn just as readily to creep, at once, on both legs? The answer to this question is not that this is impossible, only that it is less likely. During the first year the legs move, in the hip joint, much more readily sideways, than in later life. This is due to the position of the fetus before birth, which changes but gradually after birth and enables infants even for years to put their toes into the mouth, a feat impossible in later life, as we all know. When the baby is lying on the stomach and the legs are drawn in, the legs are not likely to get under the body, but move outwards, in frog fashion. At the ninth or tenth month, however, the child
(146) begins to roll over, and when now, in consequence of an unusually strong stimulation, the drawing in of the legs is accompanied by a rolling movement of the body toward one side, a chance is given for one of the legs to get under the body. It, is most; natural, therefore, that the creeping on one leg should be learned first. After some skill has been attained in this, the other leg is likely to get under the body too, and the baby then creeps on both legs.
We stated that creeping usually makes its appearance about the time when the baby has learned to pull himself up and to walk along pieces of furniture. Creeping now has a pronounced influence on the child's progress in upright locomotion, in either of two ways. (1) As soon as the child has learned to creep on both legs—or knees, if we prefer this word, – he easily gets from the lying to the upright position without depending any longer on pieces of furniture or other objects which he can grasp, for the change from creeping to squatting is easy. Without being able to stand up from the ground freely, walking is of but limited usefulness. Thus creeping contributes, though indirectly, toward perfection in upright locomotion. (2) If, however, free walking is not yet a firmly established habit, the newly acquired form of locomotion, creeping, may so seriously interfere with the acquisition of that other habit as to hold it back for several months. Children who early become skilled creepers, usually learn to walk freely two or three months later than those children who little or never creep. This is comprehensible enough. The creeping child is not so exposed as the walking child to falling and to the consequent pain stimulation with its varied and strong motor responses, interfering by deflection with the learning process. Further, creeping brings the young child more quickly to the object which stimulates the child's eyes than unskilled walking, and thus as-
(147) -sures the repetition of the creeping movement by the repetition of the stimulus from nearer by, much more than walking assures the repetition of the walking movement.
In other words, the very nature of the case makes rapid improvement of skill in creeping more likely than of skill in walking; and when one form of locomotion has once been well learned, the other kind of locomotion, not yet well learned, is excluded by the simple rule of the effect of different resistances of various nervous paths, until, at a later time, new conditions arise. Some have drawn the practical conclusion, that therefore parents must prevent their children from creeping whenever they are seen to try it, before having become skilled walkers. It seems so simple: if creeping delays walking, stop the creeping and hasten thereby the walking. This conclusion, however, implies several important assumptions. First, walking is assumed to be the only kind of locomotion needed by a human being. This is somewhat doubtful. Not that we wish to assert that grown people ought to make frequent use of creeping movements, but it is highly probable that a complete analysis of our motor activities in later life would show of the elementary activities which are exercised in creeping many applications in new combinations. If this is true, the suppression of this exercise during infancy would be a grave mistake. Secondly, one must not think that the suppression of creeping before walking must be harmless since, after walking is thoroughly established, the child may be permitted to creep and thus exercise the same activities. Who knows whether exercise, then, brings about the same results in the education of the nervous system which it might have brought about previously? As long as we know nothing about this question, it is hazardous to try to improve upon nature because we, as parents,
( 148) happen to be exaggeratedly proud of our children's early accomplishments in walking and indifferent to all other kinds of motor accomplishments. Different children differ greatly different talents, and we know that their success in life depends largely on the proper training of the most pronounced talent of the individual. It is possible, even highly probable, that a special talent means merely a special form of interconnection of the fundamental reflexes common to all; and such special interconnection may early show itself in such phenomena as this, where creeping does or does not precede walking. We might then really interfere with the child's most favorable development if we try to arrange the fundamental reflexes in groups different from those intended by nature.
To these arguments, of course, some one might rejoin that he does not feel convinced that to prevent a child from creeping during a few months can be of such consequence, positively or negatively, to his later intellectual and moral development. Very well then, we can answer that to make a child walk freely at the age of twelve months, instead of letting him use for locomotion creeping during the thirteenth and fourteenth and free walking only from the fifteenth month, does not seem to be of much significance for his later life either. The safest course in education—in this simple case as in the most complex problems of educational theory—is probably the one which interferes least with the development designed by nature and which trusts nature rather than traditional ideals of education or, worse, parental vanity, unquiness we have the most certain—experimental—evidence that in this or that way nature can be improved upon.
Before leaving the discussion of creeping, let us mention two further accomplishments connected with its develop-
( 149) -ment. The creeping child has acquired a second position of rest in addition to that of lying: he can rest at any time in a sitting position. It is true that children can sit, with support in the back and at the sides, when a few weeks old, and that they can sit on the floor without any further support when about six months old. But the ability to sit does not Include the ability to seat himself, to sit up. The latter comes with creeping. The creeping child can sit up on the plain floor on which no objects offer themselves to his hands to be taken hold of. Thus when tired, he can take for resting the sitting as well as the lying position, and he often takes the former owing to the multitude of sensory-motor reactions of the nervous system which are only in this position possible. For example, the child when sitting can freely turn his head.
The creeping child further acquires a play of his hands formerly impossible. During the first half year, whenever the child takes anything in his hands, he almost invariably puts it into his mouth, and often, when he has nothing in his hands, he puts one or more fingers in his mouth. These reactions become less frequent when the child begins to creep and sit up. Objects can now call forth numerous other responses. The child learns to push or throw away things, to creep after them and take them again; and this more complicated game, more likely to bring about repetition of activity by the repetition of stimulation of the eye and, consequently, more likely to become a strong habit, gradually supersedes the simple reflex of putting things into the mouth. It is the exceptional child that retains the finger sucking habit after the acquisition of locomotion.
We stated above that children learn to stand freely, that is, to balance the body continuously in the upright
( 150) position, before they learn to move in this position. While this is generally [rue, there are also exceptional cases where children, being held in the upright position, are suddenly attracted by in object, perhaps the mother's voice, and start off running successfully five or six steps until they (have reached the object. In such a case a, child really learns to walk before he has learned to stand without support. However, as a rule, a child learns first to stand; and then, standing, in response to a stimulation of his eyes by an object, lie moves one leg slightly toward the object, shifts his weight so that it rests on this leg and draws the other leg after, secures his balance, then moves again the first leg toward the object, and so on. One might call this form of locomotion walking on one leg only. In a week or two this one-sidedness gives place to the regular form of walking in which both legs take part equally. For many months thereafter, however, a child's walk remains clumsy because the legs are kept so far apart, owing to the anatomical fact already mentioned that this opening of the legs sideways is the normal position until birth, which but gradually changes into that of the older child and adult, and also to the fact that balancing is easier in this position.
If walking is thus the outgrowth of standing, it is well to "encourage" free standing as much as possible after the baby has learned to stand while holding to things. What does it mean to "encourage" him? Let us reduce the process to its essential elements. (1) The child, when beginning to tumble, reflexly draws in his legs. (2) He has often tumbled, when standing and losing the hold of his hands. (3) Subsequently, by a" variation of response" lie draws in his legs at once (in other words, he sits down) when standing and losing the hold of his hands. But he can-not practice balancing his body if he sits down. Therefore
( 151) (4) we give his hands the same or similar sensory impressions as if they were supporting the body. For example, we let the standing child grasp for support a small stick or pencil which we are holding, and then, gradually, we cease to hold it. The child then balances and, although nothing supports him, receives almost the same stimuli in his hands and eyes as if he were still supported by the stick in his hands. The process of balancing suffers no sudden interference by a new stimulation (caused by the withdrawal of an object from his hands) and its reaction of sitting down. The "encouragement" which we give the child is therefore a purely negative event in the education of his nervous system: we keep an obstacle out of the way.
After the establishment of free locomotion, further activities make their appearance, which are often referred to as the constructive and destructive instincts. It seems very doubtful, however, whether it is justifiable to speak of such instincts. A child, let us say, picks up one of a number of wooden blocks lying about in his room. He receives the visual stimulation of a similar block, and since the nervous path is still favored by the reduction of the resistance due to the previous stimulation, reacts in the same way, walks towards it and puts on it his hand in which he still has the first block. Since now, lie cannot pick up the second block, he opens and raises his hand and, there, has before him a structure, one block upon another. Since this double block is a more striking stimulus than any of the single ones, it is quite natural that he returns to it, after having picked up one more of the blocks lying about. Is not all the so-called constructive activity simply a more or less complicated habit of the same kind as this very simple example? This habit of gathering and piling up must develop from the reflexes and habits which we have studied thus far, provided the child is surrounded by things
( 152) which are sufficiently similar so that two or more of them together make a similar, but snore intensive sensory impression than a, single one; and what child does not live under such surroundings? It is hardly necessary, then, `' to assume a mysterious particular instinct of constructiveness. That, the habit of taking to pieces, which is to be derived from the ordinary reflex of grasping, becomes united with this habit of putting together is plain enough, for taking apart brings about ever new opportunities for putting together. Thus develop constructiveness and destructiveness as co-operating habits.