Popular Science Monthly/Volume 17/September 1880/Psychogenesis in the Human Infant
| PSYCHOGENESIS IN THE HUMAN INFANT.[1] |
By Professor W. PREYER, of Jena.
WHOEVER would watch the growth of the human mind must first make the soul of the child the object of a methodical investigation. The new-born child in its pitiful helplessness is already an object of extraordinary interest for the psychologist; yet it seems incomprehensible that the progressive unfolding of the senses of the infant—of his will, his reason, his passions, his virtues—has not engaged the attention of any but his relatives. For thousands of years children have been born and lovingly taken care of by their mothers, and for as long a time the learned have contended respecting the growth of their minds without studying the children themselves. The volumes that have been written on the subject without this study are of small use, because they lack the basis of fact. Schoolmasters and tutors can give but little help in the investigation, for the development of the faculties begins long before they are called in to assist it.
The study of the earliest mental growth is useful in its bearing upon the future training of the child. Only certain faculties are innate in every man. A true method of instruction should proceed from the given inherited faculties; should take account of their diversities; should not measure all children with the same measure; and should not train them after the same model. It would be desirable in respect to this point if a number of men well versed in physiology should, independently of each other, carefully observe as many infants as possible, and compare results; or if the fathers of children, friends to each other, should mutually exchange observations upon their own children. It would be well for individuals to keep a day-book of the acts of their children from their birth upward. I can say from my own experience that hardly a day passes in the first two years in which something does not occur worthy of notice in its bearing upon mental development. The study must begin with the observation of the sensations and movements of the child. There can be no mental activity without sensation to excite it by giving impressions, and affording a basis for remembrances and comparisons. The sensations are preceded by the movements which begin even before the child is born. The reciprocal action of sensation and movement leads us a step further, to the beginning of the development of the will. As soon as the will becomes effective, the intellect reveals itself, and at last the point is reached when inclination becomes a controlling influence; the feelings assume a real form, and the child begins to communicate its own purposes through speech. The first cry of the new-born child has been regarded by some as an expression of the will, and even as an appeal for relief from pain. This can not be, for a being born without understanding, in the first moment of consciousness, can not be capable of entertaining such purposes as this expression would imply. A more probable theory is that it is the result of a reflex action, like the sounds with which animals respond to a pleasing excitation, as the rubbing of the back, or like the laughter which is provoked by tickling. Frequently the child sneezes instead of crying; and this is a purely reflex action, following an irritation of the nerves of the nose.
The first motions of the limbs of the child give to the unprejudiced observer an impression of aimlessness. The changes in the expression of the face seem to result from what are more like voluntary muscular movements; but when we remember how helpless are the motions of the infant in other respects—that it will be months before it can hold up its head or take hold of any thing, or do any other simple act which seems natural to grown persons—this supposition seems no longer probable. Of what nature, then, are these singular muscular contractions which are never observed again in the whole later life, and the parallels of which are only seen in animals suddenly awakened from their winter slumbers, or occasionally from ordinary sleep? No external cause of disturbance is present to irritate the nerves of motion and the contractile fibers, and so provoke reflex movements. The sleeping infant stirs as the waking one does, only less often and more sluggishly. We can not ascribe the movements at this early period of life to attempts at imitation; the imitative faculty does not begin to be developed till the second half-year. We must look within the child for their cause. An inner cause must be either acquired or inherited. The idea of an acquired cause, presupposes varied experiences and observations, of which the child has had none. The inherited causes, then, are the only ones we can consider. It is not enough to say on this point that the child moves as it does because its ancestors did so when they were young. That would only set the problem a step further back. We should rather say that the peculiar movements take place because the central nervous motor organs, when they are fully developed, discharge irregularly the surplus store of motive energy which has been inherited. They have been called instinctive, but instinct comprehends a kind of inherited recollection, and has some definite end, while the motions are aimless. They are impulsive—the direct effect of the nervous energy of the spinal marrow before it has become subject to the restraint of the brain. As the brain is developed, and the intellect manifests itself, the excessive movements are limited, and in persons who have received the most perfect training they are hardly observed at all. They cease when the man has learned to exert the full power of his will over them.
The first manifestation of the will in the child appears when it begins to hold up its head. A chicken can not hold its head up during the first hour after it is hatched; but it can do that, and even pick up a grain of corn, before it can walk or stand firmly. It then begins to run, and learns to do in a day what it takes the human infant a year to accomplish. My attempts to hold a child up straight were not successful for fourteen weeks. Evident voluntary effort began at that time, and after four months the child was able to keep its head well balanced. The lack of power to hold the head up before was not due to want of muscular strength, for the reflex actions, such as that of turning the head, requiring as much power of muscle, were performed firmly enough. Next, after the head, the upper part of the body was balanced. The power to sit up was acquired in about the tenth month, all at once, after the child had been kept up by artificial supports for several weeks. So ability to stand was gained suddenly at the end of the first year, after numerous unsuccessful efforts to stand by the aid of chairs, tables, and the walls of the room. The next acquisition, that of walking, likewise seems to come of itself. Its beginning is obscure, for there appears no occasion in the act of standing for the alternate bendings and stretchings of the legs which enter into it. Similar movements may take place, it is true, when the child is lying down, in its bath or in its cradle, but the regular alternation of them in a standing position is quite different, and is probably, like the act of sucking, derived by inheritance.
It may often be months before the effort to walk is successful, but, if the child is allowed to creep without being interfered with, it will in time begin to walk without instruction. The efforts of walking, standing, and sitting can not be ascribed to any knowledge of the advantage of those actions. They rather arise from the growing power of the will in connection with the muscles and motor nerves, bringing those organs into the modes of action which will prove in later life to be of most advantage to the body, just as has regularly happened to our ancestors. So deeply have the traces of these motive impulses been impressed, so often has the will gone on these nerve paths and no others, that they are followed at once as soon as the motive impulses of the new-born man are developed. In other words, the efforts are instinctive. The child walks when the inclination to change place is so strong that creeping does not satisfy it, or when it wills to walk, as it sits up or stands when its will to do so is strong enough to command the requisite muscular action. A child observed by me, which could already stand well, all at once, at the end of the fifth quarter-year, for the first time ran around a table, unsteadily, like a drunken man, but without falling. From that day on it went erect, at first hurriedly, then trotting with extended arms, as if to keep from falling, then slower and more firmly. In the course of the next month it went over a door-sill an inch high between two rooms, but holding on to something, and frequently lifting its foot up too high or stamping it down, like one afflicted with a spinal disease. Its will had not yet full control of its muscles, and it could not measure the force of its efforts.
The movements of grasping afford interesting objects of observation. Their development has to be watched with care, for it sometimes takes place at a bound from a lower to a higher degree; at others, proceeds very slowly. A pencil put in the little hand was clasped by the fingers during the first quarter-year; the thumb participated in the action, but not independently—rather as if it were one of the fingers—and the infant did not seem to be aware that it had anything in its hand, holding the object mechanically, as it were. If, at this time, one puts his finger into the child's hand, it will seem to grasp it and hold it, the more so as it keeps a tight hold when the finger is moved back and forth. The action is, however, wholly reflex; there is no intended grasping. The first real effort to take hold of an object was observed in the seventeenth week, when the infant reached after a little India-rubber ball which was near it. When the ball was put into its hand it held it tight for a long time, brought it to its mouth, held it close before its eyes, and looked at it with a peculiar, novel, intelligent expression. On the next day it made many awkward but earnest attempts to take hold of objects of all kinds which were presented before it, fixing its eyes fast upon them, and reaching after things which were too far for it to seize. On the following day, it seemed to give it pleasure to take hold again and again of everything which was within its reach. Wonder was also mingled with its pleasure, and another step was noticed in the development of the infant mind. Toward the end of the fourth month the child raised its arms toward its parents with an indescribable expression of longing. The transition, from grasping after indifferent things so as to take them to itself to reaching after its parents to get nearer to them, was sudden. On the other hand, its own arms and feet appeared to the child for months as something strange, not belonging to it, and it would stare at them and examine them as it did with other objects which engaged its attention. It would take hold of its feet and bring them to its lips; it would bite its arm even in the fifth quarter-year, so as to cause it to cry out in pain; it would offer biscuit to its foot to eat, as it did to its wooden horses. There appeared, as yet, no sign of self-consciousness. The unintermitted grasping of objects leads gradually to the comprehension and knowledge of separate existences and the seclusion of self.
Now that the object which has been seen and wished for is touched, a new sensation excites the attention of the child. That which was light or dark, colored or bright, appears to be also smooth or rough, heavy or light, hard or soft, warm or cold, and presents combinations in the same thing appealing to two or three senses. The same apple is red and green, smooth and heavy, cold and hard, and also smells and tastes agreeably. The junction of the sensations of sight, touch, smell, and taste at the same point excites surprise, induces reflection, and arouses the insatiable propensity of the mind to inquire into the causes of its affections. The infant examines the object it is holding, feels of it, and rubs it every way, moves it back and forth, takes it to pieces, and tries to put it together again. With these exercises the will becomes more fully developed. As soon as it is possible to learn the nature of external objects which have affected the senses by examining them, the act of grasping becomes voluntary. Will is developed from the previous desire. The remembrance of the satisfaction which the success of an effort to grasp something has given awakens, at the sight of a new object, the idea of getting hold of it, and with it the impulse to exert the necessary movement. This impulse is called the will. It is still weak in the child, for he lacks self-control, but the obstinacy of early youth shows often enough the force that lies in the unrestrained will.
The sensibility of the skin of a new-born child is very low. We may cause it to cry in the first hour by striking it or by touching it too roughly, but its cries are only reflex actions, not expressions of pain; on the other hand, we may stick needles into its nose, lips, or hands, without its giving any sign of discomfort, even if so deep a wound is made as to draw blood. I have never tried any experiments of this kind, but I have found that the eyes of new-born children close, when they are touched, more slowly than at a later period and are only imperfectly shut at that, and that they do not close when they are wet in the bath. An increase of sensibility may be perceived in the course of one or two days, especially in relation to temperature. The earliest sensations of temperature are, however, of less immediate psychogenetic significance than those of touch. The hands of the child are the feelers of his soul. Through the excitation of the tactual corpuscles, at the points of the fingers and in the lips, the infant receives the first knowledge of things without him; and through the difference in the sensations arising from the touch of his own skin and that of foreign objects is the foundation laid for self-consciousness on one side and for making experiments on the other. His fingers are, in fact, the instruments with which he endeavors to explore everything that comes within his reach.
Professor Kussmaul has described some important experiments on the sense of taste in infants, in which he found that all new-born children could distinguish strong tastes, and that a very different reaction took place when the tongue was wet with a solution of sugar, from that which followed the application of quinine, vinegar, or salt. Signs of distaste were excited by the three latter substances, and of satisfaction by the sugar, which showed beyond doubt that the power to discriminate tastes begins at birth. The opinion that infants will take alike whatever is offered them holds good if at all, only of substances whose taste is weak. If the child seems displeased at the taste of a strong solution of sugar, as sometimes happens, that is only the effect of the surprise which all new intense sensations occasion. After the first trial, it will want more sugar, and show its satisfaction at getting it. The same is the case with the young of animals, which readily distinguish tastes and seem astonished at new ones; and the newly hatched chicken will at once select the food, where it is given a choice, which is most agreeable to it. Taste is, then, the first sense which affords clear perceptions, and is the first which gives occasion for the exercise of the faculties of memory and judgment.
The sensations of smell can hardly be separated from those of taste. Infants appear able to distinguish odors very early, but to what extent has not been ascertained. They are able to tell one kind of food from another by this means, and have been known to decline the acquaintance of a new nurse whose presence was disagreeable to them. It is known that animals that are born blind are guided to their food—the mother's milk—by this sense. Some odors, as that of tobacco smoke, have been found to be disagreeable to young animals; others, as that of camphor, pleasant.
All infants are deaf at birth, because the outer ear is as yet closed, and there is no air in the middle ear. A response to a strong sound is observed, at the earliest, in six hours, often not for a day, sometimes not for two or three days. The awakening of the sense may be recognized by means of the drawing up of the arms and the whole body, and the rapid blinking which a loud noise provokes; and it is a sign of deafness if the child, after its ears have had time to come into a suitable condition for hearing, fails to respond thus to a strong sound. No other organ of sense contributes so much to the early spiritual development of the child as that of hearing after it has become fully developed. The superiority of the ear over the eye in regard to this point is shown by the intellectual backwardness of persons who are born deaf as compared with those who are born blind. At the beginning of life, as a rule, the voices of the mother and the nearest relatives afford the first impressions of sound. Very soon these voices are distinguished, and different tones and noises are differently responded to. It is particularly interesting to compare the soothing operation of singing of the cradle melodies with the extraordinary vivacity exhibited on the hearing of dance-music, in the second month. Certain sounds, as those of the consonants sh, st, and of the male voice, are effective at a very early period in quieting the crying of a child, while other strong and strange ones, like the whistle of an engine, will cause it to cry. Observations on these points, which are easily multiplied, show that, in spite of its original deafness, the child learns very soon to discriminate between the impressions of sound.
The faculty of seeing has a similar growth. Light seems at first unpleasant, and only faint lights are borne; the baby shuts its eyes tight when a candle is brought near them. Brightness and darkness, if they are marked, can be distinguished, but with this the office of the eyes in the earliest days is exhausted. The motions of the eyes are wholly unregulated. One will look to the right, the other to the left; one may be open, the other shut; one will be still while the other moves. Among the numerous combinations of movements both eyes will occasionally move together, but no real symmetry in the muscular contractions can be predicated for the first six days. The first perceptions are evidently only those of the different degrees of strength of light. These attract attention, and some children are said to have turned their heads to the window after the first day. I have noticed it on the sixth day. On about the ninth day most infants begin to stare, into the void, or if a bright object, as a candle, is brought before them, as if they were looking at it; but it is easily found out by trial that there is no real seeing, for it is only when the light is brought directly within its line of vision that the eye is directed toward it. Not for three weeks will the eye which is turned toward a light follow it when it is slowly moved, and then only with a partial motion of the head. But little intelligence is involved in this, for the movements of the eyes and of the head are often in opposite directions. Nevertheless, the face of a month-old child gains an appearance of intelligence when it looks with both eyes upon a slowly moving object and follows its motions; but the stupid expression returns, and does not finally disappear till the second quarter-year. The face grows more human and spirited as the power is gained of regarding objects with a steady, independent look. The faculty of accommodation, or the power of rapidly adapting the eye to the perception of objects at different distances, is then in the process of development, and the unsymmetrical movements of the eyes gradually cease.
The power to distinguish colors follows. One child prefers yellow, another red; all dislike black and dark colors as well as dazzling bright ones. It is hard to decide when the finer degrees of color and their grades of brightness begin to be recognized, for the time differs with the individuals. I do not know of any child that could point out red, green, yellow, blue, correctly on demand before the beginning of the third year.
The recognition of forms proceeds very slowly. Experiments on blind persons, who have had their sight restored by operations, after they had learned to see, show that they could not distinguish curved figures from angular ones by sight alone, nor at all until they had felt of them. The same is doubtless the case with every little child. Numerous observations show how defective is the estimation of distances in early years. The well-known reaching out for the moon is a case in point. Even long use does not give accuracy in the exercise of this power. The same is the case with the perception of magnitudes. A child in its third year will try to put its larger playthings into the boxes designed for little ones, to put pieces of bread into its mouth that are too large for it, and to take hold of large things with its tiny hands. The first sensations of changes in the field of vision, such as are given when a bright object is taken from it, as by the extinction of a lamp, and when a new object is substituted for it, as when the lamp is lighted again, always make a deep impression on the young child. In the first month no notice is taken of the swiftest approach of the hand to the face, and the act of blinking when a threatening movement is made toward the eye is not acquired till the third month. This fact enables us to distinguish between inherited and acquired incidents of sight. The contraction of the pupil in the light and its expansion in the gloom are inherited, and common to all new-born children; the blinking is acquired: it is a precaution against danger, of which the child in its first months knows nothing. By frequent repetitions it becomes habitual, and at last reflexive, like other defensive contractions of the muscles. By the frequent repetition of observations and experiments of the kind described above, it is possible to follow the gradual development of the senses in individuals. But much material must yet be collected before we can clearly set forth the sensual basis of the spiritual growth of the child. The sensations are the material out of which every man makes his world. The emotions of the child, his inclinations and disinclinations, the development of his sense of obligation, the beginning of the formation of his character, the opening of his talents, all depend primarily on the unfolding of his senses. We have so far, on this subject, nothing but an array of facts, with little connection between them.
The study of the growth of the faculty of speech is also of the highest importance in its bearing upon our knowledge of the condition of the child's mind, and of his intellectual operations. I have been in the habit of setting down daily on paper every expression, every sound that could be represented in writing, uttered by a child during the first two years, and am about to publish, on the basis of the facts thus gathered, a special work on the history of the growth of the power of speech. I can give here only a few notes of general interest.
It is extremely hard to exclude the influence of imitation from the child; and, when it is not excluded, to separate what is acquired by it from what is inherited. No one will believe that a child was ever born able to speak, or that he could learn to speak without exercising the power of imitation. Yet it would be wrong to conclude that the faculty of speech is acquired, or is absolutely not inherited. Whatever properties of organisms are constantly repeated periodically are called hereditary; whatever endures through many generations is called inherited. Speech thus endures. It can not be said to be born with the child any more than the teeth and beard are born with him, but the foundation of it, the predisposition to it, is born with the child, the same as are the foundations of those organs. And when a person is prevented from speaking by some defect of his organs of speech, he proves that the faculty still exists within him by the readiness with which he will take up a substitute for speech—writing, or the sign language. The psychologist can hardly experience a greater intellectual enjoyment than that which is given by observing the development of speech from the first reflexive cry through the thousand and one days of the beginning of human life; at first unintelligible, gradually flowing slowly and interruptedly from unrevealed sources, then gushing lively and irregularly, afterward getting slowly relieved of the non-essentials and becoming more orderly and plain, clearer, and flowing; finally, proceeding in a clear stream of connected language, which testifies to the rule of reason over the natural inclination, the victory of the will, and the formation of thought.
At first only the vowel-sounds are uttered. Even in the first five weeks the tones are so diversified that the condition of the child can be learned from them alone. The periodically broken cry, with knit eyes, denoting hunger; the continuous whine for cold; the high, penetrating tone expressing pain; the laugh over a bright button; the crow of pleasure; the peculiar expression, with motion of the arms, of the wish for a change of position—are easily distinguished utterances, partly reflexive, partly expressive. The prattlings of the infant during the first six months can not be represented on paper, and appear to be significant only of the general muscular movements in which the organs of speech participate, combined with the flowing in and out of the air. I heard the first consonant, m, in the seventh week; in the seventh month only m, b, d, n, r; rarely g and h, very rarely k, could be distinguished in the babblings. Gradually the voice became more steadily modulated. When the child wanted some new thing, besides stretching out its arms and looking at it, it signified its desire by the same sound it had been accustomed to utter when it wanted to be nursed. At the same time the syllables pa, at, ta, ha, da, ma, na, common to children of all nations, were uttered plainly and frequently. They had no meaning, and were only the consequences of the involuntary exercises of the vocal apparatus.
Very imperfect imitations of sounds were noticed toward the end of the first six months. The power of distinguishing words when spoken began to appear at about the same time. The baby turned its head when it was called, and it was taught to do such little acts as give its hand when asked to. Still, the store of words it knew was not larger or more comprehensive than that of a well-trained hunting-dog. The enormous intellectual interval between the child and the trained animal was manifested less by its connection of definite objects with certain changes of sound than by its feeble attempts to repeat the syllable or the word when the impression recurred to which they corresponded.
Great progress is made in the imitation of sounds after the third half-year. Numerous objects are correctly pointed out in answer to questions, and many words are spoken with a broken articulation, but in a correct sense. The child's advancement in the power of forming notions becomes wonderfully rapid, and it learns to connect its ideas, to compare and reflect before it has acquired the use of any considerable number of words, and while it still expresses its thoughts by gestures more than by words.
The powers of articulation become well developed at the beginning of the fourth half-year, although the child may still not be able to pronounce all the sounds of his language; but an intelligent child is able to understand many more words than he can repeat, and will also repeat, in a parrot-like way, many words that he does not understand, if they please him or he finds that his speaking them pleases others.
The organs of articulation have a wonderful flexibility, putting it into the power of the child to learn to pronounce the sounds of any language which may be taught him with an ease and accuracy which can never be gained later in life. The child's own language is, however, crude and elementary, consisting in the main of inarticulate sounds, looks, gestures, parts of words that are mangled beyond all recognition, and onomatopoetic expressions. The way he learns to speak is incomprehensible to the keenest observer. He cries, laughs, babbles, smacks, crows, squeals, and understands what is said to him long before he speaks; and after he has touched, looked, listened, and tasted innumerable times, after he has amused himself and got tired with a thousand efforts to imitate, after he has been at first unable to repeat, and often would not repeat words, then he speaks spontaneously. At first he speaks in such a way as to make a single word answer for several whole phrases. Shortly, two, three words are spoken in connection; then the child is able, in broken phrases, to give an imperfect account of something that has happened. It is not a very long step from these beginnings to the construction of real sentences. The use of the pronouns, verbs, and articles, is attended with difficulties for some months, but the way is broken. The sentence gradually assumes a correct shape, and the child at last gives clear evidence of his intellectual power, more through his shrewd questions than his answers.
If we compare the defects of childish speech with the lapses of grown persons after their faculties have been disturbed by sickness, we shall discover parallels of uncommon interest and astonishing completeness. All the faults of speech caused by sickness have their miniature counterpart in the child. From illness, the matured man is no longer in a condition; in childhood, the unmatured man is not yet in a condition, to speak correctly. In the former case, existing powers are disturbed; in the latter the powers of articulation and phrase-making have not been perfected. One condition helps us to understand the other. The parallel can not, however, be pursued here, for the material for illustrating it is rich and will not admit of abridgment. My present purpose has simply been to sketch the fundamental conditions of the earliest development of the infant mind independently of the theories of the day, and to set forth the extraordinary significance of the study.
- ↑ Translated from the German by W. H. Larrabee.