Long before the thirtieth week, healthy children distinguish human faces definitely from one another; first, the faces of the mother and the nurse, then the face of the father, seen less often; and all three of these from every strange face. Probably faces are the first thing frequently perceived clearly by the eye. It has been found surprising that infants so much earlier recognize human faces and forms, and follow them with the gaze, than they do other objects. But human forms and faces, being large, moving objects, awaken interest more than other objects do; and on account of the manner of their movements, and because they are the source from which the voice issues, are essentially different from other objects in the field of vision. "In these movements they are also characterized as a coherent whole, and the face, as a whitish-reddish patch with the two sparkling eyes, is always a part of this image that will be easy to recognize, even for one who has seen it but a few times" (Helmholtz).
Hence the memory for faces is established earlier than that for other visual impressions, and with this the ability to recognize members of the family. A little girl, who does not speak at all, looks at pictures with considerable interest in the seventh month, "and points meantime with her little forefinger to the heads of the human figures" (Frau von Strümpell).
My child in the second month could already localize the face and voice of his mother, but the so-called knowing ("Erkennen") is a recognition (Wiedererkennen) which presupposes a very firm association of the memory-images. This fundamental function attached to the memory can have but a slow development, because it demands an accumulation of memory-images and precision in them.
In the second three months it is so far developed, at least, that strange faces are at once known as strange, and are distinguished from those of parents and nurse; for they excite astonishment or fear (crying) while the faces of the latter do not. But the latter, if absent, are not yet, at this period, missed by most children. Hence it is worthy of note that a girl in her twelfth month recognized her nurse after six days' absence, immediately, "with sobs of joy," as the mother reports (Frau von Strümpell); another recognized her father, after a separation of four days, even in the tenth month (Lindner).
In the seventh month my child did not recognize his nurse, to whom he had for months been accustomed, after an absence of four weeks. Another child, however, at four months noticed at evening the absence of his nurse, who had been gone only a day, and cried lustily upon the discovery, looking all about the room, and crying again every time after searching in vain (Wyma, 1881). At ten months the same child used to be troubled by the absence of his parents, though he bore himself with indifference toward them when he saw them again. At this period a single nine-pin out of the whole set could not be taken away without his noticing it, and at the age of a year and a half this child knew at once whether one of his ten animals was missing or not. In the nineteenth and twenty-first months my boy recognized his father immediately from a distance, after a separation of several days, and once after two weeks' absence; and in his twenty-third month his joy at seeing again his playthings after an absence of eleven and a half weeks (with his parents) was very lively, great as was the child's forgetfulness in other respects at this period. A favorite toy could often be taken from him without its being noticed or once asked for. But when the child—in his eighteenth month—after having been accustomed to bring to his mother two towels which he would afterward carry back to their place, on one occasion had only one towel given back to him, he came with inquiring look and tone to get the second.
This observation, which is confirmed by some similar ones, proves that at a year and a half the memory for visual and motor ideas that belong together was already well developed without the knowledge of the corresponding words. But artificial associations of this sort need continual renewing, otherwise they are soon forgotten; the remembrance of them is speedily lost even in the years of childhood.
It is noteworthy, in connection with this, that what has been lately acquired, e. g., verses learned by heart, can be recited more fluently during sleep than in the waking condition. At the age of three years and five months a girl recited a stanza of five lines on the occasion of a birthday festival, not without some stumbling, but one night soon after the birthday she repeated the whole of the rhymes aloud in her sleep without stumbling at all (Frau von Strümpell).
It is customary, generally, to assume that the memory of adults does not extend further back than to the fourth year of life. Satisfactory observations on this point are not known to exist. But it is certainly of the first consequence, in regard to the development of the faculty of memory, whether the later experiences of the child have any characteristic in common with the earlier experiences. For many of these experiences no such agreement exists; nothing later on reminds us of the once existing inability to balance the head, or of the former inability to turn around, to sit, to stand, to walk, of the inborn difficulty of hearing, inability to accommodate the eye, and to distinguish our own body from foreign objects; hence, no man, and no child, remembers these states. But this is not true of what is acquired later. My child when less than three years old remembered very well—and would almost make merry over himself at it—the time when he could not yet talk, but articulated incorrectly and went imperfectly through the first, often-repeated performances taught by his nurse, "How tall is the child?" and "Where is the rogue?" If I asked him, after he had said "Frühstücken" correctly, how he used to say it, he would consider, and would require merely a suggestion of accessory circumstances, in order to give the correct answer Fritick and so with many words difficult to pronounce. The child of three and even of four years can remember separate experiences of his second year, and a person that will take the pains to remind him frequently of them will be able easily to carry the recollections of the second and third years far on into the more advanced years of childhood. It is merely because no one makes such a useless experiment that older children lose the memory-images of their second year. These fade out because they are not combined with new ones.
At what time, however, the first natural association of a particular idea with a new one that appears weeks or months later, takes place without being called up by something in the mean time, is very hard to determine. On this point we must first gather good observations out of the second and third half-years, like the following:
"In the presence of a boy a year and a half old it was related that another boy whom he knew, and who was then in the country far away, had fallen and hurt his knee. No one noticed the child, who was playing as the story was told. After some weeks the one who had fallen came into the room, and the little one in a lively manner ran up to the new-comer and cried, 'Fall, hurt leg!'" (Stiebel, 1865).