Part of a movement, a gesture, a peculiar habit of the nurse, may become sufficient to give assurance of the welcome presence and the pleasures which the presence brings.

Two notes of my song in the night stood for my presence to H., and no song from any one else could replace it.

A lighted match stopped the crying of E.
for food in her fourteenth week, although it was but a signal for a process of food preparation lasting several minutes; and a simple light never stopped her crying under any other circumstances.
2.

With this first start in the sense of personality we find also the beginning of the recognition of different personalities.

It is evident that the sense of another's presence thus felt in the infant's consciousness rests, as all associations rest, upon regularity or repetition; his sense of expectancy is aroused whenever the chain of events is started.