activity of vocalization as from the sounds that he
produces, so that deaf children, who begin to babble much like other
children, lag behind them as the months go by, from not deriving this
auditory satisfaction from the vocal activity. Though whistling,
blowing a horn, shaking a rattle and beating a drum are not native
responses, it is clear that the child naturally enjoys producing
sounds of various sorts.

The baby's cheerful babbling is the instinctive basis on which his
speech later develops through a process of learning.

Manipulation.

While the first random activity of the baby has nothing to do with
external objects, but simply consists of free movements of the arms
and legs, after a time these give place to manipulation of objects.
The baby turns things about, pulls and pushes them, drops them, throws
them, pounds with them. Thus he acquires skill in handling things and
also learns how things behave. This form of playful activity contains
the germ of constructiveness and of inventiveness, and will come into
view again under the head of "imagination."

Exploration or curiosity.

Along with manipulation goes the examination of objects by the hand,
the mouth, the eyes and ears, and all the senses. Listening to a
sudden noise is one of the first exploratory reactions. Following a
moving light with the eyes, fixing the eyes upon a {155} bright
object, and exploring an object visually by looking successively at
different parts of it, appear in the first few months of the baby's
life. Exploration by the hands and by the mouth appear early. Sniffing
an odor is a similar exploratory response. When the child is able to
walk, his walking is dominated largely by the exploring tendency; he
approaches what arouses his curiosity, and embarks on little
expeditions of exploration. Similar behavior is seen in animals and is
without doubt instinctive. With the acquisition of language, the
child's exploration largely takes the form of asking questions.

The stimulus that arouses this sort of behavior is something new and
unfamiliar, or at least relatively so. When an object has been
thoroughly examined, it is dropped for something else. It is when the
cat has just been brought into a strange house that she rummages all
over it from garret to cellar. A familiar object is "taken for
granted", and arouses little exploratory response.

Quite a group of conscious impulses and emotions goes with exploratory
behavior. The