the effort causes the child to show signs of fatigue
(restlessness), or to become inattentive.

In the first curve, the initial work consists of two easy tasks,
carried on for a short time, and from these the child passes directly
to the serious work. The finale is a spell of rest full of thought;
the child ceases to work, but contemplates his finished task for a
long time in silence; before preparing to put it away, or, after
having contemplated his own work, he goes quietly to watch that of the
others.

In the second curve there is a very noticeable parallelism with the
line of repose; the child pursues his labors almost uniformly, and the
sole difference between the initial work and the serious work is in
their different duration. The contemplative period becomes henceforth
an obvious "period of internal work," almost a period of
"assimilation" or "internal maturation." Observation of the work of
others becomes increasingly frequent, as if it were a spontaneous
"comparative" study between the child himself and his companions; or
as if an active interest in the contemplation of the external
surroundings were developing: the period of discovery. We may say that
_the child studies himself in his own productions and puts himself
into communion with his companions and his environment_.

At this stage the completion of an entire cycle will exercise an
influence more and more far-reaching on the personality of the child.
Not only is he spurred on to a work of intimate concentration
immediately after his culminating effort; he preserves a permanent
attitude of thought, of internal equilibrium, of sustained interest in
his environment. He becomes a personality who has reached a higher
degree of evolution. This is the period when the child begins to be
"master of himself" and enters upon that characteristic phenomenon I
have called the "phenomenon of obedience." He _can obey_, that is, he
can control his actions, and therefore can direct them in accordance
with the desires of another person. He can break off a piece of work
when interrupted, without becoming disorderly or showing symptoms of
fatigue. Moreover, work has become his habitual attitude, and the
child can no longer bear to be idle. When, for instance, we call some
of the children who are in this stage to the lessons for teachers, in
which they are to serve as the "subjects of study," they lend
themselves with ready docility to that which we ask of them, they
sub