d we
must take part in the busy life about us and do as other people do; so
the instinct to imitate arises that we may learn things quickly and
easily.

We need a spur to keep us up to our best effort, so the instinct of
emulation emerges. We must defend ourselves, so the instinct of
pugnacity is born. We need to be cautious, hence the instinct of fear.
We need to be investigative, hence the instinct of curiosity. Much
self-directed activity is necessary for our development, hence the play
instinct. It is best that we should come to know and serve others, so
the instincts of sociability and sympathy arise. We need to select a
mate and care for offspring, hence the instinct of love for the other
sex, and the parental instinct. This is far from a complete list of our
instincts, and I have not tried to follow the order of their
development, but I have given enough to show the origin of many of our
life's most important activities.

MANY INSTINCTS ARE TRANSITORY.--Not only do instincts ripen by degrees,
entering our experience one by one as they are needed, but they drop out
when their work is done. Some, like the instinct of self-preservation,
are needed our lifetime through, hence they remain to the end. Others,
like the play instinct, serve their purpose and disappear or are
modified into new forms in a few years, or a few months. The life of the
instinct is always as transitory as is the necessity for the activity
to which it gives rise. No instinct remains wholly unaltered in man, for
it is constantly being made over in the light of each new experience.
The instinct of self-preservation is modified by knowledge and
experience, so that the defense of the man against threatened danger
would be very different from that of the child; yet the instinct to
protect oneself in _some_ way remains. On the other hand, the instinct
to romp and play is less permanent. It may last into adult life, but few
middle-aged or old people care to race about as do children. Their
activities are occupied in other lines, and they require less physical
exertion.

Contrast with these two examples such instincts as sucking, creeping,
and crying, which are much more fleeting than the play instinct, even.
With dentition comes another mode of eating, and sucking is no more
serviceable. Walking is a better mode of locomotion than creeping, so
the instinct to creep soon dies. Speech is found a better way than
crying to attract attention to distress