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, so this
instinct drops out. Many of our instincts not only would fail to be serviceable in
our later lives, but would be positively in the way. Each serves its day, and then
passes over into so modified a form as not to be recognized, or else drops out of
sight altogether.
Seemingly Useless Instincts.—Indeed it is difficult to see that some instincts
serve a useful purpose at any time. The pugnacity and greediness of childhood,
its foolish fears, the bashfulness of youth—these seem to be either useless or
detrimental to development. In order to understand the workings of instinct,
however, we must remember that it looks in two directions; into the future for its
application, and into the past for its explanation. We should not be surprised if
the experiences of a long past have left behind some tendencies which are not
very useful under the vastly different conditions of today.
Nor should we be too sure that an activity whose precise function in relation to
development we cannot discover has no use at all. Each instinct must be
considered not alone in the light of what it means to its possessor today, but of
what it means to all his future development. The tail of a polliwog seems a very
useless appendage so far as the adult frog is concerned, yet if the polliwog's tail
is cut off a perfect frog never develops.
Instincts to Be Utilized When They Appear.—A man may set the stream to
turning his mill wheels today or wait for twenty years—the power is there ready
for him when he wants it. Instincts must be utilized when they present
themselves, else they disappear—never, in most cases, to return. Birds kept
caged past the flying time never learn to fly well. The hunter must train his setter
when the time is ripe, or the dog can never be depended upon. Ducks kept away
from the water until full grown have almost as little inclination for it as chickens.