are
for your own welfare; so that your attitude toward "the boss" comes to
be a blend of fear, admiration and gratitude. Religion and patriotism
furnish good examples of compound emotions.

Well, then, adult behavior compared with the instinctive behavior of
the little child shows these several types of modification. This is
interesting, but it is not all we wish to know. We want to know how
the modification comes about; that is, we want to get an insight into
the process of learning. Scientifically, this is one of the most
fascinating topics in psychology--how we learn, how we are molded or
modified by experience--and practically, it is just as important,
since if we wish to educate, train, mold, improve ourselves or others,
it is the _process_ of modification that we must control; and to
control it we must understand it.

To understand it we must watch the process itself; and {302} therefore
we turn to studies that trace the course of events in human and animal
learning.

Animal Learning

Animals do learn, all the vertebrates, at least, and many of the
invertebrates. They often learn more slowly than men, but this is an
advantage for our present purpose, since it makes the learning process
easier to follow. Mere anecdotes of intelligent behavior in animals
are of little value, but experimental studies, in which the animal's
progress is followed, step by step, from the time when he is
confronted with a perfectly novel situation till he has mastered the
trick, have now been made in great numbers, and a few typical
experiments will serve as a good introduction to the whole subject of
learning.

The negative adaptation experiment.

Apply a harmless and meaningless stimulus time after time; at first
the animal makes some instinctive exploring or defensive reaction; but
with continued repetition of the stimulus, he ceases after a while to
respond. The instinctive reaction has been detached from one of its
natural stimuli.

Even in unicellular animals, negative adaptation can be observed, but
in them is only temporary, like the "sensory adaptation" described in
the chapter on sensation. Stop the stimulus and the original
responsiveness returns after a short time. Nothing has been learned,
for what is learned remains after an interval of rest.

In higher animals, permanent adaptation is common, as illustrated by a
famous experiment on a spider. While the spider was in its web, a
tuning fork was sounded, and th