placed out of reach, yet so that it could be obtained by
pulling a string, or pushing a door. The animal was
first allowed time to discover the method of obtaining it
for itself. If after a little while it showed no sign of
hitting on the right method, it was shown, and allowed to
get the food. ¹ Fresh food was then placed as before, and a
new trial began. It was of course necessary that the
experiments should be tried before the animal's ordinary
meal, but there seems to be an immense difference in the
effort which different animals will make to satisfy their
hunger, and this difference has to be kept carefully in
mind in weighing results.

2. The original object being to discover whether
what an animal sees done will have any effect, the first
thing was to secure that it should see. This can only be
done by gaining its attention, and I do not think that
any one who has experienced the difficulty of getting an
animal to attend to what is going on before his nose, will
be surprised at any number of failures to learn by
perception of results. In every case the animal is taken up,
on the one hand with its desire for the food, on the
other with its own instinctive or habitual method of
dealing with the obstacle before it. One's dog will
momentarily attend out of politeness to his master, but a
cat is moved by no such considerations, nor is an elephant,
nor a monkey. A mere mechanical performance of the
act before the animal, which it may or may not see,
has no effect whatever. I therefore always endeavoured
to call attention to what I was doing.

It must be added here that as with a human being, so
with an animal, attentive perception is something different
from mere perception. I will not attempt to determine in
what psychologically the difference consists, but there is in
some animals a certain obvious difference of expression
which strikes the observer. The pricked ears, fixed gaze,
and strained, tense, alert attitude of the attentive dog are

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