The Mental Life of the Monkeys IgI 
from the necessity of seeking some general mental differ- 
ence as the explanation of the difference in the results. 
(Un the third place it may be said by some that no com- 
parison of the monkeys with dogs and cats is valid, since, 
the former animals got ouf“6f boxes while the latter got in” 
It may be supposed that the instinctive response to confine- 
ment includes an agitation which precludes anything save 
vague unregulated behavior. } Professor Wesley Mills has 
made such a suggestion in referring to the ‘Animal Intelli- 
gence’ in the Psychological Review, May, 1899. In the 
July number of the same journal I tried to show that 
there was no solid evidence of such a harmful agitation. 
Nor can we be at all sure that agitation when present does 
not rather quicken the wits of animals. It often seems to. 
However I should, of course, allow that for purposes of 
comparison it would be better to have the circumstances 
identical. And I should welcome any antagonist who should, 
by making experiments with kittens after the fashion of 
these with the monkeys, show that they did learn as sud- 
denly as the latter. 
Again we know that, whereas the times taken by a cat 
in a box to get out are inversely proportional to the strength 
of the association, inasmuch as they represent fairly the 
amount of its efforts, on the other hand, the times taken by a 
monkey to get in represent the amounts of his efforts plus 
the amount of time in which he is not trying to getin. It may 
be said therefore that the time records of the monkeys prave 
nothing, — that a record of four minutes may mean thirty 
seconds of effort and three minutes thirty seconds of sleep, — 
that one minute may really represent twice as much effort. 
As a matter of fact this objection would occasionally hold 
against some single record. The earliest times and the 
occasional long times amongst very short ones are likely 
