my supplementary tests did I obtain
convincing indications of reasoning. What Hobhouse has called articulate
ideas, I believe to appear infrequently in these animals. But on the
whole, I believe that the general conclusions of previous experimental
observers have done no injustice to the ideational ability of monkeys.
It is clearly important, however, that we always should take into
account the species of animal observed, for unquestionably there are
extreme differences in mental development among the monkeys.

As I view my results in the light of their relations to earlier work, I
am strongly impressed with the importance of the use of improved methods
for the study of complex behavior. The delayed reaction method of
Hunter, the quadruple-choice method of Hamilton, and my multiple-choice
method offer new and promising approaches to forms of activity which
thus far have been only superficially observed.

The ability exhibited by Skirrl to try a method out and then to abandon
it suddenly is characteristic of animals high in intelligence. Most of
the problems which I presented to my animals would be rated as difficult
by psychologists, for as a rule they involved definite relations and
demanded on the part of the subject both perception of a particular
relation and the ability to remember or re-present it on occasion.

I was greatly surprised by the slow progress of the monkeys toward the
solution of these problems. It had been my supposition that they would
solve them more quickly than any lower type of mammal, but as a matter
of fact they succeeded less well than did pigs. Their behavior
throughout the work proved that of far greater significance for the
experimenter than the solution of a problem is definite knowledge of the
modes of behavior exhibited from moment to moment, or day to day. This
is true especially of those incidental or accidental modes of response
which so frequently appeared in connection with my work that I came to
look upon them, the surprises of each day, as my chief means of insight.

_Evidences of Ideation in Apes_

Reliable literature of any sort concerning the behavior and mental life
of the anthropoid apes is difficult to find, and still more rare are
reports concerning experimental studies of these animals. There are, it
is true, a few articles descriptive of tests of mental ability, but even
these are scarcely deserving of being classed as satisfactory
experimental studies of the psyc