aily wrong choices and presented
in figure 18, had it been obtained with a human subject, would
undoubtedly be described as an ideational, and possibly even as a
rational curve; for its sudden drop from near the maximum to the base
line strongly suggests, if it does not actually prove, insight.

Never before has a curve of learning like this been obtained from an
infrahuman animal. I feel wholly justified in concluding from the
evidences at hand, which have been presented as adequately as is
possible without going into minutely detailed description, that the
orang utan solved this simple problem ideationally. As a matter of fact,
for the solution he required about four times the number of trials which
Sobke required and twice as many as were necessary for Skirrl. Were we
to measure the intelligence of these three animals by the number of
trials needed in problem 1, Sobke clearly would rank first, Skirrl
second, and Julius last of all. But other facts clearly indicate that
Julius is far superior to the monkeys in intelligence. We therefore must
conclude that _where very different methods of learning appear, the
number of trials is not a safe criterion of intelligence._ The
importance of this conclusion for comparative and genetic psychology
needs no emphasis.

_Problem 2. Second from the Right End_

Julius was given four days' rest before being presented with problem 2.
He was occasionally fed in the apparatus, but regular continuation of
training was not necessary to keep him in good form. During this rest
interval, locks were attached to the doors of the apparatus so that the
experimenter by moving a lever directly in front of him could fasten
either one or both of the doors of a given box by a single movement. On
May 13 Julius was given opportunity to obtain food from each of the
boxes in turn, and trial of the locks was made in order to familiarize
him with the new situation. He very quickly discovered that the doors
could not be raised when closed, and after two days of preliminary work,
he practically abandoned his formerly persistent efforts to open them.
The locks worked satisfactorily from a mechanical point of view as well
as from that of the adaptation of the animal to the modified situation.

Problem 2 was regularly presented for the first time on May 17, on which
day a single series was given. The period of punishment adopted was
twenty seconds, and for each successful choice a small piece of banana
wa