The prolonged and varied efforts to obtain the banana were due in a measure at least to three accidental successes.  Thus on April 2, 3 and again on the 5th, by fortunate combinations of circumstances, he succeeded in getting the banana, contrary to the intention of the experimenter.

Although active at first on April 6, he soon wearied of his task and quit work.  The same was true on April 7, and again on the 8th and 9th.  On these days, although hungry, he did not care to enter the large cage and worked only a few minutes each day, seldom making more than two or three half-hearted attempts to obtain the banana.  His attitude toward the task had changed completely, in that hopelessness had taken the place of eager expectancy.  By the 13th of April he had so nearly given up voluntary efforts to solve the problem that it seemed worth while to test his ability to get the idea by watching the experimenter.  For this purpose the following test of imitation was made.

On the morning of April 14, having placed a banana in the usual position, I took Julius into the large cage, dragged the two boxes to the proper position beneath the banana, placed the smaller one upon the larger one and then climbed up on them to show the ape that I could reach the banana.  I then stepped down and gave him a chance to climb on the boxes.  He did so immediately and obtained the food.

Another piece of banana was supplied, the boxes were placed in distant corners of the cage, and fifteen minutes were allowed Julius so to place them that he could obtain his reward.  He gave no indications of having profited by my demonstration, but worked with the boxes singly, usually with the larger one.  On April 16, with the banana in position and the two boxes also in the cage, Julius was admitted and allowed to work for five minutes, but again without success.  I then placed the boxes properly for him and he immediately climbed up and got the banana.  While he was eating, the boxes were carried to distant corners of the cage and another banana placed in position.  Now thirty minutes were allowed him for unaided work on the problem.  As formerly, the larger box was used repeatedly and attempts to reach from the side of the cage appeared, but there was no tendency to try to use the two boxes together.  He worked fairly persistently, however, and showed clearly the stimulating and encouraging effect of aid from the experimenter.  Once more, on April 17, Julius was taken into the cage and allowed to watch me place the boxes in proper position.  He then climbed up and obtained the desired food.  After the bait had been renewed and the boxes displaced, he immediately tried to use the larger one, then he reached for the small one as though to use both together.  But the impulse died out and he turned again to the larger box as usual, standing it on end, and persistently trying to balance himself on it.  Nothing else of special interest happened during the interval of unaided effort.