In this problem, Sobke's improvement was steady and fairly rapid, and in the eighth series, trials 71 to 80, only correct first choices appear. Consequently, seventy trials were required for the solution of the problem. This number is in marked contrast with Skirrl's one hundred and thirty-two trials.
Immediately following the first perfect series, Sobke was given two series of control tests on April 28. Conditions were unfavorable, since the day was stormy and the rain pattering on the sheet-iron roof made a great din. Nevertheless, he worked steadily and well up to the sixth trial, which was preceded by a slight delay because of the necessity of refilling some of the food boxes. After this interruption, wrong choices occurred in trial 6. And again after trial 9, there was brief interruption, followed by wrong choices in trial 10. The ratio of right to wrong choices for this first control series was therefore 1 to .25.
TABLE 4
Results for Sobke, P. rhesus, in Problem 1
========+===========+==============+==============+==============+==============+==============+==============+==============+==============+==============+==============+===+===+===+===+========
| No. | S.1 | S.2 | S.3 | S.4 | S.5 | S.6 | S.7 | S.8 | S.9 | S.10 | | | | | Ratio
Date | of | | | | | | | | | | | R | W | R | W | of
| trials | 1.2.3 | 8.9 | 3.4.5.6.7 | 7.8.9 | 2.3.4.5.6 | 6.7.8 | 5.6.7 | 4.5.6.7.8 | 7.8.9 | 1.2.3 | | | | | R to W
————+—————-+———————+———————+———————+———————+———————+———————+———————+———————+———————+———————+—-+—-+—-+—-+————
April | | | | | | | | | | | | | | | |
19 | 1-10 | 1 | 8 | 3 | 9.7 | 6.2 | 6 | 7.5 | 4 | 9.7 | 1 | 6 | 4 | 6 | 4 | 1:0.67
20 | 11-20 | 1 | 8 | 3 | 7 | 2 | 6 | 7.5 | 8.4 | 9.9.7 | 1 | 7 | 3 | 7 | 3 | 1:0.43
21 | 21-30 | 1 | 8 | 4.3 | 9.7 | 2 | 6 | 5 | 8.4 | 7 | 1 | 7 | 3 | 7 | 3 | 1:0.43
22 | 31-40 | 1 | 8 | 3 | 7 | 6.2 | 6 | 6.5 | 4 | 7 | 3.1 | 7 | 3 | 7 | 3 | 1:0.43
23 | 41-50 | 1 | 8 | 3 | 7 | 2 | 6 | 5 | 4 | 9.7 | 3.1 | 8 | 2 | 8 | 2 | 1:0.25
24 | 51-60 | 1 | 8 | 3 | 9.7 | 2 | 6 | 5 | 4 | 7 | 2.1 | 8 | 2 | 8 | 2 | 1:0.25
26 | 61-70 | 1 | 8 | 3 | 7 | 2 | 6 | 5 | 4 | 7 | 3.1 | 9 | 1 | 9 | 1 | 1:0.11
27 | 71-80 | 1 | 8 | 3 | 7 | 2 | 6 | 5 | 4 | 7 | 1 |10 | 0 |10 | 0 | 1:0.00
————+—————-+———————+———————+———————+———————+———————+———————+———————+———————+———————+———————+—-+—-+—-+—-+————
| | | | | | | | 2.3.4 | | | 1.2.3.4.5 | | | | |
| | 2.3.4 | 6.7.8.9 | 3.4.5 | 4.5.6.7.8.9 | 6.7.8.9 | 1.2.3.4.5 | 5.6.7.8 | 3.4.5.6.7.8 | 5.6.7 | 6.7.8.9 | | | | |
| +———————+———————+———————+———————+———————+———————+———————+———————+———————+———————+ | | | |
28 | 1-10 | 2 | 6 | 3 | 4 | 6 | 5.4.1 | 2 | 3 | 5 | 5.4.2.1 | 8 | 2 | | |
" | 11-20 | 2 | 6 | 3 | 4 | 6 | 2.1 | 2 | 3 | 5 | 1 | 9 | 1 |17 | 3 | 1:0.18
| | | | | | | | | | | | | | | |
========+===========+==============+==============+==============+==============+==============+==============+==============+==============+==============+==============+===+===+===+===+========
Six minutes after completion of the first control series, a second was given under slightly more favorable conditions, and in this only a single wrong choice occurred, in that box 2 was first chosen in trial 6 instead of box 1. From the results of these two control series, it is evident that Sobke's solution of problem 1 is reasonably adequate. He is easily diverted or disturbed in his work by any unusual circumstances, but so long as everything goes smoothly, he chooses with ease and certainty. Whether it is fair to describe the behavior as involving an idea of the relation of the right box to the other members of the group would be difficult to decide. I hesitate to infer definite ideation from the available evidence, but I strongly suspect the presence of images and relatively ineffective or inadequate ideation.
It is perfectly evident that Sobke is much more intelligent than Skirrl. In practically every respect, he adapted himself more quickly to the experimental procedure and progressed more steadily toward the solution of the problem than did Skirrl. The contrast in the learning processes of the two monkeys could scarcely be better exhibited than by the curves of learning which are presented in figure 18. The first, that for Sobke, is surprisingly regular; the second, that for Skirrl, is quite as surprisingly irregular. These results correlate perfectly with the steadiness and predictability of the former's responses and the irregularity and erraticness of the latter's.
Problem 2. Second from the Right End
On the completion of problem 1 Sobke was in perfect condition, as to health and training, for experimental work. He had come to work quietly, fairly deliberately, and very steadily. His timidity had diminished and he would readily come to the experimenter for food, although still he was somewhat distrustful at times and became timid when anything unusual occurred in the apparatus.
As preparation for problem 2, a break in regular experimentation covering four days followed the control series of problem 1. On each of these four days the monkey was allowed to get food once from each of the nine boxes, both doors of a given box being open for the trial and all other doors closed. For this feeding experiment, the doors were opened in irregular order, and this order was changed from day to day.