========+===========+==============+==============+==============+==============+==============+==============+==============+==============+==============+==============+===+===+===+===+========
| No. | S.1 | S.2 | S.3 | S.4 | S.5 | S.6 | S.7 | S.8 | S.9 | S.10 | | | | | Ratio
Date | of | | | | | | | | | 3.4.5.6 | 3.4.5.6 | R | W | R | W | of
| trials | 5.6.7 | 5.6.7 | 1.2.3.4.5.6 | 1.2.3.4.5.6 | 4.5.6.7.8 | 4.5.6.7.8 | 2.3.4.5 | 2.3.4.5 | 7.8.9 | 7.8.9 | | | | | R to W
--------+-----------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+--------
| | | | | | | | | | | | | | | |
June | | | | | {3.1.2.1 | {7.8.7.8 | | | | {9.8.7.9 | | | | | |
17 | 1--10 | {6.6.7.6 | 5.7 | {4.4.3.5.4 | {4.4.2.1 | {8.8.7.8 | 8 | 2 | 3.2.5 | {8.7.6.9 | 3.8.9 | 2 | 8 | 2 | 8 | 1:4.00
| | {6.5 | | {5.4.2.1 | {5.4.6* | {7.7.4* | | | | {8.7.3* | | | | | |
| | | | | | | | | | | | | | | |
| | | | {3.4.2.5 | | {8.7.7.5 | | | | | | | | | |
18 | 11--20 | 6.6.6.5 | 5.7 | {4.5.6.4 | 3.1.4.3.6 | {8.8.7.8 | 8 | 3.2 | (3.4.2.4 | 9.8.8.7.3 | 8.6.9 | 1 | 9 | 1 | 9 | 1:9.00
| | | | {2.3.1* | | {7.8.4* | | | {4.5 | | | | | | |
| | | | | | | | | | | | | | | |
| | | | {3.6.5.4 | | {8.8.7.7 | | | | | | | | | |
19 | 21--30 | 6.5 | 7 | {2.5.2.6 | 3.6 | {7.8.8.8 | 8 | 4.3.2 | {3.2.4.2 | {9.8.7.9.7 | 9 | 3 | 7 | 3 | 7 | 1:2.33
| | | | {3.5.1* | | {8.4 | | | {2.5 | {6.5.4.3 | | | | | |
| | | | | | | | | | | | | | | |
| | | | | | (8.8.8.8 | | | | {9.9.8.9 | | | | | |
21 | 31--40 | 6.5 | 5.6.5.7 | {3.5.4.6 | 2.5.3.6 | {7.8.3.8 | 8 | 4.2 | 2.5 | {9.5.9.9 | 9 | 2 | 8 | 2 | 8 | 1:4.00
| | | | {4.3.5.1 | | {8.7.4* | | | | {9.9.3* | | | | | |
| | | | | | | | | | | | | | | |
22 | 41--50 | 7.6.5 | 6.5.5.7 | 1 | 2.1.3.6 | {8.8.8.8 | 8 | 2 | 2.3.2.2.5 | {9.8.9.8.7 | 9 | 4 | 6 | 4 | 6 | 1:1.50
| | | | | | {7.8.4 | | | | {6.5.9.3 | | | | | |
| | | | | | | | | | | | | | | |
23 | 51--60 | 5 | 6.5.7 | 1 | {1.2.1.1 | 8.5.4 | 8 | 5.4.2 | 2.4.2.5 | {9.8.4.9 | 9 | 4 | 6 | 4 | 6 | 1:1.50
| | | | | {3.2.6 | | | | | {7.3 | | | | | |
| | | | | | | | | | | | | | | |
24 | 61--70 | 7.6.5 | 7 | 2.3.1 | 2.1.5.4.2.6 | 8.7.8.4 | 8 | 4.5.4.3.2 | 2.2.4.5 | 9.7.6.8.3 | 9 | 3 | 7 | 3 | 7 | 1:2.33
25 | 71--80 | 6.5 | 5.7 | 3.1 | 6 | 8.5.4 | 8 | 2 | 3.2.5 | 9.8.7.3 | 3.9 | 3 | 7 | 3 | 7 | 1:2.33
| | | | | | | | | | | | | | | |
26 | 81--90 | 7.7.6.5 | 6.5.7 | 3.1 | {1.4.1.1 | 8.4 | 8 | 5.4.2 | 2.5 | 9.8.9.6.3 | 9 | 2 | 8 | 2 | 8 | 1:4.00
| | | | | {5.1.6 | | | | | | | | | | |
| | | | | | | | | | | | | | | |
28 | 91--100 | 7.6.5 | 7 | 1 | 1.2.4.6 | 8.4 | 8 | 2 | 3.2.2.2.5 | 9.8.8.7.9.3 | 9 | 5 | 5 | 5 | 5 | 1:1.00
| | | | | | | | | | | | | | | |
29 | 101--110 | 7.6.5 | 5.7 | 1 | {1.1.5.3 | 8.4 | 8 | 2 | 4.2.5 | {9.9.8.9.4 | 9 | 4 | 6 | | |
| | | | | {2.1.6 | | | | | {9.7.6.3 | | | | | |
| | | | | | | | | | | | | | | |
" | 111--120 | 6.5 | 6.5.7 | 1 | 2.1.1.3.6 | 8.5.4 | 8 | 2 | 3.2.5 | 9.8.7.6.4.3 | 9 | 4 | 6 | 8 |12 | 1:1.50
30 | 121--130 | 5 | 6.5.6.5.5.7 | 1 | 3.1.6 | 8.7.6.8.5.4 | 8 | 2 | 4.2.4.2.5 | 9.3 | 9 | 5 | 5 | | |
" | 131--140 | 5 | 7 | 1 | 2.3.6 | 8.5.6.4 | 8 | 2 | 5 | 9.8.3 | 3.9 | 6 | 4 |11 | 9 | 1:0.82
July | | | | | | | | | | | | | | | |
1 | 141--150 | 5 | 7 | 1 | 1.6 | 8.7.4 | 8 | 2 | 3.2.5 | 9.8.6.9.3 | 9 | 6 | 4 | | |
" | 151--160 | 5 | 7 | 1 | 2.5.3.6 | 8.4 | 8 | 2 | 2.5 | 9.3 | 8.8.7.5.4.9 | 5 | 5 |11 | 9 | 1:0.82
2 | 161--170 | 6.5 | 7 | 1 | 2.6 | 8.4 | 8 | 2 | 3.5 | 9.3 | 9 | 5 | 5 | 5 | 5 | 1:1.00
3 | 171--180 | 6.5 | 7 | 1 | 1.5.6 | 8.4 | 8 | 2 | 3.5 | 9.3 | 9 | 5 | 5 | | |
" | 181--190 | 5 | 7 | 1 | 4.6 | 8.6.4 | 8 | 2 | 5 | 9.8.4.8.5.3 | 9 | 7 | 3 |12 | 8 | 1:0.67
5 | 191--200 | 6.5 | 5.7 | 1 | 6 | 8.4 | 8 | 2 | 5 | 9.5.3 | 9 | 6 | 4 | | |
" | 201--210 | 5 | 7 | 6.1 | 2.6 | 8.6.4 | 8 | 5.3.5.4.3.2 | 4.3.5 | 9.7.3 | 9 | 4 | 6 |10 |10 | 1:1.00
| | | | | | | | | | | | | | | |
6 | 211--220 | 5 | 5.7 | 1 | 2.6 | 8.6.4 | 8 | 2 | 4.3.5 | 9.3 | {5.4.8.3 | 4 | 6 | | |
| | | | | | | | | | | {8.5.4.9 | | | | |
| | | | | | | | | | | | | | | |
" | 221--230 | 5 | 7 | 1 | 5.3.6 | 8.6.8.4 | 8 | 4.2 | 3.2.5 | 9.3 | 9 | 5 | 5 | 9 |11 | 1:1.22
7 | 231--240 | 5 | 7 | 1 | 2.6 | 8.4 | 7.4.8 | 2 | 4.3.5 | 8.3 | 9 | 5 | 5 | | |
" | 241--250 | 5 | 7 | 2.6.3.5.1 | 6 | 8.4 | 8 | 2 | 5 | 9.3 | 9 | 7 | 3 | | |
| | | | | | | | | | | | | | | |
| | | | {2.6.2.6.4 | | | | | | | | | | | |
" | 251--260 | 5 | 7 | {6.3.2.6 | 6 | 8.4 | 8 | 2 | 5 | 9.5.3 | 9 | 7 | 3 |19 |11 | 1:0.58
| | | | {5.4.3.1 | | | | | | | | | | | |
| | | | | | | | | | | | | | | |
8 | 261--270 | 7.5 | 7 | 1 | 6 | 8.4 | 8 | 5.2 | 5 | 8.3 | 8.5.4.9 | 5 | 5 | | |
" | 271--280 | 5 | 7 | 2.6.4.6.1 | 6 | 8.5.8.4 | 7.4.8 | 5.5.3.5.2 | 5 | 9.3 | 9 | 5 | 5 |10 |10 | 1:1.00
| | | | | | | | | | | | | | | |
9 | 281--290 | 5 | 5.7 | 1 | 6 | 8.4 | 8 | 2 | 2.5 | 8.3 | {7.3.8.6.8 | 5 | 5 | | |
| | | | | | | | | | | {4.7.3.9 | | | | |
| | | | | | | | | | | | | | | |
" | 291--300 | 5 | 7 | 1 | 6 | 8.4 | 8 | 2 | 5 | 9.3 | 9 | 8 | 2 | | |
" | 301--310 | 5 | 7 | 1 | 6 | 8.4 | 8 | 5.2 | 5 | 9.5.3 | 9 | 7 | 3 |20 |10 | 1:0.50
10 | 311--320 | 5 | 7 | 1 | 6 | 8.4 | 7.4.8 | 2 | 5 | 9.3 | 9 | 7 | 3 | | |
" | 321--330 | 5 | 7 | 1 | 5.2.6 | 8.7.4 | 8 | 2 | 5 | 9.3 | 9 | 7 | 3 |14 | 6 | 1:0.43
12 | 331--340 | 5 | 7 | 1 | 6 | 8.4 | 8 | 2 | 5 | 8.3 | 9 | 8 | 2 | | |
" | 341--350 | 5 | 7 | 1 | 6 | 8.4 | 8 | 5.2 | 5 | 9.3 | 9 | 7 | 3 |15 | 5 | 1:0.33
13 | 351--360 | 5 | 5.7 | 1 | 6 | 8.4 | 8 | 5.2 | 5 | 3 | 9 | 7 | 3 | | |
" | 361--370 | 5 | 7 | 6.1 | 6 | 4 | 8 | 5.2 | 3.2.5 | 9.3 | 9 | 6 | 4 |13 | 7 | 1:0.54
14 | 371--380 | 5 | 7 | 1 | 6 | 8.4 | 8 | 2 | 5 | 3 | 7.4.3.9 | 8 | 2 | | |
" | 381--390 | 5 | 7 | 1 | 6 | 8.4 | 8 | 2 | 5 | 9.3 | 4.7.3.9 | 7 | 3 |15 | 5 | 1:0.33
15 | 391--400 | 5 | 5.5.7 | 1 | 3.6 | 8.4 | 8 | 3.2 | 5 | 8.3 | 9 | 5 | 5 | | |
" | 401--410 | 5 | 7 | 1 | 6 | 8.4 | 8 | 2 | 5 | 7.3 | 6.5.3.9 | 7 | 3 |12 | 8 | 1:0.67
16 | 411--420 | 5 | 7 | 1 | 6 | 8.4 | 8 | 2 | 5 | 3 | 9 | 9 | 1 | | |
" | 421--430 | 5 | 7 | 1 | 6 | 4 | 8 | 2 | 5 | 3 | 4.7.4.9 | 9 | 1 | | |
" | 431--440 | 5 | 7 | 1 | 6 | 8.4 | 8 | 2 | 5 | 3 | 5.7.3.9 | 8 | 2 |26 | 4 | 1:0.15
17 | 441--450 | 5 | 7 | 1 | 6 | 4 | 4.8 | 2 | 5 | 4.3 | 3.5.9 | 7 | 3 | | |
" | 451--460 | 5 | 7 | 1 | 3.6 | 4 | 5.4.8 | 2 | 5 | 9.3 | 9 | 7 | 3 | | |
" | 461--470 | 5 | 7 | 1 | 6 | 4 | 8 | 2 | 5 | 3 | 9 |10 | 0 |24 | 6 | 1:0.25
19 | 471--480 | 5 | 7 | 1 | 6 | 8.4 | 8 | 2 | 5 | 3 | 9 | 9 | 1 | 9 | 1 | 1:0.11
--------+-----------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+--------
| | | | | | | | | | | | | | | |
| | 5.6 | 5.6 | 4.5.6.7.8.9 | 4.5.6.7.8.9 | 1.2.3.4.5 | 1.2.3.4.5 | 2.3.4.5.6.7 | 2.3.4.5.6.7 | 3.4.5.6.7.8 | 3.4.5.6.7.8 | | | | |
| +--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+--------
19 | 1--10 | 5 | 6 | 4 | 9 | 1 | 5 | 3.7.2 | 7 | 3 | 8 | 9 | 1 | 9 | 1 | 1:0.11
========+===========+==============+==============+==============+==============+==============+==============+==============+==============+==============+==============+===+===+===+===+========
[Footnote *: Aided by experimenter.]
The data of table 6 indicate for this problem only three pronounced
reactive tendencies: (a) As the initial tendency, the choice of the
second box from the right end. This proved surprisingly weak, in view of
the animal's long training on problem 2, and it disappeared quickly. (b)
Choice of the end boxes, and (c) direct choice of the right box.
For this, as for the other problems, extreme differences in method and
in time and degree of success appear for the different settings. Thus,
while settings 1, 2, 3, 6, 7, and 10 proved to be easy, settings 4, 5,
8, and 9 were evidently more difficult.
[Illustration: FIGURE 20.--Error curve of learning for the solution of
problem 3 (alternately the first box at the left end and the first at
the right end) by Sobke.]
From the first this problem promised to be much easier for Sobke than
problem 2, and although the actual number of trials necessary for the
solution is greater by sixty for problem 3 than for problem 2,
comparison of the data of the tables justifies the statement that the
third problem was both easier and more nearly adequately solved than the
second. This is not surprising when the nature of the two problems is
considered, for whereas problem 2 requires choice by perception of the
relationship of secondness from the right end of the group, problem 3
requires, instead, the choice of the end member of the group each time,
with the additional variation of alternation of ends. Now as it happens,
the end member is easily selected by the monkey, and it appears further
that alternation was relatively easy for Sobke to acquire. Consequently,
the combination of end and alternation proved easier than the choice of
the second from the right end of the group.
The above statements are supported by comparison of the curves of
learning. The curve for problem 2, figure 19, is extremely irregular;
that for problem 3, figure 20, much more regular. Similarly, the daily
ratios of right to wrong choices as exhibited in tables 5 and 6 indicate
smaller variations for the third problem than for the second.
Sobke made ten correct first choices in the third series for July 17,
but he was working very uncertainly and it seemed rather a matter of
good luck than good management that he succeeded in presenting this
perfect series: For this reason and also because it did not seem
feasible to have Sunday intervene between the final and perfect regular
series and the control series, an additional regular series was given on
July 19, in which, as the table indicates, a single mistake occurred, in
trial 5. The monkey was working perfectly. The series of trials required
only ten minutes, and it was evident that carelessness and eagerness to
obtain food were chiefly responsible for the mistake.
The control series given on July 19 immediately after the series just
described resulted similarly in one failure and nine successes. The
choices were made easily and with certainty, and the only mistake, that
of setting 7, was apparently due to carelessness.
This excellent showing for the control series wholly justifies the
comparison of problems 2 and 3 as to difficultness, made above. Whereas
in both problems 1 and 2 the control trials caused confusion, in the
case of problem 3, they did not essentially alter the behavior of the
animal. The fact seems to be that for this problem the particular
setting is of relatively little importance; while turning alternately to
the extreme left and the extreme right is of prime importance. That
Sobke had the idea of alternation or of the end box, there seems no more
reason for insisting than that he had the idea of secondness from the
right end in problem 2. It is possible, even probable, that these ideas
existed rather vaguely in his consciousness, but there is obviously no
necessity for insisting that the solution of the problems depended upon
them.
_Problem 4. Middle_
As the available time for the continuation of the experiment was
limited, it was decided to proceed with work on problem 4 immediately
upon the completion of problem 3, and on July 20, the problem of the
middle door was presented to Sobke. Since it was anticipated that this
sudden change would confuse and discourage him greatly, the only form of
punishment administered was the momentary lowering of the entrance door
of the wrong box. As in the previous problem, he was aided after ten
successive wrong choices. As might have been anticipated, he
persistently entered the end boxes of the groups, and this in some
instances probably would have been kept up for many minutes had not the
experimenter lured him into the right box by slightly raising the exit
door. In the first series, he had to be aided in five of the ten trials.
The total time for the series was forty-five minutes, the total number
of choices, eighty-eight. In the second series, he was aided in four of
the trials. The total time required was seventy-two minutes, and the
total number of choices was seventy-six.
Throughout the first series, Sobke worked hard, but with evidently
increasing dissatisfaction. He clung persistently to his acquired
tendency to choose the end boxes, and after each trial he returned less
willingly to the starting point. Up to this time his attitude toward the
experimenter had been perfectly friendly, if not wholly trustful. But
when on July 21 he was brought into the apparatus for the second series,
he exhibited a wholly new form of behavior, for instead of attending
diligently to the open doors and devoting his energies to trying to find
the right box, he instead, after gazing at them for a few seconds,
turned toward the experimenter and jumped for him savagely, throwing
himself against the wire netting with great force. This was repeated a
number of times during the first two or three trials, and it occurred
less frequently later in the series. Since nothing unusual had happened
outside of the experiment room, the suggested explanation of this sudden
change in attitude and behavior is that the monkey resented and blamed
on the experimenter the difficulty which he was having in obtaining
food.
From this time on until the end of my work, Sobke was always savage and
both in and out of the apparatus he was constantly on the watch for an
opportunity to spring upon me. Previously, it had been possible for me
to coax him into the apparatus by offering him food and to return him to
his cage by walking after him. But on and after the twenty-first of
July, it was impossible for me to approach him without extreme risk of
being bitten.
Doctor Hamilton when told of this behavior, reported that several times
monkeys have shown resentment toward him when they were having trouble
in the experiment. I therefore feel fairly confident that I have not
misinterpreted Sobke's behavior. When on July 22 I gave Sobke an
opportunity to enter the apparatus, he refused, and it was impossible to
lure him in with food. Two hours later, having waited meantime for his
breakfast, he entered readily and worked steadily and persistently
through his third series of trials, but in no one of these trials did he
choose correctly. Neither on this day nor the following did he exhibit
resentment while at work. He apparently had regained his affective poise
and was able to attend as formerly to the task of locating his rewards.
During these first three series, although the ratio of right to wrong
choices stood 0 to 10, there occurred a marked reduction in the number
of trials in which aid was necessary as well as in the total number of
choices, and on July 23 correct reactions began to appear. Improvement
during the next hundred trials was steady and fairly rapid, and on July
31, a record of seven right to three wrong trials was obtained. This was
surprising to the experimenter, as well as gratifying, since he was
eager to have the animal complete this problem before work should have
to be discontinued.
Everything went smoothly until August 2, when my assistant, who had been
left in charge of the experimental work for a week, attempted to
increase the number of trials per day to two series. Sobke apparently
was not quite ready for this increase in the amount of his day's labor
and refused to work at the end of the first series. In this series he
did less well than on the previous day. The following day, August 3,
unfortunately and contrary to the wishes of the experimenter, the
laboratory was painted and there was necessarily considerable
disturbance because of the presence of the workmen, and in addition, the
pervasive odor of fresh paint. Sobke chose still less successfully on
this date, and on August 4, he refused to work after the eighth trial.
It is true that during these bad days the total number of choices
steadily diminished while the successes, also, diminished, or at best,
failed to increase. When on August 9, I returned to the laboratory to
take charge, I found that Sobke was no longer trying to solve the
problem as when I had gone away. His attitude had changed in that he had
become indifferent, careless, and obviously discouraged with his task.