The Mental Life of Monkeys and Apes | Page 8

end of the group
Doors No. of No. of Settings open doors open right door
1..................5.6.7......................3..................5
2..................5.6.7......................3..................7
3..................1.2.3.4.5.6................6..................1
4..................1.2.3.4.5.6................6..................6
5..................4.5.6.7.8..................5..................4
6..................4.5.6.7.8..................5..................8
7..................2.3.4.5....................4..................2
8..................2.3.4.5....................4..................5
9..................3.4.5.6.7.8.9..............7..................3
10..................3.4.5.6.7.8.9..............7..................9 -- Total 50
PROBLEM 4. Middle mechanism of the group
Doors No. of No. of Settings open doors open right door
1..................2.3.4......................3..................3
2..................5.6.7.8.9..................5..................7
3..................1.2.3.4.5.6.7..............7..................4
4..................7.8.9......................3..................8
5..................4.5.6.7.8..................5..................6
6..................1.2.3.4.5.6.7.8.9..........9..................5
7..................1.2.3......................3..................2
8..................2.3.4.5.6..................5..................4
9..................3.4.5.6.7.8.9..............7..................6
10..................6.7.8......................3..................7 -- Total 50

It was found desirable after a problem had been solved to present a new
and radically different series of settings in order to determine to what
extent the subject had learned to choose the correct door by
memorizing each particular setting. These supplementary observations
may be known as control experiments, and the settings as
supplementary settings. In case of these, as for the original settings, the
essential facts are presented in tabular arrangement.

Settings for Control Experiments
PROBLEM 1. First at left end
Doors No. of No. of Settings open doors open right door
1..................2.3.4......................3..................2
2..................6.7.8.9....................4..................6
3..................3.4.5......................3..................3
4..................4.5.6.7.8.9................6..................4
5..................6.7.8.9....................4..................6
6..................1.2.3.4.5..................5..................1
7..................2.3.4.5.6.7.8..............7..................2
8..................3.4.5.6.7.8................6..................3
9..................5.6.7......................3..................5
10..................1.2.3.4.5.6.7.8.9..........9..................1
PROBLEM 2. Second from right end
Doors No. of No. of Settings open doors open right door
1..................5.6.7.8....................4..................7
2..................2.3.4.5.6..................5..................5
3..................1.2.3.4.5.6.7.8.9..........9..................8
4..................5.6.7......................3..................6
5..................1.2.3.4....................4..................3
6..................4.5.6......................3..................5
7..................2.3.4.5....................4..................4
8..................1.2.3......................3..................2
9..................1.2.3.4.5.6.7..............7..................6
10..................2.3.4.5.6.7.8.9............8..................8
PROBLEM 3. Alternate left and right ends
Doors No. of No. of Settings open doors open right door
1..................5.6........................2..................5

2..................5.6........................2..................6
3..................4.5.6.7.8.9................6..................4
4..................4.5.6.7.8.9................6..................9
5..................1.2.3.4.5..................5..................1
6..................1.2.3.4.5..................5..................5
7..................2.3.4.5.6.7................6..................2
8..................2.3.4.5.6.7................6..................7
9..................3.4.5.6.7.8................6..................3
10..................3.4.5.6.7.8................6..................8
PROBLEM 4. Middle
Doors No. of No. of Settings open doors open right door
1..................4.5.6.7.8..................5..................6
2..................1.2.3......................3..................2
3..................1.2.3.4.5.6.7.8.9..........9..................5
4..................2.3.4.5.6..................5..................4
5..................6.7.8......................3..................7
6..................3.4.5.6.7.8.9..............7..................6
7..................7.8.9......................3..................8
8..................1.2.3.4.5.6.7..............7..................4
9..................2.3.4......................3..................3
10..................3.4.5.6.7..................5..................5

It was my aim so far as possible to present to a given subject each day
the ten settings under a given problem in order, without interruption. If
for any reason the series of observations had to be interrupted, it was
resumed at the same point subsequently. Occasionally it was found
desirable or necessary to present only five of the series of ten settings in
succession and then to interrupt observations for an interval of a few
minutes or even several hours. But as a rule it was possible to present
the series of ten settings. All things being considered, it proved more
satisfactory to give only ten trials a day to each subject. Frequently
twenty and rarely thirty trials were given on the same day. In such
cases the series of settings was simply repeated. The only pause
between trials was that necessary for resetting the entrance doors and
replenishing the food which served as a reward for success.

III

RESULTS OF MULTIPLE-CHOICE EXPERIMENTS
1. Skirrl, Pithecus irus _Problem 1. First at the Left End_
Systematic work with the multiple-choice apparatus and method
described in the previous section was undertaken early in April with
Skirrl, Sobke, and Julius. The results for each of them are now to be
presented with such measure of detail as their importance seems to
justify.
Skirrl had previously been used by Doctor Hamilton in an experimental
study of reactive tendencies. He proved so remarkably inefficient in the
work that Doctor Hamilton was led to characterize him as
feeble-minded, and to recommend him to me for further study because
of his mental peculiarities. With me he was from the first frank,
aggressive, and inclined to be savage. It was soon possible for me to go
into the large cage, Z, with him and allow him to take food from my
hand. He was without fear of the experimental apparatus and it proved
relatively easy to accustom him to the routine of the experiment.
Throughout the work he was rather slow, inattentive, and erratic.
Beginning on April 7, I sought to acquaint him with the multiple-choice
apparatus by allowing him to make trips through the several boxes,
with the reward of food each time. Thus, for example, with the entrance
and exit doors of box 7 raised, the monkey was allowed to pass into the
reaction-compartment E and thence through box 7 to the food cup. As
soon as he had finished eating, he was called back to D by the
experimenter and, after a few seconds, allowed, similarly, to make a
trip by way of one of the other boxes. By reason of this preliminary
training he soon came to seek eagerly for the reward of food.
On April 10 the apparatus was painted white in order to increase the
lightness and thus render it easier for the experimenter to observe the
animal's movements, and when on April 12 Skirrl was again introduced
to it for further preliminary training, he utterly refused to enter the
boxes, giving every indication of extreme fear of the white floors and
even of the sides of the boxes. Finally, the attempts to induce him to
enter the boxes had to be given up, and he was returned to his cage
unfed. The following day I was equally unsuccessful in either driving
or tempting him with food into