_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 the apparatus. But on April 14 he was so
hungry that he was finally lured in by the use of food. He cautiously
approached the boxes and attempted to climb through on the sides instead
of walking on the floor. It was perfectly evident that he had an
instinctive or an acquired fear of the white surfaces. As the matter was
of prime importance for the success of my work, I inquired of Doctor
Hamilton, and of the men in charge of the cages, for any incident which
might account for this peculiar behavior, and I learned that some three
months earlier, while the animal cages were being whitewashed, Skirrl
had jumped at one of the laborers who was applying a brush to the
framework of one of the cages and had shaken some lime into his eyes. He
was greatly frightened and enraged. Evidently he experienced extreme
discomfort, if not acute pain, and there resulted an association with
whiteness which was quite sufficient to cause him to avoid the freshly
painted apparatus.
Having obtained an adequate explanation of this monkey's peculiar
behavior, I proceeded with my efforts to induce him to work smoothly and
rapidly, and on April 15, by covering the floor with sawdust, I so
diminished the influence of the whiteness as to render the preliminary
training fairly satisfactory. At the end of two more days everything was
going so well that it seemed desirable to begin the regular experiment.
On the morning of April 19, Skirrl was introduced to the apparatus and
given his first series of ten trials on problem 1. This problem demanded
the selection of the first door at the left in any group of open doors.
The procedure was as previously described in that the experimenter
raised the entrance doors of a certain group of boxes, admitted the
animal to the reaction-chamber, punished incorrect choices by confining
the animal for thirty seconds, and rewarded correct choices by raising
the exit door and thus permitting escape and the obtaining of food. The
trials were given in rapid succession, and the total time required for
this first series of ten trials was thirty-five minutes. Skirrl worked
faithfully throughout this interval and exhibited no marked
discouragement. When confined in a box he showed uneasiness and
dissatisfaction by moving about constantly, shaking the doors, and
trying to raise them in order to escape.
For the series of settings used in connection with problem 1, the reader
is referred to page 18. In the first setting, the doors numbered 1, 2,
and 3, were opened. As it happened, the animal when admitted to the
reaction-chamber immediately chose box l. Having received the reward of
food, he was called back to D, and doors 8 and 9 having been raised in
preparation for the next trial, he was again admitted to the
reaction-chamber. This time he quickly chose box 9 and was confined
therein for thirty seconds. On being released, he chose after an
interval of four minutes, box 8, thus completing the trial.
As it is highly important, not only in connection with the present
description of behavior, but also for subsequent comparison of the
reactions of different types of organism in this experiment, to present
the detailed records for each trial, tables have been constructed which
offer in brief space the essential data for every trial in connection
with a given problem.
Table 1 contains the results for Skirrl in problem 1. It is constructed
as follows: the date of a series of trials appears in the first vertical
column; the numbers (and number) of the trials for the series or date
appear in column 2; the following ten columns present respectively the
results of the trials for each of the ten settings. Each number, in
these results, designates a box entered. At the extreme right of the
table are three columns which indicate, first, the number of trials in
which the right box was chosen first, column headed R; and second, the
number of trials in which at least one incorrect choice occurred, column
headed W. In the last column, the daily ratio of these first choices
appears.
Taking the first line of table 1 below the explanatory headings, we note
on April 19 ten trials, numbered 1 to 10, were given to Skirrl. In trial
1, with setting 1, he chose correctly the first time, and the record is
therefore simply 1. In trial 2, setting 2, he incorrectly chose box 9,
the first time. At his next opportunity, he chose box 8, which was the
right one. The record therefore reads 9.8. In trial 3, setting 3, he
chose incorrectly twice before finally selecting the right box. The
record reads 6.7.3, and so on throughout the ten trials which constitute
a series. The summary for this series indicates three right and seven
wrong first choices, that is, three cases in which the right box was
entered first. The ratio of right to wrong first choices is therefore 1
to 2.33. Since the total number of doors open in the ten settings is
thirty-five, and since in each of the ten settings one door is
describable as the right door, the probable ratio, apart from the
effects of training, of right to wrong first choices is 1 to 2.50. It is
evident, therefore, that Skirrl in his first series of trials closely
approximated expectation in the number of mistakes.