Conditions of Experiment From Day To Day for Problem 2
Date Punishment Reward
May 17 …………. 20 sec. confinement …….. Food in right box for each
(Aid after 10 trials) trial
" 18 to 21 …….. 30 sec. confinement …….. Food (banana) in right box
for each trial
" 22 to June 2 …. Illness, no experiments
June 3 …………… 15 sec. confinement …….. Food (banana) in right box
for each trial
" 4 …………… 30 " " …………. Food (banana) in right box
for each trial
" 5-10 ………… 60 " " …………. Beet, carrot and loquat, in
addition to banana
" 11 ………….. 10 to 30 sec. confinement.. Beet, carrot and loquat, in
addition to banana
" 12 to 15 …….. 60 sec. confinement …….. Beet, carrot and loquat, in
addition to banana
" 16 ………….. 60 " " …………. Banana and sweet corn—former
preferred
" 17 (1st series). 60 sec. confinement …….. Food (banana, as in early
series)
" 17 (2nd series). No confinement in wrong box; Food only for correct first
but instead, return to choices
starting point by way of
alleys
" 18 to 22 …….. No confinement in wrong box; Food only for correct first
but instead, return to choices
starting point by way of
alleys
" 22 (2nd series). No punishment; allowed to Food for each trial
enter boxes until right
one was found
" 23 ………….. Return to starting point.
After five wrong choices
of a given box the animal
was held for 60 secs. in
one of the boxes and was
then released by way of
the exit door and rewarded
when the right one was
chosen
" 23 (2nd series). No punishment ………….. Reward for each trial
" 24 (1st series). Return to starting point... Food only for correct first choices
" 24 (2nd series). No punishment ………….. Reward for each trial
" 25-30 ……….. Same as on 24th …………
July 1 (1st series). No punishment ………….. " " " "
" 1 (2nd series). Return to starting point … Reward only for correct first
choices
" 2-8 …………. Same as on July 1 ……….
" 8 (2nd series). No punishment ………….. Reward for each trial
" 8 (3rd series). Return to starting point … Reward only for correct first choices
" 9-10 ………… Same as for July 8 (3rd series)
" 10 (2nd series). Momentary confinement in ….. Reward for each correct choice wrong boxes
" 12 ………….. Return to starting point ….. Reward for correct first choice
" 12 (2nd series). 30 sec. confinement ………. Reward for each correct choice
" 12 (3rd series). 5 " " …………… " " " " "
" 13 ………….. 30 " " …………… " " " " "
" 14-17 ……….. Return to starting point ….. Reward for correct first choices
" 17 (2nd series). 60 sec. confinement ………. Reward for each correct choice
" 19 ………….. 30 " " …………… " " " " "
" 20-26 ……….. 10 " " …………… " " " " "
" 27-30 ……….. Right box indicated by slight Reward in each right box raising of exit door momentarily. No punishment
" 30 (2nd series). Return to starting point ….. Reward for correct first choices
" 31 ………….. " " " " ….. " " " " "
" 31 (2nd series) to Aug. 10 …. 10 to 60 sec. confinement …. Reward for each correct choice
Aug. 10 (2nd series). Threatened with whip ……… " " " " "
" 11 (1st series). " " " ……….. " " " " "
" 11 (2nd series). 10 sec. confinement ………. " " " " "
" 12 ………….. Threatened with whip ……… " " " " "
" 12 (2nd series). 10 sec. confinement ………. " " " " "
" 19 ………….. 10 " " …………… " " " " "
" 19 (2nd series). Threatened with whip ……… " " " " "
With the above reactive tendencies and modifications of method in mind we may continue our description of results. On June 9 there developed a tendency to increase the magnitude of the original error by choosing nearer the left end of the groups. This is odd, since one would naturally suppose that an animal as intelligent as the orang utan would tend to avoid the general region in which success was never obtained and to focus attention on the right, as contrasted with the wrong end of each group. It obviously contradicts the law of the gradual elimination of use less activities. In other words, it is wholly at variance with the principle of trial and error exhibited by many infrahuman organisms. Julius, although making many mistakes, worked diligently and, for the most part, fairly rapidly. The day’s work proved most important because of the change in method and also because of the appearance of hesitation, the rejection of certain boxes, and the definite choice of others. My notes record “this is a most important day for Julius in problem 2;” but subsequent results do not clearly justify this prophecy.
The method of choosing the first box at the left and then of moving down the line until the right one was reached was so consistently followed that during a number of days it was possible for me to predict almost every choice. Indeed, to satisfy my curiosity in this matter during a number of series I guessed in advance the box which would be chosen. The percentages of correct guesses ranged from ninety to one hundred. June 10, for example, yielded two series for which the ratio of right to wrong first choices was 0 to 10, and in which the method described above was used consistently throughout.
It was inevitable that punishment by confinement and the discouragement resulting therefrom should interfere with the regularity of work and make it extremely difficult to obtain strictly comparable results from series to series and from day to day. The data for this problem, as presented in table 9, have values quite different from those for the monkeys, chiefly because of the more variable conditions of observation.
It was occasionally noted that the disintegration of a definite method and the disappearance of the tendency on which it depended occurred rather suddenly. Frequently it happened that having used an inadequate method fairly persistently on a given day, the animal would on the following day exhibit a wholly different method. Even over night a new method might develop. In the monkeys, although there was occasionally something comparable with this, it was by no means so evident.