The Mental Life Of Monkeys And Apes Part 6

This method discouraged him extremely and proved wasteful of time.

Consequently, in a second series on the same date return was made to the former method, and he was rewarded with food whenever he found the right box. But on April 28, the two methods were again employed, the first in the initial series and the second in a final series of trials. The animal's persistent attempts to raise the doors gave the experimenter so much trouble that on April 29 barbed wire was nailed over the windows of the entrance doors with the hope that it might prevent him from working at them. But he quickly learned to place his fingers between the barbs and raise the doors as effectively as ever.

On April 30 the reward of food was given only when the first choice was that of the right box and in that event it was placed in the alleyway H as stated above.

As it seemed absolutely essential to break the unprofitable habit of choosing the nearest door, on May 3 a new series of settings was presented, in which only the doors to the left of the middle of the row of nine boxes were used as right doors. That is, in this new series, doors 1 to 4 occur as right doors; 5 to 9 do not. As punishment for wrong choices on this date, Julius was confined in the wrong box from one to five minutes. It was difficult to keep him in, but by means of cords which had been attached to the doors, this was successfully accomplished. Yet another and slightly different series of settings was employed on May 4, and this, proving satisfactory, was continued in use until the end of the experiment, with punishment ranging from sixty to one hundred and twenty seconds for each mistake.

Naturally the modification of settings introduced May 3 greatly increased the proportion of wrong first choices. Indeed, as appears in table 8, the ratio of right to wrong immediately changed from 1:0.67 to 1:4.00. Between May 3 and May 10, no steady and consistent improvement in method or in the number of correct first choices occurred, and on the last named date, Julius chose correctly only three times in his ten trials. At this time there was, as my notes record, no satisfactory indication of progress, and the status of the experiment seemed extremely unsatisfactory in as much as in spite of the experimenter's best efforts to break up the habit of choosing the nearest door, the orang utan still persisted, to a considerable extent, in the use of this method. The only encouraging feature of the results was an evident tendency to choose somewhat nearer the left end of a group than previously.

TABLE 8

Results for Orang utan 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 13 1- 10 3.1 8 4.3 7 4.2 7.6 5 4 7 3.1 5 5 5 5 1:1.00 14 11- 20 3.2.1 8 4.3 7 4.4.2 6 5 4 7 3.1 6 4 6 4 1:0.67 15 21- 30 3.2.1 8 4.3 7 4.5.5.2 6 5 4 7 3.1 6 4 6 4 1:0.67 16 31- 40 3.1 8 4.3 7 4.2 6 5 4 7 3.2.1 6 4 6 4 1:0.67 17 41- 50 3.2.1 8 4.3 7 4.2 6 5 4 7 3.1 6 4 6 4 1:0.67 19 51- 60 3.1 8 4.3 7 4.2 6 5 4 7 3.1 6 4 6 4 1:0.67 20 61- 70 2.1 8 4.3 7 5.3.2 6 5 4 7 3.1 6 4 6 4 1:0.67 21 71- 80 3.1 8 4.3 7 5.4.3.2 6 5 4 7 3.2.1 6 4 6 4 1:0.67 22 81- 90 3.1 8 5.3 7 6.3.2 6 5 4 7 3.2.1 6 4 6 4 1:0.67 23 91-100 3.2.1 8 5.3 7 4.3.2 6 5 5.4 7 3.2.1 5 5 5 5 1:1.00 24 101-110 3.2.1 8 4.3 7 4.3.2 6 5 4 7 3.1 6 4 6 4 1:0.67 26 111-120 3.1 8 4.3 7 4.3.2 6 5 5.4 7 3.1 5 5 5 5 1:1.00 27 121-130 3.2.1 8 4.3 7 4.3.2 6 6.5 5.8.6.4 7 3.3.3.1 4 6 " 131-140 3.1 8 4.3 7 4.3.2 6 5 4 7 3.2.1 6 4 10 10 1:1.00 28 141-150 3.2.1 8 3 7 5.4.2 6 5 4 7 3.1 7 3 " 151-160 3.1 8 3 7 3.2 6 5 4 7 3.2.1 7 3 14 6 1:0.43 29 161-170 3.1 8 4.3 7 4.3.2 6 5 4 7 3.2.1 6 4 " 171-180 3.2.1 8 4.3 7 4.2 6 5 4 7 3.2.1 6 4 12 8 1:0.67 30 181-190 3.1 8 4.3 7 {4.5.6.4 6 5 4 7 3.1 6 4 {5.6.4.2 " 191-200 3.1 8 4.5.6.7.3 7 4.5.3.2 6 5 4 7 3.2.1 6 4 12 8 1:0.67 May 1 201-210 3.1 8 4.3 7 3.2 6 5 4 7 3.1 6 4 " 211-220 3.2.1 8 4.3 7 4.2 6 5 4 7 3.1 6 4 12 8 1:0.67 --------+-----------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+-------- 2.3.4.5 2.3.4.5 1.2.3 3.4.5.6.7 6.7.8 1.2.3 3.4.5.6.7 4.5.6.7.8.9 2.3.4.5 1.2.3 4.5.6.7.8.9 6.7.8.9 --------+-----------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+-------- 3 221-230 3.1 4.3 4.2 3.1 4.3 4 4.3.2 3.1 4 4.3.2 2 8 2 8 1:4.00 --------+-----------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+-------- 2.3.4.5 4.5.6.7 2.3.4.5 1.2.3 3.4.5.6.7 6.7.8 8.9 2.3.4.5 3.4.5.6 1.2.3 4.5.6.7.8 6.7.8.9 1.2.3 --------+-----------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+-------- 4 231-240 3.2.1 4.3 4.2 4 4.3.2 4.3 3.2.1 4 3.2 3.2.1 2 8 2 8 1:4.00 5 241-250 2.1 3 3.2 4 3.2 4.3 3.2.1 4 3.2 3.2.1 3 7 3 7 1:2.33 6 251-260 2.1 3 2 4 3.2 3 2.1 4 3.2 2.1 5 5 5 5 1:1.00 7 261-270 2.1 3 3.2 4 3.2 3 2.1 4 4.2 2.1 4 6 4 6 1:1.50 8 271-280 2.1 4.3 4.3.2 4 3.2 4.3 3.1 4 3.2 2.1 2 8 2 8 1:4.00 10 281-290 1 4.3 4.2 4 3.2 4.3 2.1 4 3.2 2.1 3 7 3 7 1:2.33 11 291-300 1 3 2 4 2 3 1 4 2 1 10 0 10 0 1:0.00 --------+-----------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+-------- 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 --------+-----------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+-------- 12 301-310 1 8 3 7 2 6 5 4 7 1 10 0 10 0 1:0.00 ========+===========+==============+==============+==============+==============+==============+==============+==============+==============+==============+==============+===+===+===+===+========

A series of correct first choices was obtained on May 11, greatly to the surprise of the experimenter, for no indication had previously appeared of this approaching solution of the problem. It seemed possible, however, that the successes were accidental, and it was antic.i.p.ated that in a control series Julius would again make mistakes. But on the following day, May 12, the presentation of the original series of ten settings, which, of course, differed radically from the settings used from May 4 to May 11 was responded to promptly, readily, and without a single mistake. Julius had solved his problem suddenly and, in all probability, ideationally.

Only three reactive tendencies or methods appeared during Julius's work on this problem: (a) choice of the open door nearest to the starting point (sometimes the adjacent boxes were entered); (b) a tendency to avoid the "nearest" door and select instead one further toward the left end of the group; (c) direct choice of the first door on the left.

The curve of learning plotted from the daily wrong choices and presented in figure 18, had it been obtained with a human subject, would undoubtedly be described as an ideational, and possibly even as a rational curve; for its sudden drop from near the maximum to the base line strongly suggests, if it does not actually prove, insight.

Never before has a curve of learning like this been obtained from an infrahuman animal. I feel wholly justified in concluding from the evidences at hand, which have been presented as adequately as is possible without going into minutely detailed description, that the orang utan solved this simple problem ideationally. As a matter of fact, for the solution he required about four times the number of trials which Sobke required and twice as many as were necessary for Skirrl. Were we to measure the intelligence of these three animals by the number of trials needed in problem 1, Sobke clearly would rank first, Skirrl second, and Julius last of all. But other facts clearly indicate that Julius is far superior to the monkeys in intelligence. We therefore must conclude that _where very different methods of learning appear, the number of trials is not a safe criterion of intelligence._ The importance of this conclusion for comparative and genetic psychology needs no emphasis.

_Problem 2. Second from the Right End_

Julius was given four days' rest before being presented with problem 2.

He was occasionally fed in the apparatus, but regular continuation of training was not necessary to keep him in good form. During this rest interval, locks were attached to the doors of the apparatus so that the experimenter by moving a lever directly in front of him could fasten either one or both of the doors of a given box by a single movement. On May 13 Julius was given opportunity to obtain food from each of the boxes in turn, and trial of the locks was made in order to familiarize him with the new situation. He very quickly discovered that the doors could not be raised when closed, and after two days of preliminary work, he practically abandoned his formerly persistent efforts to open them.

The locks worked satisfactorily from a mechanical point of view as well as from that of the adaptation of the animal to the modified situation.

Problem 2 was regularly presented for the first time on May 17, on which day a single series was given. The period of punishment adopted was twenty seconds, and for each successful choice a small piece of banana was given as a reward. After the first trial in this series, in which Julius repeatedly entered the first box at the left, that is box 7, there was but slight tendency to reenter the first box at the left of the group. Instead, Julius developed the method of moving box by box toward the right end of the group. The choices were made promptly, and their systematic character enabled the animal to obtain his reward fairly quickly, in spite of the large number of mistakes.

In the second series, the orang utan developed the interesting trick of quickly dodging out of the wrong box before the experimenter could lower the door behind him. This he did only after having been punished for many wrong choices to the point of discouragement. The trick was easily broken up by the sudden lowering of the entrance door as soon as he had pa.s.sed under it.

There appeared on May 21 an unfavorable physical condition which manifested itself, first of all through the eyes which appeared dull and bloodshot. On the following day they were inflamed and the lids nearly closed. Julius refused to eat, and experimentation was impossible. Until June 2 careful treatment and regulation of diet was necessary. He pa.s.sed through what at the time seemed a rather startling condition, but rapidly regained his usual good health, and on June 3, although somewhat weak and listless, he again worked fairly steadily.

Since it was now possible to lock the doors and confine the animal for any desired period, on June 5 the interval of punishment was made sixty seconds, and a liberal quant.i.ty of banana, beet, or carrot was offered as reward. No increase in the number of successful choices appeared, and Julius showed discouragement. Sawdust had been strewn on the floor, and in the intervals between trials as well as during confinement in wrong boxes, he took to playing with the sawdust. He would take it up in one hand and pour it from hand to hand until all had slipped through his fingers, then he would sc.r.a.pe together another handful and go through the same process. Often he became so intent on this form of amus.e.m.e.nt that even when the exit door was raised, he would not immediately go to get the food.

The reactive tendencies which appeared in the work on problem 2 will now be presented in order, since I shall have to refer to them repeatedly, and the list will be more useful to the reader at this point than at the conclusion of the presentation of daily results. The following is not an exhaustive list but includes only the most important and conspicuous tendencies or methods together with the dates on which they were most apparent.

(a) May 17, choice of first box at left of group or near it, then the next in order, and so on, until the second from the right was reached.

This method with irregularities and certain definite skipping was used at various times, sometimes over periods of several days, during the course of the work.

(b) June 3, preference for number 3 and number 4 developed immediately after the orang utan's illness and when he was working rather listlessly.

On June 9 and 10, the original tendency (a) reappeared and persisted for a number of series.

(c) June 14, a tendency to choose the box at or near the right end of a group, and then the one next to it. In connection with this tendency, which of course required only two choices in any given trial, interest in playing with the sawdust on the floor developed.

Again on June 21, the animal returned to the use of tendency (a).

(d) June 29, movement to box at right end of group, hesitation before it, and turning through a complete circle so that the second box from the right was faced. This, the correct box, was often promptly entered.

This method, if persisted in, would obviously have yielded solution of the problem.

(e) July 5, approach to and pretense to enter the box next to the right end (right one), and then choice of some other box. This _feint_ is peculiarly interesting, and its origin and persistence are difficult to account for.

(f) In connection with the tendency to pretend that he was going to enter the second box from the right end, Julius developed also the tendency to turn around in front of the box at the right end, starting sometimes to back into it, and then to enter, instead, the box second from the end.

(g) July, 6 and 7, a fairly definite tendency to take the one next in order or, instead, to go directly to the right box.

(h) July 10, direct first choices without approach to other boxes appeared for the first time on this date.

For this problem, it proved impossible to establish and maintain uniform conditions of experimentation. Instead, because of the failure of the animal to improve and the tendency to discouragement, both punishment and reward had to be altered from time to time, and other and more radical changes were occasionally made in the experimental procedure.

Below for the sake of condensed and consecutive presentation, the most important conditions from day to day are arranged in tabular form:

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