The Mental Life Of Monkeys And Apes Part 7

" 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.

TABLE 9

Results for Orang utan in Problem 2

========+===========+==============+==============+==============+==============+==============+==============+==============+==============+==============+==============+===+===+===+===+======== No. S.1 S.2 S.3 S.4 S.5 S.6 S.7 S.8 S.9 S.10 Ratio Date of 1.2.3.4.5 R W R W of trials 7.8.9 1.2.3.4 2.3.4.5.6.7 1.2.3.4.5.6 4.5.6.7.8 1.2.3 2.3.4.5 6.7.8.9 1.2.3.4 3.4.5.6.7.8 R to W --------+-----------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+-------- May {7.7.7.7 17 1- 10 {7.7.7.7 1.1.3 2.4.6 2.3.4.5 4.5.7 3.2 2.3.4 {2.3.4.5 1.2.3 3.4.5.6.7 0 10 0 10 0:10.00 {7.7.8 {6.7.8 {4.5.6.8 18 11- 20 7.8 1.3 3.4.5.6 2.4.5 4.5.6.7 2 2.3.4 {2.3.4.5 1.2.3 {8.8.8.3 1 9 1 9 1: 9.00 {6.7.8 {4.5.6.7 {2.4.7.7.2 {5.3.4.5 19 21- 30 7.8 1.3 {5.7.7.2 5 4.6.8.4.7 1.2 2.3.4 5.8 3 {6.8.4.5 2 8 2 8 1: 4.00 {3.2.4.6 {3.5.6.7 20 31- 40 {7.9.7.7 3 4.5.6 4.5 5.6.7 2 4 5.6.7.8 3 5.6.7 4 6 4 6 1: 1.50 {9.7.8 21 41- 50 7.8 3 3.4.5.6 4.5 4.5.6.7 2 3.4 4.5.6.8 3 4.5.6.7 3 7 3 7 1: 2.33 June 3 51- 60 7.8 3 4.5.6 3.4.5 4.5.6.7 3.1.2 3.4 {3.7.9.7 3 4.5.6.7 2 8 2 8 1: 4.00 {9.7.6.8 4 61- 70 7.8 3 4.5.6 4.5 4.5.6.7 3.3.1.2 4 4.5.6.7.8 3 4.5.6.7 3 7 3 7 1: 2.33 5 71- 80 7.9.7.8 3 3.4.5.6 3.6.3.4.5 4.7 3.1.2 4 3.4.5.6.7.8 3 4.5.6.7 3 7 " 81- 90 7.8 3 3.4.5.6 3.4.5 4.5.6.7 2 3.4 3.4.5.6.7.8 2.3 4.5.6.7 2 8 5 15 1: 3.00 7 91- 100 7.8 3 4.5.6 4.5 4.5.6.7 1.2 3.4 {3.4.5.6 2.3 {3.4.5.6 1 9 1 9 1: 9.00 {7.8 {8.5.6.7 8 101- 110 7.8 3 4.5.6 4.5 4.5.6.7 2 3.4 4.5.6.7.8 3 4.5.6.7 3 7 " 111- 120 7.8 3 4.5.6 3.4.5 5.6.7 2 5.5.2.3.4 4.5.6.7.8 4.4.1.2.3 4.5.6.7 2 8 5 15 1: 3.00 9 121- 130 7.8 2.3 4.5.6 4.5 4.5.6.7 2 3.4 {2.3.4.5 1.2.3 3.4.5.6.7 1 9 {6.7.8 " 131- 140 7.8 1.2.3 2.3.4.5.6 5 4.5.6.7 1.2 2.3.4 6.7.8 2.3 3.4.5.6.7 1 9 2 18 1: 9.00 10 141- 150 7.8 1.2.3 2.3.4.5.6 1.2.3.4.5 4.5.6.7 1.2 2.3.4 {1.2.3.4 1.2.3 3.4.5.6.7 0 10 {5.6.7.8 " 151- 160 7.8 1.2.3 2.3.4.5.6 1.2.3.4.5 4.5.6.7 1.2 2.3.4 {1.2.3.4 1.2.3 3.4.5.6.7 0 10 0 10 0:10.00 {5.6.7.8 11 161- 170 8 {4.1.2.4.1 2.3.4.5.6 5 6.7 {3.1.3.1 5.2.3.4 2.6.7.8 4.1.2.3 8.5.6.7 2 8 {4.1.4.1.3 {3.1.2 " 171- 180 9.7.8 4.3 5.6 4.5 7 3.1.2 5.4 8 4.2.3 7 3 7 5 15 1: 3.00 12 181- 190 7.9.7.9.8 1.2.3 3.4.5.6 6.4.5 5.6.7 2 5.3.4 7.8 4.1.2.3 4.5.6.7 1 9 1 9 1: 9.00 14 191- 200 9.8 3 7.6 6.5 8.7 3.2 5.4 6.7.8 4.2.3 7 2 8 " 201- 210 8 2.3 7.6 6.5 8.7 3.1.2 5.4 8 4.3 7 3 7 5 15 1: 3.00 15 211- 220 {7.9.7.9 4.2.3 6 5 8.7 3.2 5.4 9.8 4.3 7 3 7 {7.9.8 " 221- 230 9.8 4.3 7.6 6.5 5.6.7 1.2 2.3.4 3.4.5.6.7.8 4.3 7 1 9 4 16 1: 4.00 16 231- 240 7.9.8 3 7.6 6.5 8.7 2 5.4 5.6.7.8 4.1.4.3 8.7 2 8 " 241- 250 9.8 4.3 7.6 6.5 7 3.2 5.4 6.7.8 4.3 6.7 1 9 3 17 1: 5.67 17 251- 260 9.8 4.3 7.6 6.5 {6.5.4.6 3.2 5.4 6.5.6.7.8 3 5.6.7 1 9 {5.4.5.7 {6.6.6.5.6 {5.5.5.6.6 " 261- 270 {9.7.7.7 4.4.4.4.3 6 5 {6.6.6.6.6 {3.3.3.3 4 {4.5.4.5.4 3 {5.5.5.5 4 6 5 15 1: 3.00 {7.7.7.8 {6.5.4.5 {3.3.2 {5.6.7.8 {5.5.8.7 {6.5.5.4 {4.5.6.7 18 271- 280 {7.7.7.7 4.4.4.4.3 5.5.5.5.6 5 {5.5.5.6 {3.3.3. 4 {4.6.5.6 4.4.3 5.6.4.7 2 8 2 8 1: 4.00 {7.7.8 {5.5.6 {3.3.2 {6.7.4.8 {7.7.7.9 19 281- 290 {9.9.9.7 {4.4.4 {5.7.7 5 5.7 {3.3.3.3 4 5.8 {4.4.4.4 {6.5.6.5 2 8 {7.7.8 {4.4.3 {7.4.6 {3.3.2 {4.4.3 {5.5.7 " 291- 300 7.7.7.7.8 4.4.4.4.3 5.5.6 5 {5.6.6.5.6 3.3.2 {5.5.5.5 5.6.8 4.4.3 6.6.6.7 1 9 3 17 1: 5.67 {6.6.6.7 {3.4 {5.6.6.6.7 21 301- 310 7.7.8 4.4.3 5.6 5 {6.6.6.5 {3.3.3.3 5.5.5.2.4 {3.4.3.5.5 {4.2.2.4 5.3.7 1 9 {5.6.5.7 {3.2 {1.1.2.4.7 {4.3 {2.3.2.2.8 " 311- 320 {7.7.7.7 1.1.1.2.3 {5.5.4.2 1.1.6.5 4.6.7 1.3.2 {2.2.2.2 {1.1.2.3 {2.2.2.4 {6.3.3.8 0 10 1 19 1:19.00 {7.7.8 {2.5.6 {2.2.3.4 {6.6.6.8 {2.3 {4.8.7 22 321- 330 7.8 {2.4.2.1.4 6 5 6.6.8.7 3.2 5.5.3.3.4 3.3.7.7.8 4.4.4.2.3 6.7 2 8 {4.4.4.3 " 331- 340 7.8 3 6 5 6.7 3.2 5.4 6.7.8 3 5.6.7 4 6 6 14 1: 2.33 23 341- 350 7.8 4.2.4.3 6 5 6.7 {3.3.3.1 5.5.4 {7.5.4.3 4.4.4.3 {6.6.3.6 2 8 {3.3.3.2 {6.7.7.8 {8.6.8.7 " 351- 360 7.8 4.4.3 6 6.5 6.7 3.3.2 5.4 {6.7.6.5 4.3 5.6.7 1 9 3 17 1: 5.67 {7.6.8 24 361- 370 7.8 4.4.2.3 7.7.6 6.6.4.5 7 {3.3.3.3 5.4 8 4.4.3 5.6.7 2 8 {3.3.2 " 371- 380 8 4.3 7.6 5 7 3.2 5.4 7.6.8 4.3 7 4 6 6 14 1: 2.33 25 381- 390 8 4.4.3 7.7.7.6 {6.6.6.6 8.6.7 3.1.2 5.3.5.4 8 3 7 4 6 {6.4.6.5 " 391- 400 8 4.3 6 5 6.5.8.7 3.2 5.4 8 3 8.7 5 5 9 11 1: 1.22 26 401- 410 9.9.9.8 3 {7.7.7.7.3 {6.6.6.6 8.8.8.7 3.2 {5.5.5.5 7.8 {4.4.4.4 6.6.8.8.7 1 9 {3.7.7.6 {6.6.5 {5.5.4 {4.4.3 " 411- 420 8 4.3 7.6 6.5 7 3.2 5.4 8 4.3 8.7 3 7 4 16 1: 4.00 28 421- 430 8 {4.4.4.4 7.6 {6.6.3.6 7 {3.3.3.3 5.5.5.4 9.7.7.5.8 4.4.4.3 8.7 2 8 {4.4.3 {6.6.6.5 {3.3.2 " 431- 440 8 4.3 6 6.5 7 3.2 5.4 7.8 4.3 7 4 6 {7.6.5.4 " 441- 450 8 4.3 7.6 6.5 8.7 3.2 5.4 {3.2.1.5 4.3 7 2 8 8 22 1: 2.75 {7.9.8 29 451- 460 8 3 6 6.6.6.5 8.6.7 {3.3.3.3 5.4 8 4.3 7 5 5 {3.3.2 " 461- 470 8 4.3 6 5 8.7 3.2 3.2.3.4 7.8 4.3 7 4 6 " 471- 480 8 4.4.3 7.7.6 6.6.5 7 2 5.5.5.5.5.4 7.8 4.4.3 7 4 6 13 17 1: 1.31 30 481- 490 8 {4.4.4.4 7.7.6 6.6.6.5 8.6.6.5.7 {3.1.3.3 5.5.5.4 8 4.4.4.3 7 3 7 {4.4.3 {3.3.3.2 " 491- 500 8 4.3 7.7.7.6 6.6.5 8.8.7 3.3.3.3.2 5.4 {9.9.7.4 3 8.8.7 2 8 5 15 1: 3.00 {9.6.8 July 1 501- 510 9.7.9.8 4.3 6 6.5 8.6.7 3.3.2 5.4 8 4.3 7 3 7 " 511- 520 {9.7.7.7 4.3 7.6 6.4.5 7 3.2 4 8 4.4.4.3 8.6.5.6.7 3 7 6 14 1: 2.33 {7.9.8 2 521- 530 9.8 3 7.5.7.6 6.4.5 8.7 2 4 8 3 7 6 4 " 531- 540 9.9.7.8 3 7.4.6 5 6.6.7 3.3.2 3.4 7.3.5.4.8 4.3 {8.8.6.5 2 8 8 12 1: 1.50 {4.5.7 3 541- 550 8 4.3 6 {6.6.6.6 6.8.7 3.3.3.2 5.5.4 9.6.9.6.8 4.3 7 3 7 {6.6.5 " 551- 560 9.9.7.8 4.3 6 5 8.6.5.7 {3.3.3.3 5.4 {7.6.5.7 3 7 4 6 7 13 1: 1.86 {3.2 {9.7.9.8 5 561- 570 8 4.3 7.6 6.5 {8.8.8.8 {3.3.3.3 5.5.5.5.4 8 4.4.4.3 8.8.8.8.7 2 8 {8.8.7 {3.3.3.2 " 571- 580 9.8 4.4.4.3 6 6.5 8.8.7 {3.3.3.3.3 {5.5.5.5.5 7.6.8 4.4.3 7 2 8 4 16 1: 4.00 {3.3.3.2 {5.5.5.4 6 581- 590 9.8 4.3 7.7.6 6.6.5 7 2 5.4 7.8 4.3 7 3 7 " 591- 600 8 3 6 4.5 6.6.6.7 2 5.3.5.4 8 4.4.3 8.8.8.7 5 5 8 12 1: 1.50 7 601- 610 8 1.3 6 5 6.5.7 2 5.4 5.6.6.6.7.8 4.3 7 5 5 " 611- 620 {9.7.7.7.9 3 6 5 6.5.6.5.7 3.2 5.4 7.9.7.9.8 {4.4.4.4 8.7 3 7 8 12 1: 1.50 {7.7.7.8 {4.4.4.3 8 621- 630 {9.9.9.7.9 4.3 6 6.6.6.5 {8.8.8.8 3.2 5.4 7.6.8 3 7 3 7 {9.9.8 {5.6.5.7 {7.6.5.7 " 631- 640 9.8 3 6 6.5 7 3.2 4 {6.5.4.6 3 7 6 4 {9.7.9.8 " 641- 650 8 3 6 5 7 2 4 7.9.6.7.9.8 3 8.6.8.7 8 2 17 13 1: 0.76 9 651- 660 8 3 6 5 7 2 4 7.6.7.6.8 3 8.6.8.8.4.7 8 2 " 661- 670 9.9.8 3 7.6 5 7 3.2 5.4 7.6.7.6.8 4.3 5.6.8 3 7 11 9 1: 0.82 10 671- 680 9.8 3 5.4.5.6 5 6.4.8.6.7 3.2 {3.5.3.2.3 {7.6.5.6 3 5.4.3.7 3 7 {5.3.5.2.4 {5.8 " 681- 690 8 4.3 6 5 7 2 5.4 8 3 6.8.7 7 3 10 10 1: 1.00 12 691- 700 7.8 3 5.6 5 7 3.2 3.4 7.7.7.7.8 4.2.2.3 8.7 3 7 " 701- 710 9.8 4.3 7.6 6.5 7 3.2 5.4 {7.6.5.4.3 3 8.7 2 8 {2.1.4.8 " 711- 720 8 4.3 6 6.5 7 3.2 5.4 {7.6.5.4.3 3 {6.5.4.3.6 4 6 9 21 1: 2.33 {2.5.9.8 {5.4.3.8.7 13 721- 730 7.8 4.3 6 4.3.6.5 4.6.5.4.7 2 4 {6.5.4.3 3 {5.4.3.6 4 6 4 6 1: 1.50 {2.1.8 {8.7 {4.7.5.4 14 731- 740 8 3 5.5.6 5 {5.6.5.5 3.2 4 {7.7.4.6 3 4.6.7 5 5 {8.8.7 {5.6.8 {5.4.5.5.4 {4.4.4.5.5 " 741- 750 8 3 5.6 5 {6.5.6.6 2 4 {5.6.4.4.4 3 {5.4.8.8.4 6 4 11 9 1: 0.82 {6.8.4.7 {7.6.8 {5.5.6.4.7 15 751- 760 7.7.9.7.8 3 6 5 6.6.7 2 4 6.6.8 3 {6.6.6.8 6 4 {5.6.7 {5.4.6.6.5 " 761- 770 8 3 5.6 5 6.6.6.6.7 2 3.4 5.4.7.8 3 {5.3.5.8.5 5 5 11 9 1: 0.82 {5.5.7 {4.6.7.6.9 16 771- 780 7.7.7.8 3 6 4.5 5.7 2 3.4 {7.7.5.5 3 (5.6.8.5 4 6 {6.6.6.8 {3.7 {6.6.7.2 " 781- 790 7.8 3 {4.5.4.3 {4.6.4.4 {4.4.6.8 2 3.4 {3.4.4.4 3 6.7 3 7 7 13 1: 1.86 {2.6 {1.4.3.5 {5.7 {9.9.8 17 791- 800 7.8 2.3 6 {4.4.4.3.6 4.8.4.6.7 2 4 {5.7.6.6.1 3 5.7 4 6 {2.4.2.5 {7.4.4.8 {2.4.4.4.2 " 801- 810 7.8 {4.2.4.1.4 5.7.6 5 5.7 2 3.5.5.4 6.8 {2.4.4.2 6.8.7 2 8 6 14 1: 2.33 {2.4.3 {4.2.4 3 19 811- 820 7.9.7.8 2.4.2.4.3 5.7.6 3.6.4.6.5 7 2 3.5.4 6.8 4.4.3 6.8.7 2 8 " 821- 830 7.8 2.4.4.3 6 4.6.6.6.5 6.8.7 2 3.5.5.5.4 6.8 2.4.3 6.5.7 2 8 " 831- 840 7.9.8 2.4.4.2.4.3 7.6 5 7 2 4 7.6.4.6.8 2.4.3 6.8.7 4 6 8 22 1: 2.75 20 841- 850 7.8 3 5.7.6 4.6.5 6.8.7 2 3.5.4 3.5.8 2.4.3 6.8.6.8.7 2 8 " 851- 860 8 2.4.3 6 3.6.5 5.7 2 2.5.4 4.7.8 2.4.3 4.4.6.7 3 7 " 861- 870 7.8 2.4.3 6 5 7 2 2.4 6.8 2.4.3 4.7 4 6 9 21 1: 2.33 21 871- 880 7.9.8 2.4.3 5.7.6 {4.6.4.6 4.6.7 2 3.5.3.5.4 5.7.8 2.4.3 5.7 1 9 {3.2.4.5 " 881- 890 7.8 2.4.2.3 3.5.7.6 3.4.6.4.6.5 4.6.5.6.7 2 4 6.8 3 4.6.5.7 3 7 " 891- 900 7.8 2.4.3 5.7.6 4.5 5.7 3.3.3.2 4 {4.6.5.7.6 2.4.3 5.7 1 9 5 25 1: 5.00 {4.2.4.8 22 901- 910 7.8 2.4.3 5.7.6 4.6.5 6.8.7 2 2.5.4 5.6.8 2.3 6.7 1 9 " 911- 920 7.8 2.3 5.6 4.5 5.7 2 3.4 4.6.8 2.3 5.6.7 1 9 2 18 1: 9.00 23 921- 930 7.8 2.3 {3.2.4.4 5 4.6.5.6.7 2 3.2.4 5.4.6.8 2.3 {4.5.4.3.5 2 8 {5.6 {6.5.6.7 23 931- 940 7.9.7.8 3 5.4.6 5 5.7 2 4 6.7.8 3 6.8.7 5 5 " 941- 950 7.8 3 5.6 4.6.5 7 2 3.5.4 5.6.8 2.3 6.7 3 7 10 20 1: 2.00 24 951- 960 7.8 2.3 {2.7.7.4 4.6.5 5.7 2 4 4.6.8 3 6.8.7 3 7 {5.7.4.6 " 961- 970 7.9.7.8 3 6 5 (6.8.6.8 2 5.5.3.4 7.8 3 7 6 4 9 11 1: 1.22 {6.7 {4.2.6.4 26 971- 980 7.9.7.8 3 6 {6.4.6.4 7 2 4 6.8 3 6.8.7 6 4 {6.1.5 " 981- 990 7.9.7.8 3 6 5 7 2 4 7.6.8 3 6.8.7 7 3 991-1000 7.8 3 6 5 6.8.5.7 2 4 6.8 4.2.3 6.5.7 5 5 18 12 1: 0.67 --------+-----------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+-------- In trials 1001 to 1100 the right door was indicated by being raised before the choice was made. --------+-----------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+-------- 30 1101-1110 8 4.3 7.6 6.6.5 7 2 5.4 {7.7.7.7.7 3 6.6.7 4 6 4 6 1: 1.50 {7.6.6.7.8 {7.7.6.7 31 1111-1120 7.7.8 3 7.6 5 6.7 3.3.2 4 {7.6.6.7 4.4.4.3 7 4 6 {6.6.8* " 1121-1130 8 4.3 6 6.5 8.7 3.2 5.4 7.8 3 7 4 6 8 12 1: 1.50 August 2 1131-1140 8 4.4.3 6 5 7 3.3.3.2 4 7.8 4.3 7 6 4 " 1141-1150 7.8 4.4.3 7.6 6.5 7 3.2 5.4 8 4.3 7 3 7 9 11 1: 1.22 3 1151-1160 7.9.8 4.3 7.6 5 6.7 2 5.4 7.6.7.8 4.3 6.7 2 8 " 1161-1170 8 4.3 6 5 7 2 5.4 7.8 4.3 7 6 4 8 12 1: 1.50 4 1171-1180 8 4.3 6 6.5 6.7 3.2 5.4 7.8 4.3 6.5.6.7 2 8 " 1181-1190 8 3 6 5 7 3.3.2 4 7.8 3 7 8 2 10 10 1: 1.00 5 1191-1200 7.8 4.4.3 6 5 6.7 3.3.3.2 4 6.7.8 3 7 5 5 1201-1210 8 4.3 6 6.5 7 3.2 5.4 7.8 3 7 5 5 " 1211-1220 7.8 3 7.6.5 5 7 2 4 7.7.6.7.8 3 7 7 3 17 13 1: 0.76 6 1221-1230 8 3 6 5 {6.5.6.6 2 4 {5.6.5.7 3 6.8.6.7 7 3 {5.6.5.7 {9.7.8 " 1231-1240 7.8 3 6 4.5 7 2 4 6.7.8 3 6.7 6 4 13 7 1: 0.54 7 1241-1250 7.8 3 6 5 7 2 4 8 3 8.7 8 2 " 1251-1260 8 3 6 6.5 7 3.2 5.4 8 3 7 7 3 " 1261-1270 8 3 6 5 7 3.2 5.3.4 8 3 7 8 2 23 7 1: 0.30 9 1271-1280 8 3 6 5 7 2 5.4 9.7.8 3 7 8 2 " 1281-1290 8 3 6 5 7 3.2 4 7.8 3 7 8 2 16 4 1: 0.25 10 1291-1300 7.8 3 7.6 5 6.7 3.2 4 6.7.8 3 7 5 5 " 1301-1310 7.8 4.3 5.6 4.5 6.7 2 4 6.8 3 6.8.7 3 7 " 1311-1320 7.8 3 6 5 5.7 2 4 5.7.8 3 4.6.8.7 6 4 14 16 1: 1.14 11 1321-1330 7.8 3 6 5 6.7 3.2 4 4.6.7.8 2.3 5.7 4 6 " 1331-1340 7.8 3 6 4.5 6.7 2 4 6.7.8 3 7 6 4 10 10 1: 1.00 12 1341-1350 9.8 3 6 5 6.7 2 4 6.7.8 3 6.7 6 4 " 1351-1360 7.8 3 6 5 6.7 2 4 7.8 3 6.7 6 4 12 8 1: 0.67 19 1361-1370 7.8 3 6 5 6.7 2 4 6.7.8 3 6.7 6 4 1371-1380 9.8 3 6 5 7 3.2 4 7.9.8 3 6.8.7 6 4 12 8 1: 0.67 ========+===========+==============+==============+==============+==============+==============+==============+==============+==============+==============+==============+===+===+===+===+========

[Footnote *: Aided by experimenter.]

After two hundred and fifty trials on problem 2 had been given Julius, it seemed desirable to introduce a radical change in method in order to stimulate him to maximal effort. It was therefore decided to force him to make a round trip through the apparatus in connection with each choice, and to let this forced labor serve, in the place of confinement, as punishment for mistakes. This new method yielded peculiar and characteristic results. They differ from those previously obtained largely because of the orang utan's remarkably strong tendency to reenter the box through which he had just pa.s.sed. This occurred so persistently, as may be seen in table 9 (June 17, second series, June 18, etc.), that a further modification of method was introduced in that after the same wrong box had been entered five times in succession, the experimenter on the next choice of the box confined the animal for a stated interval, say sixty seconds, in it, and then allowed it to escape by way of the exit door and choose repeatedly until it finally located the right box. Were it not for this particular feature of the method, the number of choices recorded after June 17 would unquestionably be very much greater than the table indicates.

The new method proved a severe test of the orang utan's patience and perseverance, for he had to work much harder than formerly for his reward, and often became much fatigued before completing the regular series of ten trials. Early in the use of this method, he developed the habit of rolling around from exit door to starting point by a series of somersaults. When especially discouraged he would often b.u.mp his head against the floor so hard that I could hear the dull thud. As has been noted, I found it desirable to vary the procedure repeatedly. It proved especially interesting to give one series per day with the round trip as punishment and another series with confinement as punishment.

Day after day, as the experiment progressed, slight or great fluctuations of the ratios of right to wrong choices appeared, but without consistent improvement. There was, to be sure, as the last column of table 9 shows, a radical improvement during the first six hundred and fifty trials, for the number of right choices per series increased from 0 to 8. But, as the observations were continued from day to day, it became more and more evident that the animal was merely pa.s.sing from tendency to tendency--method to method--mixing tendencies, and occasionally developing new ones, without approach to the solution of the problem. This fact would have led me to discontinue the work much earlier than I actually did had it not been for the peculiarity of the results obtained with problem 1. It seemed not improbable that at any time Julius might succeed in perfectly solving this problem over night precisely as he had solved the first problem.

A curiously interesting bit of behavior appeared for the first time on June 29. Julius had gone to the first box at the right end of the group, and instead of entering, he had wheeled around toward his right, and turning a complete circle, faced the right box, which he promptly entered. Subsequently, the tendency developed and the method was used with increasing frequency. On June 30, it appeared in the first series, four times, in the second series, six times; on July 1, in the first series, three times, and in the second series, four times; on July 2, in the first series, five times, and in the second series, nine times. It was indeed only by accident that the animal failed to fulfill the technical requirement for perfect solution of the problem in this series. Yet, had he done so, his subsequent trials would doubtless have revealed the lack of any other idea than that of turning completely around before entering a box.

This odd bit of behavior proved peculiarly interesting and significant in that the tendency to turn became dissociated from the position (in front of the first box at the right end of the group) in connection with which it originally developed. After a few days, Julius would enter the reaction-chamber and instead of proceeding directly to the right end of the group, would stop suddenly wherever he happened to be, turn toward his right in a complete circle, and hasten into the box nearest to him which, as often as not, proved to be the wrong one. Thus the idea of turning completely about, which had it continued its a.s.sociation with the idea of facing the first box at the right, would have yielded success, instead became useless because of its dissociation. That the orang utan is capable of using free ideas seems clear enough in the light of this behavior. That he proved incapable of getting the idea of second from the right end is as clearly shown by the detailed results of table 9,--the fruits of weeks of experimenting.

Certain other interesting tricks developed in Julius's behavior. Thus, on July 5, there appeared the tendency to move as though about to enter the right box (feint), then to stop suddenly and promptly enter another box, which was, of course, a wrong one. The reason for the development of this tendency could not be discovered, but in connection with it, there appeared another tendency which possibly can be explained. Julius took to backing into the chosen box so that he could face the experimenter. He would then, after a period of hesitation, come out and promptly enter one of the other boxes. This tendency was apparently due to the fact that during one or two series the experimenter growled at the orang utan every time he made a mistake. The growl startled him and caused him to look around. He evidently felt the need of keeping his eyes on the experimenter,--Hence the backing into the open box. The tendency disappeared shortly after the experimenter gave up the use of the growl as a method of punis.h.i.+ng the animal for what were suspected to be careless choices.