The Dancing Mouse: A Study in Animal Behavior

by Robert Mearns Yerkes

TABLE 49

WHITE-BLACK TRAINING. TEN TESTS PER DAY

Males
TRAINING RETRAINING
210 220 230 410 420 AV. 210 220 230 410 420 AV.

A 6 5 6 6 6 5.8 5 4 5 4 3 4.2 B 6 8 8 5 1 5.6 8 4 5 4 6 5.4

1 6 7 6 2 4 5.0 3 3 4 7 3 4.0
2 4 3 1 2 3 2.6 2 4 2 5 3 3.2
3 3 1 4 3 4 3.0 1 4 1 4 1 2.2
4 5 0 3 3 2 2.6 0 1 0 1 2 0.8
5 3 0 4 1 4 2.4 0 2 0 2 0 0.8
6 2 1 4 0 1 1.6 0 1 0 0 2 0.6
7 1 0 3 1 0 1.0 0 0 0 0
8 0 0 1 0 0 0.2 0 0 1 0.2
9 0 0 0 1 0 0.2 0 0 0
10 0 0 0 0 1 0.2
11 0 0 0 0 0
12 0 0 0 0
13 0 0
14
15

Only three of the ten individuals failed to re-acquire the habit of white- black discrimination more quickly than it had originally been acquired, and, in the case of these exceptions, No. 220 required exactly the same number of tests in each case, and No. 420 was placed at a slight disadvantage in the re-learning series by an interruption of the training between the seventh and the eighth series. Had his training been completed by the sixth series he too would have had the same number of tests in training and re-training. Moreover, and this is of preëminent importance for a fair interpretation of the results, in several instances even those individuals which exhibited as strong a preference for the black in the memory series as in the preliminary series re-learned more quickly than they had learned. Number 210, for example, although he gave no evidence of memory, and, in fact, chose the black more frequently in the memory series than he did in the preliminary series, re-acquired the discrimination habit in less than half the number of tests which had been necessary for the establishment of the habit originally.

TABLE 50

WHITE-BLACK TRAINING. TEN TESTS PER DAY

Females

TRAINING RE-TRAINING
215 225 235 415 425 Av. 215 225 235 415 425 Av.
A 8 4 4 8 5 5.8 5 2 7 6 3 4.6
B 8 7 6 6 2 5.8 8 5 6 4 3 5.2
1 7 6 5 6 4 5.6 4 1 5 4 3 3.4
2 5 6 4 2 5 4.4 1 1 1 2 3 1.6
3 3 3 4 3 4 3.4 1 0 3 6 0 2.0
4 2 1 3 3 3 2.4 0 0 3 3 1 1.4
5 1 3 3 3 3 2.6 0 0 died 2 0 0.5
6 2 1 1 1 0 1.0 0 1 0 0.2
7 1 1 2 3 3 2.0 0 0 0
8 0 0 2 2 3 1.4 1 0.2
9 1 0 0 1 1 0.6 0 0
10 0 2 1 0 2 1.0 0 0
11 0 3 0 1 0 0.8 0 0
12 0 0 0 2 0 0.4
13 0 0 0 0 0
14 0 0 0
15 0 0

The facts which have been presented thus far become more significant when the indices of modifiability for the learning and the re-learning processes are compared.

INDICES OF MODIFIABILITY

LEARNING RE-LEARNING

Females . . . . . . . 104 42.5
Males . . . . . . . . 72 54

The behavior of the mice in the experiments, the detailed results of Tables 49 and 50, and the indices of modifiability together justify the following conclusions. Most of the ten dancers, at the end of a rest interval of eight weeks, had so far lost the habit of white-black discrimination that memory tests furnished no conclusive evidence of the influence of previous training; a few individuals seemed to possess traces of the habit after such an interval. In the case of each group of individuals re-training brought about the establishment of a perfect habit far more quickly than did the original training. This suggests the existence of two kinds or aspects of organic modification in connection with training; those which constitute the basis of a definite form of motor activity, and those which constitute the bases or dispositions for the acquirement of certain types of behavior. There are several indications that further study of the modifiability of behavior will furnish the facts which are necessary to render this suggestion meaningful.

Closely related to the facts which have been revealed by the re-training experiments are certain results of the labyrinth experiments. For the student of animal behavior, as for the human educator, it is of importance to learn whether one kind of training increases the efficiency of similar forms of training. Can a dancer learn a given labyrinth path the more readily because it has previously had experience in another form of labyrinth?

The answer to this question, which my experimental results furnish, is given in Table 51. In the upper half of the table have been arranged the results for six individuals which were trained first in labyrinth B, then in labyrinth C, and finally in labyrinth D. Below, in similar fashion, are given the results for six individuals which were trained in the same three labyrinths in the order C, B, D, instead of B, C, D. My purpose in giving the training in these two orders was to ascertain whether labyrinth C, which had proved to be rather difficult for most individuals, would be more easily learned if the training in it were preceded by training in labyrinth C.

TABLE 51

THE INFLUENCE OF ONE LABYRINTH HABIT UPON THE FORMATION OF ANOTHER LABYRINTH B LABYRINTH C LABYRINTH D NO. OF NO. OF NO. OF NO. OF NO. OF NO. OF NO. FIRST COR- LAST OF FIRST COR- LAST OF FIRST COR- LAST OF RECT TEST FIVE COR- RECT TEST FIVE COR- RECT TEST FIVE COR- RECT TESTS RECT TESTS RECT TESTS

76 8 14 3 19 4 7 78 5 20 6 14 4 5 86 13 22 5 12 3 9 75 4 15 8 19 4 13 77 7 11 11 29 11 12 87 12 22 9 20 4 9

AV. 8.2 17.3 7.0 18.8 5.0 9.2

LABYRINTH C LABYRINTH B LABYRINTH D

58 16 — 2 14 7 10 60 17 — 13 37 10 14 88 25 35 9 22 4 8 49 34 — 1 5 7 8 57 15 — 3 20 3 6 85 11 18 2 11 3 4

AV. 19.7 26.5 5.0 18.2 5.7 8.3

The results are sufficiently definite to warrant the conclusion that experience in B rendered the learning of C easier than it would have been had there been no previous labyrinth training. Those individuals whose first labyrinth training was in C made their first correct trip as the result of 19.7 trials, whereas those which had previously been trained in labyrinth B were able to make a correct trip as the result of only 7.0 trials. Similarly the table shows that training in C rendered the subsequent learning of B easier. To master B when it was the first labyrinth required 8.2 trials; to master it after C had been learned required only 5 trials. In addition to proving that the acquisition of one form of labyrinth habit may facilitate the acquisition of others, comparison of the averages of Table 51 furnishes evidence of the truth of the statement that no results of training can be properly interpreted in the absence of knowledge of the previous experience of the organism.