The Dancing Mouse: A Study in Animal Behavior

by Robert Mearns Yerkes

16 20 7 3 5 5

17 21 4 6 8 2

18 22 3 7 4 6

19 23 6 4 4 6

20 24 6 4 5 5

Twenty series, 200 tests for each of the individuals in the experiment, yielded no evidence whatever of the dancer's ability to tell green from blue. As it has already been proved that they readily learn to choose the right box under discriminable conditions, it seems reasonable to conclude either that they lack green-blue vision, or that they have it in a relatively undeveloped state.

If it be objected that the number of training tests given was too small, and that the dancer probably would exhibit discrimination if it were given 1000 instead of 200 tests in such an experiment, I must reply that the behavior of the animal in the tests is even more satisfactory evidence of its inability to choose than are the results of Table 20. Had there been the least indication of improvement as the result of 200 tests, I should have continued the experiment; as a matter of fact, the mice each day hesitated more and more before choosing, and fought against being driven toward the entrance to the experiment box. That they were helpless was so evident that it would have been manifestly cruel to continue the experiment.

TABLE 21
VIOLET-RED TESTS
With Odor of All Cardboards the Same

SERIES DATE NO. 7 NO. 998
RIGHT WRONG RIGHT WRONG
(VIOLET) (RED) (VIOLET) (RED)
A MAR. 7 8 2 5 5
B 7 3 7 2 8
1 14 3 7 6 4
2 15 4 6 4 6
3 16 5 5 5 5
4 19 4 6 4 6
5 20 5 5 6 4
6 21 4 6 8 2
7 22 8 2 4 6
8 23 4 6 6 4
9 24 6 4 4 6
10 25 4 6 6 4

Further color tests with reflected light were made with violet and red. Two dancers, Nos. 998 and 7, neither of which had been in any experiment previously, were subjected to the ten series of tests whose results are to be found in Table 21. In this experiment the cardboards used had been coated with shellac to obviate discrimination by means of odor. It is therefore impossible to give a precise description of the color or brightness by referring to the Bradley papers.[1] Both the violet and the red were rendered darker, and apparently less saturated, by the coating.