In Color Discrimination Box with 6 by 3 cm. Pieces of Hering
Papers at Entrances to Boxes
No. 2
SERIES DATE RIGHT WRONG 1906 (Yellow) (Red) 1 Jan. 16 1 9 2 17 3 7 3 18 4 6 4 19 5 5 5 20 5 5
Without further mention of the many experiments which were necessary for the perfecting of this method of testing color vision, I may at once present the final results of the tests which were made with reflected light. These tests were made with the discrimination apparatus in essentially the same way as were the brightness discrimination tests of Chapter VII.
In all of the color experiments, unless otherwise stated, a series of ten tests each day was given, until satisfactory evidence of discrimination or proof of the lack of the ability to discriminate had been obtained. The difficulties of getting conclusive evidence in either direction will be considered in connection with the results themselves. For all of these tests with reflected light the Milton Bradley colored papers were used. These colored papers were pasted on white cardboard carriers. I shall designate, in the Bradley nomenclature, the papers used in each experiment.
With colored cardboards inside the electric-boxes as well as at their entrances (see Figure 14 for position of cardboards) blue-orange tests were given to Nos. 2 and 3 until they discriminated perfectly. The papers were Bradley's blue tint No. 1 and orange. Number 2 was perfect in the twelfth series (Table 17), No 3 in the fourteenth and again in the sixteenth. They were then tested with a special brightness check series which was intended by the experimenter to reveal any dependence upon a possible brightness difference rather than upon the color difference of the boxes.
TABLE 17
LIGHT BLUE-ORANGE TESTS IN COLOR DISCRIMINATION BOX
SERIES DATE NO. 2 NO. 3 1906 RIGHT WRONG RIGHT WRONG (LIGHT (ORANGE) (LIGHT (ORANGE) BLUE) BLUE)
1 Jan. 26 7 3 1 9
2 27 7 3 5 5
3 28 7 3 6 4
4 29 7 3 7 3
5 30 7 3 4 6
6 31 10 0 7 3
7 Feb. 1 9 1 7 3
8 2 8 2 6 4
9 3 9 1 9 1
10 5 7 3 5 5
11 6 8 2 5 5
12 7 10 0 5 5
Special brightness check series (see Table 18)
13 8 10 0 7 3
Special light blue-dark blue series
14 9 8 2 10 0
15 10 9 1 9 1
Special light blue-dark blue series
16 11 9 1 10 0
Special brightness
check series
17 12 10 0 9 1