The Sense of Sight: Brightness Vision 103 



TABLE 6 

 BRIGHTNESS DISCRIMINATION 



White-Black, Series i 

 Experimented on No. 5 January 15, 1906 



black in the other, and the animal was required to enter the 

 white box. In the tables the first column at the left gives 

 the number of the test, the second the positions of the card- 

 boards, and the third and fourth the result of the choice. 

 The first test of Table 6 was made with the white cardboard 

 on the box which stood at the left of the mouse as it ap- 

 proached from A, and, consequently, with the black card- 

 board on the right. As is indicated by the record in the 

 "wrong" column, the mouse chose the black instead of the 

 white. The result of this first series was choice of the white 

 box four times as compared with choice of the black box six 

 times. On the eleventh day, that is, after No. 5 had been 

 given 100 tests in this brightness vision experiment, she 

 made no mistakes in a series of ten trials (Table 7). 



Before tests, such as have been described, can be pre- 



