The Sense of Sight: Color Vision 167 



nation of one electric-box was made 74 candle meters, that 

 of the other 3, and the changes of the lighter box from left 

 to right were made at irregular intervals. In February, No. 2 

 had been trained to go to the black in black-white tests, and 

 at the same time No. 5 had been trained to go to the white 

 in white-black tests. The results of these brightness check 

 tests, as they appear in the table, series 8 a, are indeed 

 striking. Number 2 chose the darker box each time; 

 No. 5 chose it eight times out of ten. Were it not for the 

 fact that memory tests four weeks after his black-white train- 

 ing had proved that No. 2 had entirely lost the influence of 

 his previous experience (he chose white nine times out of 

 ten in the memory series), it might reasonably be urged that 

 this individual chose the darker box because of his experi- 

 ence in the black-white experiment. And what can be said 



TABLE 26 



GREEN-RED TESTS 



Brightnesses Different for Human Eye 



Brightness tests without colors were now given to determine whether 

 the mice had been choosing the brighter or the darker instead of the green. 



