144 The Dancing Mouse 



Although conclusive proof of the truth of this statement 

 is furnished only by later experiments, the results of the light 

 blue-orange series, as given in Table 17, strongly suggest such 

 a possibility. Mouse No. 3 had not been experimented 

 with previous to these color discrimination tests. Her 

 preference for the orange, which in the case of the first series 

 was 9 to i, consequently demands an explanation. If she 

 had been trained previously to choose the white instead of 

 the black, as was true of No. 2, it might be inferred that she 

 went to the orange box because it appeared brighter than the 

 blue. As this explanation is not available, we are driven 

 back upon the results of the white-black preference tests in 

 Chapter VII, which proved that many dancers prefer the 

 black to the white. This may mean that they prefer the 

 lower degree of brightness or illumination, and if so it might 

 be argued, in turn, that the orange was chosen by No. 3 be- 

 cause it appeared darker than the blue. Since, as has al- 

 ready been stated, the orange was far brighter for me than 

 the blue, this would also mean that the brightness values 

 of different colors are not the same for man and mouse. 



Practically the same kind of color tests as those described 

 for Nos. 2 and 3 were given to Nos. 1000 and 5. The re- 

 sults appear in Table 19. These tests followed upon the 

 formation of a habit to choose white instead of black (that 

 is, the greater brightness). From the first both No. 1000 

 and No. 5 chose the light blue in preference to the orange 

 or the red. It therefore seems probable that the former 

 was considerably brighter than the latter. Number 1000, 

 to be sure, was led into three erroneous choices by the bright- 

 ness check series (series 7), but, on the other hand, No. 5 

 was not at all disturbed in her choices by similar check tests. 

 It seems natural to conclude from these facts that both of these 

 mice chose the blue at first because of its relatively greater 



