470 'Journal of Comparative Neurology and Psychology. 



average for both males and females. In table 3, for example, it 

 appears that male no. 128 chose the black box in preference to the 

 white 6 times in series A, 5 times in series B, 3 times in series i, 

 6 times in series 2. After series 15 he made no errors during 

 three consecutive series. His training was completed, therefore, 

 on the eighteenth day, as the result of 180 tests. We may say, 

 however, that only 150 tests were necessary for the establishment 

 of a perfect habit, for the additional thirty tests, given after the 

 fifteenth series, served merely to reveal the fact that he already 

 possessed a perfect habit. In view of this consideration, we shall 



TABLE 4. 

 The results of the experiments of set I, stimulus medium (300 ± 25 units). 



take as a measure of the rapidity of learning in these experiments 

 the number of tests received by a mouse up to the point at which 

 errors ceased for at least three consecutive series. 



Precisely as the individuals of table 3 had been trained by the 

 use of a weak stimulus, four other dancers were trained with a 

 medium stimulus. The results appear in table 4. All of the 

 subjects acquired a habit quickly. Comparison of these results 

 with those obtained with the weak stimulus clearly indicates that 

 the medium stimulus was much more favorable to the acquire- 

 ment of the white-black visual discrimination habit. 



In its results the strong stimulus proved to be similar to the 

 weak stimulus. All of the mice in this case learned more slowly 



