480 ^Journal of Comparative Neurology and Psychology. 



very clearly and briefly presents the chiefly significant results of 

 our investigation of the relation of strength of electrical stimulus 

 to rate of habit-formation, and it offers perfectly definite answers 

 to the questions which were proposed for solution. 



In this figure the ordinates represent stimulus values, and the 

 abscissae number of tests. The roman numerals /, //, ///, desig- 

 nate, respectively, the curves for the results of set I, set II, and set 

 III. Dots on the curves indicate the strengths of stimuli which 

 were employed. Curve I for example, shows that a strength 

 of stimulus of 300 units under the visual conditions of set I, 

 yielded a perfect habit with 80 tests. 



TABLE 15. 

 The number of tests required by the mice for the acquisition of a perfect habit of 



From the data of the various tables we draw the following 

 conclusions: 



I. In the case of the particular habit which we have studied, 

 the rapidity of learning increases as the amount of difference in 

 the brightness of the electric boxes between which the mouse is 

 required to discriminate is increased. The limits within which 

 this statement holds have not been determined. The higher the 

 curves of fig, 5 stand from the base line, the larger the number 

 of tests represented by them. Curve II is lowest, curve I comes 

 next, and curve III is highest. It is to be noted that this is the 

 order of increasing difl&cultness of discrimination in the three sets 

 of experiments. 



