Ykrkks, M Oil ip ability of Behavior. 



243 



ries the nunilter of errors made by this iii(livi(hial ra])iilly decreased 

 until in the seventh series only one was made. Then followed three 

 perfect series. For this individual, since he acquired a perfect habit 

 as the result of seventy training tests, the index of plasticity is 70. 



The tables contain, in addition to the individual results, the average 

 number of errors per series for the males and for the females. 



TABLE 3. 



Relation of Age to Modifiability of Behavior 

 White-black Discrimination Habit 



Results for dancers seven months old 



Any one who compares this account of my investigation of the re- 

 lation of age to rapidity of learning with my earlier account will 

 discover that only two pairs of dancers of one month of age for which 

 results were given previously^ have place in the group under dis- 

 cussion. This is due to the fact that I felt it highly desirable to re- 

 peat the experiments with one-month individuals in order to make 



■'J'lit' I»;iiicin^ .Mouse, jiji. '24'.', -7'. 



