The Duration of Habits 261 



INDICES OF MODIFIABILITY 



LEARNING RE-LEARNING 



Females 104 42.5 



Males 72 54 



The behavior of the mice in the experiments, the detailed 

 results of Tables 49 and 50, and the indices of modifiability 

 together justify the following conclusions. Most of the ten 

 dancers, at the end of a rest interval of eight weeks, had so 

 far lost the habit of white-black discrimination that memory 

 tests furnished no conclusive evidence of the influence of 

 previous training ; a few individuals seemed to possess traces 

 of the habit after such an interval. In the case of each group 

 of individuals re-training brought about the establishment of 

 a perfect habit far more quickly than did the original train- 

 ing. This suggests the existence of two kinds or aspects 

 of organic modification in connection with training; those 

 which constitute the basis of a definite form of motor activity, 

 and those which constitute the bases or dispositions for the 

 acquirement of certain types of behavior. There are several 

 indications that further study of the modifiability of behavior 

 will furnish the facts which are necessary to render this 

 suggestion meaningful. 



Closely related to the facts which have been revealed by 

 the re-training experiments are certain results of the labyrinth 

 experiments. For the student of animal behavior, as for the 

 human educator, it is of importance to learn whether one kind 

 of training increases the efficiency of similar forms of training. 

 Can a dancer learn a given labyrinth path the more readily 

 because it has previously had experience in another form of 

 labyrinth ? 



The answer to this question, which my experimental results 

 furnish, is given in Table 51. In the upper half of the table 



