336 J. D. DODSON 



ulus, 50 trials with a medium stimulus, and 35 trials with a 

 strong stimulus. 



2. The relation of the painfulness of the electrical stimulus 

 to the rapidity of habit formation depends upon the difficultness 

 of the visual discrimination. 



3. When the discrimination is difficult the medium strength 

 of stimulus was found to be the more favorable to habit formation ; 

 but when the discrimination is less difficult the difference between 

 the unpleasant and the very unpleasant stimuli is not marked. 

 When the discrimination is. easy the rapidity of habit formation 

 increases as the unpleasantness of the stimuli is made greater, 

 at least within certain limits. 



