REWARD AND PUNISHMENT IN HABIT FORMATION 275 



those trained with twenty-four hours hunger one made a perfect 

 retention test ; and of those trained with thirty-one hours hunger 

 there was no perfect retention test. Likewise groups trained with 

 electric shock showed no special difference in retention. Two 

 subjects for each of the strengths of electric shock, one hundred 

 and fifty and seventy-five units, made perfect records for reten- 

 tion and one subject for the strength of one hundred and fifteen ' 

 units of electric shock made a perfect retention test. These \ 

 facts indicate that subjects trained with electrical stimuli retained 4 

 better than subjects trained with hunger. Thus it seems that 

 the time required for the formation of a habit has little to do with 

 the retention of the habit but the strength of the native tendency 

 with which the habit is linked is of some importance. 



RETRAINING 



The retraining series are on the whole in harmony with the train- 

 ing series. Animals trained with twenty-four hours of hunger re- 

 learned the habit on an average in 44.4 trials; those trained with 

 thirty-one hours retrained on an average in 28 trials; subjects 

 trained with forty-eight hours retrained on an average in 22.2 

 trials; subjects trained with seventy-five units of shock retrained 

 on an average in 12.2 trials; those trained with one-hundred and 

 fifteen units retrained on an average in 14 trials; and subjects 

 trained with one hundred and fifty units retrained on an average 

 in 12.2 trials. The fact that subjects trained with forty-eight 

 hours of hunger relearned more rapidly than any of the other 

 groups is due to the increased age and adaptation of the organism 

 to long periods of starvation . Just as one should expect, there is no 

 significant difference in the time taken for the three groups trained 

 with electric shock to relearn the process, for the retraining time 

 was too short. 



CONCLUSIONS 



1. In case of hunger the rapidity of learning increases as the 

 hunger increases but the maximum hunger is reached in rats of 

 seventy-eight days of age some where between forty-one and 

 forty-eight hours. After the maximum hunger is reached there 

 is a rapid decrease in the rate of learning as the period of starva- 

 tion is increased. 



