RATn OF LEARNING IN , THE WHITE RAT 33 



trials interpolated after the first 40 training trials show 79 per 

 cent of correct response, it is safe to infer that considerable 

 transfer was made during these 40 trials. The association was 

 readily made; with, in fact, but little more difficulty than was 

 experienced when the two stimuli were presented continuously in 

 the forward direction. This small difference may be due to 

 chance or to the fact that a smaller group was used in these last 

 experiments. 



When the animals of Group XIII had learned the association 

 of negative motor response to sound, light was presented in the 

 same temporal relation to sound as sound had been to pain in 

 the previous training, i.e., in immediate succession. By this 

 means it was hoped to get some data on the relative merit of the 

 different stimuli. Table XV depicts the animals used, the num- 

 ber of trials necessary to master the problem, and the percentage 

 of right response on the last 100 trials. A comparison of this 



TABLE XV 



Rat Training Trials Test Trials % on Last 100 



53 120 50 92 



54 ioo 40 90 



55 120 50 92 



56 120 50 91 



Average 115 47.5 91.5 



table with Table XIV and of Graph 13!. in Fig. 8 (the curves 

 for the present group) with Graph 13 of the same figure shows 

 no marked difference between the two so little, in fact, that we 

 are not warranted in making the statement that it is easier to as- 

 sociate a motor response with light than with sound when all 

 other conditions are constant. It is preferable to account for 

 this small difference on the basis of the effect of transfer of 

 learning. 



In Group XIV where the sound was presented one second 

 after the pain (in most cases after the motor response to pain) 

 the conditions were in all other respects the same as those for 

 Group XIII. Under these conditions we hoped to secure data 

 showing the relative difficulty in making the association in the 



