RATE OF LEARNING IN THE WHITE RAT 39 



of a new one; namely, sound for Group I and light for Group 

 VII. The two stimuli seemed to offer about equal disturbing 

 effect at this point in the learning. 2) When the first special 

 test series was given a complete breakdown occurred in Group 

 VII while Group I only partially broke down. The drop in per- 

 centage of right response was from 85 to 55 in the former, and 

 from 84 to 62 in the latter. This breakdown was only temporary, 

 for in the next special series the percentage rose above that of 

 Group I. Light seems to be more difficult in the beginning, but 

 measured on the basis of the required number of trials in the 

 two groups there is little or no difference. 



2) Continuous Mode of Presentation. The work of these 

 two groups (Groups II and VIII) was reported with the other 

 groups on successive association, but in the table below the re- 

 sults are reproduced in order to get a quick comparison of the 

 two modes of presentation. The curves presented in Fig. 9 



TABLE XVI 



Simultaneous Trials 



Group 1 113.3 



Group VII 100 



Continuous Trials 



Group II 120 



Group VIII 100 



show the different rate of learning the association by the two 

 groups. 



With these results before us we are able to observe the follow- 

 ing facts: i) Associations are possible with either the simul- 

 taneous or the successive mode of presentation. 2) Our data 

 indicate the superiority of the simultaneous mode of presentation, 

 in that under these conditions the association is more readily 

 made i.e., fewer trials are necessary to establish it than when 

 the stimuli are presented in succession. 3) The theory that 

 associations are possible only when the terms to be associated 

 are presented simultaneously is not supported by our results. 



3. Learning the Negative Response to Pain. 1 All the animals 



1 For method of procedure, one may with profit re-examine the last few 

 pages of Section III above. 



