34 

 active and eager" to obtain their food. In all probabil- 

 ity, if rest between trials had been given, the results 

 would have been different. Only sufficient time was 

 given after each trial for a little food. This seemed 

 necessary, and was the only change in the method of ex- 

 perimentation from that with the latch-box alone. For 

 the experiments with the latch-box and maze similar 

 norms were used, an average of one second in three success- 

 ive days for the former, and six seconds without error 

 for the latter. For the new problem, the inclined plane 

 bos the norm was two seconds. The rats had to work 

 on all three problems until all three norms were reached. 

 RESUITS. 

 Behavior: As might be expected, fundamental dif- 

 ferences in behavior were noticable in learning the three 

 problems together. Some rats found one problem more dif- 

 ficult than others.. The most difficult one was the 

 inclined plane box. Of interest, in this connect ion, was 



