154 Studies in Animal Behavior 



anism of intelligent behavior. I would not be un- 

 derstood as claiming that the present account of 

 the learning process is entirely adequate. There 

 are too many little known elements in the process 

 to warrant anything more than a tentative adop- 

 tion of any one standpoint. But the view defended 

 does not postulate the existence of any physiologi- 

 cal processes beyond those known to be commonly 

 manifested in the physiology of the nervous system. 

 Nothing is assumed in regard to the physiological 

 correlates of pleasure and pain, the teleological be- 

 havior of the neurones, or the nature of the changes 

 on which associative memory depends. It is of 

 importance, I believe, to determine how far we can 

 explain intelligent behavior without multiplying en- 

 tities by calling other factors to our aid. At pres- 

 ent it is far from clear Ithat it is necessary to make 

 such an appeal. ^1 



