384 HARVEY CARR 



by those animals that relied mainly upon the factor of motor 

 attitudes in making their choices. This fact suggests the hypo- 

 thesis that the speed of learning is to some extent a function 

 of the degree of temporal contiguity between the terms to be 

 associated. Since the animals relied in part upon the sensory 

 aspects of the preceding act, we are forced to conclude that a 

 rat can establish an associative nexus between a stimulus and 

 a response separated by a time interval of 16.5 seconds, provided 

 that relatively constant sensori-motor conditions prevail during 

 that interval. 



The rate and mode of learning are apparently not dependent 

 upon vision. Rats with vision exhibited the greater speed of 

 movement and occasionally corrected their wrong choices in 

 terms of visual stimuli from the closed doors. 



