RATE OF LEARNING IN THE WHITE RAT u 



Carr and Freeman 13 report an experiment upon the problem of 

 simultaneity vs. succession, and upon backward vs. forward direc- 

 tion in forming an association. A box with zigzag runways was 

 used. In preliminary tests rats were taught to run these path- 

 ways in order to obtain food. Afterwards in 80 per cent of 

 the trials the door from the chosen pathway into the food-box 

 was closed, and the rats were forced to retrace and run the op- 

 posite pathway in order to reach food. At this stage the rats 

 were divided into three groups for the purpose of testing the 

 formation of an association between an auditory stimulus, buzzer, 

 and the act of turning in response to the closed door. With one 

 group the buzzer was sounded just as the rat was in the act of 

 turning simultaneously with the response to the closed door. 

 With another the sound was given at a definite point, P, ap- 

 proximately one second before the door was reached. The third 

 group was given the sound at point P in the return pathway 

 approximately one second after the rat had turned around from 

 the closed door. Test series wherein the sound was given at any 

 point within the pathway were used to test the formation of the 

 association. It was found that "successive presentation of the 

 two terms constitutes a much more favorable method for their 

 association than does simultaneous presentation." The groups 

 on backward association showed slight evidence of learning when 

 the experiment closed. These results are extremely suggestive, 

 but some points of weakness should be pointed out: i) The 

 time interval between the two terms to be associated was not 

 constant. Those who are acquainted with the behavior of white 

 rats would not expect them to traverse the distance from a point, 

 P, to the closed door at the same speed each time. 2) The 

 buzzer which was the source of the sound stimulus was in contact 

 with the maze. The animal may, therefore, have been responding 

 to a kinaesthetic or cutaneous sensation and not to sound at all. 



Watson's experiments also contribute data in the comparative 

 field bearing upon this problem of backward association. He 

 tested white rats for their ability to learn a maze backward after 



13 Carr, H. A., and Freeman, A. S., "Time Relationships in the Formation 

 of Association," Psychol. Rev., Vol. XXVI, p. 465. 



