A SIMPLE MAZE 361 



typical of the animals in the groups which showed marked re- 

 tardation in concentrated practice. 



The animal reaches the food and begins to eat. The experi- 

 menter puts his hand into the food compartment to transfer the 

 rat to the starting box. The rat retreats and is caught. On the 

 next trial he advances toward the food, pauses, extends his head 

 upward toward the place whence the hand came before, makes 

 several false starts, and finally advances timidly to the food, 

 giving evidence of increased tonus and readiness for flight. Under 

 the usual conditions of training (group A) this behavior rarely 

 appears on the first trial, becomes marked on the third to fifth, 

 and disappears by the end of the practice period. It seems as 

 though several trials were required to set up the association be- 

 tween the food compartment and the avoiding reaction, in each 

 day's practice, and several more to fatigue the conditioned emo- 

 tional reflex so established. This is shown clearly by the follow- 

 ing average tunes required for successive trials on the second day 

 of training by the animals in group A. 



Trial 123456789 10 



Seconds : 18 22 57 37 28 15 13 13 17 16 



The increased time in the second to fifth trials is characteristic 

 of many of the records and is correlated with the flight reactions 

 near the food compartment. 



The chief importance of these two factors in favoring distributed 

 practice lies in the fact that their effects are shown in the later 

 trials of each day's practice. When only two trials are given 

 there is not time for the summation of the exploratory and flight 

 impulses and so fewer errors due to these causes are made. That 

 they were important factors in determining the effects of dis- 

 tribution of practice is shown by the differences in the behavior 

 of the animals in the three groups which differed in the number 

 of trials required for learning. The rats in group B, which had 

 been allowed to become thoroughly familiar with the maze, 

 rarely gave the flight reactions in the food compartment and 

 there was slight indication of a summation of emotional disturb- 

 ance such as appeared in group A. Familiarity with the maze 



