MAZE STUDIES WITH THE WHITE RAT 267 



still affected but the percentage of perfect trials was increased 

 from 35 to 53 and the error record was reduced from 6.95 to 

 1.72. The shifts were not continued until complete adaptation 

 was effected. 



2. The same conditions obtained in this experiment except 

 that the maze was left in each new position until the disturbance 

 was eliminated. After adapting to the three positions, the maze 

 was returned to the normal position. This procedure was now 

 repeated until complete adaptation was effected for the four 

 rotary positions. Similar rotary shifts were now instituted 

 between the 45, 135, 225, and 315 degree positions until adapta- 



, tion for these positions was effected. Fifteen animals were 

 employed in the experiment. During the first rotation, thirteen 

 animals were disturbed, and these gave an average error record 

 of 10.7 for the first day for the three new situations. The rats 

 were not affected in every trial, as perfect records were secured 

 in 32 per cent of the first day's trials. Adaptation was effected 

 for each position on an average of four trials. The induced 

 disturbance was occasionally carried over to a slight extent to 

 the normal position of the maze. The adaptation for each 

 position secured in the first shift was not permanent. New 

 rotations disclosed a further disturbance, but the effect gradually 

 decreased with repeated shifts; fewer animals were disturbed, 

 the errors became smaller, the percentage of perfect trials 

 increased, there was less carrying over to the normal position, 

 and the time necessary to adapt for each position was lessened. 

 Complete adaptation was effected on the fifth repetition and 

 thereafter the maze could be rotated at will between any of these 

 four positions without disturbance. Complete adaptation for 

 one series of positions does not, however, involve adaptation 

 to another series of positions. Rotary shifts were now instituted 

 between the 45, 135, 225, and 315 degree positions. In the 

 first shift all of the rats were again disturbed. In the first day's 

 trials for the four positions, the average error record was 7.2 

 with a percentage of perfect runs of 20. Adaptation was again 

 effected with repeated tests. 



3. A group of animals was rotated in a well illuminated and 

 a darkened environment. The maze had been learned with the 

 illuminated condition. The room was darkened by means of 

 window shades. The animals were accustomed to running the 



