REDINTEGRATION IN ALBINO RAT— A STUDY IN RETENTION 43 



(4) Influence of Previous Training at 45- Day Retention Period 



As a final experiment in retention on the maze, it was 

 decided to give a group of rats some definite preliminary 

 training before setting them to learn the maze. Following 

 this plan two litters of six and four rats, respectively, were 

 set first to learn the inclined-plane problem. (This problem 

 is treated more fully on page 48, and for this reason it will 

 not be considered here in detail. Only the important 

 points of all preliminary training will be mentioned.) 

 Rats 1, 2, 3, 5, 7, and 9 comprise the litter of six; 4, 6, 8, 

 and 10 the litter of four. Rats 5 and 7 of the litter of six 

 and rat 10 of the litter of four failed to complete the whole 

 experiment. Concerning the remaining rats, 1, 2, 3, 4, 

 6, 8, and 9, it is a fact of importance here to note that 

 three — rats 2, 3, and 4^ — failed to solve the inclined plane 

 once after fifteen successive days. This point of informa- 

 tion is mentioned here specifically to show that the rats 

 used in this experiment were far from being above the 

 average; in fact, if we may judge from the above fact, 

 they were below the average, because the percentage of 

 failures on the inclined plane is usually low. 



At the completion of the inclined-plane problem, a 

 definite period of 70 days was allowed to elapse in the 

 case of each rat before the maze was begun. The last 

 3 days of the 70-day period was used to test the redintegra- 

 tion of each rat on the inclined plane. During the 70-day 

 period each rat was required to continue the learning of 

 one or more problems, the rope-ladder problem being first, 

 and the sawdust box second. The sawdust box was a 

 problem which necessitated the digging of a tunnel through 

 the sawdust before the rat could reach its food. 



Following the usual method, at the completion of a 

 problem each rat was fed in the next problem for four 

 days to accustom it to the environment. Rats 1 and 4 

 failed to establish perfect integration on the rope ladder, 

 but rats 2, 3, 4, 8, and 9 had learned the rope ladder and 

 had begun the learning of the sawdust box when the re- 

 spective dates for their preliminary training had ended. 

 Rats 1, 6, 8, and 9 which had learned the inclined plane 

 were then tested in redintegration on the plane, while 



