DISTRIBUTION OF EFFORT IN LEARNING 



IN THE WHITE RAT^ 



JOHN LINCK ULRICH 



The present study of the distribution of effort in learning 

 was begun with white rats as subjects in the Psychological 

 Laboratory of the Johns Hopkins University in the fall of 1911, 

 and was completed in the spring of 1913. The questions which 

 the investigation attempts to answer are as follows: (1) When 

 the rat learns a simple problem of manipulation, what is the 

 most efficient method, from a physiological standpoint, of giving 

 the trials? From the standpoint of rapidity of learning, mini- 

 mization of excess effort and length and steadfastness of reten- 

 tion, shall we allow the animal to work at the given problem 

 once per day, three times per day, or five times per day, etc.? 

 (2) Having answered this in connection with the learning of a 

 single problem, the same question comes up again when it is 

 asked whether the relations found to hold good in (1) will apply 

 to cases where the animals have to learn more than one problem 

 at a time. In other words, we shall attempt to find out whether 

 in learning three problems abreast it is more advantageous to 

 give one trial per day on each of the three problems, three trials 

 per day on each of the three problems, or five trials per day 

 on each of the three problems. (3) Since in carrying out the 

 above experiments we shall have a given problem box learned 

 under two different sets of conditions, viz., (a) alone, (b) con- 

 currently with two other problems, we shall have the data 

 necessary for answering the question whether it is method- 

 ologically more efficient (i.e., requires fewer trials) to require 

 the animals to learn (under the several t^^pes of distribution of 

 practice) one problem completely before taking up a second 

 one or whether better results may be obtained by requiring 

 them to learn the several problems abreast. (4) The final sub- 

 ject dealt with in this paper attempts to show the effect upon 

 retention of allowing the animals to learn by the one trial, 

 three, five, etc., trials methods. 



1 From the Psychological Laboratory of the Johns Hopkins University. 



