RATE OF LEARNING IN THE WHITE RAT 41 



training. The number of trials necessary to master this problem 

 varied from 684 for No. 10 to 1376 for No. 31, while the 

 average for the group was 960.6. Since no pain was given in 

 30 per cent of the trials these animals on the average encountered 

 pain 672 times before learning to make the desired response. 

 Because of the large number of trials required and the amount 

 of time lost in the long zigzag runways of this box, it was thought 

 expedient to use a simpler box in training the remaining animals. 

 The apparatus used by Carr and Freeman was selected with the 

 hope that time could be saved each day by its use. Future ex- 

 periments required that the animal be able to hold the standard 

 of correct response in the box presented in this paper and not in 

 the simpler one. It was necessary, therefore, that both apparatus 

 be learned, a necessity which made it seem probable that the 

 group working in the new box would require more trials than the 

 other group. In order to avoid any delay in making the transfer 

 of correct response from one box to the other, the animals were 

 each day given one run in the long maze after having completed 

 the day's work in the short one. In this way the two mazes 

 were learned together: the first being partially learned, then the 

 second partially learned, and finally the first and then the second 

 completely learned. In the light of the findings of Wiltbank 1 

 this was thought to be the best possible method. Table XVIII 

 gives the number of animals, the number of trials, and the num- 

 ber of turns made by each animal before reaching the required 

 standard of efficiency. The range of trials required is from 394 

 to 1196; the average for the group of 15 rats is 694,4. Since 

 in 30 per cent of these trials no pain was given, the animals 

 received pain 486 times before learning to respond to it nega- 

 tively. Not only did this method save time in giving the series 

 from day to day, but on the average it reduced the number of 

 presentations of pain from 672 (the number required for the 

 long-maze groups) to 468 a saving of 204. There are at least 

 three possible explanations of this difference: i) The increased 

 complexity of the longer box increased the difficulty of the prob- 



1 Wiltbank, R. T., "Transfer of Training in White Rat Upon Various 

 Series of Mazes," Beb. Mono., Vol. IV, 1919. 



