RATE OF LEARNING IN THE WHITE RAT 21 



pain was given. These regular tests, therefore, show the gradual 

 growth of the association if properly analyzed. The analysis 

 of Table III is given in the curve presented in Fig. 4. Each 

 point of this curve was determined by the average per cent of 

 correct responses for the group in 20 trials of the regular train- 

 ing series. The growth of the association, as determined by the 

 percentage of correct responses, is recorded for each 20 trials 

 during the entire learning period. 



The 30 per cent of trials in which no stimuli were given proved 

 to be an excellent control for determining whether or not the 

 animals had developed the habit of turning each time in the first 

 alley selected, or were turning only when the sound was encoun- 

 tered. Without an exception they continued to the food-box 

 during these trials. Very often they would proceed slowly and 

 manifest hesitancy, much as the human does during a period of 

 expectancy and uncertainty, but in no case did they turn around. 

 The following conclusion is warranted: The turning response 

 was transferred from pain to buzzer rather than to some other 

 factor; 128.5 trials were necessary to perfect this transfer. 



3) Two-second interval. The two stimuli were presented to 

 Group IV with an interval of two seconds. Again the special 

 tests were omitted and the rate of of learning measured in the 

 regular trials. Tabulated results for the group are to be found 

 in Table IV. With the exception of Nos. 10 and 39 the indi- 

 vidual differences are small. With No. 10 the association began 

 early in the period, but it was very difficult for him to hold the 

 percentage of correct response over a period of five days. Num- 



TABLE IV 



Animal Trials % on Last 100 



10 316 92 



11 210 91 



21 166 92 



23 211 90 



38 203 93 



39 269 oo 



Average 229 91.2 



