TRANSFER OF RESPONSE IN THE WHITE RAT 47 



presented. This more uniform contrast might have in- 

 creased the effectiveness. Then we still have the problem 

 of the comparative intensities of stimuli from the different 

 sense fields. For instance, how intense a sound shall be 

 considered to be equal to a given intensity of light or of 

 electric shock? We have no way of determining this inde- 

 pendent of the reaction of the animals. All that can be 

 said in the present case is that under the conditions of the 

 experiments the electric shock was the most uniformly 

 effective stimulus, the light next, and the sound least, in 

 establishing the required negative response. 



Another interesting thing not indicated in the curves and 

 tables was the attempt on the part of some of the animals 

 when learning the response to the pain to avoid the stimu- 

 lus by jumping over the places where the shock had been 

 previously received. A few typical cases are those of 

 numbers 114, 115, 124, 128. The record of number 114 

 is as follows: in the fifth series of trials, it jumped twice; 

 in the seventh series, five times; in the eighth, four times; 

 in the ninth series, once; in the eleventh series, twice. The 

 record for number 115 is as follows: in the fourth series, 

 once; in the fifth series, three times; in the eleventh series, 

 once. The record for 124 is as follows: in the twelfth series, 

 five times; in the thirteenth series, once; in the sixteenth 

 and seventeenth, once each. The record for 128 is: in the 

 eighth series, eight; in the tenth series, twice. All of these 

 " jumps " occurred before the change of procedure took 

 place as mentioned in the description of this series of ex- 

 periments. That is, they all occurred when the pain stimu- 

 lus was given at but one place in the alley rather than all 

 the way down as was the case in the method finally used. 

 It is noteworthy, too, that these " jumps " occurred as a 

 sort of preliminary method of responding to the pain stimu- 

 lus, since after the animal had really begun to choose, or, 

 in other words, to make the correct response no attempt 

 at such avoidance occurred. Not all the animals in this 

 group which learned the pain stimulus attempted to avoid 

 it in this way. The four animals mentioned are the best 

 examples in the records. 



The fact of " jumping " indicates a more or less definite 



