48 HARRY H. WYLIE 



sense of location, although there is no evidence that the 

 " jump " was even generally made at the place where the 

 last shock had been received. Most of them occurred at 

 the first place in the alley where it was possible to receive 

 the shock or at the last place. Some few occurred at every 

 place in the alley, that is, when the animal started down 

 the alley, it jumped at every place where a shock was likely 

 to be received and so complete'y avoided the shock. One 

 would be led to suspect by gross observation that vision 

 was mainly instrumental in guiding the reaction in this 

 jumping. 



(4) Summary, — If we are to gather together the results 

 for learning the negative response we find the following 

 facts outstanding: 



(a) The electric shock is the most effective stimulus, 

 both from the point of view of rapidity of learning and from 

 the point of view of smoothness of the learning curve, there 

 being practically no lapses and no plateaus. 



(b) The effectiveness of the electric shock is probably due 

 to the fact that the animals were negative to the shock. 

 The failure to show progress from the beginning was likely 

 due to the emotional disturbance produced by the strange- 

 ness of the stimulus. 



(c) The superior effectiveness of the light over the sound 

 was probably due in part but not wholly to the better control 

 of general environmental conditions in the case of the light. 



(d) *The inferior effectiveness of the sound in com- 

 parison with the light and pain might indicate also that the 

 visual and tactual stimuli play a more important part in 

 the regular life of the white rat than do auditory stimuli. 

 While the tactual has always been assigned a prominent 

 place, there has been a tendency to belittle the importance 

 of the visual. Another result pointing toward and empha- 

 sizing the visual has already been mentioned in discussing 

 the results of the experiments where pain was given as pun- 

 ishment for wrong choice when learning the positive re- 

 sponse to the sound stimulus. Also, if " jumping " just 

 reported is guided by vision, it furnishes an added case 

 in point. 



Bearing on this point, see, Pearce, Jour. Animal Beliav., Vol. 7, No. 3, p. 177. 



