144 Studies in Animal Behavior 



in the case of heat; and there is more or less evi- 

 dence for the same conclusion in regard to very in- 

 tense visual and auditory stimuli, although it can 

 not be regarded as entirely established. Even were 

 it proven that overstimulation of any sense organ 

 produces unpleasant effects (and avoiding reactions 

 as a secondary result), the unpleasantness may be 

 due not so much to the injury to the overstimu- 

 lated neurones as to the breaking over of the 

 stronger neural current into new channels. 



Certain tastes and smells are disagreeable even 

 when they can barely be perceived at all, while others 

 are welcome at almost any degree of intensity. It 

 is very improbable that the disagreeable quality of 

 the former is due to the supra-optimal stimulation 

 of certain associated neurones. It is not so much 

 the intensity of the effect produced by the stimulus 

 that gives rise to disagreeable results and inhibitory 

 effects as the channels through which the stiijiuli en- 

 ter the nervous system. Were Thorndike's theory 

 correct, we should expect to find comparatively mild 

 stimulations producing, quite generally, pleasurable 

 feelings, and strong stimuli producing disagreeable 

 feelings, and, directly or indirectly, avoiding reac- 

 tions. On the contrary, we find the organism pro- 

 vided with sets of reflex arcs, each of which tends 

 to be set into operation by its own kind of stimu- 

 lating agent, and producing feelings of much the 

 same quality, however their intensity may vary. 



Another consequence of Thorndike's theory is 



