BEGINNINGS OF INTELLIGENCE 175 



for the "increased energy of the pleasure process" to flow 

 "into the channels of the movement associated with pleasure" 

 (that is, I take it, the movement which brings pleasure) 

 is by no means evident. There is, I think, no primary ten- 

 dency, as Spencer and Bain seem to think, for the nervous 

 discharge to take the direction of the organ from which the 

 pleasure is derived. Animals, it is true, move so as to 

 bring an organ which is pleasantly stimulated again under 

 the action of the stimulus, but this is often due to the dis- 

 charge going mainly to a quite different part of the body, 

 such as distant appendages, instead of to the part directly 

 affected. 



The theory of heightened nervous discharge as expounded 

 by Spencer, Bain and Baldwin, fails to give us, I think, the 

 desired explanation of the acquirement of individual ac- 

 commodations, and one naturally turns to other theories of 

 the psycho-physiology of pleasure and pain for light. Here, 

 however, we are led into a veritable quagmire of psychological 

 speculation, for there are few fields in which there are so 

 many and so fundamental differences of opinion among 

 competent psychologists. The physiological concomitants 

 of pleasure and pain have afforded a subject of numerous 

 laboratory studies and almost no end of theories. There 

 is good evidence that pain sensations are produced by 

 the stimulation of specific nerves, but as regards the 

 physiological states accompanying pleasure and pain the 

 results of experiments as well as opinions based on them 

 are very discordant. And it is difficult to see how most 

 of the pleasure-pain theories would help us to explain 

 the mechanism of accommodation even if they were 

 established, so that the outlook for the solution of the 

 problem as it is commonly formulated does not seem, at 

 present, an encouraging one. 



