DISCUSSION 

 INTERNAL SECRETION IN LEARNING 



KNIGHT DUNLAP 



The Johns Hopkins University 



Non-psychological writers, and many psychologists, assume 

 that emotion has a direct influence on action, and in particular, 

 that pleasure (or satisfaction) and pain (or dissatisfaction) are 

 instrumental in the formation of habits. Certain writers, how- 

 ever, have objected to this assumption on various theoretical 

 grounds, the most important of which, at the present time, is the 

 alleged fact that no detailed mechanism is discoverable or has 

 even been suggested, by which the effects of emotion on action 

 might be mediated. This omission I have had it in mind for 

 several years to supply by a hypothesis which seems to offer 

 grounds for experimental test: but as I shall be able to carry 

 out the tests on only a few points, it seems proper to outline 

 the hypothesis for the consideration of others, who may be ex- 

 perimentally interested in the matter. 



The hypothesis I have in mind is a Iqgical outcome of the view 

 to which some of us were earlier forced concerning the emotions, 

 namely, that in the important bodily changes which are com- 

 monly called " expressions of emotion" (and which I, following 

 Lange, would insist are the emotions), the activities of certain, 

 probably all, of the endocrine glands play a part. Five years 

 ago I assumed that this would be found true of the " major emo- 

 tions" (or what are sometimes called " emotions" as distinguished 

 from " feelings"), as Cannon has so admirably shown. At the 

 present time, I have no hesitation in adopting it as a working 

 hypothesis for the " feelings" of pleasure and pain, and all other 

 definite affects. 



There are certain cases in which the effect of pleasure in 

 "fixing" a reaction can be explained by the immediate repeti- 



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