INTEGRATION OF MOVEMENTS IN LEARNING IN THE RAT 377 



Moreover, the physiological increase in bodily tone is not syn- 

 chronous with the successful act, but occurs when pleasure arises. 

 Since physiological processes are closely correlated, it is difficult 

 to see how this may be effected. On the other hand, it is stated 

 that pain eliminates the unsuccessful movements. It appears 

 that since pleasure and pain determine the different qualifica- 

 tions for movements, one kind of movement is set over against 

 the other, and their relative importance established and regu- 

 lated. Movements become thus, in some way or other, of con- 

 sequence to the animal, and no physiological process of " stamp- 

 ing in" the successful kind occurs until this consequence is real- 

 ized. 



This consequence is of course established through sensory chan- 

 nels, and it must be the pleasurable sensory associations that pro- 

 duce this entire effect upon the organism. Often it is supposed 

 that the successful movements are of such consequence to the 

 animal, that there arises a protreptical tendency for their recur- 

 rence and repetition, and even for their selection. 



The actual difficulty of arriving at a satisfactory view of the 

 pleasure-pain concept is due to the simple reason that the anti- 

 thetical terms, pleasure and pain, are inapplicable to any organi- 

 zation in an animal, and these concepts must, as a consequence, 

 be inappropriately applied to successful and unsuccessful move- 

 ments which can be said to have an organization in reflex mechan- 

 isms for their production. The relation and importance of the 

 pleasure-pain concept for anything like the fixation of one kind 

 of integrated movements, remains as an a priori assumption, so 

 long as this pleasure-pain concept cannot be applied to any known 

 organic process, such as hunger for instance, where an organiza- 

 tion for its arousal exists in the structure and movements of the 

 alimentary canal. Accordingly any attempt to prove the relation 

 of the kinds of movements must ever involve the proof of this 

 assumption. The terms pleasure and pain are thus hypothetical 

 terms beyond the reach of scientific method; that is, to prove 

 experimentally that pleasure, as such, does, or does not play a 

 part in the fixation of successful movements in learning, appar- 

 ently cannot be done. 



