BEGINNINGS OF INTELLIGENCE 177 



repeated its first experience. Of course inhibition of the 

 original response does not always involve contrary move- 

 ments, but there may be impulses to such movements which 

 do not issue in action. The principal feature in the modi- 

 fication of action through painful experiences is the assimi- 

 lation of impulses incongruous with the original one. 



In the reinforcement or stamping in of a reaction to a 

 particular stimulus that brings pleasure, it certainly seems 

 as if pleasure or its physiological correlate in some way 

 serves to cement more firmly the association between the 

 stimulus and the response. Let us consider, however, 

 the case in which the chick pecks at a caterpillar which 

 has a good taste. The presence of the caterpillar hi the 

 mouth excites the swallowing reflexes; in the presence of a 

 similar caterpillar the pecking response is made more readily 

 than before, and whatever hesitation there may have been at 

 first disappears. Is not the difference from the pain-re- 

 sponse due to the fact that there is an organic incompatibility 

 between the first and second responses in the pain response, 

 while there is an organic congruity or mutual reinforcement 

 of these responses in the other? Pecking and swallowing 

 form the normal elements of a chain reflex; when one part 

 of the system is excited it tends to excite the rest, to increase 

 the general tonus of all parts concerned in the reaction. 



According to the view here presented, whether a particular 

 response to a stimulus tends to be repeated more readily 

 or discontinued, depends not upon the peculiar physiological 

 state which may be produced in the brain, but upon the 

 kind of responses which the stimuli brought by the act call 

 forth. If an outreaching reaction becomes coupled with a 

 withdrawing response the result is inhibition. If the re- 

 action, on the other hand, brings stimuli which produce 



congruent reactions the association formed with these 

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