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 in 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. x 
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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