CHAPTER XI 



THE MODIFICATION OF CONSCIOUS PROCESSES BY INDI- 

 VIDUAL EXPERIENCE (continued) 



87. The Inhibition of Instinct 



IN still another form of experiment that has been devised 

 to study the ways in which animals learn by experience, the 

 object has been to secure the complete inhibition of an in- 

 stinctive action. Obviously two factors will come into play 

 here, the strength of the instinct and the force of the modi- 

 fying experience. The latter factor we might suppose to be 

 strongest when the performance of an instinctive action 

 could be made attended with pain, and less strong when 

 the performance of some action opposed to instinct has been 

 found to be accompanied by pleasure. 



The. first case we find apparently illustrated by Morgan's 

 chick in his dealings with a bee ; he needed but one experi- 

 ence with that insect to inhibit entirely, the next day, his 

 instinct to peck at it (281, p. 53). On the other hand, 

 Bethe denied consciousness to the crab because, although 

 every time it went into the darkest corner of the aquarium 

 it was seized by a cephalopod lurking there, it did not in six 

 experiences learn to inhibit its negative phototropism ; nor 

 did the crabs learn not to snap at meat, though several times 

 when they did so they were seized by the experimenter (28). 

 The case of the crabs is not, however, fairly comparable 

 with that of the chick, for the latter was not really obliged 

 to inhibit his pecking instinct altogether, but only to direct 



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