DECEPTIVE APPEARANCES OF INTELLIGENCE 161 



modify the irritability of the tentacles for some time it 

 might explain the change of behavior. This may not be 

 the true explanation of the phenomenon, but it will serve 

 to show how careful we must be, in studying the behavior 

 of lower organisms, about inferring the presence of associa- 

 tive memory. There have been almost no studies of the 

 power of association in the Ccelenterates, where the various 

 possibilities of error have been carefully excluded. 



Darwin in his work on earthworms attributes a certain 

 degree of intelligence to these creatures on account of their 

 peculiar habits of plugging up their burrows with dead leaves. 

 The worms pull in the leaves of the linden by their tips, while 

 the leaves of the rhododendron which are smaller at the base 

 are pulled in by the petiole. Pine needles which frequently 

 occur in pairs with a common base are not seized by the 

 small end, which would cause difficulty in getting both 

 needles into the hole, but by the enlargement at the basal end. 

 Darwin gave the worms triangles of paper and found that 

 they usually seized these by the most acute angle in carrying 

 them to their burrows. The conclusions of Darwin that the 

 behavior of the earthworms indicates a certain degree of 

 intelligence was a very natural one. Hanel, however, 

 who has repeated and verified Darwin's experiments and 

 performed a number of others, finds no ground for assuming 

 any intelligence in the earthworm and ascribes the behavior 

 of the animal to a series of more or less complex reflexes in 

 relation to the form and chemical nature of the objects 

 drawn in. There is no evidence of profiting by experience 

 in the earthworm's behavior and, however complex the acts 

 performed, there is nothing that is thus far known that 

 precludes us from considering them as belonging entirely 

 to the reflex type. 



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