DISTRIBUTION OF MEMORY 219 



processes is a sure criterion for the existence of as- 

 sociative memory (2). 



Associative memory probably exists in most mam- 

 mals. The dog which comes when its name is called, 

 which runs away from the whip, which welcomes its 

 master joyfully, has associative memory. In birds, it 

 is likewise present. The parrot learns to talk ; the 

 dove finds its way home. In lower Vertebrates, mem- 

 ory is also occasionally found. Tree-frogs, for ex- 

 ample, can be trained, upon hearing a sound, to go to 

 a certain place for food. In other frogs, Rana escu- 

 lenta, for instance, no reaction is as yet known which 

 proves the existence of associative memory. Some 

 fishes evidently possess memory ; in sharks, however, 

 its existence is doubtful. With regard to the Inver- 

 tebrates, the question is difficult to determine. The 

 statements of enthusiasts who discover consciousness 

 and resemblance to man on every side should not be 

 too readily accepted. 



4. In my experiments on the tropismsof animals, it 

 became clear to me how easy it is for an observer 

 who is inclined to think anthropomorphically to re- 

 gard machine-like effects of external .stimuli on lower 

 animals as the expression of intelligence. He needs 

 only to neglect the analysis of the external stimuli. I 

 have protested against the anthropomorphisms of 

 Romanes, Eimer, Preyer, and others in a series of ar- 

 ticles (2, 3). Bethe has recently published a paper on 

 the psychic qualities of ants and bees in which he 

 took special pains not to fall into the gross anthropo- 



