34 The Animal Mind 



assured that consciousness accompanies learning only when 

 the learning is so rapid as to show that the effects of pre- 

 vious experience are recalled in the guise of an idea or 

 mental image of some sort. But does even the most rapid 

 learning possible assure us of the presence of an idea in the 

 mind of a lower animal ? Where the motive, the beneficial 

 or harmful consequence of action, is very strong, may not 

 a single experience suffice to modify action without being 

 revived in idea? Moreover, animals as high in the scale 

 as dogs and cats learn to solve problems analogous to that 

 of the combination lock so slowly that we cannot infer the 

 presence of ideas. Are we then to conclude that these 

 animals are unconscious, or that there is absolutely no 

 reason for supposing them possessed of consciousness? 

 Yerkes has criticised the " learning by experience" criterion 

 by pointing out that "no organism . . . has thus far 

 been proved incapable of profiting by experience." It is a 

 question rather of the rapidity and of the kind of learning 

 involved. "The fact that the crayfish need a hundred or 

 more experiences for the learning of a type of reaction that 

 the frog would learn with twenty experiences, the dog with 

 five, say, and the human subject with perhaps a single 

 experience, is indicative of the fundamental difficulty in 

 the use of this sign" (814). Nagel has pointed out that 

 Loeb, in asserting "associative memory" as the criterion of 

 consciousness, offers no evidence for his statement (524). 

 The fact is that while proof of the existence of mind can be 

 derived from animal learning by experience only if the 

 learning is very rapid, other evidence, equally valid on the 

 principle of analogy, makes it highly improbable that all 

 animals which learn too slowly to evince the presence of ideas 

 are therefore unconscious. This evidence is of a morphologi- 

 cal character. 



