288 The Animal Mind 



reflex and unaccompanied by any consciousness whatever. 

 A dog shows depression during his master's absence, but 

 his state of mind may be merely vague discomfort at the 

 lack of an accustomed set of stimuli, not a clear idea of 

 what he wants ; as when we feel that we have forgotten 

 something or that something in our environment has been 

 altered. 



We shall first consider certain pieces of evidence which 

 indicate that in many of the lower animals the existence of 

 memory ideas is highly doubtful. Later, we shall note 

 certain testimony in favor of their existence in the minds 

 of some animals, although probably with a very restricted 

 function. 



One argument from which we may conclude that animals 

 do not make use of memory ideas where human beings would, 

 is derived from the gradual character of the dropping off 

 of useless movements in experiments of the puzzle-box 

 type. A human being who had once hit by accident on 

 the right way to open a lock could hardly fail, on being 

 confronted with the lock a second time, to recall an idea of 

 the successful movement, and to perform it at once, with- 

 out wasting time and effort on unnecessary movements; 

 but a dog or a cat makes almost as many random clawings 

 and pawings the second time as the first, and only gradu- 

 ally omits the irrelevant motions. 



In the next place, animals very generally show a lack of 

 ability to imitate other animals when the "imitatee" is not 

 actually present before them ; they cannot imitate by re- 

 membering another animal's movements. Imitation may 

 be, as various authors have pointed out, of at least two dif- 

 ferent types. The first may be called instinctive imitation, 

 and is widespread throughout the animal kingdom. It 

 occurs when the sight or sound of one animal's performing 



