558 TEE POPULAR SCIENCE MONTHLY 



cated movements are natural to the monkey than to the lower mammals. 

 Berry also maintains that his experiments " have shown that voluntary 

 imitation of a certain type does exist in white rats" and that "while 

 this imitation is not of as high a degree as that discovered by Kinna- 

 man in his experiments with monkeys, it is not different in kind." He 

 thinks, also, that "a similar type of imitation exists in cats," that 

 "cats to some extent imitate human beings" and that "cats do not 

 instinctively kill and eat mice, but do so by imitation." He holds, how- 

 ever, that " instinctive imitation in cats is more important than students 

 of animal behavior have supposed." Cole (L. W.) thinks he found 

 evidence of voluntary imitation in the raccoon. These results, however, 

 are open to the same objection as that raised against Hobhouse, namely, 

 that the experiments may not have been sufficiently "controlled." In 

 some laboratories efforts to prove the presence of voluntary imitation in 

 the lower animals have been discontinued because of the discouraging 

 uniformity with which negative results have been reached. No one 

 seems to have found indisputable evidence. It is worth noting, how- 

 ever, that the most positive results seem to have been obtained with 

 monkeys. What the experiments have shown unequivocally is that the 

 animals tested learned almost exclusively by a gradual dropping off of 

 unnecessary movements. Upon the nature of this process psychology 

 has thus far thrown little light. Jennings says that the disturbance 

 set up in the organism by the stimulus, by hunger or confinement, not 

 finding an outlet by one path of discharge, seeks others in succession 

 until one is found which relieves the disturbed condition. After repe- 

 tition the change which leads to relief is reached more directly as "a 

 result of the law of the readier resolution of physiological states after 

 repetition." This " law " is, however, merely a statement of the fact. 



It is doubtless true that intermediate stages are present between 

 instinctive and voluntary imitation. Nevertheless, unless the work of 

 expert observers of animal behavior during the past fifteen years is to 

 be overthrown, the assertion may be made that man alone has developed 

 voluntary imitation to any very important degree. 



The significance of the advance to the voluntary imitation stage in 

 development is second to none in the whole evolution of organic life for 

 by its attainment human life, as we know it, now became possible. 



It has been customary to recognize a more or less definite boundary 

 between man and his precursors based on the development of speech by 

 man. If, as a matter of fact, there is any value in attempting to define 

 the boundary by a single activity, voluntary imitation may be suggested, 

 on the objective side, at least, as of more importance than speech or lan- 

 guage. Both voluntary imitation and speech appear to require either 

 conceptual thought or something closely akin to it. Both may thus be 

 taken as objective indices of the existence of that power of abstraction 



