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THE AMEBIC AN NATURALIST [Vol. XLII 



little it is possible to find, and how uncertain is what is found, 

 even with the best of will. Kinnaman, Small and others had 

 incidentally seen a few examples of real imitation. We have 

 now from the Harvard laboratory two careful studies of this 

 matter by Berry, 3 with results that are most interesting. In 

 Berry's rats and cats we find imitation as it were in the making. 

 Our conception of imitation, and of its different kinds, loses its 

 sharp lines and angles and becomes indefinite. When one knows 

 how to escape or get food and another does not, the animals 

 do not set to work to imitate each other's actions in the clear- 

 cut way we are apt to think of as imitation. But the one that 

 doesn't "know how" does after some time begin to pay atten- 

 tion to his comrade's actions, and then in an indefinite way to 

 do something of the same sort himself. "We found that when 

 two rats were put into the box together, one rat being trained 

 to get out of the box, and the other untrained, at first they were 

 indifferent to each other's presence, but as the untrained rat 

 observed that the other was able to get out, while he was not, 

 a gradual change took place. The untrained rat began to watch 

 the other's movements closely; he followed him all about the 

 cage, standing up on his hind legs beside him at the string, 

 and pulling it after he had pulled it, etc. We also saw that 

 when he was put back the immediate vicinity of the loop was 

 the point of greatest interest for him, and that he tried to get 

 out by working at the spot where he had seen the trained rat 

 try." 4 In cats similar and more marked cases of imitation 

 were found and analyzed. 



Berry's work is the first really scientific study of imitation in 

 animals that we have had. and it shows, as so commonly happens 

 when a thorough study is made, that we can not make extreme 

 statements, whether positive or negative. Imitation is found; 

 even "reflective imitation," but it is not precise; we can often 

 hardly be certain whether it is imitation; and where it is 

 more pronounced it is difficult to distinguish imitation for the 

 mere sake of doing what a companion does, from imitation for 

 the purpose of accomplishing the result that the companion 

 accomplishes. Like all other traits of behavior, imitation grows 

 gradually out of something that seems not the same thing at 



