THE INTELLIGENCE OF MAMMALS 255 
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‘of another with the end of securing some advantage which 
the other animal enjoys. Imitation of this character 
involves a species of inference, and its occurrence in animals 
is less widespread than was commonly supposed some 
years ago. Thorndike tested cats and dogs with the view 
of ascertaining if they could learn to get out of a puzzle 
box by seeing other cats and dogs get out. After witness- 
ing a number of times the successful exits of the animals 
which had learned the means of escape these cats and 
dogs were unable to get out by themselves any more 
quickly than other individuals which had not the ad- 
vantage of seeing how the escape was effected. In all the 
experiments performed the animals did not show the least 
tendency to imitate the performances of their successful 
comrades. The experiments of Cole and Davis on the rac- 
coon yielded similar negative results. 
Small, in his studies on the white rat, finds evidence of a 
very simple kind of imitation, but no clear cases of imitation 
of the inferential type. When one rat sees another digging 
it is apt to dig also, and when one runs over a box it is apt 
‘to be followed by others. Berry, who has made a more 
thorough study of imitation in the white rat, found better 
evidence of intelligent imitation. ‘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 in- 
different to each other’s presence, but as the untrained rat 
observed that the other one was able to get out while he 
was not, a gradual change took place. The untrained rat 
began to watch the other closely; he followed him all about 
the cage, standing up on his hind legs beside him at thestring, 
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 
