Lhe Mental Life of the Monkeys 219 
his and other cages by taking out sticks hundreds of times, 
but though he escaped from his cage a dozen times in other 
ways, he never took the stick out and to my knowledge never 
tried to. -I myself and visitors smoked a good deal in the 
monkeys’ presence, but a cigar or cigarette given to them 
was always treated like anything else.| 
IMITATION OF OTHER MONKEYS 
It would theoretically seem far more likely that the mon- 
keys should learn from watching each other than from watch- 
ing human beings, and experimental determinations of such 
ability are more important than those described in the last — 
section as contributions both to genetic psychology and to 
natural history. I regret that the work I have been able to 
do in the study of this phase of the mental life of the mon- 
keys has been very limited and in many ways unsatisfactory. 
We should expect to find the tendency to imitation more 
obvious in the case of young and parents than elsewhere. I 
have had no chance to observe such cases. We should ex- 
pect closely associated animals, such as members of a com- 
mon troop or animals on friendly terms, to manifest it more 
than others. Unfortunately, two of my monkeys, by the 
time I was ready to make definite experiments, were on terms 
of war. The other had then become so shy that I could not 
confidently infer inability to do a thing from actual failure 
to do it. He showed no evidence of learning from his 
mates. I have, therefore, little evidence of a quantitative 
objective nature to present and shall have in the end to ask . 
the reader to take some opinions without verifiable proofs. 
My reliable experiments, five in number, were of the folt 
lowing nature. A monkey who had failed of himself (and 
often also after a chance to learn from me or from being put 
