2 76 POPULAR SCIENCE MONTHLY. 



of place. In the other ease I pulled a hook out from a catch but he 

 yanked at the bar to which the hook was attached and so jerked the 

 latter free. 



It might be that although the monkeys did not succeed after tuition 

 where they had previously failed, yet they attempted acts which they 

 had not previously attempted. This is not the case, however. There 

 were no signs that the monkeys tried more after tuition to do the 

 things they saw me do than they did before. Their behavior was un- 

 modified by the tuition save that in general they tried less. 



It may be objected that the acts I failed to teach the monkeys were 

 not consistent with their make-up, that a monlcey might be very intelli- 

 gent and still not manifest his intelligence by depressing levers, unwind- 

 ing wires or pulling off loops, that monkeys might be able to learn to do 

 certain things from seeing them done and still be unable to learn the 

 particular acts needed in these experiments. But as a matter of fact, 

 these particular acts were quite natural for the monkeys, quite in accord 

 with their interests and propensities. They learned by the typical 

 animal method acts of the same general sort, e. g., to open boxes and 

 operate the mechanisms throwing food into their cages by pulling bars 

 around, unliooking hooks and pulling at strings. And often the very 

 same act with which I tested one monkey in the experiments just 

 described had been learned by another through the repetition and selec- 

 tion of a chance success. Thus No. 1 learned of himself to unwind a 

 wire though No. 3 failed to do so after seeing me do it 30 times. 



The systematic experiments designed to detect the presence of abil- 

 ity to learn from human beings are thus practically unanimous against 

 it. So too was the general behavior of the monkeys, though I do not 

 consider the failure of the animals to imitate common human acts as of 

 much importance save as a rebuke to the story-tellers and casual 

 observers. The following facts are samples: The door of No. I's cage 

 was closed by an iron hoop with a slit in it through which a staple 

 passed, the door being held by a stick of wood thrust through the staple. 

 No. 1 saw me open the door of 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 given to them was always treated like anything 

 else. 



The following is a sample of the tests of the monkey's ability to 

 learn to do a thing from being made to do it : A box was arranged with 

 its door held closed by a bar of wood held in position in a slot. When 

 it was pushed back an inch and a half further into this slot the door 

 could be opened. It was fastened so that it could not be pulled out 

 from the slot altogether. The only way to get the door open was 



