552 



THE CENTURY MAGAZINE 



NO. II. I\IACACUS RHESUS ; MALE, 

 THREE YEARS OLD 



He was very vigorous, learned to get food in the chute 

 experiment by watching No. 4, and 

 was a good fighter. 



1 resolved to try the chute again, and with 

 this experiment I was led to believe that 

 the imitative tendency in monkeys was 

 very deep-seated. 



No. 4 was a large, vigorous, female 

 Cebus monkey. She was given her pre- 

 h'minary trials, during which she gave no 

 attention w^hatever to the chute. Then to 

 make sure that she did not merely follow 

 her companion about the cage and to the 

 chute, she was placed inside a wire-covered 

 observation box. This box was set on the 

 floor of the experiment cage. Jack was 

 set free in the cage to get food. No. 4 was 

 alert, for he was a stranger to her. When- 

 ever he moved, she jumped at the side of 

 her box, as if to get liold of him. Jack 

 was frightened ; he shrank into a far cor- 

 ner of the cage, and squeezed himself into 

 the smallest possible space. It was so for 

 an hour. If Jack moved. No. 4 jumped, 

 and Jack always retreated. Once some- 

 thing outside the cage attracted her atten- 

 tion ; when her head was turned away, 

 Jack gave one leap to tlie front of the cage 

 and another to the chute. Like a flash he 

 swung down, pulled tlie string, and 

 dropped to the floor. No. 4 turned her 

 head just in time to see him grab up a pea- 

 nut and retreat to his corner. She was 

 frantic to get out of the box, and Jack 

 v/as so frightened that he did not go to the 

 chute again during the morning. 



Late in the afternoon the test was re- 

 peated ; Jack was hungry, and w^nt at 

 once to the chute. No. 4 w^as all atten- 

 tion. She did her best to get out of the 

 box. When Jack had obtained food, he 

 was taken out, and No. 4 was released 

 from her box. At once she climbed the 

 wire front and leaned toward the chute. 

 She quickly drew back, and descended to 

 the floor. She climbed the wire end of the 

 cage opposite the chute, and, throwing her 

 head and shoulders toward it, caught hold 

 of the lower part of it. She swung loose 

 from the wire, caught the rungs in her 

 feet, wrapped her tail about the chute, 

 threw her head down, looked up the inside 

 of the chute, and thrust up a hand. The 

 iron rattled against the chute, and her arm 

 gave a vigorous jerk. The peanuts fell 

 upon her chest and then to the floor. All 

 of this occurred within forty seconds from 

 the removal of Jack. She repeated the 

 performance a dozen times as rapidly as 

 she could eat the food. 



My conversion to a belief in the ability 

 ot monkeys to learn by imitation soon re- 

 ceived further justification, for, shortly 

 after, two other monkeys duplicated the 

 behavior of No. 4, and No. 1 1 learned to 

 get food from the chute by a process of 

 gradual imitation. 



What I mean by "gradual imitation" 

 may be illustrated by the behavior of No. 1 3 

 in the string experiment. No. 5 had been 

 taught to pull the string to get food from 



NO. 13. MACACUS CYNOMOLGUS ; MALE, 



FOUR YEARS OLD 



He was very attentive to other animals, a good fighter, 

 imitated in the chute experiment and in the string 

 experiment; a very intelligent monkey. 



