Haggerty, Imitation in Monkeys. 391 



III. 



Cases of immediate imitation 1 



Cases of gradual imitation 3 



IV. 



Cases of imitation in whicli the imitating animal did not himself experience 

 the result of the act before performing it 3 



Cases of imitation in which the imitating animal did experience the result 

 of the act before performing it 1 



4. Paper Experiment. 



A. Description of Device. 



For this expei'iment board E was used. An opening 17 cm. square was 

 cut, the lower edge 30 cm. from the floor of the cage. The opening was 

 covered on the outside by a hinge door. In the center of this door a hole 

 5 cm. in diameter was cut and on the outside of the door, just at the lower 

 edge of the circular opening was fastened a food box. With the door open, 

 a sheet of ordinary writing paper was laid over the opening and the door 

 was then closed upon it. The hole in the door and the food in the box 

 wei-e thus hidden by the paper (fig. 6). 



The animal could get food by breaking the paper and reaching through 

 the circular hole. On the inside of board E was a wooden screen which, 

 when dropped down, covered the whole device. When the paper and food were 

 in place, and the animal or animals in the cage, this screen could be lifted 

 by the experimenter by means of a string. When an animal had broken the 

 paper, the screen was lowered by the experimenter and a new piece of 

 paper was inserted. Then the screen was lifted and all was ready for a second 

 test. 



B: Behavior of No. 2. 



On five different days, from April G to April 10, No. 2 was in the cage alone 

 for thirty minutes each day. He did not get food from the box and made 

 but little investigation of the paper. The most he did toward getting food 

 was on April 7th, when he went to the paper, put his hands on the lower 

 edge of the opening and bit at the paper, but did not tear it through. 



On April 21, in order to help No. 2 to learn, the experimenter punched 

 a hole in the paper with the point of a lead pencil and the monkey thrust 

 one finger through and tore a larger hole. This was repeated a number 

 of times and No. 2 learned to tear the paper by biting when no opening 

 was made. On April 22 he got food in this way ten times in seven or 

 eight minutes. 



C Behavior of No. 3. 

 Preliminary trials. — No. 3 was given four trials of thirty minutes each 

 in the old cage in the Harvard Laboratory. In each of the first two trials 



