410 'Journal of Comparative Neurology and Psychology. 



continuously. Between these extremes are the cases of No. 5, ]^o. 

 2 and ISTo. 3, which exhibit in a decreasing order the influence of 

 the imitatee. One can well imagine that a large number of such 

 cases would show quite a regular gradation in the complexity of 

 the imitative behavior. In view of the evident gradations in the 

 behavior of the animals I choose to call the cases of No. 5 and jSTo. 

 2, partially successful imitation. 



TABLE 24. 



Results of the Screen Experiment. 



I. 



Number of animals used in the imitation tests 5 



Cases of successful imitation 1 



Cases of partially successful imitation 2 



Cases of failure to imitate 2 



II. 

 Cases of imitation when the imitator was confined during the activity of 



the imitatee 



Cases of imitation when the two animals were in the cage together 3 



III. 



Cases of immediate imitation 



Cases of gradual imitation 3 



IV. 



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

 the result of the act before performing it 



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

 of the act before performing it 3 



6. Plug Experiment. 



/ A. Description of Device. 



In board A, a hole 5 cm. square was cut, 3.j cm. from the floor (fig. 8, a). 

 Covering this hole on the outside of the cage was a slide door, made of 

 glass, set in a wooden frame. Just outside of this glass door, food was 

 exposed. The slide door could be opened by a string, &, which passed down 

 under the cage, up the outside of the corner where the wire end met the 

 wire side and through a hole, c, 90 cm. from the floor of the cage. The 

 string was attached to the end of a plug, rf, which fitted into this hole from 

 the Inside of the cage. The plug extended into the cage 4 cm. and was IY2 

 cm. in diameter. 



