INSTINCTS AND HABITS IN CHICKS 45 



18.75 cm. In all color work the openings in the two sets of 

 cards were the same in size, 8.5 cm. wide and 11.5 cm. high. 

 These rectangular openings were cut in the lower part of the 

 card in such a way as to leave equal margins of color on either 

 side of the entry way. 



III. Method 



For a test of the reactions to color, form or size the appro- 

 priate cards were placed in the card-holders. For example, if 

 reactions to black and blue were to be tested, one might start 

 with a black card in each of the holders at D and F, right, and 

 two blue cards in the corresponding holders on the left. The 

 cage in which the animals lived was carried to a position wdth 

 reference to the table upon which the apparatus sat such that 

 one of the wire netting doors of the cage would turn back toward 

 the exit-end of the apparatus as above described, and form an 

 easy passage-way from the reaction box to the cage. 



The chick to be experimented upon, marked and numbered, 

 was carried from the cage to the entrance box. When placed 

 in A, it soon acquired the habit of crowding up near the wire 

 netting door, standing at a point equidistant from the two 

 cards exposed at D. It also soon ceased pecking at the wire 

 covering or flying against it, if it happened at first to try this 

 way of escape. The work had not gone very far before the 

 plan was rigidly adhered to of not releasing a chick from A 

 until it made an effort to escape by urging toward the screen. 

 Sometimes this meant a delay of several minutes, but it seemed 

 useless to spend time with a chick that did not react negatively 

 to the confinement or isolation. Further, care had at all times 

 to be exercised that a chick be not kept struggling in A. Results 

 were vitiated if this occurred. I feel sure that discriminating 

 ability deteriorated as the response to the isolation of the reac- 

 tion box approached too near in one direction the passivity 

 of indifference, or in the other the activity of excitement. I 

 have watched the record of indifferent chicks recover from a 

 lapse when the response to isolation was accentuated by suffi- 

 ciently prolonged solitary confinement between trials; on the 

 other hand it is easy to point to numerous instances where a 

 record has been marred by undue excitement. I concluded from 

 experience, that much the wisest plan was to watch for an 

 incipient struggle to escape, and to lift the door just when the 



