104 HAROLD C. BINGHAM 



to outside and inside corners and to stimuli. The most reliable 

 measurement of the discrimination habit itself is the number of 

 correct choices. In addition to these quantitative measurements, 

 certain qualitative criteria were found to be highly suggestive 

 of stages of learning. 



The method of punishment was found to be both valuable 

 and pernicious. If intelligently used, it seems to be highly 

 valuable; if carelessly applied, punishment can radically inter- 

 fere with learning. The maximum value of punishment in 

 chick work evidently depends upon the alertness of the experi- 

 menter in selecting an optimal punishment for each subject. 



A chick can acquire a perfect circle-triangle or circle-square 

 habit, but control tests indicate that it has no general idea of 

 circularity In contrast with triangularity or squareness. On 

 the other hand, a large-small trained chick can react positively 

 to the larger of two stimuli even though this particular stimuli 

 had been the shock sign of the training combination. Also, 

 the positive stimulus of the training pair, when presented with 

 a larger circle, may call forth negative reactions. Positive 

 results on the question of relativity were not secured from the 

 flicker experiments. 



The order of importance of the visual factors which have been 

 studied, It would seem, Is size or flicker, the brightness and 

 general Illumination complex, and form. 



Bibliography 



A selected bibliography on the origin and history of the domestic fowl appears 

 on page 5. A complete bibliography of experimental work with the domestic 

 fowl to 1916 appears on page 20. 



