68 HAROLD C. BINGHAM 



Porter finds that the sparrow and cowbird can discriminate 

 three horizontal Hnes or a black diamond from a blank card or 

 from each other. No more weight can be attached to these 

 results than could be given to his efforts to study form percep- 

 tion. On account of the widely differing method and apparatus 

 a comparison of Porter's results with my own would be quite 

 out of place. 



The chick, then appears inferior to the crow in the matter 

 of form perception. Where the crow appears to react by means 

 of a relative form difference, the chick reacts to a circle-triangle 

 situation on the basis of a specific form, or shape, difference. 

 Responses to this specific form relation are much less readily 

 acquired by the chick than responses to size differences. 



