INSTINCTS AND HABITS IN CHICKS 57 



TABLE 17 

 Reactions to Form 

 Chick no. 22. Hatched 2/5, '08. Sex, F. 

 Circle-Square 



Series Date Right Wrong 



A Mar. 9 4 6 



1 " 10 4 6 



2 " " 5 5 



3 " 12 5 5 



4 " " 5 5 



5 " 13 4 6 



6 " " 2 8 



7 " 16 6 4 



8 " " 4 6 



TABLE 18 



Reactions to Form 



Chick no. 23. Hatched 2/5, '08. Sex, LTndetermined 



Circle-Square 



Series Date Right Wrong 



A Mar. 9 4 6 



1 " " 9 1 



2 " 10 2 8 



3 " " 6 4 



4 " 12 2 8 



5 " 13 6 4 



6 " " 6 4 



7 " 16 8 2 



8 " 17 5 5 



9 " 19 4 6 



10 " 20 5 5 



chick and of forcing him gently from behind were tried without 

 effect. The chick simply " gave up," as my note has it.' 



C. Size 



The search for a second method of measuring modification of 

 behavior was continued in an investigation of the reactions of 

 the chick to size differences in two dimensions, difference in 

 form being excluded. The plan was adopted of having openings 

 in gray display-cards through which the chick had to pass. The 

 openings in one set of cards were 6.35 cm. wide and 8.89 cm. 

 high; those in the other set 8.89 cm. wide and 12.44 cm. high. 



' Later, during some work as yet unpublished, I found a chick that acquired, 

 the circle-square habit when the experiment was conducted in a dark-room. Opal 

 glass was electrically lighted from behind and the above forms, cut in black tin 

 screens, permitted illuminated areas of these shapes to be exposed to the chick. 



