290 



FREDERICK S. BREED 

 TABLE 1— Continued 



iSeries 



12 



Date 



No. 62 No. 65 



Sex, M. Sex. M. 



Red White Red White 



Control Tests — Continued 



Remarks 



13 



15 



Training Tests 



* R, 10 > W, 100 in brightness. 



Explanation of abbreviations in table: R, red; B, blue; W, white; Sk, electric shock; Dk, dark- 

 ness; Btr, brighter; Dkr, darker; Eq, equal. 



A numerical value appearing with the name of the stimulus represents distance in centimeters 

 of the source light from the screen. 



REACTIONS TO FORMS 



As a test of form discrimination chicks were afforded an oppor- 

 tunity to select a circle when appearing along with a square. 

 For this experiment the sliding frame of the apparatus was 

 fitted with three black tin plates, in two of which had been cut 

 square openings each with a side of 4.43 cm. ; in the third and 

 central one was cut a circular opening of the same area, its 

 diameter being 5 cm. Compactly behind each of the form plates 

 were mounted two plates of opal glass, each pair of plates hav- 

 ing an aggregate thickness of about .515 cm. The lamps were 

 stationed at a distance of 90 cm. from the screen. The Bausch 

 and Lomb projection-lantern water cells were adjusted imme- 

 diately back of the opal glass plates, on the side of the source 

 lights. With the above arrangement white lighted areas with 

 sharp outlines were presented to the animals, with variations 

 in brightness, size, and position under good control. 



Three chicks, nos. 73, 76, and 87 were used in these tests, 

 one of which yielded positive results. After 60 training tests, 



