126 J. C. DeVOSS AND ROSE GANSON 



CONFUSIONS OF COLORS WITH GRAYS 



In a recent report on the vision of the rabbit Miss Washburn 8 

 says, "In order to eliminate the brightness error in experiments 

 on color vision in animals, it is not sufficient to show that the 

 animal tested can distinguish a color from the gray that a color 

 blind human being would see in place of the colors, but the animal 

 must be proved capable of discriminating this color from all 

 grays." For a year before Miss Washburn published her report, 

 we had been searching for a gray which the cats would confuse 

 with orange-yellow, yellow, or blue. In their turns, cats num- 

 bered one, two, and three discriminated these colored papers 

 from each of the fifty Hering grays. 



Meanwhile some of our experiments had revealed the fact that 

 the cat could not discriminate the yellow from some other colors 

 of the same flicker equivalent. It was consequently suspected 

 that the texture of the Hering papers was furnishing the clue 

 to discrimination. But Hering grays numbered one and two 



*Throughout the paper grays will be referred to as "colors" in this way. 

 8 Washburn, M. F. Psych. Bull., vol. 9, 1912, p. 54. 



