CHAPTER VII
THE SENSE OF SIGHT: BRIGHTNESS VISION
What is known concerning sight in the dancer—Brightness vision and color vision—Methods of testing brightness vision, the visual discrimination apparatus—Motives for discrimination and choice—Punishment versus reward as an incentive in animal experiments—Hunger as an incentive—An electric stimulus as an incentive—Conditions for brightness vision tests— White-black vision—Evidence of preference—Check experiments—Conclusion.