||Uncertainty of sensory signal explains variation of color constancy
Color constancy is the ability to recognize the color of an object (or more generally of a surface) under different illuminations. Without color constancy, surface color as a perceptual attribute would not be meaningful in the visual environment, where illumination changes all the time. Nevertheless, it is not obvious how color constancy is possible in the light of metameric mismatching. Surfaces that produce exactly the same sensory color signal under one illumination (metamerism), may produce utterly different sensory signals under another illumination (metameric mismatching). Here we show that this phenomenon explains to a large extent the variation of color constancy across different colors. For this purpose, color constancy was measured for different colors in an asymmetric matching task with photorealistic images. Color constancy performance was strongly correlated to the size of metameric mismatch volumes. At the same time, sensory singularities, color categories, and cone ratios did not affect color constancy. The present findings do not only provide considerable insight into the determinants of color constancy, they also show that metameric mismatch volumes must be taken into account when investigating color as a perceptual property of objects and surfaces.