Color constancy reconsidered

This paper proposes an account of color constancy based on an examination of the relevant scientific literature. Differences in experimental settings and task instructions that lead to variation in subject performance are given particular attention. Based on the evidence discussed, the core of the proposal made is that there are two different forms of color constancy, one phenomenal and the other projective. This follows the hypothesis of Reeves et al (2008). Unlike Reeves et al (2008), it is argued that projective color constancy is crucially dependent upon phenomenal color constancy and certain aspects of scene perception. Additionally, it is hypothesized that capacities that support projective color constancy have an important role to play in facilitating our ability to quickly recognize scenes with diagnostic chromatic properties independently of assignments of colors to object surfaces. Color constancy is the stability of perceived object color across changes in viewing conditions. This is a fascinating achievement. Any given parcel of light reaching the eye from a scene (the “color signal”) may have been caused by a vast range of states of the world. There is no way of directly determining the contributions of various physical factors to that light; viz., surface reflectance and illumination. For instance, light of almost identical composition reaches the eye from dandelion flowers in deep shade and dandelion leaves in sunlight, but the flowers look yellow and the leaves green in both conditions (Brown 2003, p.268). Philosophers have shown great interest in color constancy and its empirical study, chiefly due to color’s special place in long-abiding debates about the relationship between the mind and the world. 1 I am deeply grateful to Adam Reeves for providing much helpful feedback that has sharpened my thinking on the matters addressed in this paper. A debt of thanks is also owed to Charlie Chubb, David Hilbert, Kimberly Jameson, Kent Johnson, Louis Narens, A. Kimball Romney, and Jack Yellott.