This chapter focuses on the neuropsychology of color. It considers the theme of this volume, the categorization of colors, by first discussing the category of color, a somewhat different topic which has been the subject of some important research in neuropsychology. This approach allows us to address questions concerning the relationship between color and other aspects of an object. In particular, I consider the relationship between color and shape, because we can only talk about color itself after we have disentangled the connections between the two.

Despite any possible associations between them, color and shape are quite different from each other. They are distinct, for example, in the way we talk about them: color terms are different parts of speech from shape terms. In ordinary speech, we talk about seeing a sphere; we do not talk about seeing a red. Now, this may seem to be a trivial distinction; but I think it is an important one. Colors are attributes of something else; they are qualities of surfaces or surface appearance. So if we wish to talk of color, we must disentangle talk of the surface appearance from talk of the boundary within which it is contained.

Theoretical approaches to the mental representations of objects have placed different emphases on the roles of shape and the surface held by that shape. At the extreme of complete separation between the two is nineteenth-century phrenology.