Semantic and Perceptual Representations of Color

Perceptual psychology widely operationalizes color appearance as a construct with very close, even isomorphic, ties to color naming structure. Indeed, a considerable body of psychological and psychophysics research uses naming–based tasks to derive structural properties of color appearance space. New research investigating the relations linking color similarity and color naming structures suggest that assumptions involving strong structural correspondences between appearance and naming are unfounded. Such research also reveals (i) features of the phenomena for which cognitive and perceptual learning processes play significant roles in establishing individual’s color naming similarity structures and (ii) features of the mechanisms underlying stable color naming systems and the ways such shared systems relate to varying individual perceptual color experience. Empirical support for these is summarized, as are suggestions for exploring the largely uninvestigated cognitive processes underlying color appearance and naming similarity relations. Much research on the cognitive processing of color appearance assumes that for all trichromat observers well–specified perceptual relations exist for predicting how color names will be used to label and partition color appearance space. This assumption is present in theoretical descriptions of shared color lexicons, in the practiced aggregation of color naming data across individuals to derive color naming norms, and in empirical tasks that use lexical labels when assessing individual perceptual salience and individual color space similarity relations. Actually, the perceptual basis for color naming is far from normatively uniform. Simple anomalous trichromats – who in the real world behave as normal trichromats – can have extremely different color equivalence classes compared to normal trichromats, with both smaller and larger metameric discrimination ellipses compared to normal observers (Regan et al. 1994). Even among normal trichromats, observers can experience rather deviant (i.e., ∼3 s.d.) red–green color weakness (National Reseach Council 1981), suggesting that discrimination differences among normals are enormous (Kaiser & Boynton 1996, p. 343). Large differences among trichromats are also found for “fundamental” unique hue settings, and no uniformity exists in the perceptual distances of unique hue ranges (Kuehni 2001, 2004, 2005). Such results do not support the view that uniform perceptual processing is the basis for color naming and categorization findings (Kay & Regier 2003). The absence of a uniform perceptual basis for normal appearance and naming representation raises some interesting questions. For example, what is the basis for the cognitive representation of color appearance, and for color categorization and naming systems?, and what psychological processes play a role in the representation and maintenance of such systems? Here it is shown that consideration of the constraints on color representation under normal perceptual variation can provide new insights into the cognitive mechanisms contributing to individual color appearance and naming cognitive representation. Trichromat Observer Variation To clarify the basis of individual color appearance and naming representation, it seems uncontroversial to suggest that cognitive representation of color appearance similarity must vary in a manner that accords with an individual’s variant of color perception. Figure 1 depicts color relations for two