Color categories and color appearance

Abstract

We examined categorical effects in color appearance in two tasks, which in part differed in the extent to which color naming was explicitly required for the response. In one, we measured the effects of color differences on perceptual grouping for hues that spanned the blue–green boundary, to test whether chromatic differences across the boundary were perceptually exaggerated. This task did not require overt judgments of the perceived colors, and the tendency to group showed only a weak and inconsistent categorical bias. In a second case, we analyzed results from two prior studies of hue scaling of chromatic stimuli (De Valois, De Valois, Switkes, & Mahon, 1997; Malkoc, Kay, & Webster, 2005), to test whether color appearance changed more rapidly around the blue–green boundary. In this task observers directly judge the perceived color of the stimuli and these judgments tended to show much stronger categorical effects. The differences between these tasks could arise either because different signals mediate color grouping and color appearance, or because linguistic categories might differentially intrude on the response to color and/or on the perception of color. Our results suggest that the interaction between language and color processing may be highly dependent on the specific task and cognitive demands and strategies of the observer, and also highlight pronounced individual differences in the tendency to exhibit categorical responses.

Variations in normal color vision. VI. Factors underlying individual differences in hue scaling and their implications for models of color appearance

“…A second potential nonlinearity that has been a focus of several studies could be in the degree of categorical coding, such that observers give more weight to the dominant hue component when judging the proportions (Regier & Kay, 2009). Following Webster and Kay (Webster & Kay, 2012), we modeled this as a relative weighting of the pure categorical response [the unique hue angle of the dominant component (Θ c )], and the linear response (Θ l ): $${\Theta }_{\mathrm{pred}}=\mathrm{b}{\Theta }_{\mathrm{normalc}}+(1-\mathrm{normalb}){\Theta }_{\mathrm{normall}}$$ Figures 4i and 4j show the predictions for a standard deviation of 0.15 in the value for the bias (b) [somewhat weaker than the the biases estimated by Webster and Kay (2012) for the Malkoc et al (2005) hue-scaling functions]. As with the response nonlinearity, the bias systematically alters all hues between the unique and binary axes and thus again leads to a broad pattern of loadings.…”

Variations in normal color vision. VII. Relationships between color naming and hue scaling

“…With regard to scaling, a conceptual issue is to what extent hue scaling itself is an actual measure of appearance, for it could be argued that the task is a variant on color naming where the observers are judging the salience of a small set of categories. Moreover, these judgments show some susceptibility to categorical biases with regard to the primaries used for scaling, and these biases could reflect an intrusion of linguistic coding (Webster & Kay, 2012). Nevertheless, responses from hue-scaling experiments reveal spectral sensitivities that closely resemble the functions measured by more nonverbal tasks such as hue cancellation [e.g.…”

“…in the judged similarity or the time required to discriminate a pair of colors) (Franklin, Drivonikou, Bevis, Davies, Kay & Regier, 2008, Gilbert, Regier, Kay & Ivry, 2006, Mullen & Kulikowski, 1990, Winawer, Witthoft, Frank, Wu, Wade & Boroditsky, 2007). However, these categorical effects tend to be subtle and labile (Brown, Lindsey & Guckes, 2011, Witzel & Gegenfurtner, 2011, Witzel & Gegenfurtner, 2013), and may depend strongly on whether the task used to measure them is limited by the properties of perceptual encoding versus the decision stages of the response or language processing (Kay & Kempton, 1984, Pilling, Wiggett, Ozgen & Davies, 2003, Roberson & Davidoff, 2000, Roberson, Pak & Hanley, 2008, Webster & Kay, 2012). Thus it remains unknown to what extent differences in naming patterns are tied to differences in perception.…”

Relating color working memory and color perception

“…What counts as uniformity will therefore differ between observers. Moreover, one may expect color-specific response effects with large sets of colors because spanning linguistically or categorically separable regions is known to influence discrimination thresholds and response times [7]. These effects seem to originate in perception.…”