The Biological Basis of the Experience of Constant Colour Categories

Abstract

In the work reported here, we used the Land Colour Mondrian experiments to test the degree to which subjects vary in their perception of colour categories. Twenty subjects of different ethnic and cultural backgrounds, for all but one of whom English was not the primary language, viewed 8 patches of different colour in two Mondrian displays; each patch, when viewed, was made to reflect identical ratios of long-, middle- and short-wave light. Subjects were asked to match the colour of the viewed patch with that of the Munsell chip coming closest in colour to that of the viewed patch, without using language. Overall, there was no variability in categorizing colours as red, yellow, brown and green but a small variability in categorizing them as purple, blue, orange and turquoise. In terms of hue, we found significantly less variability in matching warm hues than in cool ones. We interpret the lack of significant variability between subjects in the matches made as a pointer to similar computational mechanisms being employed in different subjects to perceive colours, thus permitting subjects to assume that their categorization of colours has universal agreement and assent.