It is in the nature of the colours.

This study corroborates the view that perceptual categorization does not require linguistic categories, and simple tasks like ordering colours on the basis of their similarities evince well-structured perceptual categories, defined relatively to visual perception and independently from experience, language and higher-level cognition. The independence of these categories from experience, language, and higher-level cognition would be an argument for their naturalness, and hence for their universality, and for their role in shaping language itself. On the other hand, the influence of language on colour perception would come about by facilitating perception-controlled behaviours. The ordering procedure which rests on perceptual similarity yields a colour system in which perceptual categories are implicit and yet clear and stable. In fact, it shows that whatever speakers in whatever language community share the same experience of colour. The arguments presented favour the 'universalist' thesis and are important in regard to both the research methodology and interpretation of the experimental data. The study's distinctive features are the interdisciplinary nature of its approach, the gestaltist theoretical and methodological conception adopted, and the concept of the naturalness of colour advanced and discussed.

The effect of illumination on gray color

The present study explored the perceptual process of integration of luminance information in the production of the gray color of an object placed in an environment viewed from a window. The mean luminance of the object was varied for each mean luminance of the environment. Participants matched the gray color of the object with that of Munsell chips in a viewing box. The results show that the Munsell values so obtained are linear measures of gray color. The results support the possibility that the gray color of the object derives from an additive integration of the information about mean luminance of the object and about mean luminance of the environment, with the weights of this information varying with the mean luminances(AU)