Biological origins of color categorization

Significance

Humans parse the continuum of color into discrete categories (e.g., “red” and “blue”), and the origin of these categories has been debated for many decades. Here, we provide evidence that infants have color categories for red, yellow, green, blue, and purple. We show that infants’ categorical distinctions align strikingly with those that are commonly made in the world’s different color lexicons. We also find that infants’ categorical distinctions relate to the activities of the two neural subsystems responsible for the early stages of color representation. These findings suggest that color categorization is partly organized and constrained by the biological mechanisms of color vision and not arbitrarily constructed by language.

Abstract

The biological basis of the commonality in color lexicons across languages has been hotly debated for decades. Prior evidence that infants categorize color could provide support for the hypothesis that color categorization systems are not purely constructed by communication and culture. Here, we investigate the relationship between infants’ categorization of color and the commonality across color lexicons, and the potential biological origin of infant color categories. We systematically mapped infants’ categorical recognition memory for hue onto a stimulus array used previously to document the color lexicons of 110 nonindustrialized languages. Following familiarization to a given hue, infants’ response to a novel hue indicated that their recognition memory parses the hue continuum into red, yellow, green, blue, and purple categories. Infants’ categorical distinctions aligned with common distinctions in color lexicons and are organized around hues that are commonly central to lexical categories across languages. The boundaries between infants’ categorical distinctions also aligned, relative to the adaptation point, with the cardinal axes that describe the early stages of color representation in retinogeniculate pathways, indicating that infant color categorization may be partly organized by biological mechanisms of color vision. The findings suggest that color categorization in language and thought is partially biologically constrained and have implications for broader debate on how biology, culture, and communication interact in human cognition.