Color Categorization Independent of Color Naming

Abstract

Summary: Color is continuous, yet we group colors into discrete categories associated with color names (e.g., yellow, blue). Color categorization is a case in point in the debate on how language shapes human cognition. Evidence suggests that color categorization depends on top-down input from the language system to the visual cortex. We directly tested this hypothesis by assessing color categorization in a stroke patient, RDS, with a rare, selective deficit in naming visually presented chromatic colors, and relatively preserved achromatic color naming. Multimodal MRI revealed a left occipito-temporal lesion that directly damaged left color-biased regions, and functionally disconnected their right-hemisphere homologs from the language system. The lesion had a greater effect on RDS’s chromatic color naming than on color categorization, which was relatively preserved on a nonverbal task. Color categorization and naming can thus be independent in the human brain, challenging the mandatory involvement of language in adult human cognition. : Color categories (e.g., red, yellow) may result from the top-down impact of language on perception. Siuda-Krzywicka et al. describe a patient with impaired color naming, after a stroke disconnects color perception from language. The patient still categorizes colors they could not name, showing robustness of color categorization against impaired linguistic processing. Keywords: brain damage, multimodal MRI, Sapir-Whorf hypothesis, optic aphasia for colors, resting-state fMRI, task fMRI, functional connectivity, structural connectivity, white matter tractography, lesion mapping