The physics of color and the psychology of color naming are not isomorphic. Physically, the spectrum is continuous with regard to wavelength – one point in the spectrum differs from another only by the amount of wavelength difference. Psychologically, hue is categorical – colors change qualitatively from one wavelength region to another. The psychological characterization of hue that characterizes color vision hasbeen revealed in a series of modern psychophysical studies with human adults and infants and with various infrahuman species, including vertebrates and invertebrates. These biopsychological data supplant an older psycholinguistic and anthropological literature that posited that language and culture alone influence perceptual processes; language and culture may modify color naming beyond basic categorizations.