Eye color for a plausible argument stating that some eyes can or do change, based on chemical reactions and hormonal changes within the body. Studies on Caucasian twins, both fraternal and identical, have shown that eye color over time can be subject to change, and major demelanization of the iris may also be genetically determined. Most eye-color changes have been observed or reported in the Caucasian population with hazel and amber eyes. Carleton Coon created a chart by the original Martin scale. The numbering is reversed on the scale below in the (later) Martin–Schultz scale, which is (still) used in physical anthropology.
Linguistic relativity and the color naming debate the study of color naming phenomena. He states that "the physics of color, the psychophysics of color discrimination, and the psychology of color naming are not isomorphic". The color spectrum clearly exists at a physical level of wavelengths (inter al.), humans cross-linguistically tend to react most saliently to the primary color terms (a primary motive of Bornstein's work and vision science generally) as well as select similar exemplars of these primary color terms, and lastly comes the process of linguistic color naming, which adheres both to universal patterns but demonstrates individual uniqueness. While one may have origins in its predecessor,