Abstract

Our version of the idea that the red-green distinction is associatively learned by experience was spawned by the notion that neural connections in the retina and LGN may be blind to their originating cone types [middle-wavelength-sensitive (M) or long-wavelength-sensitive (L)]. Red-green learning theory provides an alternative perspective for describing polymorphic models of color perception (Piantanida, Am. J. Optom. & Physiol. Opt., 1976). In these models, the M-cone spectral sensitivity maximum for a man is genetically selected from a range of wavelengths that begins with that of the normal M-cone but extends to that of the normal L-cone. A similar situation occurs for the L-cone, so a small number of men are predicted to have M-cones more sensitive to long wavelengths than their L-cones. Also a small number of heterozygotie women are expected to have two different M-cones with most sensitive wavelengths surrounding those of their L-cone. From the learning point of view there are no M- and L-cones: genetics supplies cones which the learning process groups. For opponency models that combine L- and M-inputs with opposite signs to obtain a red-green opponent process, different phenotypes emerge than those predicted by associative learning.

© 1991 Optical Society of America