527 Group â A tax-exempt group organized under section 527 of the Internal Revenue Code to raise money for political activities. These groups are typically parties, candidates, committees or associations organized for the purpose of influencing an issue, policy, appointment or election, be it federal, state or local.
Noun. 1. trichromacy-the normal ability to see colors. chromatic vision, color vision. visual modality, visual sense, vision, sight-the ability to see; the visual faculty.
There are two major theories that explain and guide research on colour vision: the trichromatic theory also known as the Young-Helmholtz theory, and the opponent-process theory. These two theories are complementary and explain processes that operate at different levels of the visual system.Trichromatic Theory.n fact, as you have seen, both theories are needed to explain what is known about colour vision. The trichromatic theory explains colour vision phenomena at the photoreceptor level; the opponent-process theory explains colour vision phenomena that result from the way in which photoreceptors are interconnected neurally.