Twо cоmpeting theоries of color vision аre discussed in the textbook. Eаch theory seems supported by some evidence but chаllenged by other findings. One observation is that people do not describe a color as a ‘greenish red’ or ‘yellowish blue,’ which seems to offer general support for the _____________ theory of color vision which proposes that certain colors and their corresponding afterimages account for perception of all variations of color.