Color categories in macaques.

Abstract

Whether macaque monkeys partition the photic spectrum into the same 4 basic hue categories that humans do, i.e., blue, green, yellow and red, was studied. Monkeys were trained to respond in the presence of 1 chromatic stimulus and were tested, in extinction, for generalization to others. In extinction, the monkeys responded at similar and high levels to stimuli that fell in the same basic human hue category as the training stimulus and at similar and much lower levels to stimuli that fell in a different human hue category from the training stimulus. Macaques and humans apparently categorize the spectrum in a similar fashion.