André Fernandez and Molly Morris have an interesting paper in American Naturalist examining the effect of color vision in primates as a bias toward the evolution of sexual signaling. Their conclusion is that the evolution of red coloration in different lineages of primates followed (rather than drove) the evolution of trichromatism. The convergent evolution of red coloration in many primate lineages can be said to result from a bias in the perceptual systems of primates with trichromatic vision.
Which is all just to say that primates who can't see red don't usually become red. Fernandez and Morris conclude that trichromatism evolved for ecological rather than social reasons, such as the detection of edible leaves and/or fruits.
(via henry)
Dennis O'Neil has put up a primer on primate color vision.
References:
Fernandez AA, Morris MR. 2007. Sexual selection and trichromatic color vision in primates: statistical support for the preexisting-bias hypothesis. Am Nat 170:10-20.doi:10.1086/518566
