Higher order color mechanisms.

Evidence supporting the existence of higher order color mechanisms, that is, ones beyond the previously identified second stage mechanisms is presented. This evidence includes a reanalysis of the data of Krauskopf, Williams and Heeley (1982) on the desensitizing effects of viewing chromatically modulated fields, new experiments on a generalized version of the "transient tritanopia" experiment of Mollon and Polden (1977), and results on the relationship between discrimination and detection of brief color changes.