Studies of animal color vision: comments on some important theoretical considerations

Eliminating brightness as a discriminatory cue is unquestionably the most important factor in animal color vision studies. Accurate descriptions of any species' color vision depends on, first, a determination of spectral sensitivity (electrophysiologically or psychophysically) which can then be used to establish a brightness match between the comparison stimuli and, second, tests of wavelength discrimination. The use of innate responses to investigate animal color vision introduces variables which are not characteristically visual. Since these innate behaviors involve neural mechanisms other than the visual system, they tend to distort the normal characteristics of the species' color vision.