Backgrounds and the evolution of visual signals

Color signals which mediate behavioral interactions across taxa and contexts are often thought of as color 'patches' – parts of an animal that appear colorful compared to other parts of that animal. Color patches, however, cannot be considered in isolation because how a color is perceived depends on its visual background. This is of special relevance to the function and evolution of signals because backgrounds give rise to a fundamental tradeoff between color signal detectability and discriminability: as its contrast with the background increases, a color patch becomes more detectable, but discriminating variation in that color becomes more difficult. Thus, the signal function of color patches can only be fully understood by considering patch and background together as an integrated whole.