The Science of Attraction

Seeing Red

Used to attract mates and defend territories, the red epaulets adorning the shoulders of blackbirds don’t come cheap. Their color comes from carotenoids in the diet that are not easy to obtain.

Red-winged blackbird. Photo by Kevin J. McGowan Cornell Lab of Ornithology
Red can inspire an intensity of emotion unrivaled by other colors. Could there be a biological explanation for this? The visual system of many species is designed to detect a limited range of colors, responding best to even fewer colors within that range. For fruit-eating animals like many birds and primates, detecting red is a matter of life and death, since it is often the color of ripe fruit. The sensitivity to red is so strong that some males have evolved red coloration as a sexual attractant, exploiting a pre-existing sensory bias in females that was initially unrelated to reproduction. This is an example of sensory exploitation, a phenomenon associated with a number of sensory systems and not always restricted to reproductive processes. Red can also be an indicator of good genes or overall health, since its intensity correlates well with a male’s foraging success or parasite load.