Research shows that red is not a proxy signal for female genitalia in humans

New research from anthropologists at the University of Kent may have important ramifications for the future study of the role of colour signals in human social and sexual interactions.

The research, which has been published by the journal PLoS One, set out to test the hypothesis that men have a biological disposition to the colour red because of its link to an implied relationship to female genital colour and women's signalling of fertility and sexual proceptivity.

However, Dr Sarah Johns and a team from the University's School of Anthropology and Conservation have shown through an experiment involving computer manipulated images of female genitalia that men do not have a preference for redder female genitalia and, by extension, that red is not a proxy signal for genital colour.

For their experiment the team manipulated four individual photographs of the human female vulva to produce four subtle, yet different colour conditions, ranging from pale pink to red. Forty males were then asked to rate the sexual attractiveness of each image. The results showed that the men rated the reddest shade significantly less attractive than the three pink shades, among which there were no significant differences in rated attractiveness.

Dr Johns said: "It has previously been argued that women use the colour red to announce impending ovulation and sexual proceptivity, with this functioning as a proxy signal for genital colour, and that men show increased attraction in consequence."

"However, with our study we have shown that the myth of red as a proxy for female genital colour should be abandoned. This view must be replaced by careful examination of precisely what the colour red, in clothing, makeup, and other contexts, is actually signalling to men. What it isn't signalling is female sexual arousal."

Dr Johns is a lecturer in evolutionary anthropology with research interests in human reproductive timing and evolved sexual behaviour. She also has interests in how public health policy and evolutionary theory can be integrated, and works to promote public understanding of evolutionary theory, particularly in how it relates to human behaviour.