Sexual Dimorphism: The Interrelation of Shape and Color

Abstract

Sex-typicality displayed as sexual dimorphism of the human face is a key feature enabling sex recognition. It is also believed to be a cue for perceiving biological quality and it plays an important role in the perception of attractiveness. Sexual dimorphism of human faces has two main components: sexual shape dimorphism of various facial features and sexual color dimorphism, generally manifested as dimorphism of skin luminance, where men tend to be darker than women. However, very little is known about the mutual relationship of these two facets. We explored the interconnection between the dimorphism of face shape and dimorphism of face color in three visually distinct populations (Cameroonian, Czech, and Vietnamese). Our results indicated that populations which showed a significant dimorphism in skin luminance (Cameroon, Vietnam) had low levels of sexual shape dimorphism, while a population with higher levels of sexual shape dimorphism (Czech Republic) did not exhibit a significant dimorphism of skin luminance. These findings suggest a possible compensatory mechanism between various domains of sexual dimorphism in populations differing in the levels of shape and color dimorphism.