Eye-mouth-eye angle as a good indicator of face masculinization, asymmetry, and attractiveness (Homo sapiens)

Past research on male facial attractiveness has been limited by the reliance on facialmetric measures that are less than ideal. In particular, some of these measures are face size dependent and show only weak sexual dimorphism, which limits the ability to identify the relationship between masculinization and attractiveness. Here, the authors show that eye-mouth-eye (EME) angle is a quantitative and face size independent trait that is sexually dimorphic and a good indicator of masculinity and face symmetry. Using frontal photographs of female and male faces, the authors first confirmed that the EME angle (measured with the vertex in the middle of the mouth and the arms crossing the centers of pupils) was highly sexually dimorphic. Then, using pictures of young male faces whose attractiveness was assessed on a 7-point scale by young women, the authors showed that attractiveness rate was negatively correlated with EME angle and with the angle asymmetry. The results are compared with those that could be obtained with interpupilary or upper face height measurements. The authors discuss the relationship between attractiveness and both EME angle and its symmetry in the light of evolutionary psychology.