What constitutes the perception of facial typicality?

Abstract

Facial typicality plays a significant role in social interactions as an ingroup marker. We have investigated how physical attributes and perceived psychological characteristics are associated with both perceived and measured facial typicality. We analyzed 195 facial portraits of individuals (106 women, 89 men) of Czech origin using a combination of geometric morphometrics and Bayesian multiple regression. Then we tested how perceived facial characteristics (trustworthiness and attractiveness) and measured characteristics (morphological uniqueness, sextypicality, distinctiveness, BMI, age, and skin color expressed in CIELab space) relate to the perception of facial typicality. The portraits were rated by 777 local raters (577 women, 200 men). Our results showed that perceived trustworthiness is tightly associated with ratings of local facial typicality in both sexes. Although other factors (skin lightness, shape distinctiveness, and BMI) also seemed to play a role, the effects of most variables were inconclusive. Based on a novel approach incorporating both perceived and measured facial typicality, we conclude that given the strong positive association with perceived trustworthiness, facial typicality might have widespread implications for various aspects of social life.