Facial shape and self-perceived personality traits in young adults.

The present study investigated the association between facial shape and self-perceived personality and psychosocial traits. The study population consisted of 613 young adults (399 females and 214 males) aged 21-35 years, with similar socioeconomic and academic backgrounds. Facial shape was studied with three-dimensional photographs, that were digitized semi-automatically using special software. Facial shape was described with 1021 landmarks and shape variation was studied with geometric morphometric methods. Personality and psychosocial traits were studied using standardized and well-validated questionnaires, that were completed by all participants on the same visit that their facial image was acquired. Associations were studied with multivariate regression models, using principal components of shape as dependent variables and questionnaire scores and age as predictors. Due to the presence of sex dimorphism in facial shape, all analyses were performed separately in males and females. The results showed a significant association between self-perceived self-esteem and facial shape in females (η2 = 0.089; P-value = 0.003) but not in males (η2 = 0.056; P-value = 0.782). No other personality of psychosocial traits had a significant effect on facial shape. Within the context of this population, the results indicate that developmental or societal factors may contribute to sex differences in the self-perception of non-physical traits.