Facial Trustworthiness is Associated with Heritable Aspects of Face Shape
Facial trustworthiness is thought to underlie social judgements in face perception, though it is unclear whether trustworthiness judgements are based on stable facial attributes. If this were the case, we could expect a genetic component of facial trustworthiness. From facial photographs of a large sample of identical and nonidentical twins and siblings (1320 individuals), we tested for genetic variation in facial trustworthiness and genetic covariation with several stable facial attributes, including facial attractiveness, two measures of masculinity, and facial width-to-height ratio. We found a significant genetic component of facial trustworthiness in men (but not women), and significant genetic correlations with the stable morphological facial traits of attractiveness (positive), perceived masculinity (negative), and facial width-to-height ratio (negative). However, there was no significant genetic or shared environmental correlation between facial trustworthiness and an objective masculinity score based on facial landmark coordinates, despite there being a significant phenotypic correlation. Our results suggest that heritable facial traits influence trustworthiness judgements.
KeywordsAttractiveness Sexual dimorphism Masculinity Facial width-to-height ratio Behavioural genetics Face perception
AJL has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 705478. This work was further supported by grants from the Australian Research Council (A79600334, A79801419, DP0212016, FT160100298) and the National Institute of Mental Health (MH085812 and MH63207). Thanks to Marlene Grace, Ann Eldridge, Daniel Park, David Smyth, Kerrie McAloney, Natalie Garden, and Reshika Chand; to Courtney Hibbs and Tess Adams for help with data collection; to the professional research assistants at the Center on Antisocial Drug Dependence for their work with the Longitudinal Twin Study; and to the volunteer research assistants who assigned trait ratings. And, thanks to the Queensland Twin (QTwin) Registry and Colorado Twin Registry twins and their families for their continued participation.
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