Does the primate face cue personality?

Abstract

When looking at others, primates primarily focus on the face – detecting the face first and looking at it longer than other parts of the body. This is because primate faces, even without expression, convey trait information crucial for navigating social relationships. Recent studies on primates, including humans, have linked facial features, specifically facial width-to-height ratio (fWHR), to rank and Dominance-related personality traits, suggesting these links’ potential role in social decisions. However, studies on the association between dominance and fWHR report contradictory results in humans and variable patterns in nonhuman primates. It is also not clear whether and how nonhuman primates perceive different facial cues to personality traits and whether these may have evolved as social signals. This review summarises the variable facial-personality links, their underlying proximate and evolutionary mechanisms and their perception across primates. We emphasise the importance of employing comparative research, including various primate species and human populations, to disentangle phylogeny from socio-ecological drivers and to understand the selection pressures driving the facial-personality links in humans. Finally, we encourage researchers to move away from single facial measures and towards holistic measures and to complement perception studies using neuroscientific methods.

Non-human contributions to personality neuroscience: From fish through primates – a concluding editorial overview

“…Thus, Wilson and Masilkova ( 2023 , §1.2) start with the hypothesis that human male relative facial width is linked to dominance and then test it in non-humans . They argue from the primate data that discrepancies in human research would be resolved with more broad ranging and nuanced analysis.…”

“…This question is addressed by Wilson and Masilkova ( 2023 ), starting from the idea that human male facial morphology is linked to dominance with relative facial width supposedly linked to skull strength. Face width has been positively linked to dominance but with mixed and null findings.…”

“…… Personality, in particular Dominance-like traits [(see also § 1.3 )], seems to have links to facial metrics in all species studied, but these relationships depend on age, sex and even subspecies, suggesting divergent selection pressures driving facial cues to Dominance. Together, these findings paint an interesting but varied picture of the role of facial morphology in primate behaviour, suggesting that human studies have only just scratched the surface of a potentially much broader field.” (Wilson & Masilkova, 2023 , p. 3)…”