Our study provides the first evidence that facial masculinity in men is an honest signal of men’s aggressive capacity and intent within same-sex contests

Caton, Neil R., Amy Zhao, David M. G. Lewis, and Barnaby Dixson. 2022. “Facial Masculinity Predicts Men’s Actual and Perceived Aggressiveness.” PsyArXiv. February 18. doi:10.31234/osf.io/qejga

Abstract: Status obtained via dominance is a phylogenetically ancient feature of human social systems. Yet empirical evidence that men’s secondary sexual traits reliably predict success in intra-sexual contests has been hard to demonstrate. The present work provides the first test of whether masculine craniofacial structures in men predicts aggressiveness in contest competition and whether people accurately assess such aggressiveness from masculine facial cues. After placing 32,447 facial landmarks on the facial stimuli of 457 male fighters, multivariate geometric morphometric analyses extracted 142 distinct facial metrics and revealed that men with better developed masculine facial traits (e.g., large jaw, large browridge, deep-set eyes) attempted more strikes and successfully struck their opponents, including targeting the face. When rating the facial stimuli of these male fighters, participants (N = 500) used men’s masculine facial traits to accurately predict these same components of aggressiveness, including targeting the face. These findings remained robust after accounting for the fighter’s age, total fights, weight division, height, fight duration, and their opponent’s striking frequency. Our findings provide the first evidence that humans accurately forecast men’s agonistic behavior from variation in facial morphology, suggesting perceptual systems have evolved to perceive physical formidability among contemporaries and competitors.