Objectives Intra-sexual selection has shaped the evolution of sexually dimorphic traits in males of many primates, including humans. In men, sexual dimorphism in craniofacial shape (i.e. facial masculinity) and facial hair have both been shown to communicate aspects of social and physical dominance intra-sexually. However, less attention has been given to how variation in physical and social dominance among receivers impacts on perceptions of facial masculinity and beards as intra-sexual signals of formidability. Methods In the current study, male participants ( N = 951) rated male faces varying in masculinity and beardedness when judging masculinity, dominance and aggressiveness. These participants also responded to scales measuring their psychological dominance, sexual jealousy, status seeking, and masculine morphology (facial masculinity, facial hair, and height). Results Beardedness exerted strong effects over clean-shaven faces on ratings of masculinity, dominance, and aggressiveness. Trait ratings of masculinity, dominance, and aggressiveness rose linearly with increasing craniofacial masculinity. The significant facial masculinity × facial hair interaction suggests that beardedness caused strong effects on all trait ratings over clean-shaven faces at every level of facial masculinity. Participants with full beards also reported higher scores on dominance and assertiveness scales. Participants high in dominance and assertiveness also gave higher ratings for dominance, but not masculinity or aggressiveness, to bearded over clean-shaven faces. Participants low in intra-sexual jealousy rated clean-shaven and/or feminised faces as less dominant, less masculine, and less aggressive. Conclusions These findings demonstrate that facial hair enhances perceptions of masculinity, dominance, and aggressiveness above ratings of facial masculinity, potentially by augmenting masculine craniofacial features. Individual differences in intra-sexual dominance showed associations with judgments of facial hair but not facial masculinity. Our study demonstrates that when two sexually dimorphic androgen dependent facial traits are judged in concert, ornamental rather than structural masculine facial features underpin men’s intra-sexual judgments of formidability.

中文翻译：

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男性对男性面部形态的知觉的多元性选择

目的性内选择影响了包括人类在内的许多灵长类动物的雄性性二形性状的进化。在男性中，颅面部形状（即面部阳刚之气）和面部毛发的性二态性已被证明可以通过性交传达社会和身体优势方面。但是，对于接受者之间身体和社会主导地位的变化如何影响面部男性气质和胡须作为性交内性信号的关注，人们的关注却很少。方法在本研究中，男性参与者（N = 951）在判断男性气质，主导力和攻击性时对男性面孔的男性气质和胡须进行了评定。这些参与者还回答了衡量他们的心理优势，性嫉妒，寻求身份和男性形态（面部阳刚，头发和身高）。结果胡须对剃光的面部产生强烈的男性气质，支配性和攻击性的效果。男子气概，统治力和侵略性的特质等级随着颅面阳刚度的增加而线性增加。明显的男性气质与面部毛发的相互作用表明，胡须对面部各个层次的清洁剃脸的所有特质等级产生了强烈影响。留着胡须的参与者在统治度和自信心量表上的得分也更高。拥有较高支配力和自信的参与者也为胡须剃光了脸的胡须赋予了较高的支配地位，但没有男子气概或侵略性。性内嫉妒程度低的参与者将剃光和/或女性化的面部评为较不占主导地位，男性化程度和攻击性较低。结论这些发现表明，面部毛发可能会通过增强男性颅面特征来增强对男性气质，支配性和侵略性的认识，高于面部男性气质的等级。性内优势的个体差异显示与面部毛发的判断相关，但与面部男性气质无关。我们的研究表明，当同时判断两个性爱双态性激素依赖的面部特征时，男性的性倾向性判断会支撑观赏性而非结构性男性面部特征。性内优势的个体差异显示与面部毛发的判断相关，但与面部男性气质无关。我们的研究表明，当同时判断两个性双态依赖雄激素的面部特征时，男性的性倾向性判断会支撑观赏性而非结构性男性面部特征。性内优势的个体差异显示与面部毛发的判断相关，但与面部男性气质无关。我们的研究表明，当同时判断两个性爱双态性激素依赖的面部特征时，男性的性倾向性判断会支撑观赏性而非结构性男性面部特征。