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In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. The strength of sexual selection on secondary sexual traits varies depending on prevailing economic and ecological conditions. Sexual selection has shaped the evolution of male secondary sexual characteristics that communicate viability in many species 1 , including humans 2.
However, female preferences for males bearing attractive traits rarely converge on an optimal phenotype. This variation in preferences for sexually selected traits may occur in response to prevailing ecological, demographic and economic conditions 3. Comparative studies suggest that men have a similar degree of sexually dimorphic secondary sexual trait development as nonhuman primate species with polygynous mating systems 4 , large social group sizes and complex multi-level social organizations 5.
This suggests that sexual selection via female choice and male-male competition has shaped the evolution of masculine traits in men 2. Physical masculinity may provide relevant information to potential mates and same-sex rivals regarding male reproductive maturity, underlying health, formidability, and social status 2.
One of the best studied sexually dimorphic traits is facial masculinity, which includes jaw size, brow ridge prominence, and robustness of the midface 6. Alternatively, facial masculinity may communicate more direct benefits like resource provisioning ability and protection 2 , More masculine looking men tend to have more muscular physiques 13 , 14 and hence greater physical strength 12 , health 15 and competitive ability Facial masculinity is also associated with behavioral dominance 17 , an open sociosexual orientation 18 , and higher social rank in same-sex dominance hierarchies Further, masculine men state higher preferences for short-term than long-term relationships 18 , 28 , engage in more short-term relationships than their less masculine peers 28 and women accurately assigned the likelihood of sexual infidelity from masculine facial shape in static photographs Thus, variation in preferences for masculine men may reflect choices for more prosocial partners and nurturing fathers over possible indirect and direct benefits associated with masculine facial traits 30 , Evolutionary mating strategies theories propose that women overlook the costs of selecting less paternally investing masculine mates to secure benefits associated with phenotypic masculinity that could enhance offspring fitness Indeed, preferences for facial masculinity were highest among women living in countries and states within the U.
