Human nature : an interdisciplinary biosocial perspective
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Several hypotheses on the form and function of sex differences in social behaviors were tested. The results suggest that friendship preferences in both sexes can be understood in terms of perceived reciprocity potential-capacity and willingness to engage in a mutually beneficial relationship. Divergent social styles may in turn reflect trade-offs between behaviors selected to maintain large, functional coalitions in men and intimate, secure relationships in women. The findings are interpreted from a broad socio-relational framework of the types of behaviors that facilitate selective advertisement and investment of reciprocity potential across individuals and within groups of men and women.
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Evolutionary models of human cooperation are increasingly emphasizing the role of reputation and the requisite truthful "gossiping" about reputation-relevant behavior. If resources were allocated among individuals according to their reputations, competition for resources via competition for "good" reputations would have created incentives for exaggerated or deceptive gossip about oneself and one's competitors in ancestral societies. Correspondingly, humans should have psychological adaptations to assess gossip veracity. ⋯ Information that suggested alternative, benign interpretations of gossip decreased its veracity. Competition between a gossiper and her target decreased gossip veracity. These results provide preliminary evidence for psychological adaptations for assessing gossip veracity, mechanisms that might be used to assess veracity in other domains involving social exchange of information.
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We examine the ontogeny and phylogeny of object and fantasy play from a functional perspective. Each form of play is described from an evolutionary perspective in terms of its place in the total time and energy budgets of human and nonhuman juveniles. As part of discussion of functions of play, we examine sex differences, particularly as they relate to life in the environment of evolutionary adaptedness and economic activities of human and nonhuman primates. ⋯ Although fantasy play has been viewed as limited to humans, we speculate that certain types of fantasy play may be present in some nonhuman primates. Fantasy play may enable juveniles to see situations from different perspectives. We conclude that fantasy play may have immediate effects and object play may have deferred effects.
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Heroism is apparently nonadaptive in Darwinian terms, so why does it exist at all? Risk-taking and heroic behavior are predominantly male tendencies, and literature and legend reflect this. This study explores the possibility that heroism persists in many human cultures owing to a female preference for risk-prone rather than risk-averse males as sexual partners, and it suggests that such a preference may be exploited as a male mating strategy. It also attempts to quantify the relative influences of altruism and bravery in the evolution of heroism. ⋯ Bravery in a male was shown to be the stronger factor influencing female choice of short-term partners, long-term partners, and male friends, with altruism playing a lesser part in their choice. Altruism was deemed important in long-term relationships and friendships, but for short-term liaisons, non-altruists were preferred to altruists. Heroism may therefore have evolved owing to a female preference for brave, risk-prone males because risk-taking acts as an honest cue for "good genes." Altruism was judged to be a less influential factor in the evolution of heroism than bravery and a demonstrated willingness to take risks.