جذابیت فیزیکی و همکاری در بازی معمای زندانی

The modulating role of age on the relationship between physical attractiveness and cooperativeness in a prisoner's dilemma game (PDG) was investigated. Previous studies have shown that physical attractiveness is negatively related to cooperative choices among young men but not young women. Following the argument that the negative relationship between physical attractiveness and cooperation is a product of short-term mating strategies among attractive men, we predicted that this relationship is unique to young men and absent among women and older men. We tested this hypothesis with 175 participants (aged 22–69 years). The results showed that physical attractiveness was negatively related to cooperative behavior among young men but not among women or older men. We further observed that the negative relationship between physical attractiveness and cooperation among young men was particularly strong when attractiveness was judged by women.

Physical attractiveness, particularly facial attractiveness, invites favorable responses from other individuals. People tend to perceive that physically attractive individuals possess desirable personal traits, such as intelligence and benevolence. This perception is referred to as the “what is beautiful is good” stereotype, which is an example of the more general halo effect studied in social psychology (Dion et al., 1972). This stereotype has considerable effects on daily life. Hamermesh and Biddle (1994) observed that individuals who were rated “above average” in physical attractiveness earned higher incomes than less attractive individuals. This “beauty premium” is caused by employers' beliefs that good-looking employees perform better than their less attractive counterparts (Mobius & Rosenblat, 2006). Mobius and Rosenblat (2006) observed that employers wrongly expect attractive individuals to perform better and pay them more than less attractive individuals, even when productivity is obviously unrelated to attractiveness. Similarly, individuals judge more attractive women as having desirable traits, such as conscientiousness, compared with their less attractive counterparts (Segal-Caspi et al., 2012). Economic game experiments also indicate that attractive individuals are treated favorably. Participants in a prisoner's dilemma game (PDG) tend to cooperate with participants they find attractive (Mulford et al., 1998). In a public goods game, participants cooperated more with attractive than less attractive partners and expected that attractive partners would be cooperative. Consequently, attractive partners earned more than less attractive partners (Andreoni & Petrie, 2008). Additionally, attractive participants in a trust game were expected to be trustworthy and were therefore trusted by their partners (Wilson & Eckel, 2006). These results consistently indicate that (1) people believe that physically attractive individuals possess desirable traits and (2) attractive individuals are treated more favorably than unattractive individuals (for a meta-analysis, see Langlois et al., 2000). Is this belief true? Empirical studies of women have revealed that attractiveness does not correlate with desirable inner traits (Segal-Caspi et al., 2012). For men, one laboratory experiment showed that attractiveness functions in the opposite direction than implied by the “what is beautiful is good” stereotype: more physically attractive men were less likely to cooperate during prisoner's dilemma or similar economic games (Takahashi et al., 2006). Zaatari and Trivers (2007) observed a similar pattern in an ultimatum game. The authors observed that the generosity of an offer from male proposers in an ultimatum game was positively correlated with fluctuations in asymmetry (FA; the deviation from bilateral symmetry in the body). Because FA is negatively related to facial attractiveness (Gangestad et al., 1994), this result suggests that the responders' physical attractiveness elicited generous offers from the matched proposer.