The effects of exogenous testosterone and facial attractiveness on men’s altruistic punishment behavior

Abstract

Altruistic punishment is crucial in promoting cooperation and maintaining social fairness. The third-party punishment (TPP) game, a typical paradigm testing altruistic punishment behavior, involves individuals incurring personal costs to punish norm violations others commit. This altruistic (costly) punishment has been suggested as an adaptive trait in human evolution, influencing behaviors such as mate selection. Additionally, testosterone levels and facial attractiveness are key factors affecting altruistic behavior and mating preferences, influencing how altruism is displayed and perceived in mating contexts. However, the causal effect of mate choice motives on altruistic punishment behavior is obscure. In this study, we combined exogenous testosterone administration and a TPP game to explore the effect of exogenous testosterone on men’s altruistic punishment behavior toward female recipients of varying attractiveness. In a double-blind, placebo-controlled within-subjects crossover design, 85 heterosexual men came to the lab twice, once receiving testosterone gel and the other time receiving a placebo gel. Our results showed that participants in the testosterone condition (compared to the placebo condition) exhibited a higher frequency of altruistic punishment behavior toward others in the presence of female recipients. The effects varied across different coin allocation conditions and female recipient facial attractiveness, with participants balancing the signaling of altruistic traits and protecting their resources. Our findings highlight the complex interaction between hormonal factors and mating-related cues, which appears to be associated with altruistic punishment behavior.