Abstract
<title>Abstract</title> <p>A growing body of research suggests that altruism can be understood through the lens of sexual selection, with altruistic behavior enhancing male mate value and reproductive fitness. However, the role of altruistic cost in shaping mate desirability remains insufficiently explored. High-cost altruistic acts may signal high genetic quality, whereas moderate-cost altruism may be more indicative of a prosocial disposition and strong parenting potential. Given the importance of relationship stability and parental investment in long-term partnerships, we predicted that moderately costly, rather than highly exaggerated, altruism would be rated as more attractive in a long-term mating context. To test this, we collected attractiveness ratings from 1,000 heterosexual female participants via an online questionnaire, in which they evaluated male behaviors varying in the level of altruistic cost. Our findings reveal a context-dependent preference: moderate-cost altruism was rated as most attractive in long-term relationship scenarios, while high-cost altruism was more strongly favored in short-term contexts. These results support a nuanced view of altruism in mate choice and highlight the importance of signaling context and cost in sexual selection dynamics.</p>