Impact of egoistic cooperation and altruistic defection strategies on the evolution of cooperation in social dilemmas

This study extends the classical prisoner’s dilemma framework by introducing two novel strategies: egoistic cooperation and altruistic defection. Egoistic cooperators choose cooperation but simultaneously appropriate a portion of the payoffs from cooperators. In contrast, altruistic defectors choose defection but mitigate the negative impact on their cooperative partners through a compensation mechanism. The payoff ranking for same-strategy interactions, from highest to lowest, is cooperation, egoistic cooperation, altruistic defection, and defection. Results show that the degrees of altruism and altruistic have nonlinear impacts on the evolution of cooperation. Optimal cooperation is achieved through moderate compensation and low degrees of self-interest, which together maximize the adaptability and success of cooperative strategies. Egoistic cooperators have advantages at moderate egoism and altruism degrees, the same effect occurs even if egoism is excessive. Altruistic defection spreads quickly at low altruism degrees by exploiting high payoffs and low costs, suppressing other strategies. At higher altruism degrees, defectors reach dynamic equilibrium with egoistic cooperators and altruistic defectors. Additionally, spatial structure clearly promotes cooperators while inhibiting defectors, enabling complex phase transitions and stable coexistence. Meanwhile, low temptation to defect clearly encourages cooperation, in stark contrast to the effects observed in well-mixed populations. This study provides new insights into the diverse strategic interactions shaping international climate governance.