AI 中文总结
该研究在社会困境中结合同伴与制度激励，通过理论分析与模拟揭示：同伴惩罚促合作、同伴奖励增福利，制度性奖励同伴激励策略效果显著，惩罚同伴激励策略则损害社会收益，为制度设计提供了原则。
AI 中文摘要
我们研究在社会困境中，同伴激励与制度激励如何共同塑造合作、社会福利及执行效率的演化。在包含无条件合作者（C）、背叛者（D）、社会惩罚者（SP）、社会奖励者（SR）四种策略的囚徒困境中，我们允许去中心化的同伴激励与中心化的制度激励同时作用，制度可对任意策略子集进行奖励或惩罚。在无限均匀混合种群中，我们分析由此产生的四策略复制动态；在结构化种群中，我们利用方格晶格上的基于智能体的模拟，研究空间效应与网络互惠性。干预方案通过无限均匀混合种群的均衡状态与演化流评估，结构化种群则通过合作水平与社会福利评估，其中社会福利定义为扣除制度成本后的种群总收益。我们发现，同伴惩罚对合作的促进作用最强，而同伴奖励对社会福利更有益；制度性奖励同伴激励策略可显著提升合作与福利，而补贴无条件合作者影响甚微。在制度惩罚下，直接惩罚背叛者是唯一始终有效的政策；惩罚同伴激励策略会瓦解去中心化激励，降低合作并损害社会福利，表明最大化合作未必能优化整体社会收益。我们的研究为寻求平衡合作促进与福利最大化的制度提供了设计原则。
英文摘要
We investigate how peer and institutional incentives jointly shape the evolution of cooperation, social welfare, and enforcement efficiency in social dilemmas. In a Prisoners Dilemma with four strategies, unconditional cooperators (C), defectors (D), social punishers (SP), and social rewarders (SR), we allow decentralised peer incentives and centralised institutional incentives to act simultaneously, with the institution able to reward or punish any subset of strategies. In infinite well-mixed populations, we analyse the resulting four-strategy replicator dynamics, and in structured populations we use agent-based simulations on square lattices to study spatial effects and network reciprocity. Intervention schemes are evaluated by equilibrium states and evolutionary flow for infinite well-mixed populations, by cooperation levels and social welfare for structured populations, defined as aggregate population payoff net of institutional cost. We find that peer punishment most strongly promotes cooperation, whereas peer reward is more beneficial for social welfare. Institutionally rewarding peer incentive strategies substantially improves both cooperation and welfare, while subsidising unconditional cooperators has little impact. Under institutional punishment, directly penalising defectors is the only consistently effective policy; punishing peer incentive strategies dismantles decentralised incentives, reduces cooperation, and harms social welfare, showing that maximising cooperation does not necessarily optimise overall societal benefit. Our findings provide design principles for institutions seeking to balance cooperation promotion with welfare maximisation.
