标题： Braess悖论在流行病博弈中：更好的条件导致更低的收益 显示英文标题

标题： Braess's Paradox in Epidemic Game: Better Condition Results in Less Payoff

摘要： 面对传染病的威胁，我们采取各种措施保护自己，但很少有研究考虑过一个具有竞争策略的演化系统。 鉴于此，我们提出了一个结合人类行为的演化流行病模型，其中个体有三种策略：接种疫苗、自我保护和放任自流，并且能够在每次疫情传播新季节开始时根据邻居的策略和收益调整自己的策略。 我们发现了一种反直觉的现象，类似于著名的\emph{布拉西斯悖论}，即更好的条件可能导致更差的表现。 具体来说，增加自我保护的成功率并不一定能够减少疫情规模或提高系统的整体收益。 这种现象对网络拓扑结构不敏感，并且可以通过平均场近似很好地解释。 我们的研究表明，个体的更好条件可能会导致社会的更糟结果，这是一个重要的事实。 显示英文摘要

摘要： Facing the threats of infectious diseases, we take various actions to protect ourselves, but few studies considered an evolving system with competing strategies. In view of that, we propose an evolutionary epidemic model coupled with human behaviors, where individuals have three strategies: vaccination, self-protection and laissez faire, and could adjust their strategies according to their neighbors' strategies and payoffs at the beginning of each new season of epidemic spreading. We found a counter-intuitive phenomenon analogous to the well-known \emph{Braess's Paradox}, namely a better condition may lead to worse performance. Specifically speaking, increasing the successful rate of self-protection does not necessarily reduce the epidemic size or improve the system payoff. This phenomenon is insensitive to the network topologies, and can be well explained by a mean-field approximation. Our study demonstrates an important fact that a better condition for individuals may yield a worse outcome for the society.