Center for Systems and Control, College of Engineering, Peking University, Beijing 100871, China.
Department of Biology, University of Pennsylvania, Philadelphia, PA 19104.
Proc Natl Acad Sci U S A. 2024 Jul 23;121(30):e2406993121. doi: 10.1073/pnas.2406993121. Epub 2024 Jul 17.
Humans update their social behavior in response to past experiences and changing environments. Behavioral decisions are further complicated by uncertainty in the outcome of social interactions. Faced with uncertainty, some individuals exhibit risk aversion while others seek risk. Attitudes toward risk may depend on socioeconomic status; and individuals may update their risk preferences over time, which will feedback on their social behavior. Here, we study how uncertainty and risk preferences shape the evolution of social behaviors. We extend the game-theoretic framework for behavioral evolution to incorporate uncertainty about payoffs and variation in how individuals respond to this uncertainty. We find that different attitudes toward risk can substantially alter behavior and long-term outcomes, as individuals seek to optimize their rewards from social interactions. In a standard setting without risk, for example, defection always overtakes a well-mixed population engaged in the classic Prisoner's Dilemma, whereas risk aversion can reverse the direction of evolution, promoting cooperation over defection. When individuals update their risk preferences along with their strategic behaviors, a population can oscillate between periods dominated by risk-averse cooperators and periods of risk-seeking defectors. Our analysis provides a systematic account of how risk preferences modulate, and even coevolve with, behavior in an uncertain social world.
人类会根据过去的经验和不断变化的环境来调整自己的社交行为。由于社交互动结果的不确定性，行为决策变得更加复杂。面对不确定性，一些人表现出风险规避，而另一些人则寻求风险。对风险的态度可能取决于社会经济地位；并且个体可能会随着时间的推移更新其风险偏好，这将反馈到他们的社交行为中。在这里，我们研究不确定性和风险偏好如何塑造社交行为的演变。我们扩展了行为进化的博弈论框架，将收益的不确定性和个体对这种不确定性的反应变化纳入其中。我们发现，不同的风险态度可以极大地改变行为和长期结果，因为个体试图从社交互动中优化自己的回报。例如，在没有风险的标准设置中，背叛总是会超过参与经典囚徒困境的充分混合群体，而风险规避可以扭转进化的方向，促进合作而不是背叛。当个体随着其策略行为一起更新其风险偏好时，种群可以在风险规避的合作者主导时期和风险寻求的背叛者主导时期之间振荡。我们的分析提供了一个系统的解释，说明风险偏好如何在不确定的社交世界中调节甚至共同进化行为。
