Doctoral Dissertation Research: Cooperation and Status Competition in Public Goods Games

这项研究阐述了在竞争激烈的社会困境中，进化过程中对可展示奖励的偏好如何调节男性和女性的慷慨。在人类社会中，利他主义合作是不可或缺的，在发展促进有利于社会的决定的机构方面取得了很大进展。经济学家一直专注于惩罚和奖励，但他们经常发现，激励可能会排挤合作的内在动机，并对效率产生不利影响。与此同时，进化生物学家早就认识到，即使没有正式的经济激励，合作，特别是食物分享，通常也是以野生食物为生的群体有效组织起来的。这项研究借鉴进化心理学，假设这种合作依赖于男性对比赛中独特且可展示的奖励(奖杯)的偏好。第一项研究使用受控实验室实验来调查合作是否在慷慨竞争中持续下去，以及合作是否在同样有价值但不独特且不可展示的奖励的环境中破裂。此外，它还调查了男性对奖杯奖励的竞争是否是这种差异的驱动力，而女性的竞争力则受到奖杯的影响。PI假设女性搭便车者对合作者的互惠缓解了她们的负面情绪，从而维持了合作。第二项研究将研究从“赢者进入”机制扩展到“输家退出”机制。人们假设女性在“输家”的环境中会更加合作。原因是，在整个人类历史上，赢得地位竞争和获得与女性接触的特权的倾向--这种倾向被“赢者在”机制捕捉到--对男性健康做出了贡献。然而，女性的健康受到生殖所需的物质资源的限制：只有未能达到资源门槛水平的相对弱势女性才无法实现生殖成功。因此，女性倾向于避免成为相对劣势，这可能会让女性对“输家出局”机制非常敏感。广泛的影响：合作弥漫于人类社会；这是一种不可或缺的人类活动。该项目在促进人类群体中的亲社会活动方面提供了新的方向，并具有广泛的跨学科应用。特别是，这项研究涉及行为经济学、进化生物学和人类学的结合点，借鉴并扩展了代价信号理论。它对那些针对在竞争倾向中观察到的性别差异的潜在因素的文献具有直接的影响，这些因素可能部分解释当代的性别工资差距。该项目开辟了在不牺牲效率的情况下促进人类群体合作的新途径。调查结果可能会对自愿遵守规定很重要的任何领域产生重要影响，包括配偶、雇主和雇员之间的关系、市场交易和遵守法律标准。

This research addresses how evolutionarily evolved preferences for displayable rewards modulates male and female generosity in competitive social dilemmas. Altruistic cooperation is indispensible in human societies, and much progress has been made towards developing institutions to promote pro-social decisions. Economists have focused on punishment and rewards, but often find that incentives can crowd out intrinsic motives for cooperation and detrimentally impact efficiency. At the same time, evolutionary biologists have long recognized that cooperation, especially food sharing, is typically efficiently organized in groups living on wild foods even absent formal economic incentives. Drawing on evolutionary psychology, the study hypothesize that such cooperation relies on male preferences for unique and displayable rewards (trophies) out of competition.The first study uses a controlled laboratory experiment to investigate whether cooperation is sustained in a generosity competition with trophy rewards, and whether cooperation breaks down in the same environment with equally valuable but non-unique and non-displayable rewards. Further, it investigates whether males' competition for trophy rewards is the driving force for such differences while female competitiveness is modulated by trophies. The PIs hypothesize that reciprocity from female free-riders towards co-operators mitigates their negative emotion and consequently sustains cooperation.The second study extends the investigation from "winner in" to "loser out" mechanisms. Women are hypothesized to be more cooperative in "loser out" environments. The reason is that the inclination to win status competitions and obtain privileged access to females, an inclination captured by a "winner-in" mechanism, has contributed to male fitness throughout human history. However, female fitness is limited by material resources necessary for reproduction: only relatively disadvantaged females who fail to achieve threshold resource levels fail to achieve reproductive success. Thus, female preference to avoid becoming relatively disadvantaged may leave females sensitive to "loser-out" mechanisms.Broader Impact: Cooperation pervades human societies; it is an indispensible human activity. The project informs new directions in promoting pro-social activity in human groups, and has wide cross-disciplinary applications. In particular, this investigation lies at nexus of behavioral economics, evolutionary biology and anthropology, drawing from and extending the theory of costly signaling. It has immediate implications for literatures aimed at underlying factors responsible for observed gender differences in competitive inclinations that might partially explain contemporary gender wage gaps. The project opens new paths to promoting cooperation in human groups without sacrificing efficiency. The results could have an important impact in any domains where voluntary compliance matters, including relations between spouses, employers and employees, market transactions, and conformity to legal standards.