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.
Intellectual Merit: Through the use of a novel experiment design our first paper (Published on PloSOne) provides the first robust empirical evidence with respect to how males’ trophy seeking preferences promote and sustain cooperation in groups. The main hypothesis is that males have an evolved preference for unique durable rewards for competitive success. Thus, even a low value trophy absent direct public acclaim can trigger male generosity and promote overall generosity in social groups. Here, we use a controlled laboratory experiment to show that cooperation is sustained in a generosity competition with trophy rewards, but breaks down in the same environment with equally valuable but non-unique and non-displayable rewards. Further, we find that males' competition for trophies is the driving force behind treatment differences. In contrast, it appears that female competitiveness is not modulated by trophy rewards. In another companion paper (Published on CESifo Economic Studies), we examine gender differences in prosociality using theories from evolutionary psychology and empirical evidence from experimental economics. Although there has been extensive prior research in both fields, there remains a large disconnect between the sources of gender differences in pro-sociality and experimental research aimed at informing cooperation and generosity. Thus, the main contribution of our paper is to bridge this gap by arguing that differences in male and female motives for prosociality stem, at least in part, from gender differences in mating strategies. In particular, we discuss gender differences in: (i) signaling behaviors; (ii) conformance to social norms; and (iii) approaches toward resolving intra- and inter-group dilemmas. This paper may be a useful resource for those hoping to gain a better understanding of the foundations of gender differences in prosociality; likewise, it draws useful attention to empirical research aimed at promoting charitable giving and enhancing resource allocation efficiency. Broader Impact: Cooperation pervades human societies; it is an indispensible human activity. Our project informs new directions in promoting pro-social activity in human groups, and has wide cross-disciplinary applications. 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. It proposes new approaches for the charitable giving literature, where trophy-seeking and ‘status’ ranking can be easily adopted within fundraising appeals. This proposal also contributes to the development of traditional theories that seem to have overlooked the potential positive impact of status and trophy-seeking in promoting the welfare of disadvantaged groups.
