Humans in social groups face a dilemma: how much of an individual's own resources should be cooperatively donated to a common pool, a public good? How can the cooperation of others be ensured? How much of the shared resources should an individual reclaim and how can the selfishness of other group members be limited? Humans, like other animals, do best evolutionarily by being selfish. Many current issues such as climate change and over-harvesting (tragedies of the commons) have arisen from a lack of cooperation by humans over shared resources such as clean air and land for growing crops. The maintenance of cooperation in social groups is therefore not only a core question in behavioral ecology and many other academic disciplines, but also one of great environmental significance. Public Goods Games are a standard laboratory technique for investigating human cooperation, but these games are not widely applicable to real-world situations. The investigators have shown that when players are allowed to compete for shared resources in a public goods game conducted under laboratory conditions (as they do over many shared resources outside the laboratory) they are significantly less cooperative. The project builds on this work and will investigate how mechanisms of enforcing fair division of a public good affect cooperation (e.g., whether people are more inclined to conserve environmental resources under different methods of allocating such resources and monitoring their conservation). In particular, the project investigates whether Policing (i.e., whether repression of competition and assigning shares of a public good based on contribution) promotes cooperation. The project involves outreach activities to junior high school students.
Animals in social groups frequently cooperate to produce resources that are shared among group members. Predicting how equitably such resources are shared, particularly the partitioning of reproductive opportunities is a key area of research in behavioral ecology. We used theory developed to analyze cooperation and competition in non-human animals, particularly social insects, and applied it to humans, in order to predict the conditions under which people will cooperate and share resources with group members. Resource sharing is frequently determined by competition among group members, and in this project we investigated the effect of two types of competition on within-group cooperation in humans. This has impacts beyond academia, as many social and environmental problems, for example conflict over limited natural resources, result from a breakdown in cooperation. In our first study, we investigated competition over shared group resources. Some resources, such as food, can be monopolized by one or a few individuals, and group members may compete with each other over who gets the largest share. Studies of human cooperation, however, have focused on cooperatively produced resources that are non-contestable, such as public radio and tax-funded infrastructure, with the implicit assumption that resources shared within human groups are automatically divided equally, with no potential for competition. We relaxed this assumption, and investigated the effects of within-group competition both on people’s cooperation and on the size of the resource shares that they obtain. Participants in our experiment played an economic game, where each of four players was given a sum of money and had to decide how much to contribute towards a shared group resource. When each individual was also given the option to pay to increase her share of the group resource, i.e. there was potential for competition, people contributed less (were less cooperative) and subsequently received less money (lower payoffs). Our results suggest that cooperation and competition in human and other animal societies evolved in similar ways, and that we should expect evolution for mechanisms to enforce equal division: for example by group members "policing" each other, and by imposing cultural norms that reduce competition. In our second study, we explored the effect of policing by investigating competition over personal resources. Members of social groups face a trade-off between keeping personal resources for themselves and cooperatively contributing them to produce a shared group resource, as in the first study; for example, hunter-gatherers may hunt small game solitarily to obtain an individual portion of food (personal resource), or hunt large game collectively to obtain food that is shared among all group members (group resource). In the first study, we investigated competition over shares of a group resource, but competition over personal resources is also possible, and people may benefit by investing in taking others’ personal resources, and in defending one’s own resources against others. In such a case, people may do better to invest their personal resources in a "policed" group resource, such as a bank, where all members obtain a share but over which there is no competition (i.e. equal sharing is enforced). We carried out two sets of economic games similar to those in the first study. Firstly, when players were given the option to pay to take the money others kept (personal resources) and to stop others doing the same, people contributed more to the group (were more cooperative). Secondly, when players always had the option to compete but only sometimes had the option to contribute, people received more money (higher payoffs) when they could give money to a group resource. These results shed light on how cooperative contributions to shared resources may have evolved, and how "policed" equal sharing may restore cooperation in the face of competition.
