We investigate experimentally the underlying motivations and individual dierences with regard to the participation in between-group conflict in nested social dilemmas. In our nested social dilemmas, the collective is divided into two groups, and individuals allocate tokens between a private, a...

The data from experiments with the Voluntary Contributions Mechanism suggest five stylized facts, including the restart effect. To date, no theory has explained all of these facts simultaneously. We merge our Individual Evolutionary Learning model with a variation of heterogenous other-regarding...

We study cooperation within and between groups in the laboratory, comparing treatments in which two groups have previously been (i) in conflict with one another, (ii) in conflict with a different group, or (iii) not previously exposed to conflict. We model conflict using an inter-group Tullock...

The data from experiments with the Voluntary Contributions Mechanism suggest five stylized facts, including the restart effect. To date, no theory has explained all of these facts simultaneously. We merge our Individual Evolutionary Learning model with a variation of heterogeneous...

We ask whether conformity, copying the most observed behavior in a population, can affect free riding in a public goods situation. Our model suggests that, if free riding is sufficiently frequent at the start of a public goods game, conformity will increase the growth rate of free riding. We...

This study disentangles experimentally imitation, reinforcement, and reciprocity in repeated prisoners' dilemmas. We compare a simple situation in which players interact only with their neighbours (local interaction) with one where players interact with all members of the population (group...

It has been shown that psychological predispositions to benefit others can motivate human cooperation and the evolution of such social preferences can be explained with kin or multi-level selection models. It has also been shown that cooperation can evolve as a costly signal of an unobservable...

In a repeated public goods setting, we explore whether individuals, acting unilaterally, will provide an effective sanctioning institution. Subjects first choose unilaterally whether they will participate in a sanctioning stage that follows a contribution stage. Only those who gave themselves...

Governments sometimes promote rules backed by sanctions too weak to make obedience privately optimal. Factors that may help make such rules effective include the presence of informal sanctions by peers, and implementation through voting. I study the impact of non-deterrent formal sanctions on...

I show how improper conditioning of beliefs can lead to under-contribution in public goods environments with interdependent values. I consider a simple model of a binary, excludable public good. In equilibrium, provision of the public good is good news about its value. Naive players who...