Repeated interactions provide a prominent but paradoxical hypothesis for human cooperation in one-shot interactions. Intergroup competitions provide a different hypothesis that is intuitively appealing but heterodox. We show that neither mechanism reliably supports the evolution of cooperation...

We define an indirect evolutionary approach formally and apply it to (Tullock) contests. While it is known (Leininger, 2003) that the direct evolutionary approach in the form of finite population ESS (Schaffer, 1988) yields more aggressive behavior than in Nash equilibrium, it is now shown that...

The prisoner's dilemma (PD) is arguably the most important model of social dilemmas, but our knowledge about how a PD’s material payoff structure affects cooperation is incomplete. In this paper we investigate the effect of variation in material payoffs on cooperation, focussing on one-shot PD...

Rather than about absolute payoffs, governments in fiscal competition often seem to care about their performance relative to other governments. Moreover, they often appear to mimic policies observed elsewhere. We study such behaviour in a tax competition game with mobile capital à la...

Nash proposed an interpretation of mixed strategies as the average pure-strategy play of a population of players randomly matched to play a normal-form game. If populations are finite, some equilibria of the underlying game have no such corresponding "mass-action" equilibrium. We show that for...

Altruists and envious people who meet in contests are symbionts. They do better than a population of narrowly rational individuals. If there are only altruists and envious individuals, a particular mixture of altruists and envious individuals is evolutionarily stable.