We introduce a generalized theoretical approach to study imitation models and subject themodels to rigorous experimental testing. In our theoretical analysis we find that the differentpredictions of previous imitation models are due to different informational assumptions, notto different...

In this paper we model the interaction between leaders, their followers and crowd followers in a coordination game with local interaction. The steady states of a dynamic best-response process can feature a coexistence of Pareto dominant and risk dominant actions in the population. The existence...

I study a sequential-move public goods game based on the notion that leadership comes with an obligation; conscientious leadership. Provision by the leader of an amount of the public good below a minimum imposes a psychological cost on the follower which increases his unit cost of contribution....

We analyze group contests for public goods by applying the solution concept of an evolutionary stable strategy (ESS). We show that a global ESS cannot exist, because a mutant free-rider can always invade group behavior successfully. There does exist, however, a unique local ESS, which we...

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.

This paper introduces two ideas, emotional state dependent utility components (ESDUCs), and evolutionary perfect Bayesian equilibrium (EPBE). Using a simple extensive form game, we illustrate the efficiency-enhancing role of a powerful ESDUC, the vengeance motive. Incorporating behavioral noise...

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...

Whether or not to vaccinate one’s child is a decision that a parent may approach in several ways. The vaccination game, in which parents must choose whether to vaccinate a child against a disease, is one with positive externalities (herd immunity). In some societies, not vaccinating is an...

Economic and social interaction takes place between individuals with heterogeneous characteristics. We investigate experimentally the emergence and informal enforcement of different contribution norms to a public good in homogeneous and different heterogeneous groups. When punishment is not...