This paper analyzes social group formation when agents are subject to peer effects within groups increasing human capital and instantaneous utility. When agents are heterogeneous on two dimensions, ability and social skills, and monetary payments are not feasible the model predicts segregation...

This paper studies many-to-one matching market in which each agent's preferences not only depend on the institution that hires her, but also on the group of her colleagues, which are matched to the same institution. With an unrestricted domain of preferences the non-emptiness of the core is not...

The belief that both the behavior and outcomes of students are affected by their peers is important in shaping education policy. I analyze two polar education systems -tracking and mixing- and propose several criteria for their comparison. I find that tracking is the system that maximizes...

This paper models the interaction between individuals' identity choices and redistribution. Both redistributive polices and identity choices are endogenous, and there might be multiple equilibria. The model is applied to ethnicity and social class. In an equilibrium with high taxes, the poor...

In small groups norm enforcement is provided by mutual punishment and reward. In large societies we have enforcement institutions. This paper shows how such institutions can emerge as a decentralized equilibrium. In a first stage, individuals invest in a public enforcement technology. This...

Democratic societies are challenged by various violent and organized groups, be they terrorists, gangs or organized hooligans. In exchange for offering an identity, leaders in such groups typically require members to be violent. We introduce a simple model to capture these stylized facts, and...

Consider a setting in which several groups of individuals with common interests ("clubs") compete with each other for recognition by other individuals. Depending on the context, recognition may be expressed by these other individuals joining a club, or choosing one club to admire. Clubs compete...

We model group formation as a response to relative deprivation. We employ two measures of relative deprivation. We show that in the case of each of these measures the process of deprivation-induced self-selection into groups reaches a steady state, and that the steady-state distribution differs...