We study the evolution of the social norm of "cooperation" in a dynamic environment. Each agent lives for two periods and interacts with agents from the previous and next generations via a coordination game. Social norms emerge as patterns of behavior that are stable in part due to agents'...

We examine the interplay between social norms and the enforcement of laws. Agents choose a behavior (e.g., tax evasion, production of low-quality products, corruption, substance abuse, etc.) and then are randomly matched with another agent. An agent's payoff decreases with the mismatch between...

Can we identify the members of a community who are best- placed to diffuse information simply by asking a random sample of individuals? We show that boundedly-rational individuals can, simply by tracking sources of gossip, identify those who are most central in a network according to "diffusion...

In this paper we analyze the problem of whether and/or when to replace a leader (agent) when no monetary rewards are available, and it is the leader's competence rather than effort that is being evaluated. The only decisions that the leader takes over time are whether to undertake risky but...

We define a general class of network formation models, Statistical Exponential Random Graph Models (SERGMs), that nest standard exponential random graph models (ERGMs) as a special case. We provide the first general results on when these models' (including ERGMs) parameters estimated from the...

There is a wealth of research in psychology demonstrating that agents process information with the aid of categories. In this paper we study this phenomenon in two parts. First, we build a model of how experiences are sorted into categories and how categorization affects decision making. Second,...

We introduce and analyze a model in which agents observe sequences of signals about the state of the world, some of which are ambiguous and open to interpretation. Instead of using Bayes' rule on the whole sequence, our decision makers use Bayes' rule in an iterative way: first to interpret each...

We examine how participation in a microfinance program diffuses through social networks. We collected detailed demographic and social network data in 43 villages in South India before microfinance was introduced in those villages and then tracked eventual participation. We exploit exogenous...

Formal financial institutions can have far-reaching and long-lasting impacts on informal lending and information networks. We first study 75 villages in Karnataka, 43 of which were exposed to microfinance after we first collected detailed network data. Networks shrink more in exposed villages....