We study from both a theoretical and an empirical perspective how a network of military alliances and enmities affects the intensity of a conflict. The model combines elements from network theory and from the politico-economic theory of conflict. We postulate a Tullock contest success function...

We develop two different social network models with different economic foundations. In the local-aggregate model, it is the sum of friends' efforts in some activity that affects the utility of each individual while, in the local-average model, it is costly to deviate from the average effort of...

This paper studies whether conformism behavior affects individual outcomes in crime. We present a social network model of peer effects with ex-ante heterogeneous agents and show how conformism and deterrence affect criminal activities. We then bring the model to the data by using a very detailed...

We test the hypothesis that "genuine" or "convincing" smiling is a costly signal that has evolved to induce cooperation in situations requiring mutual trust. Potential trustees in a trust game made video clips for viewing by potential trusters before the latter decided whether to send them...

In this chapter, we provide an overview on the literature on key players in networks. We first introduce the theoretical concept of the key player, which is the agent that should be targeted by the planner so that, once removed, she will generate the highest level of reduction in total activity....

We survey the literatures on the economic consequences of the structure of social networks. We develop a taxonomy of 'macro' and 'micro' characteristics of social inter-action networks and discuss both the theoretical and empirical findings concerning the role of those characteristics in...

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

In this chapter, we provide an overview of research on neighborhoods and social networks and their role in shaping behavior and economic outcomes. We include discussion of empirical and theoretical analyses of the role of neighborhoods and social networks in crime, education and labor-market...

We develop an unified model embedding different behavioral mechanisms of social interactions and design a statistical model selection test to discriminate between them in empirical applications. This framework is applied to study peer effects in education and delinquent behavior for adolescents...

We develop a network model looking at the role of different types of peers in education. The empirical salience of the model is tested using a very detailed longitudinal dataset of adolescent friendship networks. We find that there are strong and persistent peer effects in education but peers...