The behaviour of urban populations is compared with the systems directing behaviour in individuals. This is both a metaphor and a mechanistic parallel. The biological model draws upon recent developments in brain research and psychological and cultural anthropology. The development and operation...

Many Social Interactions display either or both of the following well documented phenomena. People tend to interact with similar others (homophily). And they tend to treat others more favorably if they are perceived to share the same identity (in-group bias). While both phenomena involve some...

The emergence of competition is a defining aspect of human nature and characterizes many important social environments. However, its relationship with how social groups are formed has received little attention. We design an experiment to analyze how individuals' willingness to compete is...

Many types of economic and social activities involve significant behavioral complementarities (peer effects) with neighbors in the social network. The same activities often exert externalities that cumulate in "stocks" affecting agents' welfare and incentives. For instance, smoking is subject to...

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 introduce a new solution concept for models of coalition formation, called the myopic stable set. The myopic stable set is defined for a very general class of social environments and allows for an infinite state space. We show that the myopic stable set exists and is non-empty. Under minor...

We conducted a framed field experiment to explore a situation where individuals have potentially competing social identities to understand how group identification and socialization affect ingroup favoritism and out-group discrimination. The Dictator Game and the Trust Game were conducted in...