Using declassified Federal Bureau of Narcotics records on 800 US Mafia members active in the 1950s and 1960s, and on their connections within the organized crime network, I estimate network effects on gangsters' economic status. Lacking information on criminal proceeds, I measure economic status...

We investigate the scope for cooperation within a community engaged in repeated reciprocal interactions. Players seek the help of others and approach them sequentially according to some fixed order, that is, a ranking profile. We study the ranking profiles that are most effective in sustaining...

Social interactions are considered pivotal to urban agglomeration forces. This study employs a unique dataset on mobile phone calls to examine how social interactions differ across cities and peripheral areas. We first show that geographical distance is highly detrimental to interpersonal...

We study the impact of research collaborations in coauthorship networks on research output and how optimal funding can maximize it. Through the links in the collaboration network, researchers create spillovers not only to their direct coauthors but also to researchers indirectly linked to them....

We consider a model where each individual (or ethnic minority) is embedded in a network of relationships and decides whether or not she wants to be assimilated to the majority norm. Each individual wants her behavior to agree with her personal ideal action or norm but also wants her behavior to...

This paper documents gender differences in social ties and develops a theory that links them to disparities in men's and women's labor market performance. Men's networks lead to better access to information, women's to higher peer pressure. Both affect effort in a model of teams, each beneficial...

Community enforcement is an important device for sustaining efficiency in some repeated games of cooperation. We investigate cooperation when information about players' reputations spreads to their future partners through links in a social network that connects them. We find that information...

By downplaying externalities, magnifying the cost of moral behavior, or suggesting not being pivotal, exculpatory narratives can allow individuals to maintain a positive image when in fact acting in a morally questionable way. Conversely, responsibilizing narratives can help sustain better...

We study the impact of research collaborations in coauthorship networks on research output and how optimal funding can maximize it. Through the links in the collaboration network, researchers create spillovers not only to their direct coauthors but also to researchers indirectly linked to them....

We survey the literature on social networks by putting together the economics, sociological and physics/applied mathematics approaches, showing their similarities and differences. We expose, in particular, the two main ways of modeling network formation. While the physics/applied mathematics...