How can economists define and measure social preferences and interactions? Through the use of new economic data and tools, our contributors survey an array of social interactions and decisions that typify homo economicus. Identifying economic strains in activities such as learning, group...

The 'friendship paradox' (Feld1991) refers to the fact that, on average, people have strictly fewer friends than their friends have. I show that this over-sampling of the most popular people amplifies behaviors that involve complementarities. People with more friends experience greater...

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 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'...