Social interactions and spillovers: incentives, segregation and topology

Abstract

The aim of this paper is to understand the interactions between productive e ort and the creation of synergies that are the sources of technological collaboration agreements, agglomeration, and social interactions. We model this interaction in a way that allows us to characterize how agents devote resources to both activities. This permits a full- edged equilibrium/welfare analysis of network formation with endogenous productive e orts, to derive unambiguous comparative statics results and to analyze community sorting by individual traits. In spite of its parsimony the model retains enough richness to replicate a broad range of empirical regularities displayed by social and economic networks, and to relate them to individual and social welfare. Key words: random network, spillovers, network formation, network topology.