Friends and rivals: Modelling the social relations of inventors

Of the different streams of empirical literature on networks and knowledge, our attention in this chapter is focused on studies that investigate the relationship between knowledge ows, as measured by patent citations, and social distance. These works (e.g. Breschi and Lissoni, 2004) nd that the probability of observing a citation tie between two patents decreases as the social distance between the two patents increases, which is suggestive of the idea that knowledge ows (with decay) through the social network. Our model replicates this evidence and, more importantly, provides new theoretical results on the impact of network structure upon knowledge ows, in a form that is potentially testable by empirical researchers.