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Network Effects and Social Inequality:
How Do Mechanisms Matter?

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Filiz Garip (Cornell)

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SeveralÌýbodies of research suggest that under many conditions social networks amplifyÌýineq­ual­ity in access to or adoption ofÌýpractices that contribute to actors’Ìýwelfare.Ìý Most of this work has remainedÌýsuggestive, however, due to two prob­lems.ÌýÌýFirst,Ìýinattention to, and lack of con­sensus about, mechanisms of influ­enceÌýimpedes interpretation of results and cumulation ofÌýknowledge. Second, few dataÌýsets have the required detail --- over-time measure­ment of com­p­lete socialÌýnetworks and memberÌýbehaviors – to draw confident conclus­ions.ÌýÌýIn this paper we address both of theseÌýquestions.Ìý ÌýFirst, we argue that networkÌýeffectsÌýoperate through three major families of mechanisms – networkÌýexternalities, social facilitation, and normative influ­ence – each ofÌýwhichÌýcan best be expressed through a distinctive set of related functionalÌýforms.Ìý ÌýSecond, to explore theÌýimplication of theseÌýdifferent mechanisms (in the absence of suitablyÌýfine-grained data), we use computational models of the diffusion of practicesÌýthrough social networks given varying levels of homophily to explore theÌýimplication of each mechanism for overall and group-specific diffusion ratesÌýand equilibrium adoption levels, and for inter­group inequality in rates andÌýlevels of adoption.