Download the Paper (PDF format) - June 23, 2009 Tell a colleague about it. Printing Tips: Select 'print as image' in the Acrobat print dialog if you have trouble printing.

ABSTRACT:
We examine how three different communication processes operating through social networks are affected by homophily - the tendency of individuals to associate with others similar to themselves. Homophily has no effect if messages are broadcast or sent via shortest paths; only connection density matters. In contrast, homophily substantially slows learning based on repeated averaging of neighbors' information and Markovian diffusion processes such as the Google random surfer model. Indeed, the latter processes are strongly affected by homophily but completely independent of connection density, provided this density exceeds a low threshold. We obtain these results by establishing new results on the spectra of large random graphs and relating the spectra to homophily. We conclude by checking the theoretical predictions using observed high school friendship networks from the Adolescent Health dataset.

SUGGESTED CITATION:
Benjamin Golub and Matthew O. Jackson, "How Homophily Affects Learning and Diffusion in Networks" (June 23, 2009). Fondazione Eni Enrico Mattei Working Papers. Working Paper 296.
http://www.bepress.com/feem/paper296