How Homophily Affects Learning and Diffusion in Networks
AbstractWe 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.
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Bibliographic InfoPaper provided by Fondazione Eni Enrico Mattei in its series Working Papers with number 2009.35.
Date of creation: May 2009
Date of revision:
Networks; Learning; Diffusion; Homophily; Friendships; Social Networks; Random Graphs; Mixing Time; Convergence; Speed of Learning; Speed of Convergence;
Find related papers by JEL classification:
- D83 - Microeconomics - - Information, Knowledge, and Uncertainty - - - Search, Learning, and Information
- D85 - Microeconomics - - Information, Knowledge, and Uncertainty - - - Network Formation
- I21 - Health, Education, and Welfare - - Education - - - Analysis of Education
- J15 - Labor and Demographic Economics - - Demographic Economics - - - Economics of Minorities, Races, Indigenous Peoples, and Immigrants; Non-labor Discrimination
- Z13 - Other Special Topics - - Cultural Economics - - - Economic Sociology; Economic Anthropology; Social and Economic Stratification
This paper has been announced in the following NEP Reports:
- NEP-ALL-2009-07-28 (All new papers)
- NEP-NET-2009-07-28 (Network Economics)
- NEP-SOC-2009-07-28 (Social Norms & Social Capital)
- NEP-URE-2009-07-28 (Urban & Real Estate Economics)
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