A Simple Model of Homophily in Social Networks

36 Pages Posted: 25 Oct 2010 Last revised: 4 May 2013

See all articles by Sergio Currarini

Sergio Currarini

University of Leicester - Department of Economics

Fernando Vega-Redondo

Universidad de Alicante - Department of Economic Analysis; European University Institute; Bocconi University

Date Written: April 15, 2013

Abstract

Biases in meeting opportunities have been recently shown to play a key role for the emergence of homophily in social networks (see Currarini, Jackson and Pin 2009). The aim of this paper is to provide a "simple" micro-foundation of these biases in a model where the size and type-composition of the meeting pools are shaped by agents' socialization decisions. In particular, agents either inbreed (direct search only to similar types) or outbreed (direct search to population at large). When outbreeding is costly, this is shown to induce stark equilibrium behavior of a threshold type: agents ``inbreed'' (i.e. mostly meet their own type) if, and only if, their group is above certain size. We show that this threshold equilibrium generates patterns of in-group and cross-group ties that are consistent with empirical evidence of homophily in two paradigmatic instances: high school friendships and interethnic marriages.

Keywords: Homophily, search, social networks, segregation

JEL Classification: D7, D71, D85, Z13

Suggested Citation

Currarini, Sergio and Vega-Redondo, Fernando and Vega-Redondo, Fernando and Vega-Redondo, Fernando, A Simple Model of Homophily in Social Networks (April 15, 2013). University Ca' Foscari of Venice, Dept. of Economics Research Paper Series No. 24, Available at SSRN: https://ssrn.com/abstract=1697503 or http://dx.doi.org/10.2139/ssrn.1697503

Sergio Currarini (Contact Author)

University of Leicester - Department of Economics ( email )

School of Business
Leicester LE1 7RH, Leicestershire LE1 7RH
United Kingdom

Fernando Vega-Redondo

European University Institute

Villa Schifanoia
133 via Bocaccio
Firenze (Florence), Tuscany 50014
Italy

Bocconi University ( email )

Via Sarfatti 25
Milan, MI 20136
Italy

Universidad de Alicante - Department of Economic Analysis ( email )

Apdo. Correos, 99
03080 Alicante
Spain
+34 96 590 3616 (Phone)
+34 96 590 3898 (Fax)

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