A simple model of homophily in social networks

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 microfoundation of these biases in a model where the size and typecomposition 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.

Social Support Networks and HIV/STI Risk Behaviors Among Latino Immigrants in a New Receiving Environment

“…Network measures were calculated for participants’ social support networks including: degree, density, homophily, average quality of relationship, average years known, relationship to participant, and network overlap with sex and drug networks. We used a homophily index, which reports the proportion of a participant’s social support network shared the same baseline characteristics (gender, ethnicity, country of origin, and age) (41). …”

Modeling Networks with a Growing Feature-Structure

“…Coming from a structural approach, differently from other models which concentrate only on assortativity [17,45,51,56], our model also accounts for the principle, known as triadic closure or transitivity, according to which, if A is a neighbor of B and B is a neighbor of C, then A and C have a high chance to be neighbors. This principle is widely supported on the empirical ground and it is at the basis of many generative network models [10,18,22,28,31,35,41,43,46,50,55,57,59].…”

Melting pot or salad bowl: the formation of heterogeneous communities

“…An individual also gets a higher payoff the more social ties he has with whom he is coordinating, again allowing for greater economic exchange. The assumption here, that more contacts are better, has support from the literature on social interaction (Currarini et al, 2009;Currarini and Vega-Redondo, 2011). It implies that individuals might trade-off cultural costs against the benefits of more contacts.…”

“…A second literature models link formation in order to study the important concept of homophily -the tendency for similar individuals to be linked. In this case individuals choose interaction but take behavior as given (Currarini et al, 2009;Bramoullé et al, 2012;Currarini and Vega-Redondo, 2011). We take a novel approach which, importantly, addresses both these choices (choice of practices and choice of interaction) within a single tractable framework.…”