Strength of minority ties: the role of homophily and group composition in a weighted social network

TL;DR

This paper extends the Weighted Social Network model to include homophily, demonstrating its ability to replicate empirical social network properties in spider monkeys and revealing how minority group reinforcement influences social structure.

Contribution

It introduces a homophilic extension to the WSN model and validates it with empirical data, highlighting the role of group composition in social network patterns.

Findings

Model accurately reproduces empirical network properties

Asymmetry in group composition explains stronger male-male interactions

Minority group reinforcement may be a general social structuring mechanism

Abstract

Homophily describes a fundamental tie-formation mechanism in social networks in which connections between similar nodes occur at a higher rate than among dissimilar ones. In this article, we present an extension of the Weighted Social Network (WSN) model that, under an explicit homophily principle, quantifies the emergence of attribute-dependent properties of a social system. To test our model, we make use of empirical association data of a group of free-ranging spider monkeys in Yucatan, Mexico. Our homophilic WSN model reproduces many of the properties of the empirical association network with statistical significance, specifically, the average weight of sex-dependent interactions (female-female, female-male, male-male), the weight distribution function, as well as many weighted macro properties (node strength, weighted clustering, and weighted number of modules), even for different age group combinations (adults, subadults, and juveniles). Furthermore, by performing simulations with fitted parameters, we show that one of the main features of a spider monkey social system, namely, stronger male-male interactions over female-female or female-male ones, can be accounted for by an asymmetry in the node-type composition of a bipartisan network, independently of group size. The reinforcement of connections among members of minority groups could be a general structuring mechanism in homophilic social networks.