Diffusion and Contagion in Networks with Heterogeneous Agents and Homophily

TL;DR

This paper analyzes how behaviors spread in social networks with segregation and homophily, revealing conditions that facilitate diffusion based on agent types and interaction patterns.

Contribution

It introduces a model linking homophily and agent heterogeneity to diffusion dynamics, highlighting how homophily can promote behavior spread from small seeds.

Findings

Homophily can facilitate diffusion from small initial seeds.

Heterogeneous interaction patterns influence adoption rates.

Conditions for persistent behavior spread depend on agent types and homophily levels.

Abstract

We study how a behavior (an idea, buying a product, having a disease, adopting a cultural fad or a technology) spreads among agents in an a social network that exhibits segregation or homophily (the tendency of agents to associate with others similar to themselves). Individuals are distinguished by their types (e.g., race, gender, age, wealth, religion, profession, etc.) which, together with biased interaction patterns, induce heterogeneous rates of adoption. We identify the conditions under which a behavior diffuses and becomes persistent in the population. These conditions relate to the level of homophily in a society, the underlying proclivities of various types for adoption or infection, as well as how each type interacts with its own type. In particular, we show that homophily can facilitate diffusion from a small initial seed of adopters.