# Homophily on social networks changes evolutionary advantage in competitive information diffusion

## TL;DR

This paper investigates how population homophily influences the dynamics of competing information diffusion on social networks, revealing that homophily can reverse which information ultimately dominates, especially when initially disadvantaged.

## Contribution

It introduces a modified SIS rumor model incorporating homophily effects and derives phase diagrams, providing new insights into how homophily alters competitive diffusion outcomes.

## Key findings

- Homophily promotes echo chamber formation.
- Homophily can reverse the evolutionary advantage of competing information.
- Disadvantaged information can prevail if it has stronger transmission ability.

## Abstract

Competitive information diffusion on large-scale social networks reveals fundamental characteristics of rumor contagions and has profound influence on public opinion formation. There has been growing interest in exploring dynamical mechanisms of the competing evolutions recently. Nevertheless, the impacts of population homophily, which determines powerful collective human behaviors, remains unclear. In this paper, we incorporate homophily effects into a modified competitive ignorant-spreader-ignorant (SIS) rumor diffusion model with generalized population preference. Using microscopic Markov chain approach, we first derive the phase diagram of competing diffusion results and examine how competitive information spreads and evolves on social networks. We then explore the detailed effects of homophily, which is modeled by a rewiring mechanism. Results show that homophily promotes the formation of divided "echo chambers" and protects the disadvantaged information from extinction, which further changes or even reverses the evolutionary advantage, i.e., the difference of final proportions of the competitive information. We highlight the conclusion that the reversals may happen only when the initially disadvantaged information has stronger transmission ability, owning diffusion advantage over the other one. Our framework provides profound insight into competing dynamics with population homophily, which may pave ways for further controlling misinformation and guiding public belief systems. Moreover, the reversing condition sheds light on designing effective competing strategies in many real scenarios.