Diffusion and Cascading Behavior in Random Networks

TL;DR

This paper models the diffusion of behaviors in random networks using a strategic game approach, revealing how network connectivity influences the spread and stability of actions differently than epidemic models.

Contribution

It introduces a strategic coordination game model for diffusion in networks and analyzes how network structure affects equilibrium outcomes and diffusion limits.

Findings

Connectivity facilitates diffusion but can also hinder it due to stable high-degree nodes.

The model shows coexistence of strategies in large connected sets.

Results differ from traditional epidemic models, highlighting the complex role of network structure.

Abstract

The spread of new ideas, behaviors or technologies has been extensively studied using epidemic models. Here we consider a model of diffusion where the individuals' behavior is the result of a strategic choice. We study a simple coordination game with binary choice and give a condition for a new action to become widespread in a random network. We also analyze the possible equilibria of this game and identify conditions for the coexistence of both strategies in large connected sets. Finally we look at how can firms use social networks to promote their goals with limited information. Our results differ strongly from the one derived with epidemic models and show that connectivity plays an ambiguous role: while it allows the diffusion to spread, when the network is highly connected, the diffusion is also limited by high-degree nodes which are very stable.