Spreading dynamics in networks under context-dependent behavior

TL;DR

This paper introduces a minimal model for context-dependent spreading in networks, showing how group behavior influences epidemic dynamics and providing a theoretical framework for higher-order interactions.

Contribution

It develops a mean-field theory for context-dependent interactions and analyzes their impact on epidemic spreading, highlighting the role of group organization and sociological factors.

Findings

Changing group contact organization can switch epidemic phases

Context-dependent behavior significantly alters basic reproduction number

Sociological factors influence ease of inducing prophylactic behaviors

Abstract

In some systems, the behavior of the constituent units can create a `context' that modifies the direct interactions among them. This mechanism of indirect modification inspired us to develop a minimal model of context-dependent spreading. In our model, agents actively impede (favor) or not diffusion during an interaction, depending on the behavior they observe among all the peers in the group within which that interaction occurs. We divide the population into two behavioral types and provide a mean-field theory to parametrize mixing patterns of arbitrary type-assortativity within groups of any size. As an application, we examine an epidemic spreading model with context-dependent adoption of prophylactic tools such as face-masks. By analyzing the distributions of groups' size and type-composition, we uncover a rich phenomenology for the basic reproduction number and the endemic state. We analytically show how changing the group organization of contacts can either facilitate or hinder epidemic spreading, eventually moving the system from the subcritical to the supercritical phase and vice versa, depending mainly on sociological factors, such as whether the prophylactic behavior is hardly or easily induced. More generally, our work provides a theoretical foundation to model higher-order contexts and analyze their dynamical implications, envisioning a broad theory of context-dependent interactions that would allow for a new systematic investigation of a variety of complex systems.