Spreading dynamics in networks under context-dependent behavior

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.

Automated summary

In some systems, the behavior of constituent units can modify direct interactions among them by creating a context. Inspired by this mechanism, we developed a minimal model to study context-dependent spreading. We divide the population into two behavior types and provide a mean-field theory to analyze mixing patterns within groups of any size. By examining an epidemic-spreading model with context-dependent adoption of prophylactic tools, we uncover the impact of changing group organization on epidemic spreading and propose a theoretical foundation to model and analyze higher-order contexts in complex systems.