Contagion Dynamics in Complex Networks

Abstract

Models of spreading processes in networks can help to provide insights into phenomena such as epidemic outbreaks, opinion formation, and failure propa- gation. Many contagion models are based on the idea that spreading occurs from an “infected” source to “non-infected” components, which may recover. In the case of social opinion formation, external factors such as media influence have to be taken into account, and in some cases multiple infectious sources are necessary to sustain spreading (complex contagion). In this chapter, I provide a brief overview of com- mon models of contagious processes and show that many of them can be treated as special cases of a general contagion model. Interestingly, despite its general formu- lation, the stationary behavior of the model is characterized by only three distinct classes. As an application of the general contagion model, I discuss its ability to describe activist-voter interactions in election campaigns.