Small-world networks and synchronisation in an agent-based model of civil violence

ABSTRACT The rapid evolution and current ubiquity of social media as a form of communication calls for a revision of many models of collective behaviour. In this paper, we modify a classic agent-based model of civil violence by Epstein (2002) consisting of citizen and law-enforcement agents by integrating a Watts-Strogatz small-world network (SWN). The SWN simulates non-local connections between citizens, enabling influence by both local and distant neighbours and providing an analogue to social media. The objective was to examine the influence of non-local connections on civil violence dynamics for varied law-enforcement concentration and network density. For lower law-enforcement concentrations, the SWN influence leads to more frequent large-scale violent outbursts, while for higher law-enforcement concentrations, outcomes depended most strongly on the number of local neighbours. The long-range coupling across the lattice due to the SWN provides a new mechanism for non-trivial dynamics and leads to a synchronisation effect.