Toward Better Management of Potentially Hostile Crowds

The U.S. Capitol protest and siege in January 2021 provides a vivid demonstration of the challenges posed by managing potentially hostile crowds. Individuals in these crowds are organized into identity groups. Crowd participants' emotions, beliefs, objectives and group affiliations are dynamic. Security forces managing such crowds are tasked with the weighty decisions of tactical rules-of-engagement and choice of weapons. We have developed an agent-based simulation modeling the detailed psychological and behavioral dynamics of individuals and groups in a potentially hostile crowd. This crowd is modeled as actively engaging with security forces that protect a compound. The user can specify crowd attributes, choose diverse non-lethal weapons and rules-of-engagement, watch the event play out, and see the impacts on key outcomes of crowd attitudes and actions. We present our prototype simulation and initial experimental results. We then discuss our future plans for this research.