Thursday, June 16, 2011
After the last Vancouver riot, we did a project looking at the applicability of an epidemic model to explain these superficially unexplainable outbursts. While it has become routine to blame criminal elements or political operatives, it is also true that crowd violence may have a contagious aspect. Many of the principles of crowd control can be understood in ways that fit with this "behavioral contagion" idea: e.g. separating (quarantine) trouble-makers, influencing factors that may affect the predilection or spread of violence (alcohol), one factor that stems largely from the epidemic model is the idea of an epidemic threshold - which implies that the size of a crowd will be an important predictor of a riot. This is perhaps a mathematical reality rather than an intuitively obvious one, such that it tends to be ignored to a greater extent than other factors. The abstract for this paper is here and here.