Epidemics of violence.

The concept of behavioral contagion implies that certain behaviors may spread through populations in a way analogous to the spread of microbial diseases. If so, mathematical models that are helpful in understanding the spread of infectious diseases may also help to understand the spread of certain behaviors. The objective of this paper was to explore the possibility that the Kermack-McKendrick model of epidemic spread may help to explain the outbreak of riots in crowds. Predictions made by the mathematical model were compared to descriptions of crowd behavior and of police methods for preventing and controlling the outbreak of riots. Many of the predictions made by the model are consistent with published observations about circumstances where riots may occur, and methods useful for controlling them.