A bistable belief dynamics model for radicalization within sectarian conflict*

Motivated by recent events, we propose a dynamical two-variable model to describe polarization, radicalization, and sectarian conflict. Individuals are described by a continuous belief variable and a discrete radicalization level indicating their tolerance to neighbors with different beliefs. A novelty of the model is the incorporation of a bistable radicalization process to address memory-dependent human social behavior. We show that bistability in behavior may be the reason for contradicting observations regarding whether social segregation exacerbates or alleviates conflicts. By extending our model to include a mechanism of institutional influence, such as propaganda or education, we show that the effectiveness of such intervention can be profoundly affected by the uncertainty due to bistability. In some parameter regimes, institutional influence may stifle the progression of radicalization, allowing a mixed population to achieve social conformity over time. In other cases, institutional influence adversely accelerates the spread of radicalization within a mixed population, implying that social segregation may be considered as a viable option against sectarian conflicts.