Endogenizing Social Norms in Epidemic Dynamics: A Behavior-Infection-Norm Framework.

A Behavior-Infection-Norm (BIN) framework is developed to endogenize injunctive norms through information transmission. Behavioral drivers are decomposed into two competing mechanisms: normative imitation driven by social influence, and infectious feedback shaped by infection risk. Time-scale separation and competitive interaction between those mechanisms govern global dynamics. The system exhibits stable equilibria and periodic oscillations. System stability depends on whether the injunctive norm crosses a critical response barrier. Numerical results show that social reinforcement is a pivotal control parameter for enhancing system resilience and mitigating disturbance impacts. The BIN framework provides a mechanistic understanding of how coevolving norms and behaviors shape epidemic outcomes, and supports a strategic shift from reactive intervention toward proactive capacity building.