Altruistic punishment supports the persistence of social norms for infectious diseases

The study examines how altruistic punishment – when individuals punish those who do not comply with social norms – can maintain social distancing norms during an epidemic. Researchers combined a disease transmission model with an imitation model of three behavioral strategies: defection, cooperation without punishment, and cooperation with punishment. They found that across a wide range of parameters, a social norm supporting social distancing can be established, where the punishment strategy is widespread. The system can reach a stable state where punishers are dominant, or create oscillatory cycles where the three strategies alternate in response to epidemic waves. These effects do not appear in models without feedback. The results show that costly peer punishment can support the persistence of social norms that mitigate disease transmission, and that epidemic feedback can create tipping points and long-term behavioral-epidemiological cycles.