Social norm dynamics in a behavioral epidemic model

TL;DR

This paper introduces a behavioral epidemic model that incorporates social norms, showing how injunctive and descriptive norms influence vaccination behavior and disease spread, with implications for policy interventions.

Contribution

It develops a novel multilayer network model integrating social norms with epidemic dynamics, highlighting the distinct impacts of injunctive and descriptive norms on vaccination uptake.

Findings

Injunctive norms have stronger, more persistent effects than descriptive norms.

Norm-based interventions targeting injunctive norms improve vaccination outcomes.

Models including social norms better predict human behavior in epidemic contexts.

Abstract

Understanding the social determinants of preventive behavior is vital for epidemic modelling and effective policy making. Traditional models emphasize imitation or rational trade-offs, but recent evidence highlights the role of social norms. We develop a behavioral epidemic model of seasonal disease on multilayer networks, where vaccination decisions combine learning from experience with coevolving social norms. The framework distinguishes descriptive norms (what others do) from injunctive norms (what others think ought to be done), while incorporating cognitive dissonance, social projection and logical consistency. Simulations show that norm dynamics yield markedly different vaccination uptake and infection levels compared to considering solely payoff-driven learning. Injunctive norms exert stronger and more persistent effects than descriptive norms. Interventions targeting injunctive expectations improve outcomes, while those on descriptive norms may be weaker or even counterproductive. Norm-based models, once empirically validated, can better capture human behavior and guide strategies for collective action problems even beyond pandemics.