Abstract
Sustained mass behaviour change is needed to tackle the COVID-19 pandemic, but many of the required changes run contrary to existing social norms (e.g., physical closeness with in-group members). This paper explains how social norms and social identities are critical to explaining and changing public behaviour. Recommendations are presented for how to harness these social processes to maximise adherence to COVID-19 public health guidance. Specifically, we recommend that public health messages clearly define who the target group is, are framed as identity-affirming rather than identity-contradictory, include complementary injunctive and descriptive social norm information, are delivered by in-group members and that support is provided to enable the public to perform the requested behaviours.