From behavioural insight to system design: Reframing the role of psychology in public health

Abstract

Contemporary public health challenges, including non-communicable diseases, persistent inequalities, misinformation, and complex organisational systems, are fundamentally shaped by behavioural, social, and psychological processes. Although this is increasingly recognised, psychological science remains unevenly integrated into public health and is often confined to individual-level interventions rather than embedded in system design, governance, and policy. A more fundamental shift is required. Psychology should be understood not as an adjunct to public health but as one of its foundational disciplines. Drawing on behavioural science, social identity research, and systems thinking, this commentary argues that psychological processes operate across multiple levels, from individual behaviour and community participation to organisational practice, leadership, implementation, and collective action. The COVID-19 pandemic illustrated this clearly: psychologically informed approaches supported public adherence, effective communication, trust, and community resilience. However, a broader conception of psychology, encompassing social identity, organisational behaviour, implementation, and structural pathways, is needed. Psychology should be recognised as a foundational contributor within the wider public health sciences ecosystem. Embedding psychological insight within the infrastructure of public health is essential if public health systems are to address the growing complexity of protecting and improving population health. A mature partnership between psychology and public health requires the systematic integration of psychological expertise into the design, implementation and governance of public health systems if they are to respond effectively to the complexity of twenty-first century population health challenges.