Abstract
Media-based interventions are common in health promotion, yet their conceptual underpinnings tend to be based on a simple linear model of direct influence on individuals' health behaviour. Recent studies have suggested that the processes through which media influence health behaviours are actually far more complex. This paper presents a conceptual model of how the medias influence the emergence and maintenance of the social norms that can contribute to shaping health behaviours. Through positive (amplifying) and negative (dampening) loops, a total of six potential influence pathways are proposed, and the role of opinion leaders and specialists is specified. Future directions for empirical tests of the model are identified.