Behavior Modification

Health Belief Model and Protection Motivation Theory

Two belief-based approaches are discussed here, although they could equally fit in the decision-making category of theories covered later. A major integrative approach to understanding health behaviors is the health belief model (HBM). It was developed to provide an overarching model explaining why people did or did not undertake various health behaviors, such as clinic visits, self-screening, or certain dietary behaviors. The HBM proposes that people will not seek (preventive) health behaviors unless they possess minimal levels of health motivation and knowledge, view themselves as potentially vulnerable to the health problem, view the condition as threatening, are convinced of the efficacy of the “treatment,” and see few difficulties in undertaking the action (see Figure 1). These factors can be modified by socioeconomic and demographic factors, as well as “cues to action,” such as media campaigns or the illness of a close friend.

There was substantial support for the model, although only small effect sizes exist for aspects of the model and the effect sizes vary greatly. Prospective studies have significantly smaller effect sizes than retrospective studies. The majority of HBM research has involved illness, sick-role, or preventive behaviors, and it has an illness-avoidance orientation. Its application to physical activity without modifications is therefore problematic because many people initiate physical activity for motives other than reducing their risk of disease.

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