Self-affirmation interventions to change health behaviors

Many messages that aim at changing people's health behaviors highlight the negative consequences of continuing to engage in current behaviors (insufficient physical activity and smoking). However, such messages are often less effective than desired because people respond defensively to threatening communication by ignoring or derogating it. In this chapter, we discuss how self-affirmation theory can assist both in understanding individual defensive responses and in improving the effectiveness of health messages. Self-affirmation theory proposes that messages that highlight negative consequences of current behavior provoke defensive responses because they threaten a person's view of themselves as being good and adequate. However, the theory also poses that if people affirm an unrelated domain of their self-system, defensive responses decrease and more adaptive behavior ensues.In this chapter, we provide an updated review of the evidence for self-affirmation effects on health behavior change, discuss circumstances under which self-affirmation might work better or worse, outline the psychological processes mediating self-affirmation effects and present some recommendations for the use of self-affirmation in interventions to change health behaviors.