Modeling health behavior change: How to predict and modify the adoption and maintenance of health behaviors

Health-compromising behaviors such as physical inactivity and poor dietary habits are difficult to change. Most social-cognitive theories assume that an individual's intention to change is the best direct predictor of actual change. But people often do not behave in accordance with their intentions. This discrepancy between intention and behavior is due to several reasons. For example, unforeseen barriers could emerge, or people might give in to temptations. Therefore, intention needs to be supplemented by other, more proximal factors that might compromise or facilitate the translation of intentions into action. Some of these postintentional factors have been identified, such as perceived self-efficacy and strategic planning. They help to bridge the intention-behavior gap. The Health Action Process Approach (HAPA) suggests a distinction between (a) preintentional motivation processes that lead to a behavioral intention, and (b) postintentional volition processes that lead to the actual health behavior. In this article, seven studies are reported that examine the role of volitional mediators in the initiation and adherence to five health behaviors: physical exercise, breast self-examination, seat belt use, dietary behaviors, and dental flossing. The general aim is to examine the applicability of the HAPA and its universality by replicating it across different health behaviors, based on various measures, time spans, and samples from different countries.