Unveiling the Multidimensional Nature of the Intention–Behavior Gap

Abstract: The intention-behavior gap (IBG) is a central challenge in health psychology, with significant implications for behavior change and health promotion. Prevailing approaches to IBG assessment involve quantifying it as either the proportion of unexplained variance in behavior attributable to intention or the ratio of unsuccessful intenders to all intenders. While these concepts provide insight into IBG variation at the between-person level, the major part of the variation of intentions and behaviors is at the within-person level. This paper addresses these limitations by introducing a novel framework, in which the IBG is mathematically conceptualized as a multidimensional difference between an individual’s behavioral intention and the individual’s subsequent observed behavior. Key tenets of this framework include: (1) Recognizing the dynamic nature of intentions as a fundamental driver of IBG, with the timing of intention measurement playing a crucial role in predicting behavior. (2) Highlighting the importance of within-person factors and contextual intricacies in influencing the translation of intentions into behavior. (3) Emphasizing the need for intensive longitudinal data with frequent measurements within individuals to capture the dynamic intention-behavior relation in daily life. This framework also highlights implications for study designs, theory, and interventions in health psychology and offers promising avenues for reducing the IBG and improving health behavior outcomes.