What Are the `Active Ingredientsu27 of Change in the Theory of Planned Behavior? Evaluating the Relative Effectiveness of Attitudes, Norms, and Perceived Behavioral Control/Self-Efficacy

摘要

Health interventions only have small to moderate effects on behavior change. The lack of a solid understanding of how the key theoretical constructs interact to motivate behavior change may be partly to blame. The current study examines the utility of each of the hypothesized determinants of behavior in the TPB (i.e., attitudes, norms, perceived behavioral control (PBC)/self-efficacy, and intentions) and explores the optimal combination of these constructs in an intervention to increase condom use intentions and behavior among college students. 287 participants were randomly assigned to one of seven computer-based interventions. 70 (24.4%) completed behavioral follow-up assessments three-months later. Simple effect analyses revealed that targeting one construct (e.g., norms) had diffuse effects on other constructs in the TPB (i.e., attitudes and intentions). Mediational analyses revealed that theory-based interventions were better at changing intentions than the control condition. Changes in attitudes toward condom use were related to changes in intentions. Finally, as predicted by the TPB, intentions predicted risky sexual behavior at follow-up. Theory-based interventions were superior to the control, but which combination of constructs is most effective at creating behavior change remains to be established.