Does Changing Behavioral Intentions Engender Behavior Change? A Meta-Analysis of the Experimental Evidence

Webb, Thomas L.
Sheeran, Paschal

¹School of Psychological Sciences, The University of Manchester, Manchester, United Kingdom,
²Department of Psychology, The University of Sheffield, Sheffield, United Kingdom.

³Correspondence concerning this article should be addressed to Thomas L. Webb, School of Psychological Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom. E-mail: [email protected].

We thank Amanda Rivis and Vikkie Buxton for coding the study characteristics, Paul Norman and Richard Cooke for coding assessed control, and Gaston Godin and Ian Kellar for providing considerable additional information about their research.

Received October 19, 2004; Revised July 18, 2005; Accepted August 16, 2005

Psychological Bulletin 132(2):p 249-268, March 2006.

Numerous theories in social and health psychology assume that intentions cause behaviors. However, most tests of the intention-behavior relation involve correlational studies that preclude causal inferences. In order to determine whether changes in behavioral intention engender behavior change, participants should be assigned randomly to a treatment that significantly increases the strength of respective intentions relative to a control condition, and differences in subsequent behavior should be compared. The present research obtained 47 experimental tests of intention-behavior relations that satisfied these criteria. Meta-analysis showed that a medium-to-large change in intention (d = 0.66) leads to a small-to-medium change in behavior (d = 0.36). The review also identified several conceptual factors, methodological features, and intervention characteristics that moderate intention-behavior consistency.