Bitter personal experience and meta-analysis converge on the conclusion that people do not always do the things that they intend to do. This paper synthesizes research on intention-
The Intention-Behavior GapGoal intentions are people's self-instructions to achieve desired outcomes (e.g., "I intend to finish this paper before I die!"; Triandis, 1980) and behavioral intentions are self-instructions to perform particular actions directed towards attaining these outcomes (e.g., "I intend to spend Monday morning working on this paper!"). Intentions capture both the level of the set goal or behavior (e.g., the number of hours that the person intends to spend working on their paper), and the person's level of commitment (e.g., how determined they are to devote that number of hours to working on the paper). Although most behavior is habitual or involves responses that are triggered automatically by situational cues (e.g., Bargh, 2006;Wood & Neal, 2007), forming intentions can be crucial for securing long-term goals (Baumeister & Bargh, 2014;Kuhl & Quirin, 2011). The concept of intention has thus proved invaluable for researchers concerned with behavior change, and interventions designed to promote public health, energy conservation, and educational and organizational outcomes generally rely on frameworks that construe intentions as a key determinant of behavior change (e.g., Ajzen, 1991;Bandura, 1996;Locke & Latham, 1992;Rogers, 1983).Numerous correlational studies indicate that intentions predict behavior. For instance, Sheeran (2002) meta-analyzed 10 previous meta-analysis (422 studies in total) and found a 'large' sample-weighted average correlation between intentions measured at one time-point and measures of behavior taken at a subsequent time-point (r + = 0.53). Moreover, intention offers superior prediction of behavior in correlational tests compared to other cognitions including (explicit and implicit) attitudes, norms, self-efficacy, and perceptions of risk and severity (e.g., McEachan et al., 2011; Sheeran, Harris, & Epton, 2014; Sheeran et al., in press) as well as personality factors (e.g., Chiaburu et al., 2011;Poropat, 2009;Rhodes & Smith, 2006). These findings would seem to suggest that forming an intention to change is vital if people are to initiate new behaviors or to alter courses of action that are no longer seen as desirable.
The Intention-Behavior Gap: The Proverbial 'Road to Hell' is Well PavedHow well a variable predicts behavior in correlational studies does not indicate how much change in behavior accrues from manipulating that variable, however (Sheeran, Klein, & Rothman, in press). A meta-analysis of experiments that manipulated intention showed that a medium-to-large-sized change in intentions led to only a small-to-medium-sized change in behavior (d + = .36; Webb & Sheeran, 2006; see also Rhodes & Dickau, 2012). Findings from statistical simulations also converge on the conclusion that changing intentions does not guarantee behavior change (Fife-Schaw, Sheeran, & Norman, 2007)...