Conscientiousness and the Theory of Planned Behavior: Toward a more Complete Model of the Antecedents of Intentions and Behavior

Two studies explored the relationship between past behavior, personality traits, intentions, and behavior. Study 1 (N = 181) considered intentions to engage in goal-directed activity (health protection). Cognitions specified by the Theory of Planned Behavior were examined as mediators of the relationship between past behavior, personality, and intentions. The effect of conscientiousness on intention was partially mediated by cognitions, whereas the effect of past behavior was partially mediated by cognitions and conscientiousness. Study 2 (N = 123) examined predictions of intentions and self-reported behavior in relation to both health protection and exercise, a more specific behavior. In both cases, the effect of conscientiousness on intention was totally mediated, whereas the effect on behavior was partially mediated. Similarly, the effects of past behavior on intentions were totally mediated, whereas the effects on behavior were partially mediated by cognitions and conscientiousness. Thus, combining personality traits and cognitions provided a more sufficient account of the determinants of intentions and behavior.