The theory of planned behavior and lower-order personality traits: interaction effects in the exercise domain

A leading theoretical model explaining informational and motivational influences on exercise behavior is the theory of planned behavior (TPB). Despite the relatively consistent performance of the TPB, over half of the variance remains unexplained in intention and behavior. One possibility for this unexplained variance may be underlying moderating effects that bias linear coefficients. The purpose of this study was to examine lower-order personality facet traits of neuroticism, extraversion, and conscientiousness as moderators of the TPB. Hypotheses were generated based upon the specific personality traits and previous research, but all possible moderating effects were examined given the exploratory nature of the research. Participants were 298 undergraduate students (mean age=19.97) who completed measures of the TPB, personality, and a two-week follow-up of exercise behavior. Results showed that two personality facets (i.e., industriousness-ambition, irritability) significantly (p<0.01) moderated the relationship between the TPB and exercise behavior and two personality facets (i.e., insecurity, activity-adventurousness) significantly (p<0.01) moderated the relationship between the TPB and intention. The moderating effects were small-to-moderate (e.g., 3-4% additional explained variance). Theoretical and practical implications for exercise behavior were discussed.