Conscientiousness reliably predicts health behavioral patterns, and the same is true of executive function. However, few investigations have examined their relative predictive power, or probed for possible indirect effects and age-moderated effects. In the current study, we examined the predictive validity of all Big Five personality traits, executive function and IQ in relation to an index of health behaviors in an age-stratified community sample. Results indicated that conscientiousness, neuroticism and executive function were significant predictors of health behavior in age-corrected regression analyses. Using bootstrapping methods, we found that executive function partially explains the relationship between both personality dimensions and health behavior. Moderational analyses revealed that effects of personality traits on health behavior were uniformly modest across the age span, whereas the predictive power of executive function became more amplified with increasing age. Both conscientiousness and neuroticism predict health behavior patterns, though their magnitude of association is significantly weaker than executive function and some of their effects are explained by executive function.
