Certainty improves the predictive validity of Honesty-Humility and Dark Triad traits on cheating behavior

This research examined the extent to which certainty can strengthen the relationship between individual differences and cheating behavior. In the first two studies, participants completed the Honesty-Humility or the Dark Triad scales. Then, they rated the certainty they had in their responses to each of those two inventories. In the third study, participants completed both scales within the same experimental design and were randomly assigned to a certainty vs. doubt condition. As the dependent variables, we used different cheating outcomes across studies. As predicted, the link between these two traits and cheating behavior was greater for participants with higher levels of certainty in their responses to the inventories (Studies 1 and 2) or for those assigned to the certainty (vs. doubt) condition (Study 3). Incorporating the certainty with which individuals hold their traits contributes to enhancing the predictive validity of personality measures relevant to cheating. • Honesty-Humility and the Dark Triad are important predictors of cheating behavior. • The predictive validity of these traits can be increased by considering the certainty in the responses to those inventories. • An incidental manipulation of certainty also leads individuals to rely more on these traits to guide their cheating behavior. • Consistent with SVT, certainty improves the predictive ability of personality measures, strengthening their impact.