Abstract

A short measure of the Dark Triad (Machiavellianism, psychopathy, and narcissism) showed consistent factorstructure and convergent validity. Narcissism, however, didn’t contribute with information to the coreconstitution of the Dark Triad. Instead, a Single Item Dirty Dark Triad (SIDDT: exploitation of others),accounted for the core of the measure.

Supporting summary

Background: The dark side of human character has been conceptualized in the Dark Triad Model:Machiavellianism, psychopathy, and narcissism. These three dark traits are often measured using single longinstruments for each one of the traits. Nevertheless, there is a necessity of short and valid personality measuresin psychological research. As an independent research group, we replicated the factor structure, convergentvalidity and item response for one of the most recent and widely used short measures to operationalize thesemalevolent traits, namely, the Dark Triad Dirty Dozen. We aimed to expand the understanding of what the DirtyDozen really captures because the mixed results on construct validity in previous research.

Method: We used the largest sample to date to respond to the Dirty Dozen (N = 3,698). We firstly investigatedthe Dirty Dozen’s factor structure using Confirmatory Factor Analysis. Secondly, using sub-sample (n = 500)and correlation analyses, we investigated the Dirty Dozen dark traits convergent validity to Machiavellianismmeasured by the Mach-IV, psychopathy measured by Eysenck’s Personality Questionnaire Revised, narcissismsusing the Narcissism Personality Inventory, and both neuroticism and extraversion from the Eysenck’squestionnaire. Finally, besides these Classic Test Theory analyses, we analyzed the responses for each DirtyDozen item using Item Response Theory (IRT).

Results: The results confirmed previous findings of a bi-factor model fit: one latent core dark trait, plus thethree dark traits. An additional exploratory distribution analysis showed that all three Dirty Dozen traits had astriking bi-modal distribution, which might indicate unconcealed social undesirability with the items. The threeDirty Dozen traits did converge to, although not strongly, with the contiguous single Dark Triad scales (rbetween .41-.49). The probabilities of filling out steps on the Dirty Dozen narcissism-items were much higherthan on the Dirty Dozen items for Machiavellianism and psychopathy. Overall, the Dirty Dozen instrumentdelivered the most predictive value with persons with average and high Dark Triad traits (Theta > -0.5).Moreover, the Dirty Dozen scale was better conceptualized as measured of a combined Machiavellianismpsychopathyfactor, not narcissism, that can be replaced with item 4: ‘I tend to exploit others towards my ownend’.

Conclusion: The Dirty Dozen showed a consistent factor structure, a relatively convergent validity similar tothat found in earlier studies. Narcissism measured using the Dirty Dozen, however, did not contribute withinformation to the core constitution of the Dirty Dozen construct. More importantly, the results imply a SingleItem Dirty Dark Triad (SIDDT) measure of a manipulative and anti-social core as the content of the DirtyDozen scale.