The "Core" of the Dark Triad: A test of competing hypotheses

As research on the Dark Triad (DT; the interrelated constructs of Machiavellianism, narcissism, and psychopathy) has accumulated, a subset of this research has focused on explicating what traits may account for the overlap among the DT members. Various candidate traits have been investigated, with evidence supporting several of them including Antagonism (vs. Agreeableness), Honesty-Humility, and Callousness and Interpersonal Manipulation (the latter two as a set). The present study sought to test the leading candidates against one another in their ability to account for the shared variance among the DT members. Using a pre-registered analytical plan, we found that Agreeableness (as measured by the IPIP-NEO-120), Honesty-Humility from the HEXACO, and the SRP-III subscales of Callous Affect and Interpersonal Manipulation accounted for all or nearly all of the shared variance among the DT members. BFI-based measures of Agreeableness (BFI and BFI-2) accounted for notably less variance in most cases. The results were consistent across two large samples (Ns of 627 and 628), and across various DT measurement approaches. We argue that the most parsimonious explanation for findings on the core of the DT is that such traits all fall under the umbrella of Antagonism.