The Dark Triad (DT) has emerged as a popular
extension to the extant literature on personality psychology. The DT is
comprised of three similar and yet distinct constructs: Machiavellianism,
narcissism, and psychopathy. Recent research has criticized the DT for
suffering from a number of measurement problems, including a failure of
existing Machiavellianism measures to adequately capture the construct. Prior research
has chiefly been conducted using domain level information, thus neglecting item
level information. The present thesis investigates the possibility of
empirically distinguishing between DT constructs with particular focus on
Machiavellianism and psychopathy, using item level information. In Article
I, the Dirty Dozen inventory
is analyzed using latent variable models in order to replicate its structural
properties. Results indicate that narcissism is more independent from
Machiavellianism and psychopathy than the latter two are with each other. These
results provide initial evidence that Machiavellianism and psychopathy are
empirically indistinguishable. In Article II, the Short Dark Triad (SD3) is analyzed in a
series of factor analytic models testing whether Machiavellianism and
psychopathy can be jointly modeled. The models fit similarly across two and
three factor solutions, thus favoring a two factor model based on the principle
of parsimony. In Article III,
the SD3 is modeled using Item Response Theory in order to analyze how much
information the SD3 provides across the latent trait continuum. Results
indicate that SD3 items from the domain of Machiavellianism may be less severe
in content than psychopathy items, thus yielding differential item endorsement
rates, albeit along a unitary dimension. In Article IV, the overarching literature on Machiavellianism
is extended by analyzing Machiavellianism items from 7 different measures using
an hierarchical analysis. This analysis is subsequently compared with expert
rated Five Factor model prototype scores o