The Dark Side of Humanity Scale: A Reconstruction of the Dark Tetrad Constructs

A myriad of criticisms have been directed at the widely available scales which measure the Dark Tetrad (DT), constructs of Machiavellianism, psychopathy, narcissism and everyday sadism. These have included construct incongruence, unstable factor structures, sex and age variance. Sex and age are salient variables in research studies and as such, their reported variance was considered to be a weakness of the measures, which contributed to their instability. To ascertain whether this was indeed the case, an investigation of the widely available DT measures was conducted in study one (n=605). Through the use of Classical Test Theories, Exploratory Graph Analysis and Item Response Theory, the criticisms of past research were supported, including variance across age and sex. Mediated by the evidenced issues and in order to address them, the Dark Side of Humanity Scale (DSHS), was developed, which was the main aim of this thesis. The focus of the measure was to assesses the DT personality constructs as they manifest in the general population, whilst also being sex and age invariant. Using a diverse range of statistical methods and guided by theory, expert ratings and past research, where available, the development of the DSHS began in the second study (n=667). During analyses, a divergence from the widely available DT measures emerged, whereby primary psychopathy and Machiavellianism were unified. However, this corroborated past research which has discussed the two constructs as being parallel. It further afforded the DSHS with a shift away from the traditional DT conceptualisation. The resulting scale encompasses four factors. The first represents the successful psychopath, factor two addresses the grandiose form of entitlement, factor three taps into everyday sadism and includes sadistic fantasies, direct and vicarious psychological malevolence, whilst factor four pertains to narcissistic entitlement rage. Each factor is specific to the traits and behaviours of the construct they address. Study three reports on the convergent and discriminant validity of the DSHS (n=712), and test-retest validity (n = 413), for which temporal reliability as well as nomological validity was achieved. The unique contributions of this thesis are discussed in the final chapter. The DSHS provides an alternative approach to investigating the dark side of human nature in general population samples, whilst also being sex and age invariant.