Date of Award





Personality measures have been criticized for their lack of coverage of some traits. As a result, researchers have examined and combined measures to better understand and predict target behaviours. The Supernumerary Personality Inventory (SPI; Paunonen, 2002) was designed to measure a wide range of personality traits, including antisocial tendencies. The Dark Triad (Paulhus & Williams, 2002) was developed specifically to measure the socially malevolent traits of psychopathy, narcissism, and Machiavellianism. Previous studies revealed significant correlations between the SPI traits and the Dark Triad traits, which suggest that the two measures may share some of the same theoretical underpinnings. The present study investigated the Dark Triad’s incremental validity beyond the SPI in predicting both prosocial and risky behaviours. Participants were 118 university students (31 males, 87 females) who completed self-report measures of the SPI and the Dark Triad traits. Hierarchical linear regression analyses were conducted with the 10 SPI traits inputted in the first model, and the three Dark Triad traits inputted in the second model in order to predict a series of behavioural criteria. Results showed that the SPI significantly predicted risky behaviours, but not prosocial behaviours. It was also showed that the Dark Triad did not add incrementally to the SPI’s prediction of prosocial and risky behaviours.