The relationship between psychopathy and indirect aggression in a commuity sample.

This thesis sought to investigate the relationship between psychopathy and indirect
aggression use. Psychopathy has been strongly linked with increased levels of aggressive
behaviour and in particular violence (Porter & Woodworth, 2006). However, thus far
research has predominantly focused on direct forms of aggression with minimal research
considering indirect forms of aggression. On the basis of previous research, it was
hypothesised that not only would psychopathy be significantly related to indirect
aggression use, but that this relationship would remain after controlling for the shared
variance with direct aggression. It was also hypothesised that this relationship would be
mediated by deficits in affective empathy and moderated by both gender and levels of
social skills.
A series of quasi-experimental studies were conducted to test this hypothesis using
regression analysis and structural equation modelling. Study 1 sought to test the basic
relationship between psychopathy and indirect aggression using the Psychopathic
Personality Inventory - Revised and the Indirect Aggression Scale respectively on a sample
of 103 university students. Study 2 & 3 then expanded this and sought to investigate both
the role of empathy, using the Empathy Quotient (Study 2), and gender (Study 3) using a
sample of 201 university students, 83 males and 118 females. Study 4 used the Social
Skills Inventory in a sample of 107 students to test the hypothesised social skill moderation
of this relationship. Finally Study 5 and 6 sought to redress issues of both the limited
samples and use of self-report measures in the previous studies by replicating these
findings in a general community population of 204 (Study 5) and using behavioural
measures of empathy on a sample of 117 (Study 6).The results indicate that psychopathy is
significantly related to the use of indirect aggression, even after controlling for direct
aggression, and that this was driven predominantly by the impulsive antisociality and
coldheartedness factors. This relationship was found to be significantly mediated by
affective, but not cognitive, empathy deficits although only for males, not for females,
which may arguably point towards differences in the function of indirect aggression for
male compared to female psychopaths. Non-verbal social skills were found to significantly
moderate this relationship among students, however this finding could not be replicated.
These findings would appear to imply that psychopathy is related to a general increase in
aggression, rather than a specific increase in violence. This supports the theorisation of
non-criminal psychopathy as a moderated behavioural manifestation of the underlying
personality traits rather than a sub-clinical version of the disorder. The sex differences in
the relationship would seem to imply that the different types of aggression use may have
different underlying meanings for males and females high on psychopathic traits.