an examination of the factor structure of the psychopathy checklist

Because the interpersonal and affective characteristics of psychopathy arguably
distinguish psychopathy from comparatively less severe antisocial disorders (Hare,
1996, 2006; Rogstad & Rogers, 2008), Agar reasoned that youth who engage in
instrumental homicide should score higher on the interpersonal and affective
dimensions of psychopathy, specifically. As expected, the results indicated that only the
interpersonal and affective components of psychopathy (i.e., Facet 1 and Facet 2) were
significantly correlated with instrumentality, such that those scores increased as the
instrumentality of the homicide increased.
The relationship between the interpersonal features of psychopathy (i.e., Facet 1)
and instrumental violence has also recently been demonstrated among less severe
juvenile offenders (i.e., Carpenter, 2010). Carpenter’s examination of a mixed, although,
once again, primarily male, sample of generally violent offenders, demonstrated that the
interpersonal features of psychopathy were positively related to instrumental aggression
which is consistent with other findings in the youth literature (e.g., Agar, 2009; Flight &
Forth, 2007). In contrast to Agar, however, there was no relationship between the
affective (i.e., Facet 2) component of psychopathy and instrumental aggression. This
discrepancy in findings between youth who have committed homicide and those who
have perpetrated less serious violent offences, suggests that there are likely important
differences that exist between these two types of offenders in what contributes to their
use of instrumental violence. Adding to the uncertainty, Carpenter speculated that this
finding may be related to reduced power, rather than the absence of a relationship given
that affective deficits would logically be related to the callous treatment of others.
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