an examination of the factor structure of the psychopathy checklist

instrumental/reactive, and (d) purely instrumental. In this model, purely reactive and
purely instrumental violence represent the polar ends of a continuum of motivation.
However, these extremes are separated by violence that is primarily driven by reactive
emotionality, but has some elements of instrumentality, and violence that is primarily
driven by instrumental gain, but has some elements of reactivity.
It has been suggested (i.e., Vitacco et al., 2006) that viewing instrumental
aggression through the lens of psychopathy can provide useful information pertaining to
the causes of aggression. The adult psychopathy literature has recognized a substantial
connection between psychopathic traits and instrumental aggression (e.g., Cornell et
al., 1996; Walsh, Swogger, & Kosson, 2009; Williamson, Hare, Wong, 1987; Woodworth
& Porter, 2002). Two studies have arguably been particularly relevant in informing the
literature on the nature of psychopathy and instrumental aggression in adult samples.
Cornell et al. (1996) completed an important study on the nature of psychopathy and
instrumental aggression in 106 male inmates and 50 pre-trial forensic referrals with
violent histories. In completing their study, Cornell and colleagues developed an
innovative coding system for classifying aggression which assessed six distinct
domains: (a) planning, (b) goal directedness, (c) provocation, (d) anger, (e) victim injury,
and (f) victim relationship. They found that 50% of PCL–R items were significantly
higher in offenders who had histories of instrumental aggression compared with those
with no documented history of instrumental aggression.
The second study was conducted by Woodworth and Porter (2002) on a sample of
125 Canadian offenders convicted of homicide. Woodworth and Porter rated each
homicide on their continuum described earlier in this section. Results indicated that
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