Psychopathic offenders also might be more likely than other offenders to resist an impulse to kill someone when caught in an emotion-driven dispute or less likely to experience such powerful emotions in the first place. Thus, the impulsive behavior often seen in psychopaths outside of the context of homicide may not be simply uncontrollable or reflect an inability to consider the con- sequences but rather may be a function of not caring to control or inhibit the behavior. In fact, our results indicated that of the three dimensions of instrumentality we considered, impulsivity contrib- uted most to the variance of the instrumental/reactive scores and was, surprisingly, negatively related to the overall PCL–R score in these homicide offenders. It is clear that this issue must be inves- tigated in future research before solid conclusions can be formulated.
The results indicate that the PCL–R factor scores were differ- entially related to the instrumentality of the homicides. Specifi- cally, Factor 1 scores accounted for much of the variance associ- ated with the instrumentality of the homicides, whereas Factor 2 scores did not significantly contribute to this dimension. These findings appear to be consistent with Dempster et al.’s (1996) study of 75 adult male violent offenders attending an inpatient treatment program for violent offenders. They found that Factor 1 was significantly related to ratings of planning and instrumentality, whereas Factor 2 actually had a negative relationship with ele- ments of planning during the offense (see also Cunningham & Reidy, 1998; Patrick & Zempolich, 1998).
This study had many strengths in addition to being the first to examine the relationship between psychopathy and homicide. Our results supported the contention of researchers such as Bushman and Anderson (2001) that many acts of aggression cannot be categorized as strictly instrumental or reactive but, rather, contain elements of both. Further, we had access to a large sample to study a poorly understood and highly consequential form of abnormal behavior, devised a highly reliable and rich coding scheme for
characterizing instrumentality and its basic elements, and ensured that no circularity problem was present.
Future studies could explore consistencies (or inconsistencies) between the offender’s primary motivation (instrumental or reac- tive) for previous homicides and other violent acts and his or her motivation for the current homicide. Research examining whether these results would generalize across a range of criminal offenses would be useful in testing the validity of our selective impulsivity hypothesis (e.g., examining whether psychopaths who had com- mitted instrumental homicide also had committed reactive, non- homicidal violence). It is also possible that research examining particular groups or subcultures could obtain different results. For example, research on homicides committed by inner-city gangs, organized criminals, or terrorists could yield different results re- garding both the type of homicides committed and the perpetra- tors’ motivations.
In conclusion, we carefully investigated the psychological as- pects of homicide—a type of violent behavior that often seems incomprehensible to both the public and mental health profession- als—and found that the construct of psychopathy contributes much to our understanding of the phenomenon. Psychopaths engage in far more instrumental or cold-blooded homicides than other of- fenders. Given the wealth of information now available on the behavioral and personality patterns seen in psychopaths across the life span (e.g., Porter, Birt, & Boer, 2001), the homicide investi- gator could potentially reduce the field of suspects in difficult investigations. In terms of treatment planning in the prison setting, it seems clear that a consideration of psychopathy and the type of violence committed is necessary (e.g., anger management would not seem to be an optimal approach for the psychopathic mur- derer). Future research should attempt to differentiate nonpsycho- pathic offenders (nearly half in this study) who commit primarily instrumental homicides from those who commit primarily reactive homicides. Further, in light of these results, classic conceptions of impulsivity in psychopaths may need to be reconsidered. As we have argued, it may be that “impulsivity” in psychopaths has less to do with a lack of control than with conscious decision making that depends on a rapid consideration of the gravity of the consequences.
References Abbott, A. (2001). Into the mind of a killer. Nature, 410, 296–298. Amir, A. (1995). Organized crime and violence. Studies on Crime and Crime Prevention, 4, 86–104.