Psychopathy

Woodworth, M., & Porter, S. (August 2002). In Cold Blood: Characteristics of

Criminal Homicides as a Function of Psychopathy. Journal of Abnormal

Psychology, 111 (3), 436-445. [Electronic Version].

Psychopathy is a "personality disorder characterized by a profound affective deficit accompanied by a lack of respect for the rights of others and societal rules (p. 436)". Although previous studies have investigated the relationship between psychopathy and criminal behavior, little was known about the relationship between psychopathy and the act of homicide, specifically. "An obvious reason for the lack of research on the psychology of homicide is that it is uncommon compared with other forms of antisocial and violent behavior (p. 436). The article, "In Cold Blood: Characteristics of Criminal Homicides as a Function of Psychopathy," hypothesized that:

The homicides committed by psychopathic offenders would be more

likely to be primarily instrumental (i.e., associated with premeditation,

motivated by an external goal, and not preceded by a potent affective

reaction) or "cold-blooded" in nature, whereas homicides committed

by nonpsychopaths often would be "crimes of passion" associated

with a high level of impulsivity/reactivity and emotionality. (p. 436)

For the reader to be able to understand this hypothesis, the authors begin the article by giving us a better understanding of "violence". "Bandura (1983) viewed aggression primarily as an instrumental and goal-driven behavior contingent on external rewards and reinforcement (p. 437). Many researchers argue that violence may have elements of both instrumentality and emotionality/reactivity. According to Woodworth and Porter (2002), instrumental violence occurs when the injury of an individual is secondary to the acquisition of some other external goal while reactive violence encompasses impulsive, immediate, and emotion-driven acts in response to a perceived threat, danger or insult. The determination of whether violence is instrumental or reactive, "may be one of the most relevant criteria in assessing risk for future violence and for treatment prognosis in criminal offenders (p. 437).

This study investigated the relationship between psychopathy and the characteristics of criminal homicides committed by a sample of 125 Canadian offenders. The authors note that the sample came from two Canadian federal institutions, one from the west coast and one on the east coast. "The inclusion of offenders from two prisons allowed a large sample size and could increase the generalizability of the findings (p. 438)". The study required the use of various materials. The first one being the PCL-R, which is widely used for the assessment of psychopathy in forensic populations. "PCL-R assessments are typically conducted as part of the intake assessment and for conditional release decisions and are based on a structured interview as well as a thorough review of all collateral and historical information (p. 438). The PCL-R scores were available for all except for 29 offenders from one of the prison samples. For this study, "a graduate student in psychology and a senior undergraduate student who had been trained in administering the PCL-R reviewed all available official file information and scored the 29 other PCL-R's. These raters were kept blind to the purpose and hypotheses of the study to prevent any bias in their scoring of the PCL-R (p. 438)".

Once the PCL-R scores were available for all 125 inmates, the interrater reliability of the PCL-R assessments for the entire sample was examined in two ways. First, 21 offenders were randomly chosen for dual coding. "In these cases, with exception of the Psychological Assessment Reports documenting the original PCL-R score, all file information was made available on each offender to the blind coder (p. 438)". For the second reliability test, 33 offenders were randomly selected for dual coding. "However, for these cases, all details pertaining to the current homicide offense were completely removed prior to coding (p. 438)". This was done to ensure that the coding was done properly without knowing whether the offender was psychopathic and to make sure that the PCL-R scores were not biased by the coders knowledge of the details of the homicide. To avoid rating bias, the coder was not able to see the PCL-R scores. However, because many of the inmates had committed more than two homicides, only the most recent homicide for each offender was coded.

Each homicide was rated on a Likert-scale with possible ratings from 1 to 4. "[We] also examined this issue categorically to test whether the psychopaths and nonpsychopaths had engaged in primarily reactive (rating 1 or 2) or instrumental violence (rating 3 or 4) (p. 439)". Instrumental violence was further classified as primary and secondary instrumental violence. For this study the various motives that each offender may have had to commit homicide were investigated. "A homicide was not coded if the motive or rationale for committing the homicide could not be determined or if it was not possible to ascertain whether the homicide had been spontaneous or planned (p. 439)". "Instrumental gain, impulsitivity and level of affective arousal were coded for the entire sample of the homicides, 19 of them were dual coded for a reliability check (p. 439)".

According to Woodworth and Porter (2002), the results for the PCL-R scores determined that 91 offenders scored below the cut-off score of less than 30 and were classified as nonpsychopaths, whereas 34 offenders scored within the psychopathic range.

The interrater reliability for homicide coding was done and tested highly reliable both times. The results of the relationship between psychopathy and homicide offense were as follows:

Overall, 45 homicides were purely instrumental, 25 were

instrumental/reactive, 29 were reactive instrumental, 16 were

purely reactive, and 10 could not be coded. Possible differences

in the violence committed by the psychopathic and nonpsychopathic

groups were examined... Specifically,