Review: An Empirical Investigation of Psychopathy in a Noninstitutionalized and NonCriminal Sample by Christine Chen
Many studies have been conducted on psychopaths found in jail but little is known about noninstitutionalized psychopaths. The little data that is available comes mainly from studies conducted on the student population. David DeMatteo and his group document their attempt at contributing to the scant reservoir of information available on psychopaths in the general population in “An Empirical Investigation of Psychopathy in a Noninstitutionalized and Noncriminal Sample”, a paper published in the journal Behavioral Sciences and the Law. However, their attempt proves to be useless as the experimental design limits the generalizations that they can make.
The purpose of this study was to use the PCL-R test, which is used for the identification of psychopaths, on subjects gathered from the general population and to compare these results with those obtained from incarcerated psychopaths. DeMatteo hypothesized that the noninstitutionalized sample, or those with no criminal record, would have lower overall PCL-R scores and higher factor one scores in comparison with incarcerated psychopaths. After the PCL-R test was conducted on the sample, a t-test was done and comparisons were made between the data gathered and those obtained from conducting the PCL-R test on incarcerated psychopaths. During analysis of these results, DeMatteo factored in the backgrounds and criminal history of the test subjects and concluded that high factor one scores, which are related to personality, may provide an explanation for the lack of criminal record for noninstitutionalized test subjects despite their elevated overall PCL-R scores. Because the PCL-R scores for subjects in the High Psychopathic Group were similar to those in the institutionalized sample, DeMatteo also concluded that these participants are more likely to commit a crime. While his hypotheses were supported by the results, some of the claims that DeMatteo made are not.
The correlation between high factor one scores and the lack of a criminal record is unsupported. DeMatteo made this claim because the factor one scores for the noncriminal group were higher than their factor two scores, which determine the extent to which one’s behavior rather than personality matches that of a psychopath’s. However, the data is inadequate in supporting the conclusion because there are many flaws in the design of the experiment. These include: a small sample size, the exclusion of females, the lack of incentive for participation, and a restricted location. These factors can all affect the outcome of the experiment.
Another claim that DeMatteo made is that the participants who were part of the high psychopathic group are more likely to commit a crime due to their high total PCL-R scores. As aforementioned, DeMatteo attributed part of the sample’s lack of criminal record to their high factor one scores; yet, in assessing the chances of these participants posing a danger to society, he compared their total PCL-R scores. Although their total PCL-R scores were elevated, their factor one scores were higher than their factor two scores. Even though it is not supported, according to DeMatteo’s previous conclusion, this would mean these participants’ psychopathic qualities are exhibited more strongly in their personalities rather than their behaviors, a contradiction to his conclusion regarding the participants’ risk of committing a crime.
The findings in the study provide insight on psychopaths in the general population; however, the flaws in the experiment overshadow what new data the study can contribute. Although the results generated are limited in its usefulness for making generalizations, this study provides impetus for the continued research on noninstitutionalized psychopaths.
References
DeMatteo, D., Heilbrun, K. and Marczyk, G. (2006), An empirical investigation of psychopathy
in a noninstitutionalized and noncriminal sample. Behav. Sci. Law, 24: 133–146. doi: 10.1002/bsl.667
