Factor Structure of the Self-Report Psychopathy Scale: Two and Three factor solutions Kevin Williams, Craig Nathanson, & Delroy Paulhus Department of Psychology University of British Columbia Poster presented at the 2002 meeting of the Canadian Psychological Association, Vancouver, BC
ABSTRACT We investigated the factor structure and predictive validity of a self-report measure of psychopathy (SRP-II; Hare, 1985). Data from an undergraduate sample (N = 356) were used to compare a two-factor (Harpur, Hakstian, & Hare, 1988) and three-factor (Cooke & Michie, 2001) structure of sub-clinical psychopathy. Results showed that, although both two and three-factors solutions were viable, the three-factor solution may be more useful for predictive purposes. The two-factor solution replicated an earlier analysis with Anti-social Behavior and Cold Affect factors. In the three-factor solution, the second factor decomposed into Deficient Affect and Interpersonal Callousness. The three-factor solution clarified the relation between psychopathy and delinquency in that Anti-social Behavior and Interpersonal Callousness predicted delinquency, but Deficient Affect (i.e., low anxiety), did not.
INTRODUCTION Recently the personality structure underlying the dark and dangerous mind of the psychopath has been the source of some debate. Conceptual and empirical work by Hare (1980; 1985) distinguished two factors inherent to psychopathy: one behavioural and one personality-based. More specifically, the two factors were interpreted as antisocial behaviour and low emotionality (Harpur, Hakstian, & Hare, 1988). These factors are now scored separately in the standard interview measure of psychopathy, the Psychopathy Checklist (PCL-R; Hare, 1991). This two-factor structure has recently been challenged by a three-factor solution (Cooke & Michie, 2001) in which Hare s low emotionality factor is partitioned into two distinct factors. Cooke and Michie s three labels are impulsive and irresponsible behavioural style, arrogant and deceitful interpersonal style, and deficient affective response. The debate has not yet been resolved. Although psychopathy has been well examined in forensic populations, relatively little research has been performed with subclinical samples. Such research has been facilitated by the development of a self-report measure (SRP-II: Hare, 1985). The present study addressed the factor debate in a large subclinical sample. First, exploratory factor analyses were conducted to determine whether the two and three factor structures could be reproduced using (a) an undergraduate sample as opposed to an incarcerated sample, and (b) a self-report method as opposed to an interview method. Second, the factors derived from an empirical factor analysis of the data were used to predict
anonymous self-reports of delinquency to determine which solution might better predict delinquent behavior.
METHOD Participants. 356 students (133 male, 218 female, 5 no response) attending a second-year undergraduate psychology course at a major Canadian university participated in the study for bonus credits. Students were asked to take a questionnaire package to complete on their own time and return to class at a later date. To ensure anonymity, participants were instructed to not put any identifying information anywhere on the questionnaire sheets. Materials. An abbreviated 31-item version of the Self-Report Psychopathy Scale II (SRP-II), based on the work of Hare (1985), was used to measure psychopathy. Participants respond to items on a five-point scale (1 = disagree strongly, 5 = agree strongly), with each item designed to capture the behaviours, emotions and attitudes associated with psychopathy. Examples of items include Rules are made to be broken and It is sometimes fun to see how far you can push someone before they catch on. The self-report inventory used to measure delinquency contained 43 items based on the work of Elliot and Ageton (1980). The items describe various anti-social acts ranging from minor misbehaviours to felony crimes. Participants are asked to estimate how many times in the past five years they had committed each of the acts. Nine additional items ask subjects about personal information regarding various types of drug use (eg. alcohol, ecstasy, marijuana, etc.). Each item was then standardized.
RESULTS Factor analyses. Principal components factor analyses were conducted on the data, using a direct oblimin rotation. Results of the two-factor solution are displayed in Table 1. The first factor appears to represent Hare s (1991) antisocial behaviour component. Examples of strongly loading items include I get a kick out of conning someone and I have often done something dangerous just for the thrill of it. The second factor included items that assessed anxiety such as I often worry unnecessarily and I worry a lot about possible misfortunes. Psychopaths scored on the low end of this factor, revealing a general lack of anxiety or distress. This factor represents Hare s (1991) low emotionality factor. The correlation between the two factors was -.20. The three-factor solution is summarized in Table 2. Again, the first factor appeared to represent the antisocial and impulsive behaviour displayed by psychopaths. The strongest item loadings were I enjoy taking chances and I have often done something dangerous just for the thrill of it. This factor seems to represent the impulsive and irresponsible behavioural style factor of Cooke and Michie (2001). On the second factor, the three strongest item loadings were the same as those created by the second factor of the two factor solution and in the same order. These results appear to represent Cooke and Michie s (2001) Deficient Affective Response factor. The third factor emerging from the principal components analysis appeared to tap the interpersonal callousness of psychopaths. The strongest loadings belonged to the items Not hurting others feelings is important to me and When I do something wrong I feel guilty even though nobody else knows it, with a strong negative loading on the item I get a kick out of conning someone. Psychopaths scored in the negative direction
of this factor, providing evidence of their manipulative social conduct and general lack of empathy. This factor appears similar to the Arrogant and Deceitful interpersonal style factor of Cooke and Michie (2001) but for simplicity, we labeled it Interpersonal Callousness. The intercorrelations among the factors ranged from.00 to -.26. The same pattern was found in both genders. Predicting delinquency. Detailed results are provided in Table 3. A factor analysis of the delinquency data revealed a five-factor solution: The five factor scores were added to create an overall delinquency score. In order to avoid any artifactual inflation of correlations, two SRP-II items were removed from the analysis due to their similarity with delinquency items. With the two-factor psychopathy solution, the Antisocial Behaviour factor was a strong predictor of delinquency (r =.52, p <.01). In contrast, the Low Emotionality factor did not correlate significantly with delinquency (r =.10, n.s.). Predictions from the three-factor solution are reported in Table 4. The Anti- Social Behavior factor significantly predicted delinquency (r =.42, p <.01), as did the third factor, Interpersonal Callousness (r =.37, p <.01). However, the deficient affective response factor failed as a predictor (r =.01, n.s.). When total delinquency was regressed on the two-factor and three-factor subscales, the R 2 was.30 for both two- and three factor regressions.
DISCUSSION Both factor solutions of subclinical psychopathy proved interpretable. The twofactor solution effectively captured the behavioural component of normal psychopathy as well as the emotional deficits. For the most part, this solution concords with the twofactor conception behind the PCL-R (Hare, 1991). The three-factor solution also proved interpretable and appeared to support the work of Cooke and Michie (2001). These factors outperformed the two factors in predicting delinquency, in that one of Cooke and Michie s personality factors Interpersonal Callousness -- correlated significantly with delinquency. This finding helps clarify the personality component of psychopathy. However, neither of the intrapersonal coldness factors from their respective solutions correlated with delinquency. This finding likely reflects some characteristic of the sample used in the current study, rather than to the conceptualizations of psychopathy put forth by Hare (1991) and by Cooke and Michie (2001). It is likely that low levels of anxiety reflect different phenomena in the two samples. In a forensic sample, low anxiety likely distinguishes psychopaths from other offenders, while in a normal population, low anxiety may distinguish emotionally stable individuals from those with more general psychological distress. Thus it is not surprising that low anxiety does not correlate with delinquency in normal populations. Overall, these results highlight an important difference between hardcore psychopaths in correctional and clinical environments and their subclinical counterparts. Our conclusions have been supported in a recent replication of the above factor analytic results in a larger sample (N = 494). In another study, we have also confirmed the predictive validity of the SRP using objectively scored delinquency measures.
REFERENCES Cooke, D. J., & Michie, C. (2001). Refining the construct of psychopath: Towards a hierarchical model. Psychological Assessment, 13, 171-188. Elliott, D. S., & Ageton, S. S. (1980). Reconciling race and class differences in selfreported and official estimates of delinquency. American Sociological Review, 45, 95-110. Hare, R. D. (1980). A research scale for the assessment of psychopathy in criminal populations. Personality and Individual Differences, 1, 111-117. Hare, R. D. (1985). Comparison of procedures for the assessment of psychopathy. Journal of Consulting and Clinical Psychology, 53, 7-16. Hare, R. D. (1991). The Hare Psychopathy Checklist Revised (PCL-R). Toronto, ON: Multi-Health Systems. Harpur, T. J., Hakstian, A. R., & Hare, R. D. (1988). Factor structure of the Psychopathy Checklist. Journal of Consulting and Clinical Psychology, 56, 741-747.
Table 1. SRP-II principal components analysis: Two-factor solution. Item Loading Factor 1 Factor 2 I get a kick out of conning someone..659.147 I have often done something dangerous just for the thrill of it..614 -.004 I enjoy gambling for large stakes..571.005 I prefer having many sexual partners rather than just one..570.105 I often worry unnecessarily..008.785 I worry a lot about possible misfortunes..124.720 Sometimes at night I get so worried about something that my heart pounds and I can t fall asleep..106.718 Note. Components extracted using a direct oblimin rotation. The intercorrelations of the factors was -.20. Items that loaded at least.500 on one factor are displayed.
Table 2. SRP-II principal components analysis: Three-factor solution. Item Loading Factor 1 Factor 2 Factor 3 I enjoy taking chances..707 -.009.173 I have often done something dangerous just for the thrill of it. I would be good at a dangerous job because I like making fast decisions..630.004.001.625 -.225.155 I enjoy drinking and doing wild things..569.008.010 I often worry unnecessarily. (r).006.789.133 I worry a lot about possible misfortunes. (r).007.722.007 Sometimes at night I get so worried about something that my heart pounds and I can t fall asleep. (r).002.707.002 Not hurting others feelings is important to me. (r).010.147.609 When I do something wrong, I feel guilty even though nobody else knows it. (r) -.003.317.607 I get a kick out of conning someone..005.150 -.528 Note. Components extracted using a direct oblimin rotation. Correlations between factors ranged from.00 to -.26. Only items that loaded at least.500 on one factor are displayed.
Table 3. Correlations between two psychopathy factors and delinquency factors. Two-factor solution Delinquency factors SRP total Antisocial score Behaviour Low emotionality Serious/ violent.14.25.02 crime Alcohol/drugrelated.23.34.20 crime Minor theft/.30.39.02 cheating Bullying.29.40.04 Anti-authority.17.16.03 Overall delinquency.38.52.10 Note. N = 287. All correlations above.12 are significant at p <.05, and all correlations above.15 are significant at p <.01, two-tailed. Table 4. Correlations between three psychopathy factors and delinquency factors. Delinquency factors SRP total score Impulsive and irresponsible behavioural style Three-factor solution Deficient affective response Arrogant and deceitful interpersonal style Serious/ violent.14.16 -.02.22 crime Alcohol/drugrelated.23.34.12.22 crime Minor theft/.30.30 -.05.30 cheating Bullying.29.28 -.02.34 Anti-authority.17.15 -.01.11 Overall delinquency.38.42.01.40 Note. N = 287. All correlations above.12 are significant at p <.05, and all correlations above.15 are significant at p <.01, two-tailed.