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Remembering details of emotional events: A comparison between psychopathic and nonpsychopathic offenders
Pergamon 0191-8869(95)00220-O
Person. indiuid. DijjJ Vol. 20, No. 4, pp. 43743, 1996 Copyright 0 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0191-8869/96
$15.00+0.00
REMEMBERING DETAILS OF EMOTIONAL EVENTS: A COMPARISON BETWEEN PSYCHOPATHIC AND NONPSYCHOPATHIC OFFENDERS Sven-Ake Christianson,‘* Adelle E. Forth,’ Robert D. Hare,3 Catherine Strachaq3 Lars Lidberg and Lars-Hakan ThorelP ‘Department of Psychology, University of Stockholm, Stockholm, S-10691, Sweden, ‘Department of Psychology, Carleton University, Ottawa, Ontario, Canada KIS 5B6, ‘University of British Columbia, Vancouver, British Columbia, Canada V6T lW5, 4Karolinska Institute, Solnavlgen 1, P.O. Box 60400, Stockholm, 10401, Sweden and ‘University of Linkdping, Linkiiping, Sweden (Receioed 1 August 1995) Summary-Recent research indicates that recall of the central details of a negative emotional event is better than is recall for peripheral details. We predicted that psychopaths-because of their difficulty in processing emotional information-would not show this narrowing of attention for negative events. Criminal psychopaths and nonpsychopaths, defined by the Hare Revised Psychopathy Checklist (PCL-R; Hare, 1991), were shown a series of 15 color slides. The content of the eighth (critical) slide was either emotional or neutral; in each case the critical slide contained a central detail (the color of a woman’s coat) and a peripheral detail (the color of a car in the background). There were no group differences in recall of the details of the neutral slide; in each case, the central and peripheral details were recalled equally well. The nonpsychopaths recalled the central detail of the emotional slide far better than they did the peripheral detail; that is, they showed the expected narrowing of attention with negative emotion. The psychopaths, on the other hand, failed to show this effect; their recall of the central and peripheral details was the same for the emotional slide as it was for the neutral slide. The results provide further support for the hypothesis that psychopaths have difficulty in processing emotional information.
INTRODUCTION
The clinical proposition that psychopaths generally fail to experience or appreciate the emotional significance of events (see Cleckley, 1976; Hare, 1991; McCord & McCord, 1964) is strongly supported by empirical research. Although most of this research has been concerned with the autonomic correlates of psychopathy (e.g. Hare, 1978; Larbig et al., 1992; Lykken, 1957; Ogloff & Wong, 1990; Raine & Venables, 1988) several investigators have recently broadened the research base on psychopathy and emotion by adapting procedures and variables from cognitive science and psycholinguistics. As the summary below indicates, the results of these integrations of conceptual and research domains have been remarkably consistent. Williamson et al. (1991) recorded event-related brain potentials (ERPs) and reaction-times (RTs) while Ss performed a lexical decision task with neutral and emotional words. Nonpsychopaths showed the similar ERP and RT differentiation between neutral and emotional words as found with noncriminals, whereas psychopaths did not. In another study, Williamson et al. (1991) had Ss group words and verbal descriptions of situations on the basis of emotional similarity. They found that psychopaths had difficulty in differentiating between negative and positive affect. The results of these studies suggest that psychopaths make little use of the connotative aspects of meaning. Day and Wong (1993) used a divided-visual field paradigm to present pairs of neutral and negative emotional words, one member of the pair to the S’s left visual field (right hemisphere) and the other member to his right visual field (left hemisphere). As predicted (on the basis of findings with noncriminals) nonpsychopaths performed the task better (lower error rates and shorter RTs) when the emotional member of the pair was directed to their right hemisphere than when it was directed to the left hemisphere. Psychopaths failed to show this pattern of responses, leading the authors to conclude that the right hemispheres of psychopaths have difficulty in processing emotional material.
*To whom all correspondence
should be addressed.
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Although each of the studies described above involved linguistic processing, the results of several studies suggest that psychopathy is characterized by more general difficulties in experiencing affect. For example, Patrick et al. (1993) found that, psychopaths failed to show the potentiation of the startle blink reflex during exposure to unpleasant visual stimuli that is commonly found with nonpsychopaths. Larbig et al. (1992) found that the slow cortical potentials in the frontal regions of the brain associated with anticipation of an aversive stimulus were smaller in psychopaths than in nonpsychopaths, a finding that is consistent with the hypothesis (Hare, 1978) that psychopaths are relatively unaffected by threats of pain or punishment. Finally, several studies have found that the emotional experiences of psychopaths do not appear to be as intense as are those of nonpsychopaths (Day & Wong, 1993; Williamson et al., 1991). The present study extends research on psychopathy and affect to the investigation of memory for emotional events. Recent research on both adults and children has shown that central details of negative emotional events (i.e. information that is connected with the source of emotional arousal) are better retained than are peripheral details (i.e. information preceding and succeeding emotional events, or that is irrelevant or spatially peripheral information within an emotional scenario; see Christianson, 1992; Goodman et al., 1991, for reviews). There are several possible explanations_ for this pattern of enhanced memory for central detail and reduced memory for peripheral detail. One plausible explanation concerns attention, which may be qualitatively different for emotional vs nonemotional events. It is possible that any unusual or distinctive event which captures attention would facilitate memory for details of that event. It is also possible that an attention-catching event is associated with more elaborate processing of the information to which the individual attends (cf. Craik & Blankstein, 1975). For example, compared to watching a neutral eye-catching event, witnesses to an emotion-provoking event, such as an accident or a crime, might be more concerned with what they have just seen. Ss may think about and react with empathy to the emotion-provoking information. For example, Ss may react to the injuries of a female victim by imaging her to be a helpless victim who needs assistance. This process of elaboration will imply a psychological focusing on those critical details which are the source of the emotional stress reaction, and at the same time limit access to the information in the mental periphery (see Christianson & Safer, 1995). In cases of very strong emotional reactions, the individual may be occupied by intrusive thoughts about the emotion-provoking event. Thus, while a distinctive and unusual event, may enhance memory for event information in a general way, emotional reactions to certain emotion-provoking information of the event may further induce a differential processing of details of that event. This latter mode of processing would promote memory for central detail information, but actively inhibit processing of peripheral details, that is, details that are irrelevant and/or spatially peripheral to the emotion-eliciting event or the source of emotional arousal (cf. Christianson et al., 1991). It is also possible that the emotional reaction itself acts as a cue for the emotion-provoking information in a specific event. That is, feelings of disgust, fear, or some other negative emotional reaction, will cue the individual that something very negative is happening in the stimulus event. Neutral details, or emotional details which are experienced as neutral will not elicit feelings which are intrinsically related to certain critical details of the to-be-remembered event. In the present study, criminal psychopaths and nonpsychopaths were shown a series of slides in which the content of one (critical) slide was either neutral or emotional. Given that psychopaths appear to have difficulty in processing affective information, we predicted that they would engage in less elaborate processing of the details of the emotional slide, and therefore would not show enhanced memory for central details of an emotional event as compared with details of a nonemotional event.
METHOD
Participants Participants were 62 male inmates of a federal medium-security correctional institution near Vancouver, Canada. Each inmate volunteered to be interviewed and tested, gave his informed consent, and provided written permission for his institutional files to be inspected. He was paid $5
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for his participation in the study. The research was approved by the university and institutional ethics review boards and by the inmate committee. File and interview information were used to complete the PCL-R (Hare, 1991). The PCL-R is a 20-item symptom checklist that measures the personality traits and behaviors characteristic of the psychopath. Each item is scored on a 3-point scale according to the extent to which it applies to the inmate. Item scores were summed to yield a total score that can range from 0 to 40. There is a large body of evidence attesting to the reliability and validity of the PCL-R in use with forensic populations (Hare, 1991; Hare et al., 1990; Hart et al., 1992; Kosson et al., 1990). To assess interrater reliability, two raters independently completed the PCL-R on 32% The Spearman-Brown intraclass correlation coefficient of reliability (Bartko, 1976) for these ratings was 0.92. The mean PCL-R score was 26.92 (SD = 7.1 l), a value slightly (about 3 points) higher than that typically obtained with male offenders (Hare, 1991). In accordance with previous research the sample was divided into 25 psychopaths (PCL-R score 30 or greater) and 37 nonpsychopaths (PCLR score less than 30). The mean PCL-R score for the psychopaths and nonpsychopaths was 33.1 (SD =2.66) and 22.8 (SD= 6.05) respectively. Psychopaths and nonpsychopaths did not differ significantly in age (M=28.9 and 28.8 yr, respectively) or formal education (M=8.0 and 8.9 yr, respectively). The racial composition of the sample was 84 % White, 10 % Native American Indian, and 6 % other. Stimulus materials The stimulus materials consisted of a thematic series of 15 color slides. Slides ll7 and 9- 15 depicted everyday scenes of what a person might see while leaving home to go to work (e.g. a kitchen table, a bus stop, a pedestrian on a sidewalk). There were two versions of the eighth (critical) slide. In the neutral condition, the critical slide depicted a woman bicycling on the street in front of a car; a second car was in the background driving in the opposite direction. In the emotional condition, the critical slide depicted the woman lying beside her bicycle (bleeding from a head injury) on the street in front of the car; the same second car could be seen driving in the background. The noncritical slides were the same regardless of whether the critical slide was neutral or emotional. (For a more detailed description of the stimulus slides used in this experiment see Christianson & Loftus, 1991). Procedure Within groups, offenders were randomly assigned to the neutral condition (13 psychopaths, 19 nonpsychopaths) or the emotional condition (12 psychopaths, 18 nonpsychopaths). Offenders were tested individually by a female experimenter in a quiet research room at the prison. Each participant was seated 3 m in front of a screen and instructed to pay close attention to the slides to be presented. He was not told about the content of the slides or about the forthcoming memory test. Each slide was projected on to the screen for 3 set, with a 2 second inter-slide interval. Image size was 63 x 96cm. Immediately after the slide presentation, the S was asked to give a global rating of the pictures along the dimension of pleasantness-unpleasantness (1 =very pleasant, 7 =very unpleasant). The S was also asked to identify the most emotion-provoking slide and to rate his feelings about this slide on a 1 l-point scale (1 = very pleasant, 6 = neutral, 1 1 = very unpleasant). For the next 5 min he performed a filler task in which he had to copy as precisely as possible five figures, each presented for 60sec. Following the filler task, the S was asked nine questions. For the first five questions the S was shown the critical slide, but with the portion that depicted the woman, bicycle, and the distant car obscured by a darkened field. Question 1: ‘What color was the woman’s coat’? Question 2: ‘What color was the car in the far background?’ Questions 3-5 asked if the following objects had been seen: No. 3 (dog); No. 4 (motorcycle); No. 5 (couple). Question 6: ‘How many slides did you see in the original series?’ Question 7: ‘How long did the entire slide sequence last?’ Question 8: ‘What was the object on the table in the first slide you saw?’ Question 9: ‘What was the object on the table in the last slide you saw?’ These questions were followed by a four-alternative-forced-choice test of five slides from the series: 1, 7, 8 (critical), 9, and 15. Each recognition slide consisted of four simultaneously presented alternatives, one being identical to the slide shown in the study phase. The other three alternatives
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L
70
E -
60
8 E
50
8 e,
40
p
30
et al.
20
10 ” Nonpsychopaths
Noncriminals
Psychopaths
Group Fig. 1. Percentages of Ss who correctly recalled the central or the peripheral detail information of the critical picture in the emotional condition. For comparison purposes, data for noncriminals (78 students; Christianson & Loftus, 1991) are included.
were pictures that depicted the same event but varied with respect to either the central detail, the peripheral detail, or both the central and peripheral details. Each recognition test slide was exposed for 25 set; and the participants were instructed to select the picture they had seen earlier by marking an X in the corresponding box on an answer sheet. The position of the target picture of each test slide was random. Finally, the participant was asked to describe the slide he found to be the most attention-catching and the one that was easiest to remember. RESULTS Recall data Figures 1 and 2 depict the percentage of participants in each group who correctly recalled the central (the color of the woman’s clothing) and peripheral (the color of the car driving in the background) information for the emotional and neutral condition, respectively. For comparison purposes, data from a sample of 78 college students (Christianson & Loftus, 1991) are included in the figures; these data were not included in the statistical analyses described below. A x2 analysis conducted on the central detail indicated that the overall difference between groups and conditions was not significant. However, the response pattern of the nonpsychopaths was similar to that typically found with noncriminals (see Fig. 1); that is, they tended to recall the central information better in the emotional condition than the peripheral detail. The psychopaths, on the other hand, failed to show this pattern of responses. A x2 analysis conducted on the peripheral data indicated that the overall difference between
E 040 2
tm 20 10 n Nonpsychopaths
Noncriminals
Group Fig. 2. Percentages of Ss who correctly recalled the central or the peripheral detail information of the critical picture in the neutral condition. For comparison purposes, data for noncriminals (78 students; Christianson & Loftus, 1991) are included.
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Remembering details of emotional events Table 1. Percentages of nonpsychopaths and psychopaths who correctly recognized both the central and the peripheral detail information or who recognized either the central or peripheral detail information from an emotional or a neutral event Nonpsychopaths Detail Information Central and peripheral Central Peripheral
Psychopaths
Emotional
Neutral
Emotional
Neutral
22.2 61.1 44.4
52.6 68.4 84.2
50.0 56.7 56.7
53.8 69.2 69.2
groups and conditions was significant, x2 (3)= 8.00, P~0.05. To determine which cell made the major contribution to the significant x2, we analyzed the standardized residual for each cell (Haberman, 1973). The results of these analyzes indicated that the major contributor to the significant x2 was the nonpsychopath-emotional cell (R=2.63). That is, the relatively poor recall of the nonpsychopaths in the emotional condition. As with the recall of central details, the pattern shown by the nonpsychopaths was much the same as that shown by noncriminals.* Recognition data The recognition data for the critical slide is presented in Table 1. A comparison of the proportion of participants who correctly recognized the central information, the peripheral information, or both the central and the peripheral information in slides 1, 7, 8 (the critical slide), 9, and 15, suggested only marginal differences between groups. In line with the recall data, the nonpsychopathemotional group was inferior to the other groups in recognizing peripheral information of the critical slide, otherwise there were no reliable effects between groups and conditions. x2 comparisons conducted on these sets of data did not reveal any significant differences between groups. Mean percentages recall of miscellaneous information in the series of slides, such as questions asked about different objects in the critical slide (i.e. dog, motorcycle, couple), objects in the first and in the last slide in the series, and the number of slides, are presented in Table 2. The values in this table indicate a similar recall performance for psychopaths and nonpsychopaths to all the questions. Affective ratings A group (psychopaths vs nonpsychopaths) by type of event (emotional vs neutral) analysis of variance (ANOVA) was performed on the rated pleasantness-unpleasantness (7-point scale) of the two series of slides. Neither the main effect for groups nor the group x condition interaction was significant. Both groups rated the emotional series of slides as more unpleasant (M=4.33) than the neutral series (M=3.85), F(l,58)=6.01, P~0.05. Most offenders (83.3 % of the psychopaths and 88.9 % of the nonpsychopaths) selected the critical 8th slide as the most emotion-provoking slide in the emotional series. This slide was selected as the most attention-catching slide by 75 % of the psychopaths and 83.3 % of the nonpsychopaths, Table 2. Percentages of nonpsychopaths and psychopaths who were correct about various detail information in the series of slides
Questions Did you see a dog? Did you see a motorcyle? Did you see a couple? Object in the first slide? Object in the last slide? Number of slides?
Nonpsychopaths
Psychopaths
91.3 78.4 100.0 64.9 59.6 13.5
92.0 92.0 92.0 64.0 32.0 8.0
*Two independent raters used interview and file information to assess 43 inmates for Antisocial Personality Disorder (APD), using the DSM-III-R criteria (American Psychiatric Association, 1987). The interrater reliability (K) for presence (both raters) or absence of the diagnoses was 0.74. Using this procedure, 31 Ss, (72.1 %) met the criteria for APD. Reanalysis of the memory data failed to reveal any significant differences between offenders who met the criteria for APD and those who did not.
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and as the easiest slide to remember by 83.3 % and 66.7 % of the psychopaths and the nonpsychopaths, respectively. There were no group differences in the pleasantness-unpleasantness rating of the slide (1 l-point scale) in each series perceived as the most emotionally provoking. Both groups rated the selected slide in the emotional series to be more unpleasant (M= 8.13) than the selected slide in the neutral series (M=5.68), F(1,57)=25.24, P
DISCUSSION
Noncriminals recall equally well the central and peripheral details of a neutral event, but they recall the central details of a negative emotional event much better than they do the peripheral details (see Christianson, 1984; Christianson & Loftus, 1987, 199 l), This psychological focusing on certain detail information of negative events was exhibited by the nonpsychopaths in the present study, but not by the psychopaths. The latter group recalled equally well the central and peripheral details of both the neutral and the emotional slide. These results are consistent with the findings of other studies (e.g. Day & Wong, 1993; Larbig et al., 1992; Williamson et al., in preparation) and suggest a lack of differential processing of emotional information in psychopaths. The affective coloring that ordinarily serves to differentiate emotional from neutral events apparently does not exist to the same degree in psychopaths as it does in other individuals. In this sense, psychopaths probably find most events affectively neutral. Even so, it is interesting that their ratings of the affective nature of the stimuli used in this study were much the same as those made by the nonpsychopaths. Similar discrepancies between psychopaths’ verbal/rated affect and their performance on affective tasks have been observed in several other studies (e.g. Forth, 1992; Patrick et al., 1993; Williamson et al., 1990,199l). Apparently, psychopaths are able to use emotional descriptors for subjective states they do not actually experience as emotional, at least not in the same sense as other individuals do. As (Cleckley, 1976, p. 230) put it, they “can learn to use ordinary words . [and] will also learn to reproduce appropriately all the pantomime of feeling.. . but the feeling itself does not come to pass.” We note that the two groups of offenders did not recall the central detail of the emotional slide quite as well as did the noncriminals. It is possible that the emotional slide had less impact on the offenders than it typically does on noncriminals. More generally, it is likely that emotional reactions to the injury of others are more difficult to elicit from offenders (most of whom have had frequent exposure to violence) than from the general population. The self-reports of the offenders support this suggestion; they considered the slides to be less emotion-provoking than do noncriminals (Christianson & Loftus, 1991). In spite of this, the present task was able to differentiate-in a theoretically meaningful way-between psychopathic and other offenders. A limitation of this study is that it used a laboratory task. As yet, we do not know if psychopaths fail to focus on the central details of a real-life emotional event. However, we might speculate that such an event would have far greater impact on nonpsychopaths than on psychopaths, and that the differences between them would be accentuated. Finally, much of the empirical research on affective processing in psychopaths has focused on negative or aversive stimuli. It is possible that their memory for central and peripheral detail would be more like that of normals if the events involved positive emotional states (cf. Newman et al., 1991; Newman & Wallace, 1993). Ackwoi~/edgenzenIs_This research was supported by grant F. 35887 from The National Council for Crime Prevention, Sweden. to Sven-Ake Christianson, and by grant MT-451 1 from the Medical Research Council of Canada to Robert D. Hare. We are grateful to the staff and inmates of Matsqui Institution for their cooperation and participation. We would also like to thank Susan Nurse and Cathy Lewis for assisting with diagnostic assessments and experimental testing.
REFERENCES American Psychiatric Association (1987). Diagnostic and statistical manual of mental disorders (rev. 3rd edn). Washington, DC: APA. Bartko, J. J. (1976). On various intraclass correlation reliability coefficients. Psychological Bulletin, 83, 762-765. Christianson, S.-A. (1984). The relationship between induced emotional arousal and amnesia. Scandinavian Journal of Psychology, 25, 147-160.
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Christianson, S.-A. (1992). Emotional stress and eyewitness memory: A critical review. Psychological Bulletin, 112,284309. Christianson, S.-A. & Loftus, E. F. (1987). Memory for traumatic events. Applied Cognitive Psychology, 1,225-239. Christianson, S.-A. & Loftus, E. F. (1991). Remembering emotional events: The fate of detailed information. Cognition and Emotion, 5, 81-108. Christianson, S-A., Loftus, E. F., Hoffman, H. & Loftus, G. R. (1991). Eye fixations and memory for emotional events. Journal of Experimental Psychology: Learning, Memory, and Cog&ion, 17, 693-70 I Christianson, S.-A. & Safer, M. A. (1996). Emotional events and emotions in autobiographical memories. In Rubin, D. C. (Ed.). Remembering our past: Studies in autobiographical memory. Cambridge: Cambridge University Press. Cleckley, H. (1976). The mask ofsanity (5th edn). St Louis, MO: Mosby. Craik, F. & Blankstein, K. (1975). Psychophysiology and human memory. In Venables, P. H. & Christie, M. J. (Eds), Research in psychophysiology (pp. 389417). London: Wiley. Day, R. & Wang, S. (1993). Psychopaths process emotional words in their left hemispheres. Unpublished manuscript. Forth, A. E. (1992). Emotion and psychopathy: A three-component analysis. Unpublished doctoral dissertation, University of British Columbia, Vancouver. Goodman, G. G., Hirschman, J. E., Hepps, D. H. & Rudy, L. (1991). Children’s memory for stressful events. Merrill Palmer Quarterly, 37, 109-158. Haberman, S. J. (1973). The analysis of residuals in cross-classified tables. Biometrics, 29, 205-220. Hare, R. D. (1978). Electrodermal and cardiovascular correlates of psychopathy. In Hare, R. D. & Schalling, D. (Eds), Psychopathic behavior: Approaches to research (pp. 1077143). New York: Wiley. Hare, R. D. (1991). The Hare Psychopathy Checklist-Revised /PCL-R). Toronto, Ontario: Multi-Health Systems. Hare, R., Harpur, T. J., Hakstian, A. R., Forth, A. E., Hart, S. D. & Newman, J. P. (1990). The Revised Psychopathy Checklist: Reliability and factor structure. Psychological Assessment A Journal of Consulting and Clinical Psychology. 2. 338-341. Hart, S. D., Hare, R. D. & Harpur, T. J. (1992). The Psychopathy Checklist: An overview for researchers and clinicians. In McReynolds, I?. & Rosen, J. (Eds), Advances in psychological assessment (Vol. 8, pp. 1033129). New York: Plenum Press. Kosson, D. S., Smith, S. S. & Newman, J. P. (1990). Evaluating the construct validity of psychopathy on Black and White male inmates: Three preliminary studies. Journal of Abnormal Psychology, 99, 250-259. Larbig, W., Veit, R., Rau, H., Schlottke, P. & Birbaumer, N. (1992). Cerebral and peripheral correlates in psychopaths during anticipation of aversive stimulation, Paper presented at the meeting of the Society for Psychophysiological Research, San Diego. Lykken, D. T. (1957). A study of anxiety in the sociopathic personality. Journal of Abnormal and Social PsJ’chology, 55, b 10. McCord, W. & McCord, J. (1964). The psychopath: An essay ONrhe criminal mind. Princeton, NJ: Van Nostrand. Newman, J. P. & Wallace, J. F. (1993). Psychopathy and cognition. In Kendall, P. & Dobson, K. (Eds), Psychopathology and cognition (pp. 293-349) New York: Academic Press. Newman, J. P., Patterson, C. M., Howland, E. W. & Nichols, S. L. (1991). Passive avoidance learning in psychopaths: The effects of reward. Personality and lndiuidual Differences, 11, 1101-l 114. Ogloff, J. & Wang, S. (1990). Electrodermal and cardiovascular evidence of a coping response in psychopaths. Criminal Justice and Behacior, 17, 23 l-245. Patrick, C. J., Bradley, M. M. & Lang, P. J. (1993). Emotions in the criminal psychopath: Startle reflex modulation. Journal of AbnormalPsychology, 102, 82-92. Raine, A. & Venables, P. H. (1988). Skin conductance responsivity in psychopaths to orienting, defensive, and consonantvowel stimuli. Journal of Psychoph.vsiology, 2. 221-225. Williamson, S., Harpur, T. J. & Hare, R. D. (1990, August). Sensitivity to emotional polarity in psychopaths. Paper presented at the meeting of the American Psychological Association, Boston. Williamson, S., Harpur, T. J. & Hare, R. D. (1991). Abnormal processing of affective words by psychopaths. Psychophysiology, 28, 260-273.
Person. indiuid. DijjJ Vol. 20, No. 4, pp. 43743, 1996 Copyright 0 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0191-8869/96
$15.00+0.00
REMEMBERING DETAILS OF EMOTIONAL EVENTS: A COMPARISON BETWEEN PSYCHOPATHIC AND NONPSYCHOPATHIC OFFENDERS Sven-Ake Christianson,‘* Adelle E. Forth,’ Robert D. Hare,3 Catherine Strachaq3 Lars Lidberg and Lars-Hakan ThorelP ‘Department of Psychology, University of Stockholm, Stockholm, S-10691, Sweden, ‘Department of Psychology, Carleton University, Ottawa, Ontario, Canada KIS 5B6, ‘University of British Columbia, Vancouver, British Columbia, Canada V6T lW5, 4Karolinska Institute, Solnavlgen 1, P.O. Box 60400, Stockholm, 10401, Sweden and ‘University of Linkdping, Linkiiping, Sweden (Receioed 1 August 1995) Summary-Recent research indicates that recall of the central details of a negative emotional event is better than is recall for peripheral details. We predicted that psychopaths-because of their difficulty in processing emotional information-would not show this narrowing of attention for negative events. Criminal psychopaths and nonpsychopaths, defined by the Hare Revised Psychopathy Checklist (PCL-R; Hare, 1991), were shown a series of 15 color slides. The content of the eighth (critical) slide was either emotional or neutral; in each case the critical slide contained a central detail (the color of a woman’s coat) and a peripheral detail (the color of a car in the background). There were no group differences in recall of the details of the neutral slide; in each case, the central and peripheral details were recalled equally well. The nonpsychopaths recalled the central detail of the emotional slide far better than they did the peripheral detail; that is, they showed the expected narrowing of attention with negative emotion. The psychopaths, on the other hand, failed to show this effect; their recall of the central and peripheral details was the same for the emotional slide as it was for the neutral slide. The results provide further support for the hypothesis that psychopaths have difficulty in processing emotional information.
INTRODUCTION
The clinical proposition that psychopaths generally fail to experience or appreciate the emotional significance of events (see Cleckley, 1976; Hare, 1991; McCord & McCord, 1964) is strongly supported by empirical research. Although most of this research has been concerned with the autonomic correlates of psychopathy (e.g. Hare, 1978; Larbig et al., 1992; Lykken, 1957; Ogloff & Wong, 1990; Raine & Venables, 1988) several investigators have recently broadened the research base on psychopathy and emotion by adapting procedures and variables from cognitive science and psycholinguistics. As the summary below indicates, the results of these integrations of conceptual and research domains have been remarkably consistent. Williamson et al. (1991) recorded event-related brain potentials (ERPs) and reaction-times (RTs) while Ss performed a lexical decision task with neutral and emotional words. Nonpsychopaths showed the similar ERP and RT differentiation between neutral and emotional words as found with noncriminals, whereas psychopaths did not. In another study, Williamson et al. (1991) had Ss group words and verbal descriptions of situations on the basis of emotional similarity. They found that psychopaths had difficulty in differentiating between negative and positive affect. The results of these studies suggest that psychopaths make little use of the connotative aspects of meaning. Day and Wong (1993) used a divided-visual field paradigm to present pairs of neutral and negative emotional words, one member of the pair to the S’s left visual field (right hemisphere) and the other member to his right visual field (left hemisphere). As predicted (on the basis of findings with noncriminals) nonpsychopaths performed the task better (lower error rates and shorter RTs) when the emotional member of the pair was directed to their right hemisphere than when it was directed to the left hemisphere. Psychopaths failed to show this pattern of responses, leading the authors to conclude that the right hemispheres of psychopaths have difficulty in processing emotional material.
*To whom all correspondence
should be addressed.
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Although each of the studies described above involved linguistic processing, the results of several studies suggest that psychopathy is characterized by more general difficulties in experiencing affect. For example, Patrick et al. (1993) found that, psychopaths failed to show the potentiation of the startle blink reflex during exposure to unpleasant visual stimuli that is commonly found with nonpsychopaths. Larbig et al. (1992) found that the slow cortical potentials in the frontal regions of the brain associated with anticipation of an aversive stimulus were smaller in psychopaths than in nonpsychopaths, a finding that is consistent with the hypothesis (Hare, 1978) that psychopaths are relatively unaffected by threats of pain or punishment. Finally, several studies have found that the emotional experiences of psychopaths do not appear to be as intense as are those of nonpsychopaths (Day & Wong, 1993; Williamson et al., 1991). The present study extends research on psychopathy and affect to the investigation of memory for emotional events. Recent research on both adults and children has shown that central details of negative emotional events (i.e. information that is connected with the source of emotional arousal) are better retained than are peripheral details (i.e. information preceding and succeeding emotional events, or that is irrelevant or spatially peripheral information within an emotional scenario; see Christianson, 1992; Goodman et al., 1991, for reviews). There are several possible explanations_ for this pattern of enhanced memory for central detail and reduced memory for peripheral detail. One plausible explanation concerns attention, which may be qualitatively different for emotional vs nonemotional events. It is possible that any unusual or distinctive event which captures attention would facilitate memory for details of that event. It is also possible that an attention-catching event is associated with more elaborate processing of the information to which the individual attends (cf. Craik & Blankstein, 1975). For example, compared to watching a neutral eye-catching event, witnesses to an emotion-provoking event, such as an accident or a crime, might be more concerned with what they have just seen. Ss may think about and react with empathy to the emotion-provoking information. For example, Ss may react to the injuries of a female victim by imaging her to be a helpless victim who needs assistance. This process of elaboration will imply a psychological focusing on those critical details which are the source of the emotional stress reaction, and at the same time limit access to the information in the mental periphery (see Christianson & Safer, 1995). In cases of very strong emotional reactions, the individual may be occupied by intrusive thoughts about the emotion-provoking event. Thus, while a distinctive and unusual event, may enhance memory for event information in a general way, emotional reactions to certain emotion-provoking information of the event may further induce a differential processing of details of that event. This latter mode of processing would promote memory for central detail information, but actively inhibit processing of peripheral details, that is, details that are irrelevant and/or spatially peripheral to the emotion-eliciting event or the source of emotional arousal (cf. Christianson et al., 1991). It is also possible that the emotional reaction itself acts as a cue for the emotion-provoking information in a specific event. That is, feelings of disgust, fear, or some other negative emotional reaction, will cue the individual that something very negative is happening in the stimulus event. Neutral details, or emotional details which are experienced as neutral will not elicit feelings which are intrinsically related to certain critical details of the to-be-remembered event. In the present study, criminal psychopaths and nonpsychopaths were shown a series of slides in which the content of one (critical) slide was either neutral or emotional. Given that psychopaths appear to have difficulty in processing affective information, we predicted that they would engage in less elaborate processing of the details of the emotional slide, and therefore would not show enhanced memory for central details of an emotional event as compared with details of a nonemotional event.
METHOD
Participants Participants were 62 male inmates of a federal medium-security correctional institution near Vancouver, Canada. Each inmate volunteered to be interviewed and tested, gave his informed consent, and provided written permission for his institutional files to be inspected. He was paid $5
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for his participation in the study. The research was approved by the university and institutional ethics review boards and by the inmate committee. File and interview information were used to complete the PCL-R (Hare, 1991). The PCL-R is a 20-item symptom checklist that measures the personality traits and behaviors characteristic of the psychopath. Each item is scored on a 3-point scale according to the extent to which it applies to the inmate. Item scores were summed to yield a total score that can range from 0 to 40. There is a large body of evidence attesting to the reliability and validity of the PCL-R in use with forensic populations (Hare, 1991; Hare et al., 1990; Hart et al., 1992; Kosson et al., 1990). To assess interrater reliability, two raters independently completed the PCL-R on 32% The Spearman-Brown intraclass correlation coefficient of reliability (Bartko, 1976) for these ratings was 0.92. The mean PCL-R score was 26.92 (SD = 7.1 l), a value slightly (about 3 points) higher than that typically obtained with male offenders (Hare, 1991). In accordance with previous research the sample was divided into 25 psychopaths (PCL-R score 30 or greater) and 37 nonpsychopaths (PCLR score less than 30). The mean PCL-R score for the psychopaths and nonpsychopaths was 33.1 (SD =2.66) and 22.8 (SD= 6.05) respectively. Psychopaths and nonpsychopaths did not differ significantly in age (M=28.9 and 28.8 yr, respectively) or formal education (M=8.0 and 8.9 yr, respectively). The racial composition of the sample was 84 % White, 10 % Native American Indian, and 6 % other. Stimulus materials The stimulus materials consisted of a thematic series of 15 color slides. Slides ll7 and 9- 15 depicted everyday scenes of what a person might see while leaving home to go to work (e.g. a kitchen table, a bus stop, a pedestrian on a sidewalk). There were two versions of the eighth (critical) slide. In the neutral condition, the critical slide depicted a woman bicycling on the street in front of a car; a second car was in the background driving in the opposite direction. In the emotional condition, the critical slide depicted the woman lying beside her bicycle (bleeding from a head injury) on the street in front of the car; the same second car could be seen driving in the background. The noncritical slides were the same regardless of whether the critical slide was neutral or emotional. (For a more detailed description of the stimulus slides used in this experiment see Christianson & Loftus, 1991). Procedure Within groups, offenders were randomly assigned to the neutral condition (13 psychopaths, 19 nonpsychopaths) or the emotional condition (12 psychopaths, 18 nonpsychopaths). Offenders were tested individually by a female experimenter in a quiet research room at the prison. Each participant was seated 3 m in front of a screen and instructed to pay close attention to the slides to be presented. He was not told about the content of the slides or about the forthcoming memory test. Each slide was projected on to the screen for 3 set, with a 2 second inter-slide interval. Image size was 63 x 96cm. Immediately after the slide presentation, the S was asked to give a global rating of the pictures along the dimension of pleasantness-unpleasantness (1 =very pleasant, 7 =very unpleasant). The S was also asked to identify the most emotion-provoking slide and to rate his feelings about this slide on a 1 l-point scale (1 = very pleasant, 6 = neutral, 1 1 = very unpleasant). For the next 5 min he performed a filler task in which he had to copy as precisely as possible five figures, each presented for 60sec. Following the filler task, the S was asked nine questions. For the first five questions the S was shown the critical slide, but with the portion that depicted the woman, bicycle, and the distant car obscured by a darkened field. Question 1: ‘What color was the woman’s coat’? Question 2: ‘What color was the car in the far background?’ Questions 3-5 asked if the following objects had been seen: No. 3 (dog); No. 4 (motorcycle); No. 5 (couple). Question 6: ‘How many slides did you see in the original series?’ Question 7: ‘How long did the entire slide sequence last?’ Question 8: ‘What was the object on the table in the first slide you saw?’ Question 9: ‘What was the object on the table in the last slide you saw?’ These questions were followed by a four-alternative-forced-choice test of five slides from the series: 1, 7, 8 (critical), 9, and 15. Each recognition slide consisted of four simultaneously presented alternatives, one being identical to the slide shown in the study phase. The other three alternatives
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L
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8 E
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8 e,
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p
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20
10 ” Nonpsychopaths
Noncriminals
Psychopaths
Group Fig. 1. Percentages of Ss who correctly recalled the central or the peripheral detail information of the critical picture in the emotional condition. For comparison purposes, data for noncriminals (78 students; Christianson & Loftus, 1991) are included.
were pictures that depicted the same event but varied with respect to either the central detail, the peripheral detail, or both the central and peripheral details. Each recognition test slide was exposed for 25 set; and the participants were instructed to select the picture they had seen earlier by marking an X in the corresponding box on an answer sheet. The position of the target picture of each test slide was random. Finally, the participant was asked to describe the slide he found to be the most attention-catching and the one that was easiest to remember. RESULTS Recall data Figures 1 and 2 depict the percentage of participants in each group who correctly recalled the central (the color of the woman’s clothing) and peripheral (the color of the car driving in the background) information for the emotional and neutral condition, respectively. For comparison purposes, data from a sample of 78 college students (Christianson & Loftus, 1991) are included in the figures; these data were not included in the statistical analyses described below. A x2 analysis conducted on the central detail indicated that the overall difference between groups and conditions was not significant. However, the response pattern of the nonpsychopaths was similar to that typically found with noncriminals (see Fig. 1); that is, they tended to recall the central information better in the emotional condition than the peripheral detail. The psychopaths, on the other hand, failed to show this pattern of responses. A x2 analysis conducted on the peripheral data indicated that the overall difference between
E 040 2
tm 20 10 n Nonpsychopaths
Noncriminals
Group Fig. 2. Percentages of Ss who correctly recalled the central or the peripheral detail information of the critical picture in the neutral condition. For comparison purposes, data for noncriminals (78 students; Christianson & Loftus, 1991) are included.
441
Remembering details of emotional events Table 1. Percentages of nonpsychopaths and psychopaths who correctly recognized both the central and the peripheral detail information or who recognized either the central or peripheral detail information from an emotional or a neutral event Nonpsychopaths Detail Information Central and peripheral Central Peripheral
Psychopaths
Emotional
Neutral
Emotional
Neutral
22.2 61.1 44.4
52.6 68.4 84.2
50.0 56.7 56.7
53.8 69.2 69.2
groups and conditions was significant, x2 (3)= 8.00, P~0.05. To determine which cell made the major contribution to the significant x2, we analyzed the standardized residual for each cell (Haberman, 1973). The results of these analyzes indicated that the major contributor to the significant x2 was the nonpsychopath-emotional cell (R=2.63). That is, the relatively poor recall of the nonpsychopaths in the emotional condition. As with the recall of central details, the pattern shown by the nonpsychopaths was much the same as that shown by noncriminals.* Recognition data The recognition data for the critical slide is presented in Table 1. A comparison of the proportion of participants who correctly recognized the central information, the peripheral information, or both the central and the peripheral information in slides 1, 7, 8 (the critical slide), 9, and 15, suggested only marginal differences between groups. In line with the recall data, the nonpsychopathemotional group was inferior to the other groups in recognizing peripheral information of the critical slide, otherwise there were no reliable effects between groups and conditions. x2 comparisons conducted on these sets of data did not reveal any significant differences between groups. Mean percentages recall of miscellaneous information in the series of slides, such as questions asked about different objects in the critical slide (i.e. dog, motorcycle, couple), objects in the first and in the last slide in the series, and the number of slides, are presented in Table 2. The values in this table indicate a similar recall performance for psychopaths and nonpsychopaths to all the questions. Affective ratings A group (psychopaths vs nonpsychopaths) by type of event (emotional vs neutral) analysis of variance (ANOVA) was performed on the rated pleasantness-unpleasantness (7-point scale) of the two series of slides. Neither the main effect for groups nor the group x condition interaction was significant. Both groups rated the emotional series of slides as more unpleasant (M=4.33) than the neutral series (M=3.85), F(l,58)=6.01, P~0.05. Most offenders (83.3 % of the psychopaths and 88.9 % of the nonpsychopaths) selected the critical 8th slide as the most emotion-provoking slide in the emotional series. This slide was selected as the most attention-catching slide by 75 % of the psychopaths and 83.3 % of the nonpsychopaths, Table 2. Percentages of nonpsychopaths and psychopaths who were correct about various detail information in the series of slides
Questions Did you see a dog? Did you see a motorcyle? Did you see a couple? Object in the first slide? Object in the last slide? Number of slides?
Nonpsychopaths
Psychopaths
91.3 78.4 100.0 64.9 59.6 13.5
92.0 92.0 92.0 64.0 32.0 8.0
*Two independent raters used interview and file information to assess 43 inmates for Antisocial Personality Disorder (APD), using the DSM-III-R criteria (American Psychiatric Association, 1987). The interrater reliability (K) for presence (both raters) or absence of the diagnoses was 0.74. Using this procedure, 31 Ss, (72.1 %) met the criteria for APD. Reanalysis of the memory data failed to reveal any significant differences between offenders who met the criteria for APD and those who did not.
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and as the easiest slide to remember by 83.3 % and 66.7 % of the psychopaths and the nonpsychopaths, respectively. There were no group differences in the pleasantness-unpleasantness rating of the slide (1 l-point scale) in each series perceived as the most emotionally provoking. Both groups rated the selected slide in the emotional series to be more unpleasant (M= 8.13) than the selected slide in the neutral series (M=5.68), F(1,57)=25.24, P
DISCUSSION
Noncriminals recall equally well the central and peripheral details of a neutral event, but they recall the central details of a negative emotional event much better than they do the peripheral details (see Christianson, 1984; Christianson & Loftus, 1987, 199 l), This psychological focusing on certain detail information of negative events was exhibited by the nonpsychopaths in the present study, but not by the psychopaths. The latter group recalled equally well the central and peripheral details of both the neutral and the emotional slide. These results are consistent with the findings of other studies (e.g. Day & Wong, 1993; Larbig et al., 1992; Williamson et al., in preparation) and suggest a lack of differential processing of emotional information in psychopaths. The affective coloring that ordinarily serves to differentiate emotional from neutral events apparently does not exist to the same degree in psychopaths as it does in other individuals. In this sense, psychopaths probably find most events affectively neutral. Even so, it is interesting that their ratings of the affective nature of the stimuli used in this study were much the same as those made by the nonpsychopaths. Similar discrepancies between psychopaths’ verbal/rated affect and their performance on affective tasks have been observed in several other studies (e.g. Forth, 1992; Patrick et al., 1993; Williamson et al., 1990,199l). Apparently, psychopaths are able to use emotional descriptors for subjective states they do not actually experience as emotional, at least not in the same sense as other individuals do. As (Cleckley, 1976, p. 230) put it, they “can learn to use ordinary words . [and] will also learn to reproduce appropriately all the pantomime of feeling.. . but the feeling itself does not come to pass.” We note that the two groups of offenders did not recall the central detail of the emotional slide quite as well as did the noncriminals. It is possible that the emotional slide had less impact on the offenders than it typically does on noncriminals. More generally, it is likely that emotional reactions to the injury of others are more difficult to elicit from offenders (most of whom have had frequent exposure to violence) than from the general population. The self-reports of the offenders support this suggestion; they considered the slides to be less emotion-provoking than do noncriminals (Christianson & Loftus, 1991). In spite of this, the present task was able to differentiate-in a theoretically meaningful way-between psychopathic and other offenders. A limitation of this study is that it used a laboratory task. As yet, we do not know if psychopaths fail to focus on the central details of a real-life emotional event. However, we might speculate that such an event would have far greater impact on nonpsychopaths than on psychopaths, and that the differences between them would be accentuated. Finally, much of the empirical research on affective processing in psychopaths has focused on negative or aversive stimuli. It is possible that their memory for central and peripheral detail would be more like that of normals if the events involved positive emotional states (cf. Newman et al., 1991; Newman & Wallace, 1993). Ackwoi~/edgenzenIs_This research was supported by grant F. 35887 from The National Council for Crime Prevention, Sweden. to Sven-Ake Christianson, and by grant MT-451 1 from the Medical Research Council of Canada to Robert D. Hare. We are grateful to the staff and inmates of Matsqui Institution for their cooperation and participation. We would also like to thank Susan Nurse and Cathy Lewis for assisting with diagnostic assessments and experimental testing.
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