Psychopathy and Physiological Responses to Threat of an Aversive Stimulus

Physiological activity was monitored while 64 prison inmates awaited delivery of a 120dB tone during a 12-sec “count-down” procedure. The inmates were divided into four groups on the basis of global ratings of psychopathy (interrater reliability = .86) and scores on the Socialization (So) scale. Twelve inmates in the group considered to be most psychopathic (high ratings of psychopathy and low So scores) showed larger increases in heart rate and smaller increases in electrodermal activity in anticipation of the tone than did 20 inmates in the group considered to be least psychopathic (low ratings of psychopathy and high So scores). These findings were consistent with those of several previous studies, and were interpreted as a reflection of an association between psychopathy and the operation of efficient mechanisms for coping with threat.     

Psychopathy and Physiological Activity During Anticipation of an Aversive Stimulus in a Distraction Paradigm

Two investigators independently rated 51 white, male prison inmates on a 7-point psychopathy scale (interrater reliability = .89). The combined ratings were used to divide the inmates into low (1), medium (M). and high (H) psychopathy groups of 17 subjects each. Following a sample trial, each inmate was given two trials in which he could choose how to spend his time during a 5–6 min wait for an aversive stimulus (120dB tone). Three choices were available: 1) continuous white noise, 2) a recording of a nightclub comedian, or 3) a continuous tone that changed in frequency 10 sec before delivery of the aversive stimulus. The aversive stimulus could be avoided on one trial but not on I he other (the order was counterbalanced). When the aversive stimulus was unavoidable (Trial UA), 46 (90.2%) of the inmates spent all or most of their time listening to the comedian, i.e., they adopted a “nonvigilant” strategy, while 38 (74.5%) adopted this strategy when the aversive stimulus was avoidable (Trial A). There were no group differences in the type of strategy used on either trial, or in the physiological responses given by the nonvigilant subjects on Trial UA. Group H tended to give smaller electrodermal responses and a larger increase in HR in anticipation of the sample tone than did Group L, a pattern that is consistent with previous research using classical conditioning or “count down” procedures. On Trial A the nonvigilant subjects in Group H showed a significantly smaller increase in nonspecific skin conductance activity than did Group L. It is suggested that making use of distraction when an aversive stimulus is avoidable results in less conflict and heightened emotional arousal in psychopaths than in other inmates. Some speculations on how psychopaths cope with threat are offered.     

Skin Conductance Recovery and Pupillometrics in Chronic Schizophrenia

A group of 31 chronic male shizopherics were found to be heterogeneous with respect to skin conductance recovery, when response was made to non-signal tones. Fast skin conductance recovery was related to slow pupillary constriction in the light/dark reflex. Conversely, slow skin conductance recovery was related to fast pupillary constriction in the light/dark reflex. The cholinergic nature of pupillary constriction and the implications of these findings for a generalized cholinergic hypothesis of schizophrenia are discussed.     

Psychopathy, startle blink modulation, and electrodermal reactivity in twin men

Psychopathy is a personality disorder with interpersonal-emotional and antisocial deviance facets. This study investigated these facets of psychopathy prospectively using normal-range personality traits in a community sample of young adult men who completed a picture-viewing task that included startle blink and skin conductance measures, like tasks used to study psychopathy in incarcerated men. Consistent with prior research, scores on the interpersonal-emotional facet of psychopathy ("fearless dominance") were associated with deficient fear-potentiated startle. Conversely, scores on the social deviance facet of psychopathy ("impulsive antisociality") were associated with smaller overall skin conductance magnitudes. Participants high in fearless dominance also exhibited deficient skin conductance magnitudes specifically to aversive pictures. Findings encourage further investigation of psychopathy and its etiology in community samples.     

Orienting in Schizophrenia: Habituation to Auditory Stimuli of Constant and Varying Intensity in Patients High and Low in Skin Conductance Responsivity

Groups of schizophrenics and normal controls were exposed to different series of tones of constant (80dB) and variable intensity (60, 80, and 100 dB). Measurements included bilateral skin conductance, finger pulse volume, and heart rate. Both groups were split on the common median in skin conductance response to constant intensity tones to form matched patient and control groups of low and high responsivity. The low and high responsive schizophrenic groups were more clearly separated than the two control groups in rate of spontaneous skin conductance fluctuations, skin conductance magnitudes, and skin conductance levels, primarily because of generalized hyperactivity in high responsive patients. This pattern was clearest for the most intense tone and left hand recordings. High responsive schizophrenics also showed larger response amplitudes, shorter rise and recovery times, and a smaller ratio of elicited to spontaneous responses, than high responsive controls. Finger pulse volume responses recorded from the left hand were smaller in the patient groups, whereas patients and controls did not differ in right hand recordings. High skin conductance responsive subjects showed more heart rate deceleration than low responsive subjects, and schizophrenics had more decelerative responses than controls.     

Diagnosis of psychopathology with and without an interview

This research compared independent ratings of criminal psychopathy (Hare's Psychopathy Checklist, Hare, 1991) from National Parole Board case files alone with ratings based upon file information plus a semi-structured interview. Notwithstanding high interrater reliability using National Parole Board (NPB) case files alone (n = 35), Psychopathy Checklist (PCL-R) scores had to be prorated because 30% of the items could not be scored. Comparisons between file only and independent file plus interview ratings of criminal psychopathy for a larger sample (N = 120) resulted in relatively low inter-rater reliability. Interrater agreement for ratings of psychopathy with and without an interview was statistically significant (p <.006), yet 40% of the cases received different diagnoses when the different procedures were used. Contrary to earlier findings (Wong, 1988), file only PCL-R ratings were not routinely an underestimate of file plus interview PCL-R ratings.     

Effect of early environment on electrodermal and cognitive correlates of schizotypy and psychopathy in criminals

This study examined hypotheses concerning electrodermal hyporeactivity and psychopathy, electrodermal hyporeactivity in schizoid antisocials, poorer scores on the Attention-Distraction factor of the WAIS in schizoid antisocials and stronger support for these relationships in those from intact as opposed to broken home backgrounds. Thirty-seven prisoners were assessed for psychopathy, schizotypy (anhedonia-psychoticism and schizophrenism), the WAIS, and skin conductance recorded to orienting, consonant-vowel, and 90 dB stimuli. All hypothesized relationships for psychopathy were non-significant. High anhedonia-psychoticism scores were significantly associated with reduced orienting frequency (r = -0.43) and with poor performance on Attention-Distraction (r = -0.43). Reduced orienting frequency was itself associated with poor Attention-Distraction (r = 0.61). These relationships were stronger in subjects from intact as opposed to broken home backgrounds. Conclusions are drawn with respect to the mediating effects of attentional and social background factors in psychophysiology-schizotypy relationships.     

Aversive associative conditioning of prepulses in a startle inhibition paradigm

Prepulse inhibition of startle (PPI) represents an automatic mechanism that reflects sensorimotor gating and early attention processes. PPI neither is the consequence of conscious behavioral modulation nor does it depend on learning and conditioning. However, pairing of weak tones and aversive startle stimuli during PPI testing may induce associative learning. Thus, in the present study ( n =60) we tested whether prepulses may be subject to aversive conditioning. Eyeblink EMG and electrodermal responses to intense (100 dB) acoustic stimuli, presented either alone or preceded by weak tones (prepulses, 50 ms, 70 dB, SOA=120 ms), were measured. We found that after strong contingent pairing of weak tones with startle stimuli (PPI paradigm) intense versions of these tones induced significantly larger eyeblink and skin conductance responses than did never paired control tones. We conclude that during PPI testing, prepulses may be subject to aversive conditioning.     

Spontaneous autonomic activity as related to psychopathy

Spontaneous fluctuations and levels in skin conductance and finger pulse volume recordings were studied in criminal subjects during three experimental periods, before, during and after a series of auditory stimuli, and related to psychopathy as estimated by scores in the Gough delinquency scale (De). The sample was subdivided into two groups, containing subjects with scores above (HD) and below (LD) the median in the De scale. Analyses of variance yielded significant group x period interaction effects for skin conductance fluctuation and level measures. The more psychopathic group (HD) had a lower number of skin conductance fluctuations in stimulation and post-stimulation periods, and had lower levels, decreasing over periods. No differences were obtained in the pulse volume measurements. The lower skin conductance reactivity in the more psychopathic subjects was discussed in terms of lower cortical arousal, and the implications for the interpretation of skin conductance fluctuations were analysed.     

Callous‐unemotional,impulsive‐irresponsible,and grandiose‐manipulative traits: Distinct associations with heart rate,skin conductance,and startle responses to violent and erotic scenes

The present study aimed to examine whether callous‐unemotional, grandiose‐manipulative, and impulsive‐irresponsible dimensions of psychopathy are differentially related to various affective and physiological measures, assessed at baseline and in response to violent and erotic movie scenes. Data were collected from young adults (N = 101) at differential risk for psychopathic traits. Findings from regression analyses revealed a unique predictive contribution of grandiose‐manipulative traits in particular to higher ratings of positive valence for violent scenes. Callous‐unemotional traits were uniquely associated with lower levels of sympathy toward victims and lower ratings of fear and sadness during violent scenes. All three psychopathy dimensions and the total psychopathy scale showed negative zero‐order correlations with heart rate at baseline, but regression analyses revealed that only grandiose manipulation was uniquely predictive of lower baseline heart rate. Grandiose manipulation was also significantly associated with lower baseline skin conductance. Regarding autonomic activity, findings resulted in a unique negative association between grandiose manipulation and heart rate activity in response to violent scenes. In contrast, the impulsive‐irresponsible dimension was positively related with heart rate activity to violent scenes. Finally, findings revealed that only callous‐unemotional traits were negatively associated with startle potentiation in response to violent scenes. No associations during erotic scenes were identified. These findings point to unique associations between the three assessed dimensions of psychopathy with physiological measures, indicating that grandiose manipulation is associated with hypoarousal, impulsive irresponsibility with hyperarousal, and callous‐unemotional traits with low emotional and fear responses to violent scenes.     

Facial electromyographic reactions and autonomic activity to auditory stimuli

This study explored whether high- and low-intensity auditory stimuli evoke different facial electromyographic reactions and autonomic responses. Subjects were repeatedly exposed to 95-dB and 75-dB tones (1000 Hz, 40 ms rise and fall times) while their facial electromyograms from the corrugator and zygomatic muscle regions, heart rate, skin conductance responses, skin conductance half recovery time and ratings were measured. The 95-dB tone evoked a "negative" reaction with increased corrugator activity and an autonomic response pattern that carried aspects of a defense reaction, that is, slowly habituating skin conductance responses with retarded recovery rate and an initial tendency to heart rate acceleration. Furthermore, the 95-dB tone was rated as unpleasant. The 75-dB tone elicited an orienting response indicated by a distinct heart rate deceleration and fast habituating skin conductance responses with a relatively short recovery time. Thus, the present study demonstrated that the facial electromyographic technique is sensitive to simple environmental stimuli such as auditory stimuli and that the facial response is consistent with the autonomic response patterns and the experience of the stimuli.     

Electrodermal Activity in Patients with Huntington''s Disease and Their Progeny

Skin conductance was examined in patients with Huntington's disease (HD) and progeny at risk for HD to determine if electrodermal characteristics had potential to identify those progeny likely to succumb to HD. The two experimental groups chosen for study consisted of 7 patients in the early stages of HD and 29 progeny of HD patients. Because the HD and at-risk groups differed in age and sexual composition, each was matched by age and sex to separate psychiatrically and medically healthy normal control samples. Skin conductance was recorded bilaterally while subjects listened to three series of stimuli: 8 85dB tones, 12 105dB tones, and two familiar sounds. Dependent measures included skin conductance level, number of nonspecific responses, number of responses elicited by each tone series and the sounds, the amplitude, latency, rise time, and half-recovery rime of the first tone-elicited response in each series, and habituation rate to the soft and loud tones. The data analysis was carried out by comparing each experimental group to its matched comparison sample. A variety of parametric and nonparametric tests were carried out; no significant differences emerged either between the HD patients and their control group or between the at-risk subjects and their normal comparison group. Ninety-seven percent and 86% of the at-risk and HD subjects, respectively, responded at least once to the experimental stimuli, compared to 90% and 86% of the corresponding control groups.     

Psychophysiological Responsiveness to Auditory Stimulation during Transcendental Meditation

The Transcendental Meditation (TM) technique has been reported to produce cortical states of both steady responsiveness and lack of responsiveness to external stimulation during meditation. The present study examined alpha blocking, skin conductance, and phasic heart rate response to 80dB tones in 17 TM meditators and 17 controls. There were no significant differences between groups in rate of habituation of alpha blocking or skin conductance response, and neither group showed habituation of heart rate responding. Controls displayed a more labile and accelerative cardiac response. Results suggest the possible usefulness of cardiac waveform activity in the study of meditation.     

Cephalic and Digital Vasomotor Orienting Responses: The Effect of Stimulus Intensity and Rise Time

This study evaluated the effects of rise-decay time and intensity (70dB; 90dB| of pure tones on cephalic and finger vascular responses. Cephalic dilation responses similar to those reported by Sokolov were obtained, as well as cephalic dilation response*, which were interpreted as attributable to startle. Cephalic constriction responses were observed at 90dB only and occurred more frequently for slow rise than for fast rise tunes which were conducive to the production of startle. The negative results with respect to (he cephalic vasomotor response, reported by most American investigators, can be rationalized from the results of the present study.     

Probing the orienting response with startle modification and secondary reaction time

Current models of orienting suggest a relationship between the orienting response and attentional processing. This relationship was examined using two independent probe techniques to index attentional processing: secondary reaction time and startle eyeblink modification. Twenty-eight college-age subjects received intermixed presentations of to-be-attended and to-be-ignored tones. Skin conductance orienting responses were obtained during a subset of the tones. Each of the remaining tones contained either a secondary reaction time probe at lead intervals of 150 or 2,000 ms or a startle eyeblink probe presented at lead intervals of 120 or 2,000 ms. In addition, reaction time and startle probes also were presented during selected intertone intervals, and responses to these stimuli served as the baselines from which to compare changes in reaction time and blink amplitude produced by the attended and ignored tones. The results revealed that, compared with the ignored tones, the attended tones were associated with larger skin conductance orienting responses, greater blink inhibition at the 120-ms lead interval, greater blink facilitation at the 2,000-ms lead interval, and greater reaction time slowing at the 2,000-ms lead interval. Consistent with previous findings, the ignored tone was associated with greater reaction time slowing than was the attended tone at the 150-ms lead interval. The results support a relationship between elicitation of the skin conductance orienting response and attentional processes and suggest that the secondary reaction time and blink modification techniques may provide unique information regarding this relationship.     

Skin conductance and heart rate in women with premenstrual syndrome

This study investigated the effects of the menstrual cycle phase on certain components of autonomic arousal and task performance. Premenstrual syndrome (PMS) women and matched controls (non-PMS) were tested both premenstrually and postmenstrually. The conditions selected were a) the presentation of 10 tones, b) a proofreading performance task, and c) a word-association learning task. Skin conductance and heart rate were continuously monitored. No significant effects were found on baseline physiological measures, or on proofreading or word-association performance. A significant point in cycle effect for skin conductance and HR orienting response to the tones was found showing smaller HR and skin conductance responses postmenstrually. Several significant PMS classifications by point in menstrual cycle interactions were found. These indicated that, paradoxically, the non-PMS subjects showed higher spontaneous skin conductance responding during the word association task and higher skin conductance responses to tones prior to menses. While in contrast, PMS subjects yielded higher responding on the same measures postmenstrually. On stress ratings, PMS subjects reported experiencing more stress postmenstrually. Results are discussed in terms of the possible role of expectancy factors and inaccurate self-monitoring.     

Event-Related Potentials and Autonomic Responses to a Change in Unattended Auditory Stimuli

Event-related brain potentials (ERPs) and autonomic nervous system (ANS) responses to occasional pitch and rise-time changes in a task-irrelevant auditory stimulus repeating at short intervals were measured while the subject performed a difficult intellectual task (Raven Matrices). It was found that deviant stimuli elicited the mismatch negativity (MMN) component of the ERP even when they elicited no ANS response. There was no significant difference in the mismatch negativity between trials in which the skin conductance response was or was not elicited. The pitch deviant tone also elicited heart rate deceleration, whereas the rise-time deviant tone tended to elicit a later heart rate acceleration. Neither heart rate change correlated with the mismatch negativity. The pattern of results obtained suggests that the mismatch negativity is generated by an automatic discrimination process associated with the cerebral events initiating the orienting response to stimulus change, but does not necessarily lead to the orienting response elicitation. Longer-latency ERP components tended to show slight covariation with ANS responses. The P3 was larger when a skin conductance response was elicited than when it was not elicited. Further, heart rate change trials tended to be accompanied by larger slow waves than trials with no heart rate response. Heart rate acceleration trials were accompanied by a larger slow parietal positivity and a smaller frontal negativity than were heart rate deceleration trials.     

Organismic,stimulus and task determinants of phasic and tonic heart rate and skin conductance changes

The effects of three variables (perceptual style ‘leveling-sharpening’, stimulus intensity and task) on tonic and phasic heart rate and skin conductance responses were studied. 24 levelers and 24 sharpeners received a series of 25 auditory stimuli under two instructions (task): in one task the subject had to listen carefully to possible small differences between tones (intake task) and in the other task the subject had to count back silently and could neglect the tones (rejection task). One third of each group received tones of 50 dB, one third 75 dB and one third 100 dB. Results show that task has a strong effect on tonic responses in the direction predicted from Lacey's intake-rejection hypothesis. There is hardly any effect of task on phasic responses: only at the first trial heart rate tends to decelerate more in the intake than in the rejection task. Stimulus intensity does not influence tonic responses but very strongly affects phasic responses: deceleration to 50 and 75 dB, acceleration to 100 dB. GSR amplitude increases monotonically as a function of stimulus intensity. There is no difference between levelers and sharpeners with regard to tonic responses. Concerning phasic heart rate, sharpeners decelerate more than levelers and levelers have greater GSRs than sharpeners. It is suggested that tonic changes are relatively more under cognitive control, whereas phasic changes are more of a non-cognitive reflex-like nature. A relationship between the distinction arousal-activation as proposed by Pribram and McGuinness (1975) and the results of this experiment was suggested.     

Continuous Recordings of Impedance and Phase Angle During Electrodermal Reactions and the Locus of Impedance Change

The relatively few studies that use alternating current (AC) in exosomatic electrodermal recording techniques focus on tonic measurement but not on phasic measures. AC methods of phasic measurement, however, are most useful in testing electrical models of the electrodermal response. Problems arising from AC recording of fast electrodermal changes are discussed, and an appropriate measurement concept for continuous recording of impedance and phase angle is developed. This enables tonic values of both parameters to be offset in order to sufficiently amplify small changes. An AC frequency of 100 Hz was used in recording electrodermal activity in 10 subjects during an habituation series of 80dB 1000 Hz tones. Comparison of transformed curves showed that the main component of electrical changes accompanying electrodermal response is a shift in conductance while susceptance shows only small fluctuations. According to a widely accepted simple electrical model of skin, these results indicate that electrodermal responses take place mainly in the resistive element which parallels the capacitance associated with the stratum corneum, but that other components may be involved too.     

Habituation and Dishabituation of the Orienting Reaction to Between and Within Trial Changes in Pitch and Loudness

We investigated the effect of between and within trial changes in pitch and loudness on the electrodermal orienting reaction (OR), perceptions of movement, and their interaction. First, following 20 habituation trials (6-s, 80dB, 1000 Hz), four groups of 10 subjects experienced either an increase or a between-trial decrease in pitch (2000 or 500 Hz) or loudness (90 or 70 dB) on the 21st trial. Second, four additional groups of 20 subjects heard 20 tones that, within each 6-s trial, either increased or decreased in pitch (500 to 2000 or 2000 to 500 Hz) or loudness (70 to 90 or 90 to 70 dB). During a dishabituation phase each group was split into halves having a nonchanging tone either increasing or decreasing relative to mean pitch or loudness. After each session subjects rated whether they perceived tones as approaching, retreating, or motionless. Compared with groups experiencing constant stimuli, groups presented tones changing within trials had greater skin conductance responses that habituated slower irrespective of direction of change or its perception. During dishabituation a similar number of subjects dishabituated to a stimulus increase as compared to a decrease irrespective of whether the change was in pitch or loudness. Perceptions of movement treated as an independent variable did not predict habituation or dishabituation of the OR. The results generally support Sokolov, and are discussed in relation to hypotheses presented by Sokolov, O'Gorman, and Bernstein.