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Detection threshold and tolerance level for electric shock in psychopaths Thorvaldson, Sveinn Albert 1969

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DETECTION THRESHOLD AND TOLERANCE LEVEL FOR ELECTRIC SHOCK IN PSYCHOPATHS by Sveinn Albert Thorvaldson. B.A., University of Manitoba, 1955 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS in the Department of Psychology We accept this thesis as conforming to the required standard _ THE UNIVERSITY OF BRITISH COLUMBIA April, 1969 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced deg ree at the U n i v e r s i t y o f B r i t i s h C o l u m b i a , I ag ree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r ag ree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y pu rpo se s may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n -t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f Psychology  The U n i v e r s i t y o f B r i t i s h Co lumb ia Vancouve r 8, Canada Date Aprils/, 1969 i i Abstract Detection threshold (DT) for electric shock under both incentive (IDT; cigarettes) and no-incentive (NIDT) conditions was determined in psychopathic and nonpsychopathic criminals and noncriminal controls (N•••=. L4 each group). A modified forced-choice procedure permitted E to vary stimulus intensity from t r i a l to t r i a l in an attempt to counteract boredom or inattentiveness. The use of a constant-current stimulator, a concentric electrode, and monitoring of skin/electrode impedance allowed reasonably pre-cise control over current intensity. There were no differences between groups in NIDT or IDT, a result not consistent with previous findings of relatively high DTs in psychopaths. The result was in-terpreted in terms of the concept of arousal. An additional result was that IDT was lower than NIDT for a l l groups. Tolerance level (TL) for shock was also determined in the same groups under both no-incentive (NITL) and incentive (ITLj cigar-ettes) conditions. Although there was no difference between groups in NITL, psychopaths had a significantly higher ITL than the other groups. The result? supported the hypothesis of relatively high sti--. mulus tolerance in psychopaths. An additional result noted was that TL did not correlate with DT, a finding which appears consistent with evidence suggesting that the two parameters have somewhat different response determinants. i i i Table of Contents Page Title page i Abstract i i Table of Contents i i i List of Tables iv List of Figures v List of Appendices v i Acknowledgements v i i Introduction 1 The Psychopath 1 Statement of the Problem 5 Design and Experimental Hypotheses 15 Msthod 18 Subjects 18 Apparatus and Procedure 20 Scoring Procedure 27 Results 29 Discussion 36 Notes 43 Bibliography 4-5 Appendices 51 iv List of Tables Table 1 Characteristics of the groups Table 2 Product-moment correlations between age and selected dependent variables Table 3 Summary of analysis of variance for NIDT and IDT by groups, incentive conditions and sequence of conditions Table 4 Standard deviations for Detection Thresholds and Tolerance Levels Table 5 Summary of analysis of variance in NITL and ITL by groups and conditions Table 6 Product-moment correlations between DT and TL according to incentive conditions Page 19 29 31 32 34 35 V List of Figures Figure 1 MMPI profiles for psychopathic and nonpsychopathic penitentiary inmates 21 Figure 2 Detection Thresholds for electric shock under nc—incentive and incentive conditions for psychopaths, nonpsychc— paths and staff 30 Figure 3 Pain ratings and toieranee levels for electric shock under no-incentive and incentive conditions for psychopaths, nonpsychopaths and staff 33 v i L i s t of Appendices Page Appendix A Instructions to .Penitentiary C l i n i c a l Staff for Selection of Subjects 51 Appendix B Control Variables 54 Appendix C Instructions to Subjects 58 Appendix D Sample Data Sheet 61 Appendix E Subjects' Individual Detection Threshold Graphs 62 Appendix F Dependent Variables 76 v i i Acknowled gments I wish to express sincere thanks to Dr. Robert D. Hare for his example, his encouragement, and the consistent care with which he examined and criticized my work. The ready cooperation of "Warden G. E. DesEosiers, inmates and staff of the British Columbia Penitentiary is also very much appreciated. My deepest gratitude goes to my wife, Anne. 1 Introduction Recent research (Schoenherr, 1964j Hare, 1968a) suggests that psychopaths may have a higher-than-norna 1 threshold for the detection of electric shock. One implication may be that psycho-paths are more tolerant of shock, or noxious stimulation in general, than are normal subjects (Schoenherr, 1964), and that this might account, in part, for the poor performance of the former, in learn-ing tasks involving an aversive stimulus (e.g. Lykken, 1957). It is known, however, that both detection threshold and tolerance level may be influenced by motivation, attention and other subjective fac-tors. The present study attempts to determine both of these para-meters while controlling for the effects of such psychological variables. The Psychopath Psychopathy may be seen as a pattern of aggressive or parasitic behaviour without apparent concern for the welfare of others and taking place in the absence of organic disease or injury, neurosis, psychosis, mental defectiveness, or socialization i n a deviant subculture. The literature seems to pinpoint as fundamental the psychopath's apparent lack of a normal emotional response to others, his guiltlessness and lovelessness (McCord and McGord, 1964), his egocentricity and lack of empathy (Foulds, 1965; Buss, 1966). 2 Descriptions, accordingly, frequently include characteristics such as affective poverty, "hollow nan", narcissism, vanity, lack of honor, empathy or pride, lack of sincerity, r e l i a b i l i t y or truthfulness. While his behavior may be violently aggressive or, perhaps more typically, passively manipulative, i t i s the absence of real feeling or compunction i n an antisocial act, and lack of subsequent guilt or shame, that characterizes the psychopath. A striking feature of the psychopath i s that, with his profound emotional d e f i c i t , he appears normal both intel l e c t u a l l y and physically. Karpman (1961), i n this connection, describes the psychopath as "two-dimensional", while Cleckley (1964) suggested the term "semantic dementia" to describe the s p l i t between i n t e l l e c t and amotion. One of the consequences would seem to be that while the psychopath lacks any real concern for others, he may be quite adept at simulating and verbalizing appropriate feeling; he may develop considerable s k i l l as a charming and plausible dissembler whose techniques may range from righteous indignation to pitiable self-deprecation, and whose exploits i n confidence games may be legendary. His mimicry means that rather nice distinctions are of-ten necessary to t e l l the psychopath from the nonpsychopath. For example, his use of people i s not neurotic dependence, his emotional flatness i s not stoicism or denial, and his momentary destructiveness 3 is not simply sadism (See Karpman, 1961)* A l i s t of characteristics of psychopathy provided by Cleckley (1964) was employed in the present study to select sub-jects (see Appendix A), There have been a number of major contri-butors, however, toward clarifying the definition of psychopathy. Karpman (1941)» for example, long insisted that for proper diagnosis i t was necessary to look beneath the surface of psychopathic beha-vior to itB motivation. Those cases where skilled investigation revealed the behavior to be a manifestation of underlying neurosis or psychosis he termed "symptomatic" psychopathy, while those cases where investigation, no matter how patient, revealed no psychogenic factors he termed "idiopathic" psychopathy. These terms are more or less equivalent, respectively, to what other writers have called pseudppsychopathy. neurotic or secondary psychopathy, and true,  classical, or primary psychopathy. The "acting-out neurotic" (Alexander, 1930) would f a l l into the symptomatic group. Hare (in press) points out however, that one of the difficulties with the terms secondary or neurotic psychopathy is that they imply that in-dividuals so labelled are basically psychopaths when, in fact, the motivations behind their behavior, as well as their personality struc-ture, l i f e history, response to treatment, and prognosis, are quite different from those of the psychopath. He suggests that a more appropriate term at this stage of knowledge might be one that empha-sizes the neurotic element in the behavior, such as the term neurotic 4 personality disorder suggested by the Group for the Advancement of Psychiatry (1966). Arieti's (1967) descriptions of what he terms the simple and complex psychopath are further conceptualizations which seem consistent with Cleckley's description and Karpman's idiopathic type. The simple psychopath appears the more primitive of the twoj he may have adequate knowledge of normal means of attaining goals but seems unable to delay gratification of needs and is unable to experience what Arieti terms "long-circuited anxiety", a vague ex-pectation of some possible danger or discomfort. The complex psycho-path, on the other hand, seeks immediate gratification but also de-sires to "get away with i t " . Professional criminals or some un-scrupulous politicians and businessmen might be included i n this category. Such consensus as there may be in defining the psychopath has been long in arriving. Although the concept first appeared as a clinical entity in the late eighteenth century, its definition and etiology have been extremely controversial (Maughs, 1941; Ehrlich and Keough, 1956). By the end of World War II, however, the dispute over the meaningfulness of the term had been largely settled, a l -though disagreement over etiology continued (McCord and McCord, 1964). And in 1959, Hervey Cleckley could point out that at any meeting of clinicians a reference to a psychopath is recognized 5 immediately as meaning a "... grave character and behaviour dis-order so familiar to most psychiatrists as a distinct and easily recognizable entity" (1959, p. 568). Moreover, several recent studies (Albert, Brigante and Chase, 1959; Gray and Hutchison, 1964), as well as the results of research (see reviews by Hare, in press), clearly indicate that the concept of psychopathy i s a meaningful one. Statement of the Problem Detection threshold. The term detection threshold is usually defined as the minimal amount of stimulation required for the subject to detect its occurrence (see Dember, 1965). A rather Large number of variables appears to affect the threshold for elec-tric shock. Green (1962), for example, has reported the effect of various skin and electrode factors. Thus a "wet" contact or cool skin tend to yield low thresholds while thick skin appears associa-ted with high thresholds. However, room temperature within 65° to 75°, humidity, or pressure of contact short of causing numbness, have no appreciable effect. In a study of avoidance conditioning in psychopaths, Schoenherr (1964) routinely obtained two measures of response to shock detection threshold and tolerance level (defined below)., While the psychopaths had a mean tolerance level similar to that of the nonpsychopaths, their mean detection threshold was significantly 6 higher than that of the other groups. The latter finding is somewhat difficult to evaluate in view of weaknesses in the Method of Limits procedure as employed by Schoenherr. This pro-cedure typically requires the subject to respond "yes" or "no" as to whether he detected a stimulus in each t r i a l . The subject, however, is constantly experiencing fluctuating sensory excitation or 'noise1, and therefore must decide whether his excitatory state during each t r i a l was due to noise alone or noise plus the signal. To make his decision he is obliged to establish some standard or "response criterion". It has been demonstrated that the criterion adopted by the subject is influenced by such factors as the expec-tation that a t r i a l will contain a stimulus, motivation to achieve a low threshold (Blackwell, 1953), or probability of payoff for accuracy (Swets and Tanner, 1954)* The response criterion thus tends to shift with changes in the subject's motivation, expectancy, and other nonsensory variables. Unless such bias ses are removed by-special procedures and statistical tfeatment,-"- the Ses/No response confounds their influence with the measure of sensitivity. (Swets, 1961; Ctoombs, in press). It is conceivable, for example, that psycho-paths are more careless about the task or about the possibility of injury and therefore tend to establish a relatively high response criterion, overlooking very weak stimuli. The "forced-choice" indicator response, however, serves to control the influence of criterion factors (Swets, 1961). The stimu-7 lue occurs i n one of several intervals or locations; the subject is required only to choose the interval he thinks contained the signal and to guess i f necessary. He is thus "... not asked for an introspective report" (Dember, 1965, p. 32). Hare, (1968a) employed the forced-choice procedure in a study of detection thresholds for shock in three ^ penitentiary inmate groups. Consistent with Schoenherr's (1964) finding, psycho-2 paths showed the highest, secondary psychopaths intermediate, and nonpsychopaths the lowest thresholds. Hare (1968a) points out, however, that despite the use of the forced-choice procedure, "... correct identification of the interval containing the shock requires a degree of sustained attentiveness that the psychopath may be unable or unwilling to give!' (p. 270). There is some evidence to support the suggestion (Hare, 1968aj Quay, 1965) that psychopaths may experience difficulty in maintaining attention to a task involving low sensory input or re-quiring vigilance. Orris (1967), for example, tested psychopathic, neurotic and subcultural delinquents in a task requiring them to watch for unusual deflections in a voltmeter pointer. The psycho-paths detected significantly fewer such deflections in this boring task than did the other subjects. Further, Forssman and Frey (1953) found that psychopathic boys not only exhibited a high incidence of slow-wave activity (suggesting drowsiness) in their EBGs, but also tended to f a l l asleep more readily during the examination than did 8 other boys. They suggested that psychopathy i s characterized by a wavering or decrement in attentiveness. Petrie's (I960, 1967) comment that lobotomized patients who show 'psychopathic* behavior, juvenile delinquents, and extraverts, tend to be intolerant of sensory deprivation may also be mentioned here. Eysenck's (1967) discussion of vigilance i s also relevant assuming that his conception of the psychopath as a neurotic extro-vert has something in common with the conception adopted here.3 According to Eysenck's (1957) personality theory, extroverts (and psychopaths?) are characterized by a rapid build up of cortical inhibitory potentials. Further, in any task requiring sustained attention the subject may experience an involuntary rest pause (LHP) whenever cortical inhibition equals cortical excitation or drive, resulting in a cessation of activity. It follows that extroverts will be more susceptible to such IRPs and, i f these coincide with a signal in a vigilance task, can be expected to perform more poorly than introverts (Eysenck, 1967). Thus Glaridge (I960) found that a group of hysterics (neurotic extroverts) performed more poorly than a group of dysthymics (neurotie introverts) in tasks requiring them to pick out certain numbers in a series of digits. Studies of cortical activity in psychopaths are pertinent to the present study in view of evidence that cortical underarousal is associated with low tactile thresholds (Edelberg, 1961). Rose (1964) found that less anxious, more impulsive psychopathic subjects 9 had a relatively high two-flash threshold — the minimum time interval required for two brief flashes of light to be seen as double rather than as single ~ a measure negatively related to cort i c a l arousal. Further, Hare (1968b) found that psychopaths had a lower level of autonomic v a r i a b i l i t y , a finding which i s relevant because of the hypothesis (Lacey and Lacey, 1958) that fluctuations i n autonomic a c t i v i t y generally tend to be co r t i c a l l y arousing. Turning to the relationship of cortical arousal to de-tection threshold, Bdelberg (196l) found that increases i n skin conductance and decreases i n finger pulse volume were associated with a drop i n tactile threshold. He interpreted this relationship, i n part, as reflecting "... central arousal associated concurrently with autonomic a c t i v i t y and increased perceptivity" (p. 193). He concluded that i t -,-is essential to control or monitor indices of arousal i n any experiment which assumes a static tactile threshold. Autonomic functioning i t s e l f , however, may also be asso-ciated with detection thresholds. Silverman, Cohen and Shmavonian (1959), for example, found that an increase i n galvanic skin response (GSR) a c t i v i t y was reflected i n a decrease i n detection threshold for electric shock. But whether the finding of these investigators implies low detection thresholds i n psychopaths i s not clear. While psychopaths appear to have low levels of resting skin conductance and spontaneous electrodermal ac t i v i t y , they seem to show normal GSRs to simple tones and shock, i. e . their responsivity may be normal (Hare, 1968b). 10 Eysenck (1967) has recently discussed cortical excita-tion/inhibition balance in terms of arousal. He predicts that extrtprerts have higher sensory thresholds than introverts due to a relative lack of cortical excitation, and perhaps also due to higher levels of reactive inhibition resulting from the monotony and low-level stimulation associated with threshold measurement experiments. Extroverts, for example, have been found to have higher thresholds for the detection of electrical stimulation of the vestibular apparatus (Dunstone, Dzendolet and Henckeruth, 1964). In summary, evidence from a number of quarters holds out the possibility that previous findings of high detection thresholds in psychopaths may have been related both (§J to psychological vari-ables such as a careless attitude or inattentiveness and (b) to low levels of cortical and autonomic arousal. The present experiment attempts to take these factors into account by employing a slightly unorthodox psychophysical procedure and offering payoff for good performance. Tolerance Level. Stimulus tolerance level, or simply tolerance level, is defined here as the maximum stimulus intensity an individual is willing to accept under given experimental conditions and, for present purposes, is considered a measure of pain toler-ance .4 Care should be taken to differentiate i t from the term pain  threshold which has been defined as "... that stimulus value which 11 gives rise to just noticeable pain" (Wolff, 1964, p. 252). Mersky and Spear (196?) point out that historically there has been considerable controversy as to whether pain is a physiological or psychological phenomenon or a combination of the two. They conclude that i t i s impossible to divide the pain ex-perience into cognitive/affective components and sensory/reactive components. In any event, research has shown that tolerance levels for pain are subject to a host of psychological variables, including cultural background (Poser, 1963; Zborowski, 1952), group identity (Lambert, Libman and Poser, I960), attitude (Clark and Bindra, 1956), age, sex and verbal IQ (Hall, 1953), body boundary (Nichols and Tursky, 196?), instructions (Gelfand, 1964a; Wolff and Horland, 1967), and hypnosis (Melzack, 1966). In fact, i t i s interesting to note that psychological factors appear to predominate: over physiological ones as a source of individual variation i n pain tolerance (Clark and Bindra, 1956j Gelfand, 1964aj Wolff and Horland, 1967). Pain threshold, in contrast, seems re-latively stable, unaffected, for example, by placebos or drugs (Beecher, I960, Gelfand, Ullman and Krasner, 1963) or prefrontal lobotomy (Petrie, 1967). Turning to pain tolerance in psychopaths, there have been very few studies foGuased on the topic. A number of experiments which routinely determined shock tolerance levels report no signi-ficant differences between psychopaths and nonpsychopaths, e.g. 12 Schoenherr, (1964)} Hare, (1965b, 1966). Further, Schacter and Latane (1964) found psychopaths to be similar to normal subjects in rating the "painfulness" of shock of given intensity. Schal-ling and Levander (1964), on the other hand, found that a psycho-pathic group of institutionalized delinquents tolerated signifi-cantly more (continuous) electric shock than did a group rated high in anxiety-proneness. The psychopathic delinquents also per-sisted longer in keeping a leg extended. The results of this study are, however, rather difficult to evaluate since the tolerance scores are reported in multiples of each subject's detection thresh-old for the stimulus. In a later study of the relationships between shock tolerance and various personality inventory scores (Schalling, unpublished), results are reported in absolute values as well as multiples. Shock tolerance levels were consistently related to a carefreeness/inconsistency/immaturity factor which appears to re-flect an aspect of extroversion most consistent with psychopathy. While direct evidence as to shock tolerance in psycho-paths is at best equivocal, there have been a number of studies of the relationship between pain responsivity and behavioral and per-sonality variables which are relevant to psychopathy. Tong (1959) tested the relationship between reactivity to laboratory stressors and various forms of conduct disorder, e.g. larceny, assault, inde-cent exposure, etc. Although his subjects were certified mental patients of below average intelligence, he found those conduct dis-orders suggesting psychopathy to be low in stress reactivity accord-13 ing to verbal report of pain. Eysenck's (195'/) personality theory leads to the pre-diction that extroverts have high pain tolerance due to (a) a relatively high level of cortical inhibition which tends to dampen stimulus input, and (b) poor conditioning of anticipatory arousal responses which can be expected to summate with the physiological response to the pain stimulus. Using heat as the stimulus, Lynn and Eysenck correlated extroversion (E) and Weuroticism (N) scores on the Maudsley Personality Inventory (MPI) with pain tolerance scores (defined as the difference between pain threshold and toler-ance level). They obtained significant correlations of .61 and -.36 respectively, thus supporting predictions. However, Levine, Tursky and Nichols (1966) replicated the experiment using electrical stimu-lation administered in discrete steps. They obtained no correlation between shock tolerance and either E or N scores for groups of stu-dents and housewives. A series of experiments by Petrie (1967) and her associates seems to suggest, when strung together, higher pain tolerance in psychopaths. In summary, she has reported that: (a) brain operations which increase pain tolerance also make the patient more •psychopathic1 or more extroverted (Petrie, 1952) but there i s no such personality change after operations which do not increase pain tolerance (Petrie, 1958); (b) high extroversion (MPI) scores characterize both thepost-lobotomy and the more psychopathic patient (Petrie, 1967); (c) pain tolerant subjects receive significantly higher extroversion scores u than do nontolerant subjects (Petrie, Collins and Solomon, I960); and (d) juvenile delinquents tend to perceptually reduce sensory input, a factor which strongly correlates with pain tolerance. Finally, there would seem to be a direct connection be-tween anxiety level and pain tolerance. Beecher, (1959) has pointed out that physiological pain i s always accompanied by apprehension of (or anxiety about) future pain (see also Melzack and Wall, 1965). Thus H i l l , Kornetsky, Flanary and Wikler (1952) found that noxious stimuli were perceived as being significantly more intense under anxiety producing conditions than under anxiety reducing conditions. On the other hand, Piercy, Elithorn, Pratt and Grosskey (1955) found no differences between two groups of psychiatric patients, differing in degree of rated anxiety, in tolerance for electric shock (expressed as a ratio of pain threshold to tolerance level). The more anxious group did, however, show greater galvanic skin responses both to the warning light and to the shock. In any event, the psychopath (a) is considered typically "anxiety-free" (e.g. Albert, Brigante and Chase, 1959; Lykken, 1957) and (b) shows attenuated fear arousal (GSR) with impending noxious stimulation (Hare, 1965a; Lippert and Senter, 1966). Further, Hare (1966) reports that, when given a choice of immediate or delayed shock, psychopaths chose immediate shock on significantly fewer occasions than did nonpsychopaths and normal controls, and that they "... reported that waiting.for the occurrence of delayed shock bothered them very l i t t l e " (p. 27). Although these studies offer only 1 5 indirect evidence, a plausible inference would seem to be that psychopaths are more tolerant of pain. In summary, while some investigators find that psychopaths seem to have shock tolerance levels similar to those of nonpsychopaths, i t can be plausibly argued that they are not r e a l l y 'suffering' as much as normals at these levels. Schoenherr (1964) has suggested that 'normal' tolerance levels declared by psychopaths may be spuri-ously low, perhaps due to an unusual tendency to avoid discomfort. The present experiment attempts to control for such motivational fac-tors. Design and Experimental Hypotheses Detection threshold. As i n the Hare (1968a) study, the present experiment used a forced-choice indicator response and the constant-stimulus method of stimulus selection (see Dember, 1965) but with a change i n the method of presenting stimuli. Usually, the forced-choice method involves the selection of about five stimulus intensity levels and each of these i s presented i n blocks of ten t r i a l s . Such block presentation, however, tends to be a rather boring and tedious procedure for the subject. Subjects i n Hare's study were apt to say that they knew from the f i r s t few t r i a l s i n each block whether or not they had a chance of detecting a shock. If the chance seemed borderline they might have quickly assumed a "set" to guess u n t i l there was clear evidence that the intensity had changed. In the present experiment, therefore, the block presentation procedure 16 was discarded and the stimulus intensity was varied from t r i a l to t r i a l . This enabled the experimenter to (a) protect the subject from extended 'failures' i n detection, (b) counteract a developing set, and (c) attempt to keep the subject involved, interested and encouraged. Further, three intervals, rather than the usual four, were used in order to simplify the task and allow rapid presentation of trials. Finally, the number of trials at any one stimulus level was not kept constant. This allowed concentration of relatively large numbers of trials around the threshold and avoided tedious re-petition of trials well above or well below the threshold. Despite the possible virtues of the above procedure, i t was not expected that i t would be either sufficiently arousing or sufficiently interesting to induce the psychopath to show a 'normal' threshold. Cigarettes were therefore introduced as an incentive for accuracy in detecting the shock. Subjects were tested under both incentive and no-incentive conditions, with sequence of conditions balanced across groups. The experimental hypothesis is that under the no-incentive condition psychopaths have higher detection thresholds for shock than do nonpsychopaths. A further hypothesis is that both psychopaths and nonpsychopaths have a lower threshold under the incentive condition than they have without the incentive. Tolerance level. Shock tolerance was determined first under a no-incentive, and then under an incentive, condition. It was 17 not expected that psychopaths would differ from nonpsychopaths in tolerance level for shock under the no-incentive condition. The experimental hypothesis is that under the incentive condition psycho-paths have higher tolerance levels for electric shock than do non-psychopaths. Further, both psychopaths and non-psychopaths are ex-pected toBShow higher tolerance for shock with the incentive than they do without i t . 18 Method Subjects Three groups of 14 subjects each, representing psychopathic inmates (P), nonpsychopathic inmates (NP) and staff (C), were selected from the British Columbia Penitentiary. A procedure similar to that employed by Lykken (1957), Schoenherr (1964), and Hare (1968a) was used. The institution psychiatrist and senior counsellors were given (a) Lykken's modified l i s t of Cleckley's (1955) c r i t e r i a defining psychopathy, and (b) the description of the Sociopathic Personality  Disturbance; Anti-social Reaction (American Psychiatric Association, i960, See Appendix A). They were asked to l i s t a number of inmates known to them and check off the l i s t as to whether or not Cleckley's c r i t e r i a applied. The experimenter and a colleague then independently examined the psychological and general f i l e s of these inmates, using the Cleckley c r i t e r i a as a guide. Emphasis was placed on the actual re-ported behavior of the subject rather than on opinion. Where a diag-nosis was recorded i n the f i l e , care was taken to discover and evaluate the behavioral evidence supporting i t . Each subject was then rated on a 7-point scale representing degree of psychopathy. The staff c l i n i -cians' assessments as recorded i n the check-off l i s t were kept separate during this procedure. The experimenter and his colleague then consulted and compared their respective ratings and the check-off l i s t of the 19 staff. Each subject was given a f i n a l rating on the 7-point scale and subjects were chosen randomly from those rated on the extreme ends of the scale* Table 1 contains some of the characteristics of the groups Table 1 Characteristics of the Groups Groups Variable Measure P NP G Test Age (years) N u u U M 32.2 28.0 37.3 F = 2.80* SD 12.1 7.8 9.9 a b Education N 12 13 n/a (years) M 9.5 9.5 NS SD 2.2 2.5 Revised Beta N 14 14 n/a IQ M 110*2 106.1 NS SD 8.9 9.4 Time-served- "H 13 14 n/a current sent- M 2.4 1.3 t = 1.94** ence (years) SD 1.7 0.9 MMPI Pd. "N 12 12 n/a scale M 86.1 68.7 t = 2.37*** SD 19.7 L4.3 MMPI Ma. "N 12 12 n/a scale M 67.7 61.3 NS SD 7.8 10.8 a Data not available on a l l Ss b Not applicable or data not available * p <.10 p < .05 one tailed p < .025 one tai l e d 20 (see Appendix B for data). The significant t test for the difference between the inmate groups (P and NP) in time-served-on-current-sentence would seem consistent with expectation; i.e. psychopaths could be ex-pected to have been sentenced to longer terms, perhaps due to serious-ness of their offences or length of their criminal records. The Minnesota Multiphasic Personality Inventory (MMPI) data (available i n inmate files) appear partially supportive of the clinical selection procedures used; i.e. the psychopaths scored significantly higher on the psychopathic deviant scale (Pd) and the hypomania scale (Ma) although not significant, is in the expected direction (Craddick, 1962} Dahlstrom and Welsh, I960). Eigure 1 is a plot of the group mean MMPI scores for a l l scales. The subjects for Group C (penitentiary staff) were selected by a random procedure from the l i s t of staff volunteers. This group served as a control group for the possible effects of institutionaliza-tion and criminality. Apparatus and Procedure Shock was administered by means of a Lafayette constant-current stimulator'fitted with a vernier dial to permit fine adjustments in cur-rent intensity. A Hunter electronic timer served to time the shock de-livered by means of a concentric electrode (Tursky, Watson and O'Connell, 1965) placed on the volar surface of the subject's left forearm. 21 22 Tursky and Watson (1964) nave shown that electric shock causes marked fluctuation in skin/electrode impedance at the electrode site and that this results, in accordance with Ohm's Law, in fluctua-tions in current passing through the circuit. To assure constancy in skin/electrode impedance and therefore eontrol over current strength, a procedure developed by these investigators was followed. The elec-trode site was rubbed briskly for about 30 seconds with Sanborn Redux electrode paste, using cotton gauze as the applicator to ensure ade-quate abrasiveness. .Additional paste was then smeared on the site with the amount being adjusted so as to reduce skin/electrode impedance to 5,000 ± 500 ohms. The impedance was checked about twelve times at regular intervals during the course of the experiment. In this way the skin/electrode impedance was artifically reduced to a predetermined level, i t was then kept more or less constant by adding or removing electrode paste i f necessary. In addition, a 100,000-ohm resistor was placed in series with the subject so that such variations in skin/eleo-trode impedance that did occur would represent only a small proportion of the total circuit impedance and therefore could be considered to have a negligible effect. Instructions (Appendix C) and stimuli (a 100-millisecond tone of moderate pitch and fairly low intensity) signalling the inter-vals during which shock (300 milliseconds) was presented, were pro-grammed on a Uher tape recorder and fed to the subject through padded earphones. A Uher diapilot used with the tape recorder permitted the simultaneous control of shock delivery. 23 The experiment took place in an 8 f t . x 8 f t . room construc-ted of sound-absorbent wallboard and fitted with a fan for ventilation and masking of extraneous noise. Room temperature remained fairly con-stant at about 75° • So far as possible a subject was selected from each group in turn} due to administrative difficulties, however, Group C subjects tended to be tested a l i t t l e later in the course of the re-search and later in the day. In fact, a number of Group C subjects were tested immediately as they came off shift when they may have been more fatigued than the subjects from the other groups. Each subject was called to the test room individually and his participation was requested. He was assured that the research had no offi c i a l connection with the institution, that i t was for scientific pur-poses only, and that he had nothing to gain or lose by participating. Only a few subjects declined and these were about evenly divided between the inmate groups. The subject was briefly given an idea of the purpose of the first part of the experiment, i.e., to determine "the smallest amount of shock (he could) just feel", and was informed that further instructions were on the tape. (The tolerance level procedure, which would later require the subject to accept much stronger shock, was not mentioned at this stage). The subject was then comfortably seated at one side of a table separated from the experimenter by a blind. A rough estimate of the subject fs detection threshold (DT) was first determined by the Method of Limits. Signal tones were programmed about five seconds apart and were followed immediately by shock. The program was described to the 24 subject and he was instructed to report whether he felt any sensation after each tone by saying "yes", "no", or "not sure". About 20 trials were used. The resulting estimate of the subject's DT served as a pre-liminary guide for the selection of shock intensities to be used i n the forced-choice response procedure which immediately followed. The program for this procedure consisted of two blocks of about 180 trials each, with the first nine trials serving as training trials. Each t r i a l consisted of a series of three tones about 2% seconds apart, while about 5 seconds elapsed between trials. A shock was programmed after one of the tones with the location of the interval containing the shock being randomly determined. The subject's task was to decide which tone the shock followed and to guess i f necessary. In order to balance the sequence of incentive and nc—incen-tive conditions, each block of trials was preceded on the tape by two sets of instructions: those offering incentive (cigarettes) and those not offering incentive. . Thus, the experimenter could, by running the tape to the appropriate point, select a program i n either of two se-quences: (a) no-incentive/incentive, and (b) incentive/no-incentive. The sequence for each subject was randomly determined beforehand and balanced within groups. Later, for tabulating convenience, the sub-jects were numbered so that subjects 1 to 7 in each group had received the no-incentive/incentive sequence and subjects 8 to 14 had received the reverse sequence. 25 In the no-incentive/incentive sequence the subject was in-structed in the following way. For the first block of trials, the instructions simply described the procedure and informed him of his task. Then, after a short rest break between blocks, he was told that the same procedure would continue except that this time he could win a cigarette for every two correct answers or guesses, and that he could win anywhere from two to four packs in this way. A small electronic counter, which the experimenter operated by a foot pedal, was placed directly in front of the subject so that he could easily see his score. A partially opened carton of cigarettes was also placed on the table i n his line of vision. In the incentive/noincen-tive sequence the instructions and procedure were reversed. Responses were recorded on a data sheet (Appendix D) which blocked put a l l trials according to the interval containing the shock (i.e., after tone 1, 2 or 3). The experimenter's task was to enter the chosen shock intensity for each t r i a l and record the subject's response. The experimenter manipulated the shock intensity from t r i a l to t r i a l choosing a range of values from the level where the subject's performance was no better than chance (33 1/3$ correct responses since three intervals were involved) to the level where he performed perfect-l y (100$ correct responses). The tolerance level (TL) procedure followed immediately after the second block of DT trials. The subject was told (not taped, see Appendix C) that the level of shock would gradually be increased 26 and that his task was to indicate the subjective intensity of each shock. He was provided with a chart which described a series of pain levels as follows: (1) uncomfortable or just unpleasant or irritating but not yet painful, (2) just getting painful or fairly strong or just starting to hurt, (3) painful or hurting or strong, (4) very strong or very painful or hurts a lot, (5) Stop. Don't wish to go any higher. The subject was asked to "rate or grade" each shock by calling out the number which applied. He was told that he could use a number once or many times or skip a number i f he wished. The shock stimuli (300 milliseconds) were spaced about 10 seconds apart; a signal tone (100 milliseconds) was presented two se-conds before each shock. The experimenter increased the intensity of current at the rate of about 0.8 milliamperes (ma.) per step. The fifth level described above was, of course, the subject's TL under the no-incentive condition (NITL). The TL under the incen-tive condition (ITL) was then determined as follows. The subject was told that i f he was prepared to accept further shocks he would be paid two cigarettes for every step he might wish to go. He was informed that the intensity would increase in the same way as previously and that he could stop at any time. It was made clear that the choice was completely his and that i t made no difference to the experiment whether he did or did not accept more shock. 27 Scoring Procedure The flexible DT procedure used resulted i n varying numbers of t r i a l s at any given intensity level, i . e . , the r e l i a b i l i t y of the data varied. Thus, i n order to evaluate the performance data (percen-tage of correct responses at any given intensity level) i t was necessary to roughly "weight" each score according to the number of t r i a l s on which i t was based. This resulted i n three categories of data: (a) "weak" data based on i to 10 t r i a l s (median = 4), (b) "moderate" data based on 11 to 30 t r i a l s (median = 18), and (c) "strong" data based on over 30 t r i a l s (median = 42). The data were then plotted (percentage of correct responses against shock intensity) on semi-log paper using different symbols according to the weight of the entry (see Appendix E for each subject's graph). A straight line based mostly on the entries representing "strong" data was f i t t e d to the plot by visual inspection (Woodworth and Schlosberg, 1954). The 50% threshold, corrected for chance success, was taken as the point midway between chance and perfect performance, i. e . , the intensity required for the subject to achieve 66 2/3% correct responses. The scoring procedure for the pain rating ( 1 - 4 ) , NITL and ITL data was much simpler. The subject's score for a given pain level was taken as the median intensity of a l l shocks rated at that level, e.g., i f an S rated 6.74, 6.82 and 6.90 ma. a l l as "4" (very painful), his score for this level would be taken as 6.82 ma. If a rating was 28 skipped, i t was estimated by taking the intensity midway between , the two adjacent levels. The "5" level appeared only once as i t was the subject's NITL. The subject's ITL was simply the quit point under the incentive condition. I f the subject chose to accept no further shocks beyond his NITL, then his NITL was taken as his ITL as well. 29 Results Control variables* In view of the nearly significant age difference between the groups, correlations were calculated to test the relationship between age and some of the dependent varia-bles (Table 2). None of these correlations was significant. Table 2 Product-moment correlations between age and selected dependent variables Variables r * — X y Age x NIDT .26 Age x NITL -.20 Age x ITL -.28 * r =s .53 needed for significance at .05 level. Since Petrie (1967) has suggested,that fatigue is associa-ted with increased reduction of stimulus input, NIDT scores were plotted against time-of-day of testing (Appendix B). Visual inspec-tion of the plot revealed no relation between these variables. Detection threshold. The mean DTs for each group under no-incentive and incentive conditions are shown in Figure 2. Table 3 summarizes a three-factor analysis of variance (groups, incentive con-ditions, and sequence of conditions) with repeated measures across in-centive conditions (Winer, 1962)-". While the analysis reveals the Fig. 2. Detection Thresholds for electric shock under no-incentive (NIDT) and incentive (IDT) conditions for psychopaths (P), nonpsychopaths (NP), and staff (C). 31 Table 3 Summary of Analysis of Variance for NIDT and IDT by groups, incentive conditions and sequence of conditions Source SS df MS F Between Ss 11.61 41 A (groups) .92 2 .460 1.58 B (sequences) .17 1 .170 AB .04 2 .020 Sub. w. groups 10.48 36 .291 (error between) Within Ss .43 42 G (conditions) .06 1 .060 6.25* AG .01 2 .005 BC .00 1 .000 ABC .01 2 .005 G x sub. within groups (error .347 36 .010 within) * p ^ .05 expected significant main effect for incentive,^ the important find-ing i s the lack of a significant main effect for groups or interaction between groups and incentive conditions. (In view of the lack of a main effect for sequence of incentive conditions, the data for both sequences were combined i n Figure 2. See Appendix F for raw data.) 32 It is apparent then, that Group P did not show a higher mean NIDT as predicted; i.e. while i t was expected that the incentive would be required before Group P would show a 'normal' threshold, the data clearly suggest that the incentive was not necessary. In fact, under both incentive conditions, Group P had the lowest mean DT in absolute terms. Further, Group P had the lowest standard deviation (SD) in both NIDT and IDT (Table 4). The larger SD i n the other groups, however, may have been due to the unusually high DTs for one subject in each of these groups (NP5 and C7). Table 4 Standard Deviations for Detection Thresholds and Tolerance Levels (in milliamperes) Group NIDT • IDT NITL :ITL P 0,26 0.18 3.54 8.16 NP 0.41 0.39 4.34 5.08 C 0.45 0.4.1 3.00 4.09 Tolerance level. The mean group scores for a l l pain levels .(1-4)', NITL, and ITL are.presented in Figure 3 (See Appendix F for raw data). A one-way analysis of variance for differences in magnitude of increase between pain level 1 (uncomfortable) and NITL was not significant (F = 1.54; 2.39). However, a two-factor analysis of variance with repeated measures across conditions (Table 5) for the 33 0! i i 1 1 1 1— 1 2 3 4 NITL ITL R e s p o n s e L e v e l s Fig. 3. Pain ratings (1 - 4) and tolerance levels for electric shock under no-incentive (NITL) and incentive (ITL) conditions for psychopaths (P), nonpsychopaths (NP) and staff (C). 34 Table 5 Summary of Analysis of Variance in NITL and ITL by groups and conditions Source SS df MS F Between Ss I960 a - -A (groups) 279.0 2 139.50 3.24* Ss within groups 1681.0 39 43.10 -Within Ss 854.1 42 - -B (conditions) 325.7 1 325.70 30.73** AB (grps x cond.) 1H.8 2 57.40 5.42** B x Ss within grps. 413.6 39 10.60 * p < .05 ** p < .01 difference between NITL and ITL showed a main effect for groups and interaction between groups and conditions. It would seem clear that the interaction was due mainly to the striking increase in Group P's tolerance level with the addition of the incentive. The analysis also yielded the expected main effect for incentive conditions; i.e. a l l groups responded to the incentive to some degree. Examination of the data revealed great individual variation in response to the incentive (Table 4). In Group P only one subject (P7) chose not to accept higher shock with incentive while this was true for five subjects in each of the other groups. Again, in Group P, three subjects (P4» U and 14) at least tripled their NITL with 35 incentive and one (P12) doubled i t j in Group NP only one subject (NP13) doubled his NITL, while in Group C no subjects showed such increases* In view of Schoenherr's (1964) assumption that a high DT may imply a high TL, correlations were computed between DT and TL. Table 6 gives the correlations for each group and for combined groups, according to incentive condition. None of the correlations was sig-nificant. Table 6 Product-moment correlations between DT and TL according to incentive condition (df = 12 for groups, 40 for combined groups) Variables P* NP* G* A l l groups** NIDT x NITL .48 -.04 .14 .10 IDT x ITL .19 -.18 .07 -.12 * r = .53 required for significance at .05 level ** r = .30 required for significance at .05 level • 36 Discussion Detection threshold. The finding of 'normal1 detection thresholds in psychopaths even without special incentives is not consistent with previous findings of high thresholds in this group. Perhaps the most plausible explanation rests on the concept of arousal. As outlined previously there is evidence to suggest (aj that psycho-paths are more prone to underarousal than are normals,and (b) that such underarousal may be associated both with high sensory thresholds and poor performance in tasks requiring sustained attention or involv-ing low sensory input. Arousal or activation refers to a dimension representing the physiological and psychological state of an organism. At certain optimum levels, the organism experiences maximum awareness of i t s environment (e.g. attentiveness, concentration), and peak behavioral efficiency (coordination, timing, flexibility, etc.) (Malmo, 1966). Of primary interest here is the fact that cortical arousal is increased not only when a stimulus is intense but when i t is novel, complex, puzzling, varied or,"meaningful" (Berlyne, 1960j Fiske and Maddi, 1961). Applying arousal 'theory' to the present study, i t is noted that the experimenter was able to present stimuli in a varied and un-predictable way. Further, an attempt was made to break up the tedium of the procedure by inserting trials containing easily detected supra-threshold shocks. These intermittent stronger shocks may have not 37 only given the subject some encouragement as originally intended, but helped to make the task more interesting by providing helpful reference points i n an otherwise rather d u l l discriminative task. The modified forced-choice procedure, then, may have been i n i t s e l f sufficiently arousing to enable the psychopaths to function at an efficient level and thus show thresholds as low as those of the nonps ychopa ths• Hare's (1968b) study of autonomic responses i n psychopaths i s of interest i n the present context. While the psychopaths showed lower levels of autonomic v a r i a b i l i t y (an index of arousal) than the nonpsychopaths, the difference disappeared when the subjects were re-quired to solve arithmetic problems. The apparent connection between cognitive a c t i v i t y and arousal led Hare (1968b) to suggest, i n fact, that psychophysical procedures which increase the psychopath's arousal level should lower his sensory threshold. Implicit i n Eysenck's (1967) discussion of sensory thresholds i s a similar suggestion that an i n -crease i n excitation i n extraverts (psychopaths?) should result i n a drop i n thresholds. Finally, i t may be noted that i n Hare's (1968a) study detection threshold scores were calculated on the basis of the last five of ten blocks of t r i a l s ; perhaps by this time his psychopaths were at a particularly low level of cortical arousal, or, to put i t another way, had become bored with the task. The interpretation of the present results i n terms of arousal i s , of course, speculative. However, i t i s apparent that further re-search on the determination of detection thresholds i n psychopaths 38 under 'arousing' and 'non-arousing1 conditions i s warranted. One of the implications of the present "arousal" interpre-tation i s that, as suggested by Hare (in press), i f a situation i s colourful, interesting, or entertaining enough, the psychopath w i l l perform normally. His reputation for calmness and efficiency i n chaotic l i f e situations would seem consistent with this analysis. Arousal theories of psychopathy (Eysenck, 1964j Quay, 1965), which suggest that the psychopath's intolerance for routine and his reck-less, impulsive behavior may be seen as stimulus seeking.? also imply improved performance with increased stimulation. An alternative explanation for the present results i s simply that the selection procedure was not successful and that the psycho-pathic group was therefore i n fact a mixed group. Some doubt would seem to be cast on this possibility, however, by the fact that the psychopaths did perform as predicted i n the tolerance level task. The p o s s i b i l i t y that certain technical factors distorted the results should be mentioned, (a) The design required that the experi-menter have control over the intensity of the stimulus so as to vary i t from t r i a l to t r i a l . Assuming that such variations affected thresh-olds by contributing to arousal, an experimenter-effect i s conceivable. The experimenter may have unconsciously attempted to provide a more interesting stimulus pattern for psychopaths than for the other groups. It would seem highly unlikely, however, that such a factor was of ap-preciable importance, (b) The use of a forced-choice procedure per-39 mitted the assumption that response criterion factors were adequately controlled. It does not succeed, however, in separating criterion and sensitivity factors which combine to produce the subject's threshold. It would seem desirable that further research employ procedures which do isolate sensitivity, (c.) Finally, i t is noted that, in absolute terms, the thresholds here are much lower than those obtained in Hare's (1968a) study. This is difficult to explain. One possible rea-son may be the fact that in the present study cotton gauze, rather than cotton batting, was used to prepare the skin surface at the elec-trode site. The gauze may have had a more abrasive action with the result that skin resistance was more effectively reduced. Tolerance level. As outlined earlier, stimulus tolerance is highly susceptible to a number of psychological variables. The pre-sent experiment attempted to control for the effect of one of these variables; i.e. motivation, by introducing an incentive. The first question, then, is whether the cigarettes used as the incentive can be assumed to be of equal value for, at least, the inmate groups (P and HP) (Cigarettes cannot be considered to have had comparable value for penitentiary staff). There would seem no apparent reason to reject the assumption of equality. Although the psychopaths had been institu-tionalized longer than the nonpsychopaths, they would not necessarily have a stronger desire for cigarettes; in fact, they may have had the time to achieve higher inmate pay rates. Further, since the object of the experiment was to reveal differences between personality groups, 40 the incentive was offered in a manner designed to appeal equally to a l l groups. The cigarettes were offered in somewhat dispassion-ate or commercial termsj for example, the instructions included: ...just say stop when i t (is) no longer worth i t to you in terms of cigarettes... it's a l l the same to mej it's up to you ..." It may, then, be a reasonable assumption that the incentive was equal for a l l groups. Since anxiety or anticipatory fear arousal may also affect stimulus tolerance (Beecher, 1959), an effort was made here also to avoid an experimental bias for or against any of the groups. It is recalled that subjects were given a chart describing the series of ascending pain levels, the purpose being to give them some notion of what to expect and thus reduce anxiety. It is possible, however, that the chart in fact contributed to greater fear arousal in the nonpsycho-paths than in the psychopaths, particularly since the words "hurt" and "pain" were frequently included. If i t can be assumed, however, that both the incentive and the experimental procedure were free of bias, and, of course, that a l l other determinants of stimulus tolerance were equal, the results do seem to support the general hypothesis that psychopaths have a higher tolerance level for shock than do nonpsychopaths. The generality of the finding awaits research using other pain modalities and other in-centive procedures. Further, other facets of psychopathy could be tested in a stimulus tolerance paradigm. Psychopaths might, for example, 41 respond differentially (a) to delayed and immediate incentives,or (b) to incentives benefitting others rather than themselves. The psychopath's high tolerance level for shock when 'motivated' would seem to support suggestions (Schoenherr, 1964j Hare, 1966) that previous findings of 'normal' tolerance levels in the psychopath are indeed spurious and due to his relative lack of motivation; i t seems he will tolerate more pain i f (immediate? mater-ial?) rewards are offered. This is consistent with the primary role psychological variables appear to play in determining pain tolerance. It does not contradict, of course, the possible additional role of central or peripheral physiological factor such as cortical inhibitory processes (Eysenck, 1967; Hare, in press) or attenuated autonomic fear responses (e.g.. Hare, 1965b).^ One specific implication would seem to be that psychological and personality factors must be controlled when tolerance levels are determined for use as 'aversive' stimuli (cf. Eysenck, 1967). A possible technical defect in the tolerance level procedure was the use of verbal rather than taped instructions. Despite an at-tempt to be objective, an experimenter-effect, tending to encourage psychopaths to accept more shock, was possible. Finally, i t is of interest to note that the results do not indicate a correlation between detection threshold and tolerance level. There seem to be limited data on this matter and what data are-available appear somewhat inconsistent. Schalling (unpublished), for example, found no correlation between the two parameters. And Hare (1968a), 42 calculating the correlations in Schoenherr's data, found that while the nonpsychopathic and control groups showed low positive correla-tions, the psychopaths showed a significant negative correlation. There i s some indirect evidence, however, which seems to bear upon the topic. Gelfand (1964a) reports that pain threshold shows no correlation with pain tolerance when the latter is defined as the difference between pain threshold and tolerance level. As mentioned previously, Gelfand suggests that the subject's response determinants seem to shift quite radically from physiological to psychological ones as stimulation increases from pain threshold to tolerance levels. Thus a lack of correlation between detection threshold and tolerance level would seem to be indicated. 43 Notes 1. The Theory of Signal Detectibility (TSD) provides a mathema-tically precise method of isolating the effects of the response criterion, leaving a relatively pure measure of sensitivity (Swets, 1961; Coombs, in press). The theory separates the ob-server's function as a (rather noisy), sensory device from his function as a decision maker who operates in accord with sta-t i s t i c a l decision theory (SDT). The problem of deciding whe-ther an observation occurred as a result of noise alone or noise plus, the stimulus is a decision based on the ratio of two conditional probabilities or likelihood ratio. The ratio may be represented as a .single dimension on which the observer chooses a certain value as a decision point. This, of course, is the observer's response criterion. It can be shown that i t varies in accord with (a) the observer's assessment of the a priori probabilities that a signal will occur in a given t r i a l or interval, and (b) the relative value (or cost) of a correct or incorrect response. If the observer is induced to change his criterion (e.g. by payoff) from one set of trials to ano-ther, the response criterion can be estimated by appropriate statistical procedures. 2. Defined as subjects who are characterized by a pattern of psycho-pathic behavior but where underlying neurosis, psychosis or or-ganic deficit may exist. In other words, there is some doubt as to proper diagnosis and a mixed group may result. 3* The extent of overlap between the conceptions is not clear, how-ever. First, i t is apparent that Eysenck's description of the psychopath as neurotic (emotionally unstable) contradicts the present concept which regards the psychopath as showing an ab-sence of neuroticism or emotionality. Secondly, there is some empirical data that conflicts with Eysenck's findings of high extraversion in psychopaths. Thus Schoenherr (1964) found no significant difference between psychopaths and nonpsychopathic groups in either extraversion or neuroticism (MPI). It has been suggested, however, that the (primary) psychopath may be a stable extravert, low in neuroticism and high in extraversion (Franks, I960; Hare, in press). 4* whether tolerance level is properly a measure of pain tolerance is a controversial point beyond the scope of this paper. Some investigators (Wolff, 1964) do use the term pain tolerance for this parameter, while others (Gelfand, 1964a, 1964b) suggest that pain tolerance is properly conceived as the individuals tolerance for painful stimulation. The latter definition thus measures pain tolerance as the difference (in stimulus intensity or tempotal units) between pain threshold and stimulus tolerance level. 44 5. One subject's (NP5) NIDT was 0.56 ma. and his IDT then rose to 1.89 na. (no-incentive/incentive sequence). His IDT was thus about 3.4 times his NIDT and, in terms of the variability in IDT for his group, including his own score, the z_ score equivalent i s 3.63 (p. .0001, two-tailed). The score must, therefore, be Considered invalid, although there is no apparent reason for this bizarre result. No special notis by the ex-perimenter appear on this subject's record. It may be noted, however, that he is of Canadian Indian descent, from a rural area, and a rather unstable and self-conscious person. He may have become somewhat anxious over the demands of the task to the point where he was unable to sustain attention. His IDT was, therefore, treated as lost data (Winer, 1962). An analysis of variance (as in Table 3) with this subject's ac-tual IDT included sharply distorts the results. The analysis yields a significant main effect for sequences (F = 10.66} 1,36} p<.01,). No other effects approach significance. 6. The effect of the incentive would seem largely due to the know-ledge of results (K0R) received by the subject after each t r i a l . There is empirical data demonstrating the effect of K0R (Blackwell, 1953), and i t is noted that while a l l groups appear to have shown a similar response to the incentive, cigarettes cannot be expected to have had equal value to both staff (Group C) and inmates (Groups P and NP). Subjects were not questioned as to whether or not they smoked, but there seemed to be very few non-smokers at least among the inmates and these seemed evenly divided between these groups. In any event, cigarettes are of value as a barter in the institution. 7. The explanation rests, in part, on the fact that at optimum levels of arousal the individual experiences not only peak e f f i -ciency but pleasant affect, while deviations to very low (or very high) levels become increasingly 'painful* (Malmo, 1966} Eysenck, 196v). 8. 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APPENDICES 51 APPENDIX A Instructions to penitentiary c l i n i c a l staff for selection of subjects: Your cooperation i s requested i n selecting subjects for the person-a l i t y study now being conducted. Please note carefully the l i s t of 15 descriptive items below, paying particular attention to those items marked with an asterisk. These are the principal c r i t e r i a . The l i s t w i l l be used to select subjects according to whether or not the c r i t e r i a apply to them. On the attached chart please l i s t the names of inmates known to you. Then check each name against each of the 15 descriptive items denoted by the numbers 1 to 15 at the top of the chart. When an item applies to a particular subject place a check mart i n the appropriate squarej when an item does not apply leave the square blank; when you are doubtful place a question mark i n the appropriate square but use the question mark as sparingly as possible. A general description of the sociopathic personality, taken from the APA diagnostic and S t a t i s t i c a l Manual, 1952, i s as follows: Sociopathic Personality Disturbance, Antisocial reaction; This term refers to chronically antisocial individuals who are always i n trouble, profiting neither from experience nor punishment, and maintaining no real loyalties to any person, group, or code. They are frequently callous and hedonis-t i c , showing marked emotional immaturity, with lack of sense of respon-s i b i l i t y , lack of judgment, and an a b i l i t y to rationalize their behavior so that i t appears warranted, reasonable, and j u s t i f i e d . The term includes cases previously classified as "constitutional psychopathic state" and "psychopathic personality". As defined here the term i s more limited, as well as more specific i n i t s application. Criteria 1. Average or superior intelligence. *2. Free from i r r a t i o n a l i t y and other commonly-accepted symptoms of psychosis. *3. Free from any marked nervousness or other common symptoms of psychoneurosis. 4. No sense of responsibility. "Though he may give an early impression of being a most reliable person, i t w i l l soon be found that he has ho sense of responsibility whatsoever to others. Furthermore, the question of whether or not he i s to be confronted with his failure or his disloyalty and called to account for i t appears to have no effect on his attitude." 52 Appendix A (cont'd) 5. Disregard for truth, " . . . i s to be trusted no more i n his accounts of the past than i n his promises for the future or his statement of present intentions ... however ... no matter how v i v i d l y or how repeatedly his utter f a l s i t y i s demonstrated to him, he i s not con-founded but continues to expect his work to be regarded as a very serious matter." *6. No sense of shame, "...does not show the slightest evidence of humiliation or regret. This i s true of matters pertaining to his personal and s e l f i s h pride and to esthetic standards that he avows as well as to moral or humanitarian matters." *7. Antisocial behavior without apparent compunction. "He w i l l commit theft, fraud, and other deeds for astonishingly small stakes and under much greater risks of being discovered than w i l l the ordinary scoundrel. He w i l l , i n fact, commit such deeds i n the absence of any apparent goal at a l l . " *8. Inability to learn from experience. "Despite his excellent rational powers he continues to show the most exercrable judgment about attaining what one might presume to be his ends. It i s this writer's opinion that no punishment w i l l make (him) change his ways." *9. General poverty of affect. "Vexation, spite, quick and labile flashes of quasi-affection, peevish resentment, shallow moods of self-pity, puerile attitudes of vanity, absurd and showy poses of indignation are a l l within his emotional scale ... but mature, whole-hearted anger, true or consistent indignation, honest, solid grief, sustaining pride, deep joy, despair are never found within this scale." *10. Lack of genuine insight. "In a special sense (he) lacks insight to a degree seldom i f ever found i n other mental disorders. He has ab-solutely no capacity to see himself as others see him. Occasionally, however, he w i l l perfunctorily admit himself to blame for everything and analyze his case from what seems almost to be a psychiatric viewpoint, fet (he), shows not only a deficiency but apparently a to t a l absence of insight as a real and moving experience." *U. L i t t l e response to special consideration or kindness. "No matter how well he i s treated ... he shows no reaction of appreciation except superficial and transparent protestations." *12. No history of sincere attempts at suicide. 13. Sex l i f e shows peculiarities. "... they regard sexual a c t i v i t y very casually. None ... (seem to have) ... particularly strong sex-cravings even i n (the) uncomplicated and poverty-stricken sense (of l i t e r a l physical contact). They usually have records of great promiscuity which i s readily understandable i n view of their almost tot a l lack of self-imposed restraint." 53 Appendix A (cont'd) 14-. No strongly adverse or neuropathic heredity; family background not markedly sociopathic or deviant. 15. Onset of psychopathic characteristics no later than early twenties. APPENDIX B: CONTROL VARIABLES Age (years) Time of Day of Testing*  S Group P Group NP" Group G Group, P Group NP Group C 1 16.8 19.7 43.8 4 1 5 2 50.5 22.3 36.2 2 4 3 3 37.7 29.7 22.2 2 4 5 4 25.2 29.2 43.0 3 3 5 5 42.7 25.9 43.7 3 3 3 6 27.1 23.0 37.2 4 4 5 7 22.7 51.8 55.2 3 3 5 8 18.7 27.1 23.3 4 3 3 9 30.2 31.7 47.5 1 1 5 10 37.2 31.4 38.8 3 2 6 11 22.2 23.9 42.4 2 4 5 12 18.7 22.6 20.9 2 4 5 13 50.4 20.8 28.8 2 4 6 U 50.4 32.6 40.6 4 4 4 M 32.2 28.0 37.3 2.8 3.1 4.6 SD 12.1 7.8 9.9 - - -* Code: 1 = 9 a.m., 2 = 11 a.m.. 3 = 2 p.m., 4 = 4 p.m., 5 = 5 p.m., 6 = 9 p.m. Appendix B (cont'd) Revised Beta I.Q. Time Served on Current Sentence (years) Education (years) s Group P Group NP Group P Group NP Group P Group NP 1 100 111 0.25 " 1.00 8 10 2 119 102 3.75 0.92 14 8 3 119 93 3.50 3.50 9 9 4 116 99 3.42 2.17 8 11 5 119 86 2.50 0.50 — -6 99 101 1.17 1.17 8 11 7 101 123 0.83 0.58 - 15 8 116 115 0.50 1.75 8 8 9 110 106 4.83 1.50 11 11 10 118 105 1.50 2.50 13 4 11 103 109 5.42 1.92 8 9 12 123 114 0.42 0.42 8 9 13 102 116 2.83 0.42 7 11 14 98 105 - 0.58 12 7 M 110.2 106.1 2.38 1.35 9.5 9.5 SD 8.9 9.4 1.67 0.89 2.3 2.5 Appendix B (cont'd) MMPI Scores* for Group P s L F K 1 2 3 4 "5 6 7 8 ? 1 5 32 16 62 76 71 98 51 85 74 76 68 2 4 2 18 47 48 53 53 61 47 43 a a 3 3 17 — 40 42 62 60 63 65 41 40 63 4 0 28 18 83 87 73 106 59 100 91 106 81 5 2 10 17 47 72 47 87 63 70 53 65 59 6 7 — : — 90 53 69 75 55 59 66 63 75 8 5 u 18 62 65 51 * 81 59 65 64 83 63 9 6 5 - 40 51 58 78 59 44 46 52 66 10 n 3 4 14 a 48 60 76 69 56 48 51 70 12 0 21 17 17 80 75 119 71 94 77 98 77 13 1 6 17 69 63 65 83 57 67 71 70 75 14 5 5 21 44 60 74 117 54 58 50 45 54 M - - 53.3 62.1 63.2 86.1 60.1 67.5 60.3 65.8 67.7 SO _ _ _ 19.7 _ mm 7.8 * The "?" (evasion) score not available Appendix B (cont'd) MMPI Scores* for Group NP s L F K L 2 ' " 3 4 5 6 7 8 9 1 4 I 1 6 52 84 58 58 63 53 64 53 52 2 •a - - - 4 9 53 58 78 51 59 4 8 4 7 50 4 3 5 1 7 4 5 48 69 53 65 56 4 5 4 4 4 5 5 4 1 7 18 7 2 68 66 78 4 9 85 84 87 7 0 6 3 8 17 54 56 55 50 53 4 4 4 8 51 6 1 7 3 1 16 4 7 56 4 9 50 61 50 53 a 57 8 — _ _ _ — — — _ _ _ _ 9 2 4 6 a 75 49 67 59 6 1 69 4 6 53 1 0 2 3 2 17 85 9 5 69 98 50 9 7 88 107 7 2 1 1 3 4 1 7 6 2 68 7 1 73 68 6 2 a 59 59 1 2 1 10 17 51 53 4 5 63 53 53 63 60 79 13 9 27 19 6 2 7 2 55 7 0 59 73 59 9 2 79 U 2 13 18 9 0 9 6 84 86 63 88 7 4 66 59 M - - - 5 9 . 2 6 8 . 7 6 0 . 7 6 8 . 7 5 7 . 8 6 5 . 1 6 3 . 0 6 4 . 4 6 1 . 3 SD _ _ _ _ 1 4 . 2 1 0 . 8 * The "?" (evasion) score not available 58 APPENDIX C Instructions to Subjects Detention Threshold (on tape) I Method of Limits In the first part of this study we want to determine the lowest level of shock you can just feel. About every five seconds you will hear a tone over the earphones. This is your signal that a shock will follow immediately after the tone. The shock will be very small and you may or may not feel i t . 2bur job is to let me know whether or not you feel i t by saying "yes", "no", or "not sure". I '11 just repeat that. Immediately after each signal tone you may feel something under the elec-trode on your arm. Just say "yes", "no", or "not sure" to let me know whether or not you felt anything. 2su can just use your normal speaking voice and I will hear you quite easily. If you have any questions you may ask now or at any time during the study. (Pause). 5bu will hear the first tone in a few seconds. II Modified Constant-Stimulus Method (1) No-incentive/ihcentive sequence a) No incentive condition; We will now continue in a different way. This time you will hear the tone i n sets of three; that i s , you will hear the tone three times about two seconds apart. A shock will follow one of the tones. 3bur job i s to wait until you have heard a l l three tones and then 1st me know which tone the shock came after by saying "one", "two" or "three". There will always be one shock and only one shock i n each set of three tones. Now i f you did not feel anything or are not sure, guess as best you can as to where the shock might have been. Just to repeat, wait until you have heard a l l three tones and then say "one", i f you felt something after the first tone, "two", i f i t was after the second, and "three" i f i t was after the third tone. If you did not feel anything or are not sure, take a guess as to where you think i t might have been. (Pause). 2ou will hear the first set of tones in a few seconds. 5 9 Appendix G (cont'd.) b) Incentive condition: We'11 now continue i n the same way only this time you can win a cigarette for every two correct answers even though you may get i t right by a guess. If you don't smoke I ' l l arrange to get something else of equivalent value for you at the canteen. Each time you are correct I'11 press a button to operate the counter i n front of you. For every two points, you win one cigarette. 2bu should be able to win anywhere from two to four packs i n this way. Sou w i l l be able to see your score easily. (Pause). The f i r s t set of tones w i l l follow i n a few seconds. (2) Incentive/no-incentive sequence a) Incentive condition: We w i l l now continue i n a different way. This time you w i l l hear the tones i n sets of threej that i s you w i l l hear the tones three times about two seconds apart. A shock w i l l follow one of the tones. 2bur job i s to wait u n t i l you have heard a l l three tones and then l e t me know which tone the shock came after by saying "one", "two", or "three". There w i l l always be one shock and only one shock i n each set of three tones. If you did not fee l anything or are not sure, guess as best you can as to where the shock might have been. Now, you can win a cigarette for every two correct answers even though you may get i t right by a guess. If you don't smoke, I ' l l arrange to get something else of equivalent value for you at the canteen. Each time you are correct, I ' l l press a button to operate the counter i n front of you. For every two points you win one cigarette. Ibu should be able to win anywhere from two to four packs of cigarettes i n this way. Ifou w i l l be able to see your score easily. Just to repeat: wait u n t i l you have heard a l l three tones and then say "one" i f you f e l t something after the f i r s t tone, "two" i f i t was after the second, and "three" i f i t was after the third tone. If you did not feel anything or are not sure, take a guess as to where you think i t might have been. Sbu win one cigarette for every two points on the counter. (Pause). 2bu w i l l hear the f i r s t set of tones i n a few seconds. b) No incentive condition: We'11 now continue i n the same way only from here on no cigarettes w i l l be offered. Just continue to l e t me know which tone the shock came after. (Pause). The f i r s t set of tones w i l l follow i n a few seconds. 60 Appendix 0 (cont'd) Tolerance Level (not on tape) (1) No incentive condition: I'm nov going to gradually increase the level of shock i n small steps. Your job i s to rate or grade the shock as i t reaches different levels. Here i s a chart drawn up as a rough guide. As you see I've said (E read from the chart with the S) "Let me know when you feel the shock strength reaches each of these levels: 1. Uncomfortable or just unpleasant or i r r i t a t i n g but not yet painful. 2. Just getting painful or f a i r l y strong or just starting to hurt. 3. Painful or hurting or strong. 4. Very strong or very painful or hurts a l o t . 5. Stop. Don't wish to go any higher. Just l e t me know how each shock feels by calling out the num-ber on the chart which seems to f i t best, for example: "one" "one", "two" "two", and so on. Ibu may wish to use a number only once or many times or even skip a number. It's up to you. There w i l l be about ten seconds between shocks. !>u w i l l hear a short signal tone about two seconds before each shock just to l e t you know when to expect i t . (E would repeat instructions i f necessary). 5bu w i l l hear the f i r s t signal tone i n about 10 seconds. (2) Incentive condition: Now, i f you wish to go any higher, I ' l l pay you two cigarettes for each step you may wish to go. I would press the button to operate the counter (which was again placed before the S) four times after each step. This would represent two ciga-rettes. I would repeat the last shock you just received and we would then go up i n the same sort of steps as we did before. 5bu could just say stop when i t was not worth i t to you i n terms of cigarettes. If you don't wish to go any higher right now that's quite a l l right with me. Or i f you want to go up a l i t t l e or a l o t i t ' s a i l the same to mej i t ' s up to you. (If S indicated that he didn't care about cigarettes you would say or clearly imply that he would "take" more to help the experi-ment, E simply repeated that i t was up to the Sj he could quit i f he f e l t i t was not worth i t or he could go higher and quit when he though i t was no longer worth i t . If S decided to ac-cept further shocks he was told he would hear the f i r s t signal tone i n about 10 seconds. 61 Name Seq. APPENDIX D Sample Data Sheet (condensed) BCP# S# Pun. Temp. Method of Limits Dial Response Setting (3BS/?/NO) (cont'd) Date Time Forced-choice Interval Dial Response number setting (Cor/lnc) (Random order of stimulus intervals proceeds as follows, left to right: 2* 2 3 2 2 1 1 3 3 1 2 2 1 3 3 2 1 3 3 2 3 1* 3 1 1 2 2 2 3 1 3 1 3 2 2 2 2 1 2 3 3 2 1 2 3 3 3 1 1 3 2 2 2 2 3 1 1- 1* 2 2 3 2 2 2 2 3 3 2 3 1... 1 1 2 1 3 1 3 3 2 2 3 1 3 3 1 1 1 2 3 2 1 1 2 2 1 1 1 1 2 3 1* 2 2 1 1 1 3 3 3 3 3 1 2 3 2 1 3 1 1 2 1 1 3 2 3 1 2 1 1 1 2 2 2 2 3 2 2 1 3 2 3 3 3 1 1 1* 3 2 1 1 1 3 3 3 2 3 3 3 3 3 3 2 3 1 2 2 3 2 1 2 3 2 1 1 1 3 1 2 3 2 3 2 3 2 2 3 3 1 3 1 3 1 1 1 1- 2 1 2* This order is repeated in the alternate incentive con-dition which follows.) Tolerance Level Dial Rating Setting Response (cont'd) Notes: * Skin/electrode resistance check point Appendix E: Individual Detection Threshold Graphs 0.7 0.8 0.9 0.2 0.3 0.4 0.5 0.6 0.1 0.2 0. £9 Appendix E : Individual Detection Threshold Graphs (cont'd) i * • • • ' • — i > • > — t 1 1 —i i i i 1 • i 0.2 0.3 0.-4 0.5 0.6 0.7 0.1 0.2 0.3 0.1 0.2 0.3 0.3 0.4 0.5 0.6 0. Appendix E : Individual Detection Threshold Graphs (cont'd) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.0 0.1 0.2 0.3 0.1 0.2 0. Mllliamperes Percentage Correct Responses (Log^o) Incentive Conditions 99 Percentage Correct Responses (Log^) Appendix E: Individual Detection Treshold Graphs (cont'd) 1.3 1.4. 1.5 1.6 1.7 1.8 1.9 2.0 2.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 100 90 80 70 60 50 40 30 NP7 NP8 • o o-® > 30 t r i a l s « 11-30 t r i a l s o < 11 t r i a l s 1.3 1.4 1.5 1.6 1.7 1.8 0.1 0.2 0.3 0.4 Milliamperes 0.5 0.6 0.7 0.8 0.9 1.0 1.1 Appendix E: Individual Detection Threshold Graphs (cont'd) 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 0.1 0.2 0.3 0.4 0.1 0.2 0.3 0.4 0.5 MLlliamperes Percentage Correct Responses (Log,n) Percentage Correct Responses (Log^) 00 vO o o o o o •i>-o o ON o rlf-V j J o o Ul ON «J 0J\O o o o o o o o o 00 o o ON o o 00 o o H O JO o o o • 0 A f V p u> v*> H O O ei- et- ct-*t H n H H H w m xa IDT NIDT Incentive Conditions XL 30 Appendix E: Individual Detection Threshold Graphs (cont'd) "t i_ O > 30 trials • 11-30 trials ° < 11 trials 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 0.4 0.5 0.6 0.7 0. 100 90 80 70 60 50 40 30 o — o C6 © / l 1 1 / ' / i 1 I 1 • / / i ' 1 1 1 T , • . 1 1 1 i • 1 1 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 Milliamperes 2.4 0.4 0.5 0.6 0.7 0.8 0. Percentage Correct Responses (Log^) < 03 v O O o o o o o o o o o o O^ < GO sO Q o o o o o o « o o o Vn o ON o ro o o o o • fo o o o c*- e+ H H H ta ta IDT NIDT Incentive Conditions a Appendix E: Individual Detection Threshold Graphs (cont'd) E-t Q 0.3 0.4- 0.5 0.6 0.7 0.8 0.3 0.4 0.5 0.6 0.7 0.8 0.1 0.2 0.3 0.4 0.5 100 90 80 70 60 50 40 30 0 Cll © > 30 trials *11-30 trials o < 11 trials 0.3 0.4 0.5 0.6 0.7 0.1 0.2 0.3 0.4 0.5 Millia rape res 0.6 0.7 0.8 0.2 0.3 0.4 0.5 o tf ra © CQ a o &. ra O CD f n 8 8> 48 CD O CD P-. 100 90 80 70 60 50 40 (-30 Appendix E: Individual Detection Threshold Graphs (cont'd) o— 013 0 ~ i — 0.4 • i i Q > 30 trials • 11-30 trials ° < 11 trials 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 100 90 80 013 < • GL4 • . 70 60 0 , 0 o 50 40 1 1 ; 30 1 0 1 1 1 > 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 Millia mperes APPENDIX F: DEPENDENT VARIABLES Detection Thresholds under No-incentive (NIDT) and Incentive (IDT) Conditions (in ndlliamperes) Group P Group NP Group C s NIDT IDT NIDT IDT NIDT IDT 1 1.16 6.67 0.16 0.15 0.13 0.19 2 0.46 o .H 0.39 0.25 0.64 0.51 3 0.17 0.15 0.55 0.84 0.71 0.55 4 0.21 0.21 0.51 0.23 0.20 0.38 5 0.42 0.51 0.56 0.49* 1.98 1.88 6 0.23 0.25 0.29 0.21 0.61 0.64 7 0.35 0.34 1.85 1.62 0.47 0.59 8 0.41 0.46 0.25 0.35 0.23 0.29 9 0.18 0.16 0.91 0.81 0.30 0.25 10 0.25 0.16 0.34 0.34 0.68 0.49 11 0.54 0.36 0.44 0.29 0.61 0.55 12 0.20 0.18 0.34 0.27 0.29 0.33 13 0.73 0.66 0.41 0.45 0.96 0.59 14 0.23 0.20 0.81 0.86 0.92 0.99 M 0.40 0.32 0.56 0.51* 0.62 0.59 SD 0.26 0.18 0.41 0.39* 0.45 0.41 * This score interpolated (see note 5 ) . S NP5 actual score = 1.89 ma. Resulting M = 0.61 ma. and SD = 0.52 ma. Appendix ff (cont'd) Pain Rating Scores for Group P (in milliamperes) 1 2 3 4 (uncomfortable) (slightly painful) (painful) (Very painful) 1 1.24 2.89 4.54 8.66 2 1.29 3.61 5.41 6.44 3 1.65 3.71 5.36 7.01 4 1.24 2.47 5.77 9.49 5 2.89 6.60 8.66 9.90 6 2.06 3.71 4.54 5.77 7 1.24 2.47 2.75 2.95 8 1.24 3.71 6.60 8.25 9 1.24 3.30 5.77 8.66 10 1.03 2.32 3.61 5.15 11 2.06 5.77 7.63 9.12 12 3.71 7.84 9.07 10.31 13 1.54 5.15 9.97 14.85 14 0.51 1.03 1.29 1.81 M 1.64 3.90 5.77 7.74 Appendix F (cont'd) Fain Rating Scores for Group HP (In railliamperes) 1 2 3 (uncomfortable) (slightly painful) (painfuJ 1 0.77 2.06 3.35 2 2.47 5.36 8.25 3 2.47 5.77 7.84 4 1.49 4.12 5.67 5 2.47 5.36 7.01 6 3.30 6.60 7.84 7 3.30 7.42 9.07 8 1.29 2.57 3.35 9 1.24 2.89 4.54 10 1.24 2.47 5.77 11 1.65 3.71 5.77 12 0.82 3.71 8.66 13 1.24 2.47 4.54 14 3.71 7.84 9.07 M 1.96 4.45 6.48 4 (very painful) 5.41 10.72 10.31 6.19 8.25 9.49 9.28 4.89 7.01 9.07 7.84 17.72 7.01 10.31 8.82 Appendix F (cont'd) Pain Rating Scores for Group G (in milliamperes) 1 2 s (uncomfortable) (slightly painful) 1 0.77 1.29 2 1.24 2.89 3 1.03 2.57 4 1.24 2.47 5 1.24 2.47 6 0.82 2.47 7 2.47 5.36 8 1.24 2.89 9 1.24 2.47 10 2.47 6.19 11 2.06 4.95 12 2.47 4.95 13 1.24 2.47 1.24 2.47 M 1.48 3.28 3 4 (painful) (very painful) 1.49 2.06 3.71 4.12 4.12 6.45 3.30 3.71 3.71 6.60 4.54 8.66 6.60 7.42 4.54 6.19 4.12 6.60 8.66 10.31 6.60 8.25 6.60 9.07 3.30 3.71 2.89 3.30 4.58 6.17 Appendix F (cont'd) Shock Tolerance Levels Under No-incentive (NITL) and Incentive (ITL) Conditions(in adlliampe Group P " Group NP Group C s NITL ITL NITL ITL NITL ITL 1 12.37 16.50 7.22 13.40 2.52 2.52 2 7.22 12.78 11.55 16.08 4.95 4.95 3 8.25 11.55 12.37 14.85 8.25 12.16 4 10.72 31.34 6.70 6.70 4.12 4.12 5 10.72 11.55 9.07 12.37 9.07 10.72 6 6.60 8.25 10.72 14.85 12.37 16.50 7 3.30 3.30 9.90 9.90 8.25 10.72 8 9.07 12.37 6.19 6.19 7.42 11.55 9 10.72 14.85 9.07 13.20 8.25 10.72 10 6.19 11.34 9.90 9.90 11.55 14.02 11 10.10 32.99 9.07 11.55 9.90 9.90 12 11.55 24.74 24.74 27.19 10.72 12.37 13 16.50 20.62 8.25 18.97 4.12 5.77 14 2.57 14.23 11.55 U.55 4.12 4.12 M 8.99 16.17 10.45 13.34 7.54 9.30 SD 3.54 8.16 4.34 5.08 3.00 4.09 


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