Bdwr
au\ x
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l-hrr‘,p\. viii 17. pp. 215 10 ?‘? Press Lid 1979. Punted SD Great Britain
DEVIANT H.
0005.7967 79 OSOl-O~lJSO2oO 0
SEXUAL
AROUSAL
IN RAPISTS
E. BARBAREE, W. L. MARSHALL and R. D. LANTHIER
Department of Research, Regional Psychiatric Centre, and Queen‘s University. Kingston. Ontario, Canada (Received 23
August
1978)
Summary-Increases in penile circumference of 10 incarcerated rapists and 10 male graduate students were measured during verbal descriptions of mut~ily~onsenting sex, rape and violent non-sexual assault. Mutually-co~enting sex evoked sexual arousal in both groups. Rape evoked comparable arousal in rapists but significantly less arousal in non-rapists. Assault evoked significantly less arousal in non-rapists and tended to evoke less arousal in rapists. However, the rapists did not exhibit greater sexual arousal to forced or violent sex compared with consenting sex, either as a group or as individuals. It is not necessarily true that forced or violent sex evoked rapists’ arousal but perhaps that force or violence failed to inhibit their arousal.
Deviant sexual arousal is often invoked to explain deviant sexual behavior. For example. it is well known that males evoke sexual arousal in homosexuals, and children evoke sexual arousal in pedophiles. A similar explanation may be offered to account for violent sexual assaults and rape. Abel, Barlow, Blanchard, and Guild (1977) recorded sexual arousal of rapists and non-rapists during 2-min verbal descriptions of mutuallyconsenting sex and rape, and found that rapists were more aroused by descriptions of rape than were non-rapists. As a group, rapists were equally aroused by rape and mutually-consenting sex, while non-rapists were considerably less aroused by rape than mutually-consenting sex. According to the explanation implied by these authors, rape is motivated by sexual arousal evoked by the non-consent of the victim and the offender’s use of force or violence, and reinforced by sexual ratification. This explanation of rape would suggest that the reduction of deviant arousal (e.g. Barlow, Leitenberg and Agras, 1969; Feldman and McCulloch, 1965; Marshall, 1973) must be an essential treatment goal in the rehabilitation of rapists. The work presented here re-examined deviant sexual arousal in rapists and was prompted by two possible flaws in the Abel et al. (1977) study. First, Abel et ai. (1977) constructed idiosyncratic verbal descriptions of rape designed to maximally arouse each individual rapist (Abel, Blanchard, Barlow and Mavissakalian, 1975) modeled after each rapist’s description of their own rape behavior. Since non-rapists had never raped, equivalent rape episodes designed to maximally arouse the non-rapists would have been difficult to construct and must have been based on arbitrary decisions by the investigators. Verbal descriptions of rape may have been more arousing to the rapists than non-rapists simply because these investigators took care to maximize rapists’ arousal to rape cues. Second, Abel et al. (1977) group of non-rapists may have been inappropriate. Sexual arousal can only be specified as deviant after comparing such arousal with arousal evoked by the same stimuli in normal males who prefer mutuallyconsenting sex with adult females. Abel et al. (1977) control group consisted of bisexuals, exhibitionists, pedophiles, and voyeurs whose deviant sexuality may have contributed in unknown ways to their lowered arousal to rape cues, indicating perhaps incorrectly that enhanced arousal to rape in rapists was deviant. In the present study, a standard set of 2-min audio-taped verbal descriptions of mutually-consenting sex, rape and non-sexual assault were presented to 10 incarcerated rapists and 10 graduate students whose adult sexual behavior had been restricted to mutually-consenting sex with post-pubescent females. * Requests for reprints should be addressed to Dr. H. Barbaree, Department chiatric Center (Ontario), Box 22, Kingston. Ontario K7L 4V7. 215
of Research, Regional Psy-
H. E. BARBAREE,W. L. MARSHALL and R. D. LANTHIER
216
METHOD
Subjects
Ten men incarcerated in Canadian Federal Penitentiaries aged between 24 and 37 (x = 30.7) years volunteered as experimental subjects. Seven were serving between 4 and 15 (H = 8.5) years for the crime of rape. An eighth man was serving an indeterminate sentence, functionally equivalent to a life sentence, for the crime of rape. A ninth man was serving a life sentence for non-capital murder committed during an attempted rape, while the tenth man was serving a seven year sentence for robbery. and had volunteered for treatment to rid him of his urges to rape. A summary of convictions for each rapist was derived from his criminal record and is presented in Table 1. Obviously, several men in this group of rapists had been convicted of rape and sexual assault. Rape charges had been laid against men in this group which had not resulted in conviction and several men admitted in confidence to rapes and sexual assaults they had committed but for which they had not been apprehended or charged. The sex offences committed by these men were confined to rapes and sexual assaults against post-pubescent femaies. None had ever been convicted of nor admitted to other sexual offences such as child molestation, voyeurism, exhibitionism. frottage. homosexuality. or fetishism. Typical of rapists, these men had been convicted of a wide range of criminal offences besides rape and sexual assault. Five had been convicted of violent offences which did not involve sexual behavior or female victims, and seven had been convicted of Break and Enter or Theft. Each of these men had begun their criminal careers at an early age. Since records of juvenile offences do not appear on their criminal records, some of these men may have begun their criminal careers at an earlier age. On the basis of these considerations, the rapists studied here were similar to rapists studied elsewhere (Amir, 1971; Cohen, Garafalo, Boucher and Seghorn, 1971; Gebhard, Gagnon, Pomeroy and Christenson, 1965; Christie, Marshall and Lanthier, to be published). Ten graduate students at Queen’s University aged between 21 and 34 (x = 26.2) years volunteered to serve as subjects in the control group and received remuneration for their experimental participation. None of the men in the control group had a criminal record and all were heterosexuals by self report. Apparatus
Sexual arousal was measured by mercury-in-rubber strain gauge plethysmography (Abel, Levis and Clancy, 1970; Bancroft, Jones and Pullman, 1966; Fisher, Gross and Zuck. 1965; Laws and Rubin, 1969; Rosen, 1973; Marshall, 1973; Quinsey and Bergerson. 1976). A mercury filled sylastic rubber tube (digital or closed gauges, Parks EiecTable
1. Summary
of convictions
for the rapists Convictions
Subjects
at test
Rl R2 R3 R4 R5 R6 R7 R8 R9 RlO
26 31 37 36 37 24 31 26 24 36
at latest: conviction 23 31 35 35 36 19 30 22 24 33
at
first: 17 16 19 20 18 19 16 18 23 21
Of latest victim 15 22 18 12 20 15 14 18 20 24
* Sex oliences: A = Rape, B = Sexual assault, other t Non-sexual violent offences: A = Murder, D = Robbery. $ Property offences: break and enter, theft.
Sex offences* B A 1 0 2 1 1 0 2 1 1 2
1 0 0 0 5 0 0 3 0 2
Non-sexual violentt offences A B C D 0 0 0 0 0 1 0 0 0 0
0 2 0 1 1 0 0 3 0 1
0 2 0 0 1 0 0 0 0 0
0 2 0 0 1 0 0 0 0 0
sex ogences against adult females. B = Assault, C = Dangerous weapons
property: 0Rence-s 1 3 2 0 5 0 0 3 1 2
otTences.
Deviantsexual arousal in rapists
217
tronics) of appropriate diameter for each subject was fitted midway along the longitudinal axis of the subject’s penis. A plethysmograph (Parks Electronics, Model 270) monitored conductance of the mercury column which decreased as the mercury was stretched by increases in penile circumference. The output of the plethysmograph, a d.c. voltage proportional to the conductance of the mercury column, was monitored by a digital voltmeter (DVM, Hewlett Packard, Model 343OA). Care was taken to ensure that increases in voltage output of the plethysmograph were linearly related to increases in penile circumference (Davidson, Lanthier and Barbaree, to be published). Verbal descriptions of sexual episodes were recorded on audio tape and presented to subjects from one channel of a stereo reel-to-reel tape recorder (Sony, Model TC-270) via monaural headphones. Sexual arousal was measured while subjects sat comfortably in a ‘lazy-boy’ chair in a sound-attenuated room. The experimenter, tape recorder. and DVM were housed in an adjacent room. Communication between the experimenter and subject was accomplished by an intercom system and a microphone connected directly to the subject’s headphones.
Verbal descriptions of seven episodes were written in the second person to indicate to the subject that he was the male in the episode. Six of these episodes included sexual foreplay and intercourse between an adult male and adult female which culminated in the male’s orgasm. Each of these six sexual episodes were designed to be different in (a) the consent given by the woman to the proposed and ongoing sexual behavior, and (b) the force and violence perpetrated by the male protagonist on the woman victim in the course of the sexual episode. There were three episodes of mutuallyconsenting sexual foreplay and intercourse in which the degree of consent to sexual behavior given by the woman was varied. In Episode 1, the woman was described as being enthusiastic in her sexual behavior with the male, and she initiated most of the sexual behavior. In Episode 2, the woman was passive, neither initiating nor rejecting sexual behavior with the subject. In Episode 3, the woman was at first reluctant but was finally seduced by the subject. There were three verbal descriptions of rape episodes in which the force and violence perpetrated by the subject was varied. In Episode 4, after the woman refused sexual behavior with the subject, the subject used verbal threats to coerce her to comply with his sexual desires. In Episode 5, the subject physically restrained his victim while he raped her. In Episode 6, the subject restrained the woman and physically assaulted her, punching and slapping the woman while he raped her. Each different sexual behavior was located as close as possible to the same temporal locus in each of the six sexual episodes. The descriptions of the sexual behavior did not included oral or anal sex. The final episode was not, strictly speaking, a sexual episode. Episode 7 described the male subject physically assaulting a woman (as in Abel er al., 1977) but there was no sexual behavior described in this episode. A second similar but slightly different set of seven episodes were also written, All 14 episodes were then recorded on one channel of the stereo tape in a male voice so that each verbal description was 2 min in duration, A metronome presenting ‘beeps’ every 10 set was recorded on the second of the stereo channels and anchored temporally such that the onset of each of the 14 episodes coincided with the onset of a lo-set period. Verbal descriptions were presented from the first stereo channel through the subject’s monaural headphones while both stereo channels were heard by the experimenter in his separate room. As subjects arrived for testing, they were told that their sexual arousal would be monitored and the operation of the monitoring device and digital strain gauge was explained to them. They were told that while their sexual arousal was monitored they would be presented with verbal descriptions of mutuaIly-consenting sex, rape, and a man physically assaulting a woman. They were also told that sexual arousal in response to all these descriptions was natural and that sexual arousal evoked by violent episodes would not indicate a propensity to enact such episodes. Subjects signed a form indicating 8X.1.I7 3-D
218
H. E.
BARBAREE,W.
L.
MARSHALL and
R. D.
LANTHIER
their informed consent to the experimental procedure and were then instructed as to the proper procedure for fitting the digital strain gauge. The experimenter left the room while the subject fitted the gauge and settled comfortably in his chair. Subjects sat on the towel-covered chair with clothing lowered below mid thigh. During experimental procedures a sheet covered them from the waist down and was supported by the arms of the chair. This covering did not rest on the subject’s penis or strain gauge. Subjects were then instructed to place the headphones on and to sit back comfortably in the chair. Subsequent instruction to subjects were presented through the headphones:
I am about to present you with several descriptions of sexual behavior. We are interested in the way in which you become sexually aroused to each. During each fantasy. try as much as possible to imagine yourself being right there, doing the things described in the fantasy. Please do not try to inhibit or control your arousal. If you do, we will just have to do ail of this again. Each fantasy will last approximately 2 min and there will be time in between fantasies for you to relax. After a fantasy is over. please do not continue to think about it. The session will last less than I br. Sit back and relax and we shall begin.
In order to reduce the confounding effects of the order of presentation of the seven episodes occasioned by the ‘warm-up’ effect commonly observed in tests of sexual arousal, three warm-up verbal descriptions including mutually-consenting sex, rape, and assault were presented.prior to the seven episodes in each experimental session. These warm-up episodes were similar to some but different from all of the seven episodes. Presentation of these episodes also gave the subject prior information about the nature of all of the episodes so that the surprise occasioned by particular verbal descriptions might not unduly enhance or inhibit arousal. Sexual arousal was not measured during these warm-up descriptions which were presented in a random order to each subject. Presentation of the seven episodes followed these warm-up episodes. Seven different quasi-random orders of presentation were used providing for an equal number of presentations of each episode early and late in the session over each of the two groups of subjects. The one restriction placed on the randomness of the orderings ensured that episodes of a given type (either mutually-consenting or rape) never followed one another more than once in any order. Each subject was presented with a different order in different sessions, and generally episodes presented early in one session were presented late in the other and vice versa. The time between the offset of one episode and the onset of the next was most often between l-2 min, was never less than 1 min, and never more than 5 min. Subsequent episodes were not begun until penile erection evoked by the preceding episodes had subsided to a near flaccid state. Experimental sessions lasted approximately 45 min. Sexual arousal was recorded by the experimenter at lo-set intervals signalled by the metronome ‘beep’. At each ‘beep’, the experimenter wrote down the contents of the visual display in the DVM (i.e. the voltage output of the plethysmograph). Four such recordings were made prior to each episode, 12 such recordings were made during each 2-min episode, and six such recordings were made during the first I-min period after the end of each episode. The lowest voltage output recorded during each session was designated as 0% of full erection. At the end of each session, the subject was asked if he had achieved a full erection during the session. If he said “yes”, the largest recorded amplitude of the plethysmograph output during the session was designated as 100% full erection. If he answered “no”, he was asked to produce a full erection without disturbing the strain gauge and was given facilatory visual erotic material. In the event that a full erection was not achieved by a subject in one of the sessions, an estimate of plethysmograph output at full erection was based on the range of voltage output from 0% to 100% full erection during the subject’s other session. In the event that a full erection was not achieved by a subject during either session (this occurred in three subjects) an estimate was based on the mean range of output (0% to 100%) of the other subjects.
Deviant sexual arousal
in rapists
219
RESULTS Erectile responses evoked by sexual episodes were determined by calculating the difference between the maximum voltage output of the plethysmograph during each presentation of an episode and voltage output at 0% of full erection (the flaccid state) of individual subjects. These differences in voltage output were then expressed as a per cent of the change in voltage output from 0% to 100% of full erection of individual subjects. Average erectile responses are presented in Fig. 1. Analysis of variance together with six planned orthogonal comparisons were applied to these data, first to each group separately, then to both groups combined. The six planned comparisons were designed to detect differential responding evoked by the different verbal descriptions. First, arousal evoked by the physical assault was compared with arousal evoked by the three mutuallyconsenting and three rape episodes combined. Second, arousal evoked by the three rape episodes was compared with arousal evoked by the three mutually-consenting episodes. Third, two comparisons were designed to detect differential responding evoked by the three rape episodes. In the first of these, arousal to the most violent rape was compared with arousal to the other two rapes combined. In the second of these, arousal to the rape with verbal threats was compared with arousal to the rape with physical restraint. Finally, two comparisons were designed to detect differential responding evoked by the three mutually-consenting sexual episodes. In the first of these, arousal evoked by the episode describing sex with an enthusiastic female partner was compared with arousal evoked by the episodes describing sex with the passive and reluctant partners combined. In the second of these, arousal evoked by the passive partner was compared with arousal evoked by the reluctant partner. In order to provide a standard against which to judge the rapists’ sexual arousal, results of the control group are presented first. The seven verbal descriptions of sexual episodes evoked differential sexual arousal in the non-rapists, F (654) = 13.416, p < 0.001. The non-sexual physical assault evoked less sexual arousal than the six sexual episodes, F (1,9) = 31.037, p -C 0.001. The three rape episodes evoked less sexual arousal than the mutually~o~enting sexual episodes, F (1,9) = 27.018, p < 0.001, and this difference between rape and mutually-consenting episodes was accentuated in the second as compared with the first session, F (1,Q) = 5.388, p < 0.05. The most violent rape episode evoked less arousal then the other rape episodes, F (1,9) = 8.482, p < 0.025, while the rape with physical restraint evoked no less arousal than the rape with verbal
60
@j
RAPISTS
0
NON-RAPISTS
TT
MUTUALLY
RAPE
ASSAULT
CONSENTING
Fig. 1. Mean sexual arousal evoked by 2-min verbal descriptions of mutually-consenting sex, three varieties of rape and one assault in 10 rapists and 10 non-rapists. Joined brackets indicate the standard error of each mean.
220
H. E. BARBAREE.W. L. MARSHALL and R. D. LANTHIER
threats, F (1,9) < 1.00. Finally, no differential arousal was evoked by the three mutuallyconsenting episodes, F’s (1,9) < 1.05. In the rapists. the seven episodes did not evoke differential sexual arousal. F (6.54) = 1.763, n.s. While the difference between rapists’ arousal to the assault and arousal to the six sexual episodes approached significance, F (1,9) = 3.685, p < 0.10, their arousal to rape episodes was not significantly lower than their arousal to mutually-consenting episodes, F (1,9) < 1.00. This result could have obtained if a few rapists had exhibited rape arousal which was substantially greater than their mutually-consenting arousal. while the remainder of the group’s mutually-consenting arousal was substantially greater than their rape arousal. Such was not the case. Only three rapists became more aroused to the rape episodes than to the mutually-consenting episodes, and for two of these men, this difference was only marginal. Therefore, the group means presented in Fig. 1 accurately represent the pattern of arousal for the majority of rapists in this study. As described earlier, the non-rapists exhibited significantly lower arousal to rape than to mutually-consenting episodes, and the rapists differed from the non-rapists in this respect, F (lJ8) = 4.598, p < 0.05. None of the results of the remaining comparisons detected any differential responding to the various episodes in the rapists, nor any other differences between rapists and non-rapists. Overall sexual arousal did not change over sessions, F (1,18) < 1.00, and there was no evidence that incarcerated rapists became more aroused than non-rapists at liberty, F (lJ8) < 1.00. DISCUSSION As reported previously (Abel, Barlow, Blanchard and Mavissakalian, 1975; Abel, Barlow, Blanchard and Guild, 1977; Abel, Blanchard, Barlow and Mavissakalian. 1975; Abel, Levis and Clancy, 1970), audio-taped descriptions of sexual behavior evoked sexual arousal in male subjects, and different descriptions of sexual behavior evoked different levels of sexual arousal. Similarly, as in earlier studies, differential sexual arousal evoked by different descriptions of sexual behavior discriminated between groups of subjects when group membership was defined by previous sexual behavior. In general, the results of the present study which presented a standard set of verbal descriptions of mutuallyconsenting sex, rape, and assault to a group of incarcerated rapists and a control group of male graduate students agreed with the results of the earlier study reported by Abel et al. (1977) which presented idiosyncratic verbal descriptions to rapists and a control group of non-rapist sexual deviates. In non-rapists, descriptions of rape and assault evoked considerably less sexual arousal than descriptions of mutually-consenting sex. But, in rapists, the different descriptions of sexual behavior did not evoke different levels of sexual arousal. We intentionally structured the six descriptions of sexual behavior including the three mutually-consenting and the three rape episodes, to include the same sexual behavior. But. within these six episodes we varied the context within which the sexual behavior occurred. For example, rape and mutually-consenting episodes, although including the same sexual behavior, differed in the consent offered by the female to the proposed and ongoing sexual behavior, and the force or violence used by the male to gratify his sexual desires. Furthermore, within the three mutually-consenting episodes, the same sexual behavior was described but the degree of consent given by the female was varied from a female desiring and enjoying the sexual behavior, to a female who expressed no desire for nor objections to the sexual behavior, to a female who objected to the sexual behavior but eventually complied with the male’s wishes. Moreover, within the three rape episodes, the same sexual behavior was described, but the degree of force or violence used by the male in accomplishing the sexual behavior was varied from verbal threats to physical restraint to slapping and punching. We presented these six sexual episodes to subjects to determine how consent of the female or force used by the male affects the sexual arousal normally evoked by descriptions of sexual behavior. The non-rapists showed significantly less arousal to the rape episodes than the
Deviant
sexual
arousal
in rapists
221
mutually-consenting episodes and there are two possible explanations of this effect. First, the force and violence used by the rapists in the rape episodes inhibited or suppressed erectile responses that would in other contexts be evoked by descriptions of the sexual behavior (Abel er al., 1977). Second, consent to sexual behavior is arousing to nonrapists, and less arousal was evoked during the rape descriptions because consent to sexual behavior was not offered by the female. We prefer the first of these explanations because when consent offered by the female was systematically varied in the mutuallyconsenting episodes, no differential arousal obtained. Therefore, the non-rapists’ lower arousal to verbal descriptions of rape is best explained as a suppression or inhibition of erectile responses by the force or violent aspects in the rape episodes. Further support for this explanation is provided by the non-rapists’ differential arousal within the rape episodes. The most violent rape which included the male punching and slapping the female evoked significantly less arousal than the less violent rapes. The rapists on the other hand exhibited no differential arousal over these six sexual episodes. A consequence of this fact is that rape descriptions evoked relatively greater sexual arousal in rapists than non-rapists. We might characterize deviant sexual arousal in rapists by this general statement of fact and conclude that force, violence and nonconsent of the female is relatively more sexually arousing for rapists than non-rapists. On the basis of the evidence at hand, this conclusion is unjustified and could lead to a serious misunderstanding of rapists and rape behavior. This conclusion is based on the assumption that rapists’ sexual arousal evoked by descriptions of rape is a demonstration of control over rapists’ sexual arousal by force, violence, or non-consent of the female. However, behavioral control by a stimulus can only be inferred from differential responding over variations in some dimension of the stimulus (e.g. Nevin, 1973). A simple illustration will clarify this point. If an animal experimenter were to train a pigeon to peck a red keylight for food reinforcement, he might later discover that the pigeon also pecked a yellow keylight. The experimenter might then conclude that ‘yellow’ evoked key pecking in this pigeon. However, such was not necessarily the case. The pigeon may have simply responded to changes in luminance in the keylight, and the key’s yellowness may not have affected the bird’s responding at all. In other words. this experimenter failed to demonstrate that the colour of the key controlled the birds’ responding. When rapists in this study and in the Abel er al. (1977) study did not show differential responding to rape versus mutually-consenting sexual episodes, we failed to demonstrate oontrol over rapists’ sexual arousal by consent of the female or force of the ma1e. It might have been that rapists simply attended to the female in the episodes and responded to the descriptions of sexual behavior with her while her consent and the male’s force had no influence whatsoever on their sexual arousal. Therefore, sexual arousal in these rapists may have been deviant, not necessarily because force and violence and non-consent of the female evoked their sexual arousal, but perhaps because force, violence and non-consent of the female failed to inhibit their sexual arousal. The mechanism by which consent of. the victim, force or violence inhibits responding in the non-rapists is not known. Perhaps the non-rapists are affected emotionally by the rape episodes and fear or empathy for the victim inhibits sexual arousal. Or, perhaps the non-rapists are keenly aware of social pressure or experimenter demands against arousal to rape cues and they exert voluntary control over their sexual arousal (Freund, 1961; Laws and Rubin, 1969; Henson and Rubin, 1971; Quinsey and Bergerson, 1976). Perhaps rape arousal is not inhibited in the rapists because they have been desensitized to the emotional effects of force and violence by greater experience with violence in prison or in the subculture to which they belong. Perhaps rapists are not as we11aware of the social pressures against rape arousal or perhaps they are less able to exert voluntary control over their sexual arousal. The choice of a treatment for rapists and a method for evaluating its effectiveness depends heavily on our understanding of their deviant sexual arousal. Unfortunately, at the present time, we do not know what stimuli control rapists’ sexual arousal.
H. E. BARBAREE, W. L. MARSHALLand R. D. LANTH~ER
222
Acknowledgenrcnrs-Financial assistance was provided by the Medical Services Branch of the Department of the Solicitor General for Canada, and the Non-Medical Use of Drugs Directorate. Canadian Ministry of Health and Welfare. We wish to thank B. Malcolm who assisted in all stages of the work. and E. Backman who assisted in the testing of subjects. L. Lightfoot. P. Davidson, and D. Baxter read an earlier draft of the paper and provided most helpful comments. D. J. K. Mewhort provided invaluable advice concerning the data analysis. REFERENCES ABEL G. G., BARLOWD. H., BLANCHARDE. B. and GUILD D. (1977) The components of rapist’s sexual arousal. Archs gen. Psych&. 34, 895-903. ABELG. G., BARLOWD. H., BLANCHARD E. B. and MAVISSAKALIAN M. (1975) Measurement of sexual arousal in male homosexuals: The effects of instructions and stimulus modality. Archs Sexual Behau. 4, 623-629. ABEL G. G., BLANCHARDE. B.. BARLOWD. H. and MAVI~~AKALIAN M. (1975) Identifying specific erotic cues in sexual deviations by audio-taped descriptions. J. appl. Behau. Anal. 8. 247-260. ABELG. G., LEVISD. and CLANCYJ. (1970) Aversion therapy applied to taped sequences of deviant behavior in exhibitionism and other sexual deviations: A preliminary report. J. behac. Ther. expl Psychiar. 1, 59-66. AMIR M. (1971) Patterns in Forcible Rape. University of Chicago Press, Chicago. BANCROFT J. H. J., JONESH. G. and PULLMANB. R. (1966) A simple transducer for measuring penile erections with comments on its use in the treatment of sexual disorders. Behao. Res. Ther. 4, 239-241. BARLOWD. H.. LEITENBERG H. and AGRASW. S. (1969) The experimental control of sexual deviation through manipulation of the noxious scene in covert sensitization. .I. Abnorm. Psycho/. 74, 596-601. CHRISTIEM. M., MARSHALLW. L. and LANTHIERR. D. A descriptive study of incarcerated rapists and pedophiles. Manuscript submitted for publication, 1977. COHENM. L.. GARAFALO R., B~UCHERR. and SEGHORNT. (1971) The psvcholoav Semin. in Ps\,chiat. __- of rapists. . 3, 307-327. DAVID~CIN P., LANTHIERR. D. and BARBAREE H. E. Penile response measurement: Operating characteristics of Parks Plethysmograph. Manuscript submitted for publication, 1977. FELDMANM. P. and MACCULLOCHM. J. (1965) The application of anticipatory avoidance learning to the treatment of homosexuality. I. Theory, technique, and preliminary results. Eehac. Res. Ther. 2, 165-183. FISHERC., Gross J. and ZUCH J. (1965) Cycle of penile erections synchronous with dreaming (REM) sleep. Arch.
gen. Psychiat.
12, 29-45.
FREUNDK. (1961) Laboratory differential diagnosis of homo- and heterosexuality: An experiment with faking. Rec. Czech. Med. 7, 20-31. GEBHARDP., GAGNONJ., POMEROYW. and CHRISTENSON C. (1965) Sex Offenders. Harper & Row, New York. HENSOND. E. and RUBIN H. B. (1971) Voluntary control of eroticism. J. oppl. Behac. Anal. 4, 37-33. LAWS D. R. and RUBIN H. B. (1969) Instructional control of an autonomic sexual response. J. appi. Behac. Anal.
2, 93-99.
MARSHALLW. L. (1973) The modification of sexual fantasies: a combined treatment approach to the reduction of deviant sexual behavior. Behau. Res. Therapy 11, 557-564. NEVIH J. A. (1973) Stimulus control. In The Study of Behavior (Edited by J. A. NEVIN). Scott Foresman and Co., Glenview, Illinois. QUINSEY V. L. and BERGER~ON S. G. (1976) Instructional control of penile circumference in assessments of sexual preference. Behav. Ther. 7, 489-493. ROSENR. C. (1973) Suppression of penile tumescence by instrumental conditioning. Psychosom. Med. 35, 509-514.
au\ x
@ I’cqamon
l-hrr‘,p\. viii 17. pp. 215 10 ?‘? Press Lid 1979. Punted SD Great Britain
DEVIANT H.
0005.7967 79 OSOl-O~lJSO2oO 0
SEXUAL
AROUSAL
IN RAPISTS
E. BARBAREE, W. L. MARSHALL and R. D. LANTHIER
Department of Research, Regional Psychiatric Centre, and Queen‘s University. Kingston. Ontario, Canada (Received 23
August
1978)
Summary-Increases in penile circumference of 10 incarcerated rapists and 10 male graduate students were measured during verbal descriptions of mut~ily~onsenting sex, rape and violent non-sexual assault. Mutually-co~enting sex evoked sexual arousal in both groups. Rape evoked comparable arousal in rapists but significantly less arousal in non-rapists. Assault evoked significantly less arousal in non-rapists and tended to evoke less arousal in rapists. However, the rapists did not exhibit greater sexual arousal to forced or violent sex compared with consenting sex, either as a group or as individuals. It is not necessarily true that forced or violent sex evoked rapists’ arousal but perhaps that force or violence failed to inhibit their arousal.
Deviant sexual arousal is often invoked to explain deviant sexual behavior. For example. it is well known that males evoke sexual arousal in homosexuals, and children evoke sexual arousal in pedophiles. A similar explanation may be offered to account for violent sexual assaults and rape. Abel, Barlow, Blanchard, and Guild (1977) recorded sexual arousal of rapists and non-rapists during 2-min verbal descriptions of mutuallyconsenting sex and rape, and found that rapists were more aroused by descriptions of rape than were non-rapists. As a group, rapists were equally aroused by rape and mutually-consenting sex, while non-rapists were considerably less aroused by rape than mutually-consenting sex. According to the explanation implied by these authors, rape is motivated by sexual arousal evoked by the non-consent of the victim and the offender’s use of force or violence, and reinforced by sexual ratification. This explanation of rape would suggest that the reduction of deviant arousal (e.g. Barlow, Leitenberg and Agras, 1969; Feldman and McCulloch, 1965; Marshall, 1973) must be an essential treatment goal in the rehabilitation of rapists. The work presented here re-examined deviant sexual arousal in rapists and was prompted by two possible flaws in the Abel et al. (1977) study. First, Abel et ai. (1977) constructed idiosyncratic verbal descriptions of rape designed to maximally arouse each individual rapist (Abel, Blanchard, Barlow and Mavissakalian, 1975) modeled after each rapist’s description of their own rape behavior. Since non-rapists had never raped, equivalent rape episodes designed to maximally arouse the non-rapists would have been difficult to construct and must have been based on arbitrary decisions by the investigators. Verbal descriptions of rape may have been more arousing to the rapists than non-rapists simply because these investigators took care to maximize rapists’ arousal to rape cues. Second, Abel et al. (1977) group of non-rapists may have been inappropriate. Sexual arousal can only be specified as deviant after comparing such arousal with arousal evoked by the same stimuli in normal males who prefer mutuallyconsenting sex with adult females. Abel et al. (1977) control group consisted of bisexuals, exhibitionists, pedophiles, and voyeurs whose deviant sexuality may have contributed in unknown ways to their lowered arousal to rape cues, indicating perhaps incorrectly that enhanced arousal to rape in rapists was deviant. In the present study, a standard set of 2-min audio-taped verbal descriptions of mutually-consenting sex, rape and non-sexual assault were presented to 10 incarcerated rapists and 10 graduate students whose adult sexual behavior had been restricted to mutually-consenting sex with post-pubescent females. * Requests for reprints should be addressed to Dr. H. Barbaree, Department chiatric Center (Ontario), Box 22, Kingston. Ontario K7L 4V7. 215
of Research, Regional Psy-
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METHOD
Subjects
Ten men incarcerated in Canadian Federal Penitentiaries aged between 24 and 37 (x = 30.7) years volunteered as experimental subjects. Seven were serving between 4 and 15 (H = 8.5) years for the crime of rape. An eighth man was serving an indeterminate sentence, functionally equivalent to a life sentence, for the crime of rape. A ninth man was serving a life sentence for non-capital murder committed during an attempted rape, while the tenth man was serving a seven year sentence for robbery. and had volunteered for treatment to rid him of his urges to rape. A summary of convictions for each rapist was derived from his criminal record and is presented in Table 1. Obviously, several men in this group of rapists had been convicted of rape and sexual assault. Rape charges had been laid against men in this group which had not resulted in conviction and several men admitted in confidence to rapes and sexual assaults they had committed but for which they had not been apprehended or charged. The sex offences committed by these men were confined to rapes and sexual assaults against post-pubescent femaies. None had ever been convicted of nor admitted to other sexual offences such as child molestation, voyeurism, exhibitionism. frottage. homosexuality. or fetishism. Typical of rapists, these men had been convicted of a wide range of criminal offences besides rape and sexual assault. Five had been convicted of violent offences which did not involve sexual behavior or female victims, and seven had been convicted of Break and Enter or Theft. Each of these men had begun their criminal careers at an early age. Since records of juvenile offences do not appear on their criminal records, some of these men may have begun their criminal careers at an earlier age. On the basis of these considerations, the rapists studied here were similar to rapists studied elsewhere (Amir, 1971; Cohen, Garafalo, Boucher and Seghorn, 1971; Gebhard, Gagnon, Pomeroy and Christenson, 1965; Christie, Marshall and Lanthier, to be published). Ten graduate students at Queen’s University aged between 21 and 34 (x = 26.2) years volunteered to serve as subjects in the control group and received remuneration for their experimental participation. None of the men in the control group had a criminal record and all were heterosexuals by self report. Apparatus
Sexual arousal was measured by mercury-in-rubber strain gauge plethysmography (Abel, Levis and Clancy, 1970; Bancroft, Jones and Pullman, 1966; Fisher, Gross and Zuck. 1965; Laws and Rubin, 1969; Rosen, 1973; Marshall, 1973; Quinsey and Bergerson. 1976). A mercury filled sylastic rubber tube (digital or closed gauges, Parks EiecTable
1. Summary
of convictions
for the rapists Convictions
Subjects
at test
Rl R2 R3 R4 R5 R6 R7 R8 R9 RlO
26 31 37 36 37 24 31 26 24 36
at latest: conviction 23 31 35 35 36 19 30 22 24 33
at
first: 17 16 19 20 18 19 16 18 23 21
Of latest victim 15 22 18 12 20 15 14 18 20 24
* Sex oliences: A = Rape, B = Sexual assault, other t Non-sexual violent offences: A = Murder, D = Robbery. $ Property offences: break and enter, theft.
Sex offences* B A 1 0 2 1 1 0 2 1 1 2
1 0 0 0 5 0 0 3 0 2
Non-sexual violentt offences A B C D 0 0 0 0 0 1 0 0 0 0
0 2 0 1 1 0 0 3 0 1
0 2 0 0 1 0 0 0 0 0
0 2 0 0 1 0 0 0 0 0
sex ogences against adult females. B = Assault, C = Dangerous weapons
property: 0Rence-s 1 3 2 0 5 0 0 3 1 2
otTences.
Deviantsexual arousal in rapists
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tronics) of appropriate diameter for each subject was fitted midway along the longitudinal axis of the subject’s penis. A plethysmograph (Parks Electronics, Model 270) monitored conductance of the mercury column which decreased as the mercury was stretched by increases in penile circumference. The output of the plethysmograph, a d.c. voltage proportional to the conductance of the mercury column, was monitored by a digital voltmeter (DVM, Hewlett Packard, Model 343OA). Care was taken to ensure that increases in voltage output of the plethysmograph were linearly related to increases in penile circumference (Davidson, Lanthier and Barbaree, to be published). Verbal descriptions of sexual episodes were recorded on audio tape and presented to subjects from one channel of a stereo reel-to-reel tape recorder (Sony, Model TC-270) via monaural headphones. Sexual arousal was measured while subjects sat comfortably in a ‘lazy-boy’ chair in a sound-attenuated room. The experimenter, tape recorder. and DVM were housed in an adjacent room. Communication between the experimenter and subject was accomplished by an intercom system and a microphone connected directly to the subject’s headphones.
Verbal descriptions of seven episodes were written in the second person to indicate to the subject that he was the male in the episode. Six of these episodes included sexual foreplay and intercourse between an adult male and adult female which culminated in the male’s orgasm. Each of these six sexual episodes were designed to be different in (a) the consent given by the woman to the proposed and ongoing sexual behavior, and (b) the force and violence perpetrated by the male protagonist on the woman victim in the course of the sexual episode. There were three episodes of mutuallyconsenting sexual foreplay and intercourse in which the degree of consent to sexual behavior given by the woman was varied. In Episode 1, the woman was described as being enthusiastic in her sexual behavior with the male, and she initiated most of the sexual behavior. In Episode 2, the woman was passive, neither initiating nor rejecting sexual behavior with the subject. In Episode 3, the woman was at first reluctant but was finally seduced by the subject. There were three verbal descriptions of rape episodes in which the force and violence perpetrated by the subject was varied. In Episode 4, after the woman refused sexual behavior with the subject, the subject used verbal threats to coerce her to comply with his sexual desires. In Episode 5, the subject physically restrained his victim while he raped her. In Episode 6, the subject restrained the woman and physically assaulted her, punching and slapping the woman while he raped her. Each different sexual behavior was located as close as possible to the same temporal locus in each of the six sexual episodes. The descriptions of the sexual behavior did not included oral or anal sex. The final episode was not, strictly speaking, a sexual episode. Episode 7 described the male subject physically assaulting a woman (as in Abel er al., 1977) but there was no sexual behavior described in this episode. A second similar but slightly different set of seven episodes were also written, All 14 episodes were then recorded on one channel of the stereo tape in a male voice so that each verbal description was 2 min in duration, A metronome presenting ‘beeps’ every 10 set was recorded on the second of the stereo channels and anchored temporally such that the onset of each of the 14 episodes coincided with the onset of a lo-set period. Verbal descriptions were presented from the first stereo channel through the subject’s monaural headphones while both stereo channels were heard by the experimenter in his separate room. As subjects arrived for testing, they were told that their sexual arousal would be monitored and the operation of the monitoring device and digital strain gauge was explained to them. They were told that while their sexual arousal was monitored they would be presented with verbal descriptions of mutuaIly-consenting sex, rape, and a man physically assaulting a woman. They were also told that sexual arousal in response to all these descriptions was natural and that sexual arousal evoked by violent episodes would not indicate a propensity to enact such episodes. Subjects signed a form indicating 8X.1.I7 3-D
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L.
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R. D.
LANTHIER
their informed consent to the experimental procedure and were then instructed as to the proper procedure for fitting the digital strain gauge. The experimenter left the room while the subject fitted the gauge and settled comfortably in his chair. Subjects sat on the towel-covered chair with clothing lowered below mid thigh. During experimental procedures a sheet covered them from the waist down and was supported by the arms of the chair. This covering did not rest on the subject’s penis or strain gauge. Subjects were then instructed to place the headphones on and to sit back comfortably in the chair. Subsequent instruction to subjects were presented through the headphones:
I am about to present you with several descriptions of sexual behavior. We are interested in the way in which you become sexually aroused to each. During each fantasy. try as much as possible to imagine yourself being right there, doing the things described in the fantasy. Please do not try to inhibit or control your arousal. If you do, we will just have to do ail of this again. Each fantasy will last approximately 2 min and there will be time in between fantasies for you to relax. After a fantasy is over. please do not continue to think about it. The session will last less than I br. Sit back and relax and we shall begin.
In order to reduce the confounding effects of the order of presentation of the seven episodes occasioned by the ‘warm-up’ effect commonly observed in tests of sexual arousal, three warm-up verbal descriptions including mutually-consenting sex, rape, and assault were presented.prior to the seven episodes in each experimental session. These warm-up episodes were similar to some but different from all of the seven episodes. Presentation of these episodes also gave the subject prior information about the nature of all of the episodes so that the surprise occasioned by particular verbal descriptions might not unduly enhance or inhibit arousal. Sexual arousal was not measured during these warm-up descriptions which were presented in a random order to each subject. Presentation of the seven episodes followed these warm-up episodes. Seven different quasi-random orders of presentation were used providing for an equal number of presentations of each episode early and late in the session over each of the two groups of subjects. The one restriction placed on the randomness of the orderings ensured that episodes of a given type (either mutually-consenting or rape) never followed one another more than once in any order. Each subject was presented with a different order in different sessions, and generally episodes presented early in one session were presented late in the other and vice versa. The time between the offset of one episode and the onset of the next was most often between l-2 min, was never less than 1 min, and never more than 5 min. Subsequent episodes were not begun until penile erection evoked by the preceding episodes had subsided to a near flaccid state. Experimental sessions lasted approximately 45 min. Sexual arousal was recorded by the experimenter at lo-set intervals signalled by the metronome ‘beep’. At each ‘beep’, the experimenter wrote down the contents of the visual display in the DVM (i.e. the voltage output of the plethysmograph). Four such recordings were made prior to each episode, 12 such recordings were made during each 2-min episode, and six such recordings were made during the first I-min period after the end of each episode. The lowest voltage output recorded during each session was designated as 0% of full erection. At the end of each session, the subject was asked if he had achieved a full erection during the session. If he said “yes”, the largest recorded amplitude of the plethysmograph output during the session was designated as 100% full erection. If he answered “no”, he was asked to produce a full erection without disturbing the strain gauge and was given facilatory visual erotic material. In the event that a full erection was not achieved by a subject in one of the sessions, an estimate of plethysmograph output at full erection was based on the range of voltage output from 0% to 100% full erection during the subject’s other session. In the event that a full erection was not achieved by a subject during either session (this occurred in three subjects) an estimate was based on the mean range of output (0% to 100%) of the other subjects.
Deviant sexual arousal
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RESULTS Erectile responses evoked by sexual episodes were determined by calculating the difference between the maximum voltage output of the plethysmograph during each presentation of an episode and voltage output at 0% of full erection (the flaccid state) of individual subjects. These differences in voltage output were then expressed as a per cent of the change in voltage output from 0% to 100% of full erection of individual subjects. Average erectile responses are presented in Fig. 1. Analysis of variance together with six planned orthogonal comparisons were applied to these data, first to each group separately, then to both groups combined. The six planned comparisons were designed to detect differential responding evoked by the different verbal descriptions. First, arousal evoked by the physical assault was compared with arousal evoked by the three mutuallyconsenting and three rape episodes combined. Second, arousal evoked by the three rape episodes was compared with arousal evoked by the three mutually-consenting episodes. Third, two comparisons were designed to detect differential responding evoked by the three rape episodes. In the first of these, arousal to the most violent rape was compared with arousal to the other two rapes combined. In the second of these, arousal to the rape with verbal threats was compared with arousal to the rape with physical restraint. Finally, two comparisons were designed to detect differential responding evoked by the three mutually-consenting sexual episodes. In the first of these, arousal evoked by the episode describing sex with an enthusiastic female partner was compared with arousal evoked by the episodes describing sex with the passive and reluctant partners combined. In the second of these, arousal evoked by the passive partner was compared with arousal evoked by the reluctant partner. In order to provide a standard against which to judge the rapists’ sexual arousal, results of the control group are presented first. The seven verbal descriptions of sexual episodes evoked differential sexual arousal in the non-rapists, F (654) = 13.416, p < 0.001. The non-sexual physical assault evoked less sexual arousal than the six sexual episodes, F (1,9) = 31.037, p -C 0.001. The three rape episodes evoked less sexual arousal than the mutually~o~enting sexual episodes, F (1,9) = 27.018, p < 0.001, and this difference between rape and mutually-consenting episodes was accentuated in the second as compared with the first session, F (1,Q) = 5.388, p < 0.05. The most violent rape episode evoked less arousal then the other rape episodes, F (1,9) = 8.482, p < 0.025, while the rape with physical restraint evoked no less arousal than the rape with verbal
60
@j
RAPISTS
0
NON-RAPISTS
TT
MUTUALLY
RAPE
ASSAULT
CONSENTING
Fig. 1. Mean sexual arousal evoked by 2-min verbal descriptions of mutually-consenting sex, three varieties of rape and one assault in 10 rapists and 10 non-rapists. Joined brackets indicate the standard error of each mean.
220
H. E. BARBAREE.W. L. MARSHALL and R. D. LANTHIER
threats, F (1,9) < 1.00. Finally, no differential arousal was evoked by the three mutuallyconsenting episodes, F’s (1,9) < 1.05. In the rapists. the seven episodes did not evoke differential sexual arousal. F (6.54) = 1.763, n.s. While the difference between rapists’ arousal to the assault and arousal to the six sexual episodes approached significance, F (1,9) = 3.685, p < 0.10, their arousal to rape episodes was not significantly lower than their arousal to mutually-consenting episodes, F (1,9) < 1.00. This result could have obtained if a few rapists had exhibited rape arousal which was substantially greater than their mutually-consenting arousal. while the remainder of the group’s mutually-consenting arousal was substantially greater than their rape arousal. Such was not the case. Only three rapists became more aroused to the rape episodes than to the mutually-consenting episodes, and for two of these men, this difference was only marginal. Therefore, the group means presented in Fig. 1 accurately represent the pattern of arousal for the majority of rapists in this study. As described earlier, the non-rapists exhibited significantly lower arousal to rape than to mutually-consenting episodes, and the rapists differed from the non-rapists in this respect, F (lJ8) = 4.598, p < 0.05. None of the results of the remaining comparisons detected any differential responding to the various episodes in the rapists, nor any other differences between rapists and non-rapists. Overall sexual arousal did not change over sessions, F (1,18) < 1.00, and there was no evidence that incarcerated rapists became more aroused than non-rapists at liberty, F (lJ8) < 1.00. DISCUSSION As reported previously (Abel, Barlow, Blanchard and Mavissakalian, 1975; Abel, Barlow, Blanchard and Guild, 1977; Abel, Blanchard, Barlow and Mavissakalian. 1975; Abel, Levis and Clancy, 1970), audio-taped descriptions of sexual behavior evoked sexual arousal in male subjects, and different descriptions of sexual behavior evoked different levels of sexual arousal. Similarly, as in earlier studies, differential sexual arousal evoked by different descriptions of sexual behavior discriminated between groups of subjects when group membership was defined by previous sexual behavior. In general, the results of the present study which presented a standard set of verbal descriptions of mutuallyconsenting sex, rape, and assault to a group of incarcerated rapists and a control group of male graduate students agreed with the results of the earlier study reported by Abel et al. (1977) which presented idiosyncratic verbal descriptions to rapists and a control group of non-rapist sexual deviates. In non-rapists, descriptions of rape and assault evoked considerably less sexual arousal than descriptions of mutually-consenting sex. But, in rapists, the different descriptions of sexual behavior did not evoke different levels of sexual arousal. We intentionally structured the six descriptions of sexual behavior including the three mutually-consenting and the three rape episodes, to include the same sexual behavior. But. within these six episodes we varied the context within which the sexual behavior occurred. For example, rape and mutually-consenting episodes, although including the same sexual behavior, differed in the consent offered by the female to the proposed and ongoing sexual behavior, and the force or violence used by the male to gratify his sexual desires. Furthermore, within the three mutually-consenting episodes, the same sexual behavior was described but the degree of consent given by the female was varied from a female desiring and enjoying the sexual behavior, to a female who expressed no desire for nor objections to the sexual behavior, to a female who objected to the sexual behavior but eventually complied with the male’s wishes. Moreover, within the three rape episodes, the same sexual behavior was described, but the degree of force or violence used by the male in accomplishing the sexual behavior was varied from verbal threats to physical restraint to slapping and punching. We presented these six sexual episodes to subjects to determine how consent of the female or force used by the male affects the sexual arousal normally evoked by descriptions of sexual behavior. The non-rapists showed significantly less arousal to the rape episodes than the
Deviant
sexual
arousal
in rapists
221
mutually-consenting episodes and there are two possible explanations of this effect. First, the force and violence used by the rapists in the rape episodes inhibited or suppressed erectile responses that would in other contexts be evoked by descriptions of the sexual behavior (Abel er al., 1977). Second, consent to sexual behavior is arousing to nonrapists, and less arousal was evoked during the rape descriptions because consent to sexual behavior was not offered by the female. We prefer the first of these explanations because when consent offered by the female was systematically varied in the mutuallyconsenting episodes, no differential arousal obtained. Therefore, the non-rapists’ lower arousal to verbal descriptions of rape is best explained as a suppression or inhibition of erectile responses by the force or violent aspects in the rape episodes. Further support for this explanation is provided by the non-rapists’ differential arousal within the rape episodes. The most violent rape which included the male punching and slapping the female evoked significantly less arousal than the less violent rapes. The rapists on the other hand exhibited no differential arousal over these six sexual episodes. A consequence of this fact is that rape descriptions evoked relatively greater sexual arousal in rapists than non-rapists. We might characterize deviant sexual arousal in rapists by this general statement of fact and conclude that force, violence and nonconsent of the female is relatively more sexually arousing for rapists than non-rapists. On the basis of the evidence at hand, this conclusion is unjustified and could lead to a serious misunderstanding of rapists and rape behavior. This conclusion is based on the assumption that rapists’ sexual arousal evoked by descriptions of rape is a demonstration of control over rapists’ sexual arousal by force, violence, or non-consent of the female. However, behavioral control by a stimulus can only be inferred from differential responding over variations in some dimension of the stimulus (e.g. Nevin, 1973). A simple illustration will clarify this point. If an animal experimenter were to train a pigeon to peck a red keylight for food reinforcement, he might later discover that the pigeon also pecked a yellow keylight. The experimenter might then conclude that ‘yellow’ evoked key pecking in this pigeon. However, such was not necessarily the case. The pigeon may have simply responded to changes in luminance in the keylight, and the key’s yellowness may not have affected the bird’s responding at all. In other words. this experimenter failed to demonstrate that the colour of the key controlled the birds’ responding. When rapists in this study and in the Abel er al. (1977) study did not show differential responding to rape versus mutually-consenting sexual episodes, we failed to demonstrate oontrol over rapists’ sexual arousal by consent of the female or force of the ma1e. It might have been that rapists simply attended to the female in the episodes and responded to the descriptions of sexual behavior with her while her consent and the male’s force had no influence whatsoever on their sexual arousal. Therefore, sexual arousal in these rapists may have been deviant, not necessarily because force and violence and non-consent of the female evoked their sexual arousal, but perhaps because force, violence and non-consent of the female failed to inhibit their sexual arousal. The mechanism by which consent of. the victim, force or violence inhibits responding in the non-rapists is not known. Perhaps the non-rapists are affected emotionally by the rape episodes and fear or empathy for the victim inhibits sexual arousal. Or, perhaps the non-rapists are keenly aware of social pressure or experimenter demands against arousal to rape cues and they exert voluntary control over their sexual arousal (Freund, 1961; Laws and Rubin, 1969; Henson and Rubin, 1971; Quinsey and Bergerson, 1976). Perhaps rape arousal is not inhibited in the rapists because they have been desensitized to the emotional effects of force and violence by greater experience with violence in prison or in the subculture to which they belong. Perhaps rapists are not as we11aware of the social pressures against rape arousal or perhaps they are less able to exert voluntary control over their sexual arousal. The choice of a treatment for rapists and a method for evaluating its effectiveness depends heavily on our understanding of their deviant sexual arousal. Unfortunately, at the present time, we do not know what stimuli control rapists’ sexual arousal.
H. E. BARBAREE, W. L. MARSHALLand R. D. LANTH~ER
222
Acknowledgenrcnrs-Financial assistance was provided by the Medical Services Branch of the Department of the Solicitor General for Canada, and the Non-Medical Use of Drugs Directorate. Canadian Ministry of Health and Welfare. We wish to thank B. Malcolm who assisted in all stages of the work. and E. Backman who assisted in the testing of subjects. L. Lightfoot. P. Davidson, and D. Baxter read an earlier draft of the paper and provided most helpful comments. D. J. K. Mewhort provided invaluable advice concerning the data analysis. REFERENCES ABEL G. G., BARLOWD. H., BLANCHARDE. B. and GUILD D. (1977) The components of rapist’s sexual arousal. Archs gen. Psych&. 34, 895-903. ABELG. G., BARLOWD. H., BLANCHARD E. B. and MAVISSAKALIAN M. (1975) Measurement of sexual arousal in male homosexuals: The effects of instructions and stimulus modality. Archs Sexual Behau. 4, 623-629. ABEL G. G., BLANCHARDE. B.. BARLOWD. H. and MAVI~~AKALIAN M. (1975) Identifying specific erotic cues in sexual deviations by audio-taped descriptions. J. appl. Behau. Anal. 8. 247-260. ABELG. G., LEVISD. and CLANCYJ. (1970) Aversion therapy applied to taped sequences of deviant behavior in exhibitionism and other sexual deviations: A preliminary report. J. behac. Ther. expl Psychiar. 1, 59-66. AMIR M. (1971) Patterns in Forcible Rape. University of Chicago Press, Chicago. BANCROFT J. H. J., JONESH. G. and PULLMANB. R. (1966) A simple transducer for measuring penile erections with comments on its use in the treatment of sexual disorders. Behao. Res. Ther. 4, 239-241. BARLOWD. H.. LEITENBERG H. and AGRASW. S. (1969) The experimental control of sexual deviation through manipulation of the noxious scene in covert sensitization. .I. Abnorm. Psycho/. 74, 596-601. CHRISTIEM. M., MARSHALLW. L. and LANTHIERR. D. A descriptive study of incarcerated rapists and pedophiles. Manuscript submitted for publication, 1977. COHENM. L.. GARAFALO R., B~UCHERR. and SEGHORNT. (1971) The psvcholoav Semin. in Ps\,chiat. __- of rapists. . 3, 307-327. DAVID~CIN P., LANTHIERR. D. and BARBAREE H. E. Penile response measurement: Operating characteristics of Parks Plethysmograph. Manuscript submitted for publication, 1977. FELDMANM. P. and MACCULLOCHM. J. (1965) The application of anticipatory avoidance learning to the treatment of homosexuality. I. Theory, technique, and preliminary results. Eehac. Res. Ther. 2, 165-183. FISHERC., Gross J. and ZUCH J. (1965) Cycle of penile erections synchronous with dreaming (REM) sleep. Arch.
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MARSHALLW. L. (1973) The modification of sexual fantasies: a combined treatment approach to the reduction of deviant sexual behavior. Behau. Res. Therapy 11, 557-564. NEVIH J. A. (1973) Stimulus control. In The Study of Behavior (Edited by J. A. NEVIN). Scott Foresman and Co., Glenview, Illinois. QUINSEY V. L. and BERGER~ON S. G. (1976) Instructional control of penile circumference in assessments of sexual preference. Behav. Ther. 7, 489-493. ROSENR. C. (1973) Suppression of penile tumescence by instrumental conditioning. Psychosom. Med. 35, 509-514.
