Journal of Abnormal Psychology 1976, Vol. 85, No. 5, 489-497
Effects of Alcohol on Sexual Arousal in Women G. Terence Wilson and David M. Lawson Rutgers—The State University During weekly experimental sessions each of 16 university women received in counterbalanced order four doses of beverage alcohol prior to viewing a control film and an erotic film. Half of the subjects were instructed beforehand that alcohol would increase their degree of sexual arousal in response to the erotic film; the other half were told that alcohol would decrease their sexual arousal. Measures of vaginal pressure pulse obtained by means of a vaginal photoplethysmograph showed a significant negative linear relation with alcohol doses. A significant interaction between sessions and instructional set indicated that subjects in the increase-set condition experienced less sexual arousal. This result was attributed to performance pressure induced by the demand characteristics of the instructional set. Additional measures of sexual arousal, including Thematic Apperception Test responses and self-report, showed no differences. With increasing levels of intoxication, however, a greater proportion of subjects reported enhanced sexual arousal.
Surprisingly little is known about the effects of alcohol on sexual responsiveness despite the fact that a definite relation between the two has long been posited. A comprehensive review of the subject by Carpenter and Armenti (1971, pp. 509-543) found only four studies on the influence of alcohol on human sexual behavior. Unfortunately, these studies, all of which used an indirect measure of sexual arousal (responses on Thematic Apperception Test [TAT] protocols), were seriously flawed by major methodological errors. Two recent investigations studied alcohol's effects on objectively measured sexual arousal in male college students. Using a Latin square design, Farkas and Rosen (1976) monitored penile tumescence in response to an erotic film
The authors are especially indebted to Elizabeth Anne Kirschling, Lorraine O'Brien, and Beverly Wojciehowski, the nursing staff of the Alcohol Behavior Research Laboratory at Rutgers—The State University, for their invaluable assistance in conducting this study. The authors also wish to thank John A. Carpenter for his assistance with the statistical analyses, Wayne Kashinsky for constructing the vaginal photoplethysmograph and assembling the physiological recording apparatus, Julia Heiman for her technical advice, and Peter E. Nathan for his generous support. Requests for reprints should be sent to G. Terence Wilson, Graduate School of Applied and Professional Psychology, Rutgers—The State University, New Brunswick, New Jersey 08903.
at four different blood alcohol levels (BALs), 0 mg %, 25 mg %, 50 mg %, and 75 mg %. Although a slight facilitation in amplitude of penile tumescence was observed at the low BAL condition (25 mg %), a significant negative linear trend accounted for most of the variance for the effects of alcohol—the rate and extent of tumescence decreasing with rising BAL. Briddell and Wilson (1976) similarly demonstrated a significant negative linear effect of increasing alcohol doses on penile tumescence. Moreover, their results indicated that sexual content in TAT stories was negatively correlated with tumescence. Information on the effects of alcohol on women is so lacking that Carpenter and Armenti (1971) were led to remark that "most experts comment on human sexual behavior and alcohol as though only males drink and have sexual interests" (p. 521). Kinsey, Pomeroy, Martin, and Gebhard (1953) failed to mention the subject, and although Masters and Johnson (1966) discussed the adverse influence of alcohol on male potency, there was no mention of its effect on women. Kaplan (1974) states that "habitual heavy intake frequently seriously impairs the sexual response in both genders, but most especially of men" (p. 89). While impotence in states of acute and chronic alcohol intoxication has been clinically documented (Lemere & Smith, 1973; Masters & Johnson, 1970), there is as
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yet no empirical basis for Kaplan's perhaps widely shared appraisal with respect to women. Reliable data that would permit an adequate evaluation of alcohol's effects on female sexuality simply do not exist. In one of the few studies of its kind, Wilsnack (1974) concluded on the basis of projective test stories that women drink in order to feel more womanly, including the sensations of being "warm, loving, and sexy" (p. 44). However, it is unclear what the sexual content on these dubious projective tests means without validating the tests against appropriate objective measures. The development of a reliable physiological measure of tumescence (the penile strain gauge) heralded a significant breakthrough in the study of male sexual arousal (Zuckerman, 1971). Sintchak and Geer (1975) recently described the use of a vaginal photoplethysmograph for monitoring vaginal blood volume and pressure pulse that promises to advance the study of female sexuality significantly. Evidence on the validity of this device has been furnished by Geer, Morokoff, and Greenwood (1974), who found reliable changes in vaginal opacity during the presentation of an erotic film. Furthermore, Hoon, Wincze, and Hoon (1976) showed the device to be significantly superior to other physiological measures in accurately discriminating between erotic and nonerotic or dysphoric videotapes. Accordingly, the present study used the Sintchak and Geer (197S) photoplethysmograph as an objective index of female sexual arousal. Although Briddell and Wilson (1976) have shown that alcohol decreases male sexual arousal, many individuals frequently drink in a deliberate attempt to improve their sexual functioning. It is presumed that the experience of relaxation and disinhibition that usually accompanies alcohol-produced central nervous system depression results in the attribution of aphrodisiacal properties to alcohol (cf. Katchadourian & Lunde, 1972). In a questionnaire survey, Athanasiou, Shaver, and Tavris (1970) found that of the women sampled, 68% reported that alcohol enhanced sexual pleasure, 11% reported that it had no effect, and 21% reported that it decreased
pleasure. The comparable figures for the men sampled were 45%, 15%, and 42%. The current investigation attempted a better controlled, direct evaluation of the role of expectancy in the effect of alcohol on sexual arousal. Furthermore, the relation between a direct genital measure and subjective TAT responses was assessed. As in the Briddell and Wilson (1976) study, superior control of alcohol administration permitted a partial replication of earlier research employing the TAT as a measure of alcohol's influence on sexual imagery. Muscle tension levels were monitored because alcohol's effects on sexual behavior are often attributed to a perceived reduction in anxiety accompanied by muscular relaxation (Gallant, 1968). Changes in myotonia have also been observed to accompany the various phases of the sexual response cycle (Masters & Johnson, 1966). METHOD Subjects and Setting Sixteen undergraduate and graduate women students between the ages of 18-22 years participated in the study. All subjects were screened during detailed interviews conducted by the nursing staff to exclude anyone with a current medical disorder or a history of psychiatric problems, alcohol/drug abuse, or sexual dysfunction. Similarly, individuals with any anxiety or other reservation about the study were excluded. Only women who were moderate social drinkers and who were exclusively heterosexual were selected. Each subject was paid $40 for her participation in the study. Particular care was taken to ensure that fully informed, written consent was obtained from subjects. All procedural details (except the expectancy manipulation) were explained and demonstrated prior to subjects' inclusion in the study. The research was carried out at the Rutgers Alcohol Behavior Research Laboratory, a research/treatment unit staffed primarily by graduate students in clinical psychology and by registered nurses.
Design The experimental design consisted of four 4 X 4 Greco-Latin squares in which subjects participated in four experimental sessions and were administered a different dose of alcohol and a different TAT card in counterbalanced order during each session. This design minimizes subject variance while controlling for the habituation effects of alcohol dose administration. In addition, half of the subjects were instructed that alcohol would increase their sexual arousal in response to the erotic film; the other half were told that it would decrease their sexual arousal.
ALCOHOL AND SEXUAL AROUSAL IN WOMEN
Apparatus Erotic stimuli. The measurement room contained a reclining bed, a small bedside table and lamp, and a 19-inch (48.26 cm) black-and-white monitor positioned at the foot of the bed for the presentation of two 12-minute films. The first, nonerotic control film consisted of a graphic but rather monotonous introduction of the computer facilities at Rutgers University. The second, erotic film comprised two segments: one from a sexual education film and one from a typical pornographic film. The erotic film showed explicit heterosexual interaction between two people featuring penile-vaginal intercourse, fellatio, and cunnilingus. In view of Heiman's (Note 1) findings, an attempt was made to select stimulus material in which the female initiated action and in which most of the focus was on the woman. A uniform soundtrack of instrumental music was added for continuity. The final version of the films was videotaped for convenience and consistency of presentation. Physiological recording. Changes in vaginal opacity were directly measured using a slightly modified version of Sintchak and Geer's (1975) photoplethysmograph. This device is a Plexiglas cylinder, if inches (4.4S cm) long and i inch (1.27 cm) in diameter, that has been hollowed out to accommodate a small lamp, photo cell, and connecting wires. When it is inserted approximately 1 inch (2.54 cm) into the vagina, the amount of indirect light reflected back to the photocell from the vaginal wall is affected by changes in blood volume and pressure pulse. The attached, shielded cable is encased in soft vinyl tubing extending from the end of the cylinder and terminates in a plug that subjects attached to a 5-pin shielded connector leading to the polygraph. In its size and weight it is comparable to a tampon, and its rounded end and smooth exterior ensure that it is comfortable and that it can be simply inserted by the woman herself (cf. Sintchak & Geer, 1975). Total hygiene and safety are assured by easily sterilizing it in a solution of zephiran chloride. Changes in vaginal pressure pulse and blood volume, the ac and dc components of the signal, were continuously recorded on a Beckman Type R Dynograph. In addition, the ac component was electronically modified by means of a semi-integration technique to produce a noncyclic index of vaginal pressure pulse amplitude that was displayed on a third polygraph channel. The output from this channel was then converted from an analog to a digital form, sampled at 15-sec intervals by a DEC PDF 8/L computer and printed for later analysis. Values obtained by this technique have been shown to correlate significantly (r = .83) with manually scored measures of pressure pulse amplitude (Kashinsky & Lawson, Note 2). Measures of heart rate during the 4th, 8th, and 12th minutes of both the control and erotic films were taken directly from the polygraph records of vaginal pressure pulse. Muscle tension levels (EMG) were measured by
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the Bio-Electric Feedback System (Model B-l, BioFeedback Systems, Inc.) from exosomatic electrodes attached to the subject's forehead. This system permits the measurement of muscle action potentials by the quantification of peak-to-peak microvolts (Budzynski & Stoyva, 1969). The EMG levels were sampled every 15 sec by the computer. Changes in electromuscle action potentials were also displayed on the Beckman polygraph. The BALs were determined by means of a breathalyzer (Model 900, Smith and Wesson Electronics Co.).
Procedure Subjects were asked to fast for 4 hours and to refrain from alcohol and drugs for the 24 hours prior to each of the four weekly sessions. On arrival at the lab for each session, subjects received a breathalyzer test to ensure that they were completely sober, and they were weighed. Thereafter a predetermined amount of alcohol was administered individually to each subject prior to film viewing and measurement of sexual arousal. Subjects also received an instructional-set manipulation designed to create a particular expectancy about subjects' level of arousal during the film. Alcohol administration. In terms of absolute ethanol administered, the four doses were: A± = .05 g/kg; A2 =.25 g/kg; A 3 =.50 g/kg, and A 4 =.7S g/kg. As an example, for a 120-lb. woman, the correspondiing amount in ounces of 80-proof alcohol would be as follows: .3, 1.4, 2.9, and 4.3. In the placebo control condition (Ai), a very small amount of alcohol was administered, since both previous research with males (Briddell & Wilson, 1976), and pilot data with females had indicated that alcohol could be tasted in the lowest concentration but that in all instances subjects would remain at 0 mg % BAL. Canadian whiskey (80-proof) was mixed with two parts chilled 7-Up to form a 13.3% ethanol solution for all groups (except Ai). The alcohol for the placebo group was mixed with 20 parts 7-Up (1.33% ethanol solution) and tinted with food coloring to approximate the total fluid volume and color of the As group. Several drops of whiskey were also smeared on the inside of the drinking cup to create the alcohol smell. All drinks were delivered in a 1,000-ml beaker with an 8-oz. (2.37 dl) Styrofoam drinking cup by a male research assistant. The subject was given 20 minutes to consume the drink and a subsequent 40minute "rest period" for the alcohol absorption to take place. Closed circuit TV monitoring of the subject during this period ensured that the entire drink was consumed and remained consumed. After the absorption period a BAL test was administered and the subject was encouraged to void the bladder prior to viewing the film. Subjects were not told the result of the BAL check, nor were they told how much alcohol they had consumed. At this point a staff nurse escorted the subject to the measurement room, attached the frontalis EMG electrodes, and reviewed the procedure for using the
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vaginal photoplethysmograph. The nurse then left the room, which remained locked from the inside, permitting the subject to insert the plethysmograph in privacy. The subject was also assured that no male members of the staff would be in the vicinity of the measurement room during sessions. Instructional set. Immediately prior to alcohol administration, a staff nurse provided each subject with the appropriate instructional set, ostensibly on the basis of a (bogus) questionnaire the subject had answered earlier. It read: We always give participants as much information as possible about our studies so that they know what to expect. The questionnaire that you completed enables us to predict how alcohol will affect your level of sexual arousal while you are viewing our erotic film. Your test profile indicates that alcohol will increase [or decrease] your arousal level. Since subjects were not debriefed until the completion of all four sessions, ethical concerns dictated the presentation of the following qualifications concerning the alleged influence of alcohol: I should point out, however, that we are talking now of physiological arousal as indicated by the vaginal plethysmograph. This is, of course, different from actual sexual behavior or activity, And since the questionnaire has only been validated under standardized laboratory conditions, we really cannot predict how alcohol would affect your behavior in situations outside the lab. Following this instruction, the subject completed the procedural checklist appropriate to her instructionalset condition. Under the guise of a checklist to ensure that the subject had been fully informed, an item on the checklist was included to serve as a final written reminder of the instructional set. Finally, just prior to the showing of the film, the subject answered the self-rating questionnaire that served as the instructional-set manipulation check, determining whether or not the subject's stated expectation regarding her level of sexual arousal was consistent with the instructional set. When it was determined by intercom communication with the subject from a room adjacent to the measurement room that she had inserted the photoplethysmograph appropriately and was resting comfortably, a computer program was initiated that automatically controlled both the sequencing of events during the recording session and the digital recording of vaginal pressure pulse and EMG. The recording session lasted 34 minutes, during which the two 12 -minute films were presented, each preceded by a S-minute baseline period. At the conclusion of the erotic film the subject was told to remove the photoplethysmograph and the EMG electrodes and to meet the nurse in another room. Additional measures. A second self-rating questionnaire was administered in which the subject rated her responses to the erotic film, estimated how much
alcohol she had consumed, and indicated how intoxicated she felt and what effect alcohol had had on her sexual arousal level. In addition, each subject's response to one of four TAT cards (4, 6GF, 10, and 13MF) after each session was tape-recorded. The order of administration of the four cards was counterbalanced using a Greco-Latin square design. After the investigation, two independent raters scored each TAT story for the presence of manifest sexual content. The raters were trained to a reliability criterion of 87% with practice protocols before scoring the TAT stories for the present investigation. Reliability was calculated as the number of agreements divided by the number of agreements plus disagreements. The definition and categories of sexual content were similar to those used by Clark and Sensibar (1955): (a) primary—-mention of or evidence for sexual intercourse, genital contact, or the implied wish or desire for such contact; (b) secondary—mention of or evidence for nongenital physical contact (e.g., kissing) or the implied wish or desire for such contact, (c) tertiary—mention of romantic affiliation, relationship, or joint activity (e.g., on a date) that does not provide direct evidence for physical contact; (d) negative—no mention or evidence for sexual-physical contact or relational involvement and not classifiable within the other categories. Sexual content was scored only once for each story, and the activity that was biologically most sexual received priority. For example, if both primary and secondary content were observed, the story received a primary rating. Both raters had to have classified the story identically before they were said to be in agreement. A final BAL check concluded each session. Subjects were allowed to leave the laboratory only when their BAL reached zero. Debriefing was conducted after all subjects had completed the study.
RESULTS Blood Alcohol Levels Pre- and postfilm BALs are presented in Table 1. Duncan's multiple-range test (dj = 45) revealed significant differences (p < .01) between the mean BALs for all successive dosage levels. Mean subject estimates of alcohol content of drinks at the four dosage TABLE 1 BLOOD ALCOHOL LEVELS (mg %) IMMEDIATELY PRIOR TO AND AFTER VAGINAL MEASUREMENT Post-BAL
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ALCOHOL AND SKXUAL AROUSAL IN WOMEN
levels (postfilm self-rating questionnaire data) were as follows: AI — 1.07 oz. (.32 dl), A2 = 1.38 oz. (.41 dl), A3 = 4.26 oz. (1.26 dl), and A4 = S.26 oz. (1.56 dl). The only significant difference (p < .05) between estimates at successive dosage levels according to Duncan's test (df = 36) was between levels A2 and A3. Instructional Set The best index of the adequacy of the instructional-set manipulation is the number of subjects who expressed agreement with the experimenter's suggested effect of alcohol during the first experimental session. Of the eight subjects who were informed that alcohol increases sexual arousal, five predicted an increase in their own sexual arousal. Of the eight who were told that alcohol decreases sexual arousal, only one predicted a decrease in her own sexual arousal. Clearly, the manipulation was unsuccessful in influencing subjects to expect alcohol to reduce sexual arousal. Figure 1, based on data obtained from the prefilm self-rating questionnaire, indicates the extent to which subjects' expectations regarding the effects of alcohol on sexual arousal at each of the four alcohol dose levels were consistent with the experimentally administered instructional set. Subjects' ratings of the effect that alcohol did have on the degree of sexual arousal during the film (postfilm questionnaire data) showed an almost identical pattern. The following are the percentages of subjects, at each of the four alcohol dose
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levels, who reported that alcohol had increased their sexual arousal: AI = 25%, A2 — 43.75%, A3 = 68.75%, and A4 = 75%. The trend toward progressively greater numbers of reports of heightened sexual arousal with increasing intoxication is clear-cut. Vaginal Photoplethysmograph Measures Figure 2 summarizes the mean vaginal pressure pulse scores, averaged over sessions and alcohol levels, during both the control and erotic films. The success of the vaginal measure in discriminating between the two films is evident in the fact that subjects showed significantly more arousal in response to the erotic than the control film, / ( I S ) = 6.65, p < .001. An analysis of variance (ANOVA) of heart rate measures, computed from the vaginal pressure pulse records, failed to indicate any significant differences between the two films across the different alcohol levels or across sessions. An ANOVA and an orthogonal trend analysis were computed for two dependent measures: the mean percentage pressure pulse increase during the erotic film, erotic film — control film X 100, control film
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and the percentage difference between each subject's highest score on the erotic and control films. The ANOVA comprised four 4 X 4 Latin squares, with rows representing the 16 subjects and columns representing the four alcohol doses. The order in which the doses were administered was counterbalanced. Figures 3 and 4 summarize the mean percentage pressure pulse increase across alcohol levels and experimental sessions, respectively. A marginal main effect for sessions was obtained, ^(3,36) = 2.51, p < .10. The trend analysis showed a significant linear effect of alcohol levels, F(l, 36) = 4.S3, p < .05. An ANOVA of mean percentage pressure pulse increase during the last 6 minutes of the films shows a significant overall effect of sessions, /7(3,36) = 2.89, p < .OS. Trend analyses indicate a marginally significant linear effect of experimental sessions, F(l,36) = 3.86, p < .1, and a significant quadratic effect, /7(1,36) =4.24, p< .05.
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Percentage increases in maximum pressure pulse scores are presented in the upper halves of Figures 3 and 4. An ANOVA shows a significant overall effect of sessions, /7(3,36) = 4.35, p < .05. In addition, the Sessions X Instructional Set interaction is significant, F (3,36) = 3.67, p < .05. Trend analyses revealed a significant linear effect of alcohol levels, 77(1,36) = 5.7, p < .05, and a significant quadratic effect of experimental sessions, /7(1,36) = 10.94, p< .01.
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Neither the ANOVA nor trend analysis showed any significant effect of alcohol on this measure. Pearson product-moment correlations indicated no relation between EMG and vaginal pressure pulse scores. Thematic Apperception Test The interrater reliability for the scoring of manifest sexual content in the TAT stories
ALCOHOL AND SEXUAL AROUSAL IN WOMEN
was 87.5%. Sexual content was unaffected by alcohol levels, sessions, or instructional set. Nor was there a significant correlation between this measure and vaginal pressure pulse scores. Subjective Arousal The postfilm questionnaire required subjects to rate, on a S-point scale ranging from "not at all" to "intensely," how sexually arousing, how romantic, and how enjoyable they found the erotic film. Other scales assessed how anxious, guilty, or embarrassed they felt during the film. There were no significant effects of instructional set or alcohol dosage on responses to any questionnaire items, nor were there any significant correlations between these ratings and vaginal pressure pulse scores. DISCUSSION The data clearly demonstrate a negative linear relation between increasing levels of alcohol consumption and sexual arousal as measured by vaginal pressure pulse recordings. This finding replicates with women the results obtained with men by Farkas and Rosen (1976) using the same Latin square design, and by Briddell and Wilson (1976), who employed a completely randomized twofactor design. Increasing intoxication in both men and women results in progressively reduced sexual arousal in response to salient visual erotic stimulation. In contrast to Farkas and Rosen's (1976) results, which indicated a significant linear effect of experimental sessions, the present study found a significant quadratic sessions effect for both mean and maximum percentage pressure pulse increases. Given the identical designs and closely comparable BALs in both studies, this discrepancy may possibly be attributed to a differential response between men and women. On the assumption that university women are still more sexually inhibited and inexperienced than their male counterparts, it might be argued that the quadratic component reflects a disinhibition process followed by habituation effects. More specifically, since the women presumably had less familiarity with explicit visual erotic stimuli than the men, the first experimental session
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served to disinhibit their sexual responsiveness, which then reached peak expression on the second session. The men being less inhibited in general, and having had more exposure to similar erotic material in particular, would display maximum arousal during the first session, followed by habituation over time as the novelty wore off. However, this explanation is speculative at best, and other factors such as differences in the erotic stimuli used in these two studies cannot be discounted easily. The only significant effect of the instructional set was in terms of a significant Sessions X Instructional Set interaction on the percentage increase in maximum pressure pulse scores. As can be seen in Figure 4, this effect is attributable to the fact that, during Sessions 1-3, subjects who were told that alcohol reduces sexual arousal showed greater responsiveness than those informed that alcohol increases arousal. In Session 4, however, subjects told to expect an increase displayed slightly higher arousal than did subjects told to expect a decrease. The absence of a noinstruction control group makes it impossible to interpret this finding unequivocally. This seemingly paradoxical result might reflect the fact that subjects led to believe that alcohol increases arousal felt some pressure to perform in accordance with the obvious demand characteristics of the experiment and that this performance pressure impaired their sexual responsiveness (Masters & Johnson, 1970). Alternatively, the responsiveness of subjects given the decrease instructions might have been facilitated. Assessment of instructional set effects is hampered by the fact that an independent check showed that only 37.5% of the subjects accepted the experimental manipulation during the first session. This figure is substantially lower than the comparable figure of 58% of subjects who believed a similar manipulation in the Briddell and Wilson (1976) study, and it may indicate that subjects in the present study were skeptical of the predictive validity of the bogus questionnaire. Of considerable interest, however, is the finding that the majority of subjects showed an obvious trend toward predicting and retro-
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G. TERENCE WILSON AND DAVID M. LAWSON
spectively reporting progressively increased sexual arousal with advancing levels of alcohol consumption (Figure 1). This means that women's subjective estimates of the effect of alcohol were diametrically at odds with their vaginal pressure pulse readings. Ample evidence exists attesting to the fact that there is no simple relation between the physiological effects of alcohol and its behavioral consequences (e.g., Marlatt, Demming, & Reid, 1973). Rather, as Pliner and Cappell (1974) propose, the physiological action of alcohol may "induce a state of plasticity in which the organism responds more strongly . . . to the prevailing cognitive and social environment" (p. 418). Kalin (1972, pp. 2144) found that male subjects who had consumed alcohol responded with significantly more physically sexual themes in TAT stories in the presence of an attractive female than in her absence. Subjects who had not received alcohol did not respond differently on the TAT. On the basis of the present results, it appears that in the presence of erotic stimuli, women associate increasing alcohol intoxication with greater sexual arousal, an anticipated reinforcing consequence that may be instrumental in the development and/or maintenance of moderate or excessive drinking patterns in some individuals. Consistent with Briddell and Wilson's (1976) findings, EMG measures were essentially unaffected by either alcohol consumption or the instructional set. No evidence of a relation between EMG and vaginal pressure pulse was obtained. The absence of this effect, as Briddell and Wilson speculate, may be due to the fact that changes in muscle tonus may be more apparent in the later stages of the sexual response cycle or may occur in specific body areas other than the frontalis muscle. Sexual themes as manifested in subjects' responses to the TAT cards were not differentially influenced by alcohol consumption. Although they have in common a problem posed by the limited sampling of fantasy responses (responses to a single TAT card after each session), the present results replicate those of Briddell and Wilson (1976) in failing to support previous findings (Kalin, McClelland, & Kahn, 1965).
The data from the current study lend further support to the conclusion that vaginal vasocongestion is the most sensitive and reliable index of female sexual arousal (cf. Hoon et al., 1976). The absence of significant differences in heart rate between the control and erotic films is consistent with Geer et al.'s (1974) and. Hoon et al.'s (1976) findings with women. The failure to find a significant correlation between subjective ratings of sexual arousal and vaginal pressure pulse scores is also consistent with Geer et al.'s (1974) results. This may be a function of the subjective rating scales used and the fact that only one subjective rating was obtained for each film presentation. Kashinsky and Lawson (Note 2) found that self-reports of sexual arousal on a 10-point scale taken at 1-minute intervals during the same erotic film as that used in the present study corresponded very closely to the average vaginal pressure pulse scores presented in Figure 2. On the other hand, Heiman (Note 3) recently reported significant verbal-physiological agreement using a S-point rating scale. In conclusion, it must be cautioned that, as with the comparable studies with males, the generalizability of these findings to different populations in different settings remains to be established. And, while provocative, the clinical relevance of the present results requires more direct confirmation. In this connection, the extension of this type of investigation to alcoholics would appear to be especially important. REFERENCE NOTES 1. Heiman, J. Facilitating erotic arousal: Toward sex-positive sex research. Paper presented at the annual meeting of the American Psychological Association, New Orleans, August 1974. 2. Kashinsky, W., & Lawson, D. M. A semi-integration technique for automated recording oj vaginal pressure pulse. Unpublished manuscript, Rutgers— The State University, 1976. 3. Heiman, J. Use of the vaginal photoplethysmograph as a diagnostic and treatment aid in female sexual dysfunction. Paper presented at the annual meeting of the American Psychological Association, Chicago, August 1975. REFERENCES Athanasiou, R., Shaver, P., & Tavris, C. Sex. Psychology Today, 1970, 4, 37-52.
ALCOHOL AND SEXUAL AROUSAL IN WOMEN Briddell, D. W., & Wilson, G. T. The effects of alcohol and expectancy set on male sexual arousal. Journal of Abnormal Psychology, 1976, 85, 225234. Budzynski, T. H., & Stoyva, J. M. An instrument for producing deep muscle relaxation by means of an analog information feedback. Journal of Applied Behavior Analysis, 1969, 2, 231-237. Carpenter, J. A., & Armenti, N. P. Some effects of ethanol on human sexual and aggressive behavior. In B. Kissin & H. Begleiter (Eds.), The biology of alcoholism (Vol. 2). New York: Plenum Press, 1971. Clark, R. A., & Sensibar, M. R. The relationship between symbolic and manifest projection of sexuality with some incidental correlates. Journal of Abnormal and Social Psychology, 1955, SO, 327334. Farkas, G., & Rosen, R. C. The effects of ethanol on male sexual arousal. Journal of Studies on Alcohol, 1976, 37, 26S-272. Gallant, D. M. The effect of alcohol and drug abuse on sexual behavior. Medical Aspects of Human Sexuality, 1968, 2, 30-36. Geer, J., Morokoff, P., & Greenwood, P, Sexual arousal in women: The development of a measurement device for vaginal blood volume. Archives of Sexual Behavior, 1974, 3, 559-564. Hoon, P. W., Wincze, J. P., & Hoon, E. F. Physiological assessment of sexual arousal in women. Psychophysiology, 1976, 13, 196-205. Kalin, R. Social drinking in different settings. In D. C. McClelland, W. Davies, R. Kalin, & E. Wanner (Eds.), The drinking man. New York: Free Press, 1972. Kalin, R., McClelland, D. C., & Kahn, M. The
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effects of male social drinking on fantasy. Journal of Personality and Social Psychology, 1965, 1, 441-452. Kaplan, H. S. The new sex therapy. New York: Brunner/Mazel, 1974. Katchadourian, H. A., & Lunde, D. T. Fundamentals of human sexuality. New York: Holt, Rinehart & Winston, 1972. Kinsey, A., Pomeroy, W., Martin C., & Gebhard, P. Sexual behavior in the human female. Philadelphia, Pa.: Saunders, 1953. Lemere, F., & Smith, J. W. Alcohol-induced sexual impotence. American Journal of Psychiatry, 1973, 130, 212-213. Marlatt, G. A., Demming, B., & Reid, J. B. Loss of control drinking in alcoholics: An experimental analogue. Journal of Abnormal Psychology, 1973, 81, 233-241. Masters, W. H., & Johnson, V. E. Human sexual response. Boston: Little, Brown, 1966. Masters, W. H., & Johnson, V. E. Human sexual inadequacy. Boston: Little, Brown, 1970. Pliner, P., & Cappell, H. A comparison of social and solitary drinking. Journal of Abnormal Psychology, 1974, S3, 418-425. Sintchak, G., & Geer, J. A vaginal plethysmograph system. Psychophysiology, 1975, 12, 113-115. Wilsnack, S. C. The effects of social drinking on women's fantasy. Journal of Personality, 1974, 42, 43-61. Zuckerman, M. Physiological measures of sexual arousal in the human. Psychological Bulletin, 1971, 75, 297-329. (Received March 8, 1976; revision received May 17, 1976)
Effects of Alcohol on Sexual Arousal in Women G. Terence Wilson and David M. Lawson Rutgers—The State University During weekly experimental sessions each of 16 university women received in counterbalanced order four doses of beverage alcohol prior to viewing a control film and an erotic film. Half of the subjects were instructed beforehand that alcohol would increase their degree of sexual arousal in response to the erotic film; the other half were told that alcohol would decrease their sexual arousal. Measures of vaginal pressure pulse obtained by means of a vaginal photoplethysmograph showed a significant negative linear relation with alcohol doses. A significant interaction between sessions and instructional set indicated that subjects in the increase-set condition experienced less sexual arousal. This result was attributed to performance pressure induced by the demand characteristics of the instructional set. Additional measures of sexual arousal, including Thematic Apperception Test responses and self-report, showed no differences. With increasing levels of intoxication, however, a greater proportion of subjects reported enhanced sexual arousal.
Surprisingly little is known about the effects of alcohol on sexual responsiveness despite the fact that a definite relation between the two has long been posited. A comprehensive review of the subject by Carpenter and Armenti (1971, pp. 509-543) found only four studies on the influence of alcohol on human sexual behavior. Unfortunately, these studies, all of which used an indirect measure of sexual arousal (responses on Thematic Apperception Test [TAT] protocols), were seriously flawed by major methodological errors. Two recent investigations studied alcohol's effects on objectively measured sexual arousal in male college students. Using a Latin square design, Farkas and Rosen (1976) monitored penile tumescence in response to an erotic film
The authors are especially indebted to Elizabeth Anne Kirschling, Lorraine O'Brien, and Beverly Wojciehowski, the nursing staff of the Alcohol Behavior Research Laboratory at Rutgers—The State University, for their invaluable assistance in conducting this study. The authors also wish to thank John A. Carpenter for his assistance with the statistical analyses, Wayne Kashinsky for constructing the vaginal photoplethysmograph and assembling the physiological recording apparatus, Julia Heiman for her technical advice, and Peter E. Nathan for his generous support. Requests for reprints should be sent to G. Terence Wilson, Graduate School of Applied and Professional Psychology, Rutgers—The State University, New Brunswick, New Jersey 08903.
at four different blood alcohol levels (BALs), 0 mg %, 25 mg %, 50 mg %, and 75 mg %. Although a slight facilitation in amplitude of penile tumescence was observed at the low BAL condition (25 mg %), a significant negative linear trend accounted for most of the variance for the effects of alcohol—the rate and extent of tumescence decreasing with rising BAL. Briddell and Wilson (1976) similarly demonstrated a significant negative linear effect of increasing alcohol doses on penile tumescence. Moreover, their results indicated that sexual content in TAT stories was negatively correlated with tumescence. Information on the effects of alcohol on women is so lacking that Carpenter and Armenti (1971) were led to remark that "most experts comment on human sexual behavior and alcohol as though only males drink and have sexual interests" (p. 521). Kinsey, Pomeroy, Martin, and Gebhard (1953) failed to mention the subject, and although Masters and Johnson (1966) discussed the adverse influence of alcohol on male potency, there was no mention of its effect on women. Kaplan (1974) states that "habitual heavy intake frequently seriously impairs the sexual response in both genders, but most especially of men" (p. 89). While impotence in states of acute and chronic alcohol intoxication has been clinically documented (Lemere & Smith, 1973; Masters & Johnson, 1970), there is as
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yet no empirical basis for Kaplan's perhaps widely shared appraisal with respect to women. Reliable data that would permit an adequate evaluation of alcohol's effects on female sexuality simply do not exist. In one of the few studies of its kind, Wilsnack (1974) concluded on the basis of projective test stories that women drink in order to feel more womanly, including the sensations of being "warm, loving, and sexy" (p. 44). However, it is unclear what the sexual content on these dubious projective tests means without validating the tests against appropriate objective measures. The development of a reliable physiological measure of tumescence (the penile strain gauge) heralded a significant breakthrough in the study of male sexual arousal (Zuckerman, 1971). Sintchak and Geer (1975) recently described the use of a vaginal photoplethysmograph for monitoring vaginal blood volume and pressure pulse that promises to advance the study of female sexuality significantly. Evidence on the validity of this device has been furnished by Geer, Morokoff, and Greenwood (1974), who found reliable changes in vaginal opacity during the presentation of an erotic film. Furthermore, Hoon, Wincze, and Hoon (1976) showed the device to be significantly superior to other physiological measures in accurately discriminating between erotic and nonerotic or dysphoric videotapes. Accordingly, the present study used the Sintchak and Geer (197S) photoplethysmograph as an objective index of female sexual arousal. Although Briddell and Wilson (1976) have shown that alcohol decreases male sexual arousal, many individuals frequently drink in a deliberate attempt to improve their sexual functioning. It is presumed that the experience of relaxation and disinhibition that usually accompanies alcohol-produced central nervous system depression results in the attribution of aphrodisiacal properties to alcohol (cf. Katchadourian & Lunde, 1972). In a questionnaire survey, Athanasiou, Shaver, and Tavris (1970) found that of the women sampled, 68% reported that alcohol enhanced sexual pleasure, 11% reported that it had no effect, and 21% reported that it decreased
pleasure. The comparable figures for the men sampled were 45%, 15%, and 42%. The current investigation attempted a better controlled, direct evaluation of the role of expectancy in the effect of alcohol on sexual arousal. Furthermore, the relation between a direct genital measure and subjective TAT responses was assessed. As in the Briddell and Wilson (1976) study, superior control of alcohol administration permitted a partial replication of earlier research employing the TAT as a measure of alcohol's influence on sexual imagery. Muscle tension levels were monitored because alcohol's effects on sexual behavior are often attributed to a perceived reduction in anxiety accompanied by muscular relaxation (Gallant, 1968). Changes in myotonia have also been observed to accompany the various phases of the sexual response cycle (Masters & Johnson, 1966). METHOD Subjects and Setting Sixteen undergraduate and graduate women students between the ages of 18-22 years participated in the study. All subjects were screened during detailed interviews conducted by the nursing staff to exclude anyone with a current medical disorder or a history of psychiatric problems, alcohol/drug abuse, or sexual dysfunction. Similarly, individuals with any anxiety or other reservation about the study were excluded. Only women who were moderate social drinkers and who were exclusively heterosexual were selected. Each subject was paid $40 for her participation in the study. Particular care was taken to ensure that fully informed, written consent was obtained from subjects. All procedural details (except the expectancy manipulation) were explained and demonstrated prior to subjects' inclusion in the study. The research was carried out at the Rutgers Alcohol Behavior Research Laboratory, a research/treatment unit staffed primarily by graduate students in clinical psychology and by registered nurses.
Design The experimental design consisted of four 4 X 4 Greco-Latin squares in which subjects participated in four experimental sessions and were administered a different dose of alcohol and a different TAT card in counterbalanced order during each session. This design minimizes subject variance while controlling for the habituation effects of alcohol dose administration. In addition, half of the subjects were instructed that alcohol would increase their sexual arousal in response to the erotic film; the other half were told that it would decrease their sexual arousal.
ALCOHOL AND SEXUAL AROUSAL IN WOMEN
Apparatus Erotic stimuli. The measurement room contained a reclining bed, a small bedside table and lamp, and a 19-inch (48.26 cm) black-and-white monitor positioned at the foot of the bed for the presentation of two 12-minute films. The first, nonerotic control film consisted of a graphic but rather monotonous introduction of the computer facilities at Rutgers University. The second, erotic film comprised two segments: one from a sexual education film and one from a typical pornographic film. The erotic film showed explicit heterosexual interaction between two people featuring penile-vaginal intercourse, fellatio, and cunnilingus. In view of Heiman's (Note 1) findings, an attempt was made to select stimulus material in which the female initiated action and in which most of the focus was on the woman. A uniform soundtrack of instrumental music was added for continuity. The final version of the films was videotaped for convenience and consistency of presentation. Physiological recording. Changes in vaginal opacity were directly measured using a slightly modified version of Sintchak and Geer's (1975) photoplethysmograph. This device is a Plexiglas cylinder, if inches (4.4S cm) long and i inch (1.27 cm) in diameter, that has been hollowed out to accommodate a small lamp, photo cell, and connecting wires. When it is inserted approximately 1 inch (2.54 cm) into the vagina, the amount of indirect light reflected back to the photocell from the vaginal wall is affected by changes in blood volume and pressure pulse. The attached, shielded cable is encased in soft vinyl tubing extending from the end of the cylinder and terminates in a plug that subjects attached to a 5-pin shielded connector leading to the polygraph. In its size and weight it is comparable to a tampon, and its rounded end and smooth exterior ensure that it is comfortable and that it can be simply inserted by the woman herself (cf. Sintchak & Geer, 1975). Total hygiene and safety are assured by easily sterilizing it in a solution of zephiran chloride. Changes in vaginal pressure pulse and blood volume, the ac and dc components of the signal, were continuously recorded on a Beckman Type R Dynograph. In addition, the ac component was electronically modified by means of a semi-integration technique to produce a noncyclic index of vaginal pressure pulse amplitude that was displayed on a third polygraph channel. The output from this channel was then converted from an analog to a digital form, sampled at 15-sec intervals by a DEC PDF 8/L computer and printed for later analysis. Values obtained by this technique have been shown to correlate significantly (r = .83) with manually scored measures of pressure pulse amplitude (Kashinsky & Lawson, Note 2). Measures of heart rate during the 4th, 8th, and 12th minutes of both the control and erotic films were taken directly from the polygraph records of vaginal pressure pulse. Muscle tension levels (EMG) were measured by
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the Bio-Electric Feedback System (Model B-l, BioFeedback Systems, Inc.) from exosomatic electrodes attached to the subject's forehead. This system permits the measurement of muscle action potentials by the quantification of peak-to-peak microvolts (Budzynski & Stoyva, 1969). The EMG levels were sampled every 15 sec by the computer. Changes in electromuscle action potentials were also displayed on the Beckman polygraph. The BALs were determined by means of a breathalyzer (Model 900, Smith and Wesson Electronics Co.).
Procedure Subjects were asked to fast for 4 hours and to refrain from alcohol and drugs for the 24 hours prior to each of the four weekly sessions. On arrival at the lab for each session, subjects received a breathalyzer test to ensure that they were completely sober, and they were weighed. Thereafter a predetermined amount of alcohol was administered individually to each subject prior to film viewing and measurement of sexual arousal. Subjects also received an instructional-set manipulation designed to create a particular expectancy about subjects' level of arousal during the film. Alcohol administration. In terms of absolute ethanol administered, the four doses were: A± = .05 g/kg; A2 =.25 g/kg; A 3 =.50 g/kg, and A 4 =.7S g/kg. As an example, for a 120-lb. woman, the correspondiing amount in ounces of 80-proof alcohol would be as follows: .3, 1.4, 2.9, and 4.3. In the placebo control condition (Ai), a very small amount of alcohol was administered, since both previous research with males (Briddell & Wilson, 1976), and pilot data with females had indicated that alcohol could be tasted in the lowest concentration but that in all instances subjects would remain at 0 mg % BAL. Canadian whiskey (80-proof) was mixed with two parts chilled 7-Up to form a 13.3% ethanol solution for all groups (except Ai). The alcohol for the placebo group was mixed with 20 parts 7-Up (1.33% ethanol solution) and tinted with food coloring to approximate the total fluid volume and color of the As group. Several drops of whiskey were also smeared on the inside of the drinking cup to create the alcohol smell. All drinks were delivered in a 1,000-ml beaker with an 8-oz. (2.37 dl) Styrofoam drinking cup by a male research assistant. The subject was given 20 minutes to consume the drink and a subsequent 40minute "rest period" for the alcohol absorption to take place. Closed circuit TV monitoring of the subject during this period ensured that the entire drink was consumed and remained consumed. After the absorption period a BAL test was administered and the subject was encouraged to void the bladder prior to viewing the film. Subjects were not told the result of the BAL check, nor were they told how much alcohol they had consumed. At this point a staff nurse escorted the subject to the measurement room, attached the frontalis EMG electrodes, and reviewed the procedure for using the
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vaginal photoplethysmograph. The nurse then left the room, which remained locked from the inside, permitting the subject to insert the plethysmograph in privacy. The subject was also assured that no male members of the staff would be in the vicinity of the measurement room during sessions. Instructional set. Immediately prior to alcohol administration, a staff nurse provided each subject with the appropriate instructional set, ostensibly on the basis of a (bogus) questionnaire the subject had answered earlier. It read: We always give participants as much information as possible about our studies so that they know what to expect. The questionnaire that you completed enables us to predict how alcohol will affect your level of sexual arousal while you are viewing our erotic film. Your test profile indicates that alcohol will increase [or decrease] your arousal level. Since subjects were not debriefed until the completion of all four sessions, ethical concerns dictated the presentation of the following qualifications concerning the alleged influence of alcohol: I should point out, however, that we are talking now of physiological arousal as indicated by the vaginal plethysmograph. This is, of course, different from actual sexual behavior or activity, And since the questionnaire has only been validated under standardized laboratory conditions, we really cannot predict how alcohol would affect your behavior in situations outside the lab. Following this instruction, the subject completed the procedural checklist appropriate to her instructionalset condition. Under the guise of a checklist to ensure that the subject had been fully informed, an item on the checklist was included to serve as a final written reminder of the instructional set. Finally, just prior to the showing of the film, the subject answered the self-rating questionnaire that served as the instructional-set manipulation check, determining whether or not the subject's stated expectation regarding her level of sexual arousal was consistent with the instructional set. When it was determined by intercom communication with the subject from a room adjacent to the measurement room that she had inserted the photoplethysmograph appropriately and was resting comfortably, a computer program was initiated that automatically controlled both the sequencing of events during the recording session and the digital recording of vaginal pressure pulse and EMG. The recording session lasted 34 minutes, during which the two 12 -minute films were presented, each preceded by a S-minute baseline period. At the conclusion of the erotic film the subject was told to remove the photoplethysmograph and the EMG electrodes and to meet the nurse in another room. Additional measures. A second self-rating questionnaire was administered in which the subject rated her responses to the erotic film, estimated how much
alcohol she had consumed, and indicated how intoxicated she felt and what effect alcohol had had on her sexual arousal level. In addition, each subject's response to one of four TAT cards (4, 6GF, 10, and 13MF) after each session was tape-recorded. The order of administration of the four cards was counterbalanced using a Greco-Latin square design. After the investigation, two independent raters scored each TAT story for the presence of manifest sexual content. The raters were trained to a reliability criterion of 87% with practice protocols before scoring the TAT stories for the present investigation. Reliability was calculated as the number of agreements divided by the number of agreements plus disagreements. The definition and categories of sexual content were similar to those used by Clark and Sensibar (1955): (a) primary—-mention of or evidence for sexual intercourse, genital contact, or the implied wish or desire for such contact; (b) secondary—mention of or evidence for nongenital physical contact (e.g., kissing) or the implied wish or desire for such contact, (c) tertiary—mention of romantic affiliation, relationship, or joint activity (e.g., on a date) that does not provide direct evidence for physical contact; (d) negative—no mention or evidence for sexual-physical contact or relational involvement and not classifiable within the other categories. Sexual content was scored only once for each story, and the activity that was biologically most sexual received priority. For example, if both primary and secondary content were observed, the story received a primary rating. Both raters had to have classified the story identically before they were said to be in agreement. A final BAL check concluded each session. Subjects were allowed to leave the laboratory only when their BAL reached zero. Debriefing was conducted after all subjects had completed the study.
RESULTS Blood Alcohol Levels Pre- and postfilm BALs are presented in Table 1. Duncan's multiple-range test (dj = 45) revealed significant differences (p < .01) between the mean BALs for all successive dosage levels. Mean subject estimates of alcohol content of drinks at the four dosage TABLE 1 BLOOD ALCOHOL LEVELS (mg %) IMMEDIATELY PRIOR TO AND AFTER VAGINAL MEASUREMENT Post-BAL
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8.73 7.71 13.52
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ALCOHOL AND SKXUAL AROUSAL IN WOMEN
levels (postfilm self-rating questionnaire data) were as follows: AI — 1.07 oz. (.32 dl), A2 = 1.38 oz. (.41 dl), A3 = 4.26 oz. (1.26 dl), and A4 = S.26 oz. (1.56 dl). The only significant difference (p < .05) between estimates at successive dosage levels according to Duncan's test (df = 36) was between levels A2 and A3. Instructional Set The best index of the adequacy of the instructional-set manipulation is the number of subjects who expressed agreement with the experimenter's suggested effect of alcohol during the first experimental session. Of the eight subjects who were informed that alcohol increases sexual arousal, five predicted an increase in their own sexual arousal. Of the eight who were told that alcohol decreases sexual arousal, only one predicted a decrease in her own sexual arousal. Clearly, the manipulation was unsuccessful in influencing subjects to expect alcohol to reduce sexual arousal. Figure 1, based on data obtained from the prefilm self-rating questionnaire, indicates the extent to which subjects' expectations regarding the effects of alcohol on sexual arousal at each of the four alcohol dose levels were consistent with the experimentally administered instructional set. Subjects' ratings of the effect that alcohol did have on the degree of sexual arousal during the film (postfilm questionnaire data) showed an almost identical pattern. The following are the percentages of subjects, at each of the four alcohol dose
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levels, who reported that alcohol had increased their sexual arousal: AI = 25%, A2 — 43.75%, A3 = 68.75%, and A4 = 75%. The trend toward progressively greater numbers of reports of heightened sexual arousal with increasing intoxication is clear-cut. Vaginal Photoplethysmograph Measures Figure 2 summarizes the mean vaginal pressure pulse scores, averaged over sessions and alcohol levels, during both the control and erotic films. The success of the vaginal measure in discriminating between the two films is evident in the fact that subjects showed significantly more arousal in response to the erotic than the control film, / ( I S ) = 6.65, p < .001. An analysis of variance (ANOVA) of heart rate measures, computed from the vaginal pressure pulse records, failed to indicate any significant differences between the two films across the different alcohol levels or across sessions. An ANOVA and an orthogonal trend analysis were computed for two dependent measures: the mean percentage pressure pulse increase during the erotic film, erotic film — control film X 100, control film
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and the percentage difference between each subject's highest score on the erotic and control films. The ANOVA comprised four 4 X 4 Latin squares, with rows representing the 16 subjects and columns representing the four alcohol doses. The order in which the doses were administered was counterbalanced. Figures 3 and 4 summarize the mean percentage pressure pulse increase across alcohol levels and experimental sessions, respectively. A marginal main effect for sessions was obtained, ^(3,36) = 2.51, p < .10. The trend analysis showed a significant linear effect of alcohol levels, F(l, 36) = 4.S3, p < .05. An ANOVA of mean percentage pressure pulse increase during the last 6 minutes of the films shows a significant overall effect of sessions, /7(3,36) = 2.89, p < .OS. Trend analyses indicate a marginally significant linear effect of experimental sessions, F(l,36) = 3.86, p < .1, and a significant quadratic effect, /7(1,36) =4.24, p< .05.
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Percentage increases in maximum pressure pulse scores are presented in the upper halves of Figures 3 and 4. An ANOVA shows a significant overall effect of sessions, /7(3,36) = 4.35, p < .05. In addition, the Sessions X Instructional Set interaction is significant, F (3,36) = 3.67, p < .05. Trend analyses revealed a significant linear effect of alcohol levels, 77(1,36) = 5.7, p < .05, and a significant quadratic effect of experimental sessions, /7(1,36) = 10.94, p< .01.
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Neither the ANOVA nor trend analysis showed any significant effect of alcohol on this measure. Pearson product-moment correlations indicated no relation between EMG and vaginal pressure pulse scores. Thematic Apperception Test The interrater reliability for the scoring of manifest sexual content in the TAT stories
ALCOHOL AND SEXUAL AROUSAL IN WOMEN
was 87.5%. Sexual content was unaffected by alcohol levels, sessions, or instructional set. Nor was there a significant correlation between this measure and vaginal pressure pulse scores. Subjective Arousal The postfilm questionnaire required subjects to rate, on a S-point scale ranging from "not at all" to "intensely," how sexually arousing, how romantic, and how enjoyable they found the erotic film. Other scales assessed how anxious, guilty, or embarrassed they felt during the film. There were no significant effects of instructional set or alcohol dosage on responses to any questionnaire items, nor were there any significant correlations between these ratings and vaginal pressure pulse scores. DISCUSSION The data clearly demonstrate a negative linear relation between increasing levels of alcohol consumption and sexual arousal as measured by vaginal pressure pulse recordings. This finding replicates with women the results obtained with men by Farkas and Rosen (1976) using the same Latin square design, and by Briddell and Wilson (1976), who employed a completely randomized twofactor design. Increasing intoxication in both men and women results in progressively reduced sexual arousal in response to salient visual erotic stimulation. In contrast to Farkas and Rosen's (1976) results, which indicated a significant linear effect of experimental sessions, the present study found a significant quadratic sessions effect for both mean and maximum percentage pressure pulse increases. Given the identical designs and closely comparable BALs in both studies, this discrepancy may possibly be attributed to a differential response between men and women. On the assumption that university women are still more sexually inhibited and inexperienced than their male counterparts, it might be argued that the quadratic component reflects a disinhibition process followed by habituation effects. More specifically, since the women presumably had less familiarity with explicit visual erotic stimuli than the men, the first experimental session
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served to disinhibit their sexual responsiveness, which then reached peak expression on the second session. The men being less inhibited in general, and having had more exposure to similar erotic material in particular, would display maximum arousal during the first session, followed by habituation over time as the novelty wore off. However, this explanation is speculative at best, and other factors such as differences in the erotic stimuli used in these two studies cannot be discounted easily. The only significant effect of the instructional set was in terms of a significant Sessions X Instructional Set interaction on the percentage increase in maximum pressure pulse scores. As can be seen in Figure 4, this effect is attributable to the fact that, during Sessions 1-3, subjects who were told that alcohol reduces sexual arousal showed greater responsiveness than those informed that alcohol increases arousal. In Session 4, however, subjects told to expect an increase displayed slightly higher arousal than did subjects told to expect a decrease. The absence of a noinstruction control group makes it impossible to interpret this finding unequivocally. This seemingly paradoxical result might reflect the fact that subjects led to believe that alcohol increases arousal felt some pressure to perform in accordance with the obvious demand characteristics of the experiment and that this performance pressure impaired their sexual responsiveness (Masters & Johnson, 1970). Alternatively, the responsiveness of subjects given the decrease instructions might have been facilitated. Assessment of instructional set effects is hampered by the fact that an independent check showed that only 37.5% of the subjects accepted the experimental manipulation during the first session. This figure is substantially lower than the comparable figure of 58% of subjects who believed a similar manipulation in the Briddell and Wilson (1976) study, and it may indicate that subjects in the present study were skeptical of the predictive validity of the bogus questionnaire. Of considerable interest, however, is the finding that the majority of subjects showed an obvious trend toward predicting and retro-
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spectively reporting progressively increased sexual arousal with advancing levels of alcohol consumption (Figure 1). This means that women's subjective estimates of the effect of alcohol were diametrically at odds with their vaginal pressure pulse readings. Ample evidence exists attesting to the fact that there is no simple relation between the physiological effects of alcohol and its behavioral consequences (e.g., Marlatt, Demming, & Reid, 1973). Rather, as Pliner and Cappell (1974) propose, the physiological action of alcohol may "induce a state of plasticity in which the organism responds more strongly . . . to the prevailing cognitive and social environment" (p. 418). Kalin (1972, pp. 2144) found that male subjects who had consumed alcohol responded with significantly more physically sexual themes in TAT stories in the presence of an attractive female than in her absence. Subjects who had not received alcohol did not respond differently on the TAT. On the basis of the present results, it appears that in the presence of erotic stimuli, women associate increasing alcohol intoxication with greater sexual arousal, an anticipated reinforcing consequence that may be instrumental in the development and/or maintenance of moderate or excessive drinking patterns in some individuals. Consistent with Briddell and Wilson's (1976) findings, EMG measures were essentially unaffected by either alcohol consumption or the instructional set. No evidence of a relation between EMG and vaginal pressure pulse was obtained. The absence of this effect, as Briddell and Wilson speculate, may be due to the fact that changes in muscle tonus may be more apparent in the later stages of the sexual response cycle or may occur in specific body areas other than the frontalis muscle. Sexual themes as manifested in subjects' responses to the TAT cards were not differentially influenced by alcohol consumption. Although they have in common a problem posed by the limited sampling of fantasy responses (responses to a single TAT card after each session), the present results replicate those of Briddell and Wilson (1976) in failing to support previous findings (Kalin, McClelland, & Kahn, 1965).
The data from the current study lend further support to the conclusion that vaginal vasocongestion is the most sensitive and reliable index of female sexual arousal (cf. Hoon et al., 1976). The absence of significant differences in heart rate between the control and erotic films is consistent with Geer et al.'s (1974) and. Hoon et al.'s (1976) findings with women. The failure to find a significant correlation between subjective ratings of sexual arousal and vaginal pressure pulse scores is also consistent with Geer et al.'s (1974) results. This may be a function of the subjective rating scales used and the fact that only one subjective rating was obtained for each film presentation. Kashinsky and Lawson (Note 2) found that self-reports of sexual arousal on a 10-point scale taken at 1-minute intervals during the same erotic film as that used in the present study corresponded very closely to the average vaginal pressure pulse scores presented in Figure 2. On the other hand, Heiman (Note 3) recently reported significant verbal-physiological agreement using a S-point rating scale. In conclusion, it must be cautioned that, as with the comparable studies with males, the generalizability of these findings to different populations in different settings remains to be established. And, while provocative, the clinical relevance of the present results requires more direct confirmation. In this connection, the extension of this type of investigation to alcoholics would appear to be especially important. REFERENCE NOTES 1. Heiman, J. Facilitating erotic arousal: Toward sex-positive sex research. Paper presented at the annual meeting of the American Psychological Association, New Orleans, August 1974. 2. Kashinsky, W., & Lawson, D. M. A semi-integration technique for automated recording oj vaginal pressure pulse. Unpublished manuscript, Rutgers— The State University, 1976. 3. Heiman, J. Use of the vaginal photoplethysmograph as a diagnostic and treatment aid in female sexual dysfunction. Paper presented at the annual meeting of the American Psychological Association, Chicago, August 1975. REFERENCES Athanasiou, R., Shaver, P., & Tavris, C. Sex. Psychology Today, 1970, 4, 37-52.
ALCOHOL AND SEXUAL AROUSAL IN WOMEN Briddell, D. W., & Wilson, G. T. The effects of alcohol and expectancy set on male sexual arousal. Journal of Abnormal Psychology, 1976, 85, 225234. Budzynski, T. H., & Stoyva, J. M. An instrument for producing deep muscle relaxation by means of an analog information feedback. Journal of Applied Behavior Analysis, 1969, 2, 231-237. Carpenter, J. A., & Armenti, N. P. Some effects of ethanol on human sexual and aggressive behavior. In B. Kissin & H. Begleiter (Eds.), The biology of alcoholism (Vol. 2). New York: Plenum Press, 1971. Clark, R. A., & Sensibar, M. R. The relationship between symbolic and manifest projection of sexuality with some incidental correlates. Journal of Abnormal and Social Psychology, 1955, SO, 327334. Farkas, G., & Rosen, R. C. The effects of ethanol on male sexual arousal. Journal of Studies on Alcohol, 1976, 37, 26S-272. Gallant, D. M. The effect of alcohol and drug abuse on sexual behavior. Medical Aspects of Human Sexuality, 1968, 2, 30-36. Geer, J., Morokoff, P., & Greenwood, P, Sexual arousal in women: The development of a measurement device for vaginal blood volume. Archives of Sexual Behavior, 1974, 3, 559-564. Hoon, P. W., Wincze, J. P., & Hoon, E. F. Physiological assessment of sexual arousal in women. Psychophysiology, 1976, 13, 196-205. Kalin, R. Social drinking in different settings. In D. C. McClelland, W. Davies, R. Kalin, & E. Wanner (Eds.), The drinking man. New York: Free Press, 1972. Kalin, R., McClelland, D. C., & Kahn, M. The
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