Behar. Res. The-r. Vol. 28, No. 3. pp. 217-226, Printed in Great Britain. All rights reserved

HABITUATION

1990 Copyright

AND

DISHABITUATION

SEXUAL INGRID

Department

of Psychology,

(Received

OF FEMALE

AROUSAL and RAY OVER*

MEUWISSEN

La Trobe

0005-7967/90 $3.00 + 0.00 ICI 1990 Pergamon Press plc

University, I2 October

Bundoora,

Victoria

3083, Australia

1989)

Summary-Measures of subjective and physiological sexual arousal were taken within a session while women either viewed the same segment of erotic film on many occasions or employed the same sexual fantasy over a number of trials. For both film and fantasy there were significant reductions in subjective sexual arousal and average pulse amplitude during the course of repeated erotic stimulation. Subsequent presentation of novel erotic stimuli led to recovery in sexual arousal. Bases for habituation and dishabituation of female sexual arousal are discussed.

An issue of continuing concern in the debate about the effects of pornography has been whether erotic film, slides, text and fantasy become less sexually arousing during the course of repeated or extended presentation (see Report, 1970). This question has been addressed in research employing designs in which erotic stimulation is repeated on either a between-session basis or a within-session basis. Neither strategy has yielded unequivocal results. Several investigators have demonstrated reduction in male sexual arousal as erotic stimulation is repeated over sessions. As an example, Howard, Reifler and Liptzein (1970) recorded penile response during an erotic film shown before the men in the sample had viewed pornography for 90 min a day over 3 weeks, at the end of the 3-week period, and 8 weeks later. Tumescence levels were compared with measures taken at comparable points in time from control Ss. Extended exposure to pornography reduced sexual arousal, although the effects were short-lived since there was full recovery on testing 8 weeks later. In some subsequent studies (e.g. Rosen, 1973; Rubin & Henson, 1976; Julien & Over, 1984; Smith & Over, 1987a), there was no diminuation of male sexual response with repeated erotic stimulation. When stimulation varied in content over sessions, novelty may have operated against a decrement. However, Rubin, Henson, Falvo and High (1979) found no reduction in penile tumescence across 6 sessions, 3-5 days apart, in which men viewed the same film. Reduction in response when the same stimulus is repeatedly presented within a session is traditionally referred to as habituation, provided the decrement is not attributable simply to neural adaptation or fatigue (Thompson & Spencer, 1966). O’Donohue and Geer (1985) found habituation in sexual arousal when men viewed a series of erotic slides, each for 1 min with a 1 min interstimulus interval. Although the reduction in penile tumescence and subjective arousal was more rapid when the men viewed the same slide than different slides on successive trials, the extent of decrement was similar for same-slide and varied-slide presentation over the 27 trials in the session. In contrast to these effects demonstrated with slides, Smith and Over (1987b) found no decline in physiological or subjective arousal when men engaged in structured fantasy over repeated trials within a session. Arousal remained at a stable level irrespective of whether the content of the fantasy remained fixed over trials or was varied. There has been limited study of the effect of repeated erotic stimulation on female sexual arousal. Zillman and Bryant (1988) found that women as well as men were less satisfied with their current partner after exposure to pornography for 1 hi-/week over 6 weeks, while Kelley and Musialowski (1986) reported a decline in sexual arousal over 4 sessions, each 1 day apart, during which women viewed the same erotic film. However, satisfaction and arousal were assessed in these studies only through self reports. In a psychophysiological study, Heiman (1977) measured vaginal pulse amplitude over two sessions, 2 weeks apart, during which women listened to erotic tapes and

*To whom

all correspondence

should

be addressed. 217

218

INCRID MEUWISSEN and RAY OVER

engaged in fantasy. Arousal levels were lower in the second session than in the first. However, in other studies where physiological as well as subjective measures of female sexual arousal have been taken over 2 or more sessions there was no significant decrement in level of arousal over sessions (Henson, Rubin & Henson, 1979; Morokoff & Heiman, 1980; Wilson & Lawson, 1976; Wincze, Hoon & Hoon, 1978; Hoon, Bruce & Kinchloe, 1982; Morrell, Dixon, Carter & Davidson, 1984). At the same time, none of these studies had been designed to test for repeated exposure effects, and there were differences in methodology between studies (for example, whether stimulation was constant or varied between sessions) that may have affected outcome. There has not to date been a study assessing whether female sexual arousal habituates with repeated erotic stimulation on a within-session basis. The aim of the present research is to establish whether there is cumulative decline in physiological and subjective sexual arousal when women are presented with the same erotic stimulus on repeated trials within a session. Since habituation of male sexual arousal has been demonstrated with visual stimuli (O’Donohue & Geer, 1985) but not with fantasy (Smith & Over, 1987b), the question of whether female sexual arousal habituates is addressed in the present study in relation to film and fantasy. There are claims in the literature that at least some sexual fantasies retain high erotic saliency despite repeated use. For example, Crepault and Couture (1980) drew attention to primary fantasies, which “. . .have a very strong erotic valency and generally are not subject to extinction. Once found. they keep their erotic drive and become almost permanent” (p. 566). Masters, Johnson and Kolodny ( 1982) claimed that, “Among the most common varieties of sexual fantasies are those that can be described as old familiar stories. . . . The person using this fantasy finds it particularly pleasing and returns to it again and again” (p. 337). In the present study women viewed the same film segment on many occasions within one session, and in another session they engaged repeatedly in the same structured fantasy. The order of testing for film and fantasy was counterbalanced across Ss. The objective was to determine whether within-session decrement in female sexual arousal is found for fantasy as well as for film. The effects of repeated stimulation on arousal can be assessed more powerfully by establishing whether dishabituation occurs in conjunction with habituation. Dishabituation is defined operationally as recovery in response when a novel stimulus is presented after there has been habituation to a sequence of uniform stimulation. If arousal has decreased over repeated trials (habituation), it should be possible to reverse this effect through introduction of a stimulus which is discernibly different from that to which the S was repeatedly exposed (dishabituation). Demonstrating dishabituation in addition to habituation eliminates the possibility that the response decrement found over repeated trials can be attributed to neural adaptation or fatigue. In their study of male sexual arousal O’Donohue and Geer (1985) did not test for dishabituation. Smith and Over (1987b) found that the arousal level increased when the structured fantasy in which the S was to engage changed suddenly after 18 trials. Since the Ss had not demonstrated habituation over the preceding 18 trials, Smith and Over interpreted the increase in arousal as a novelty effect rather than a dishabituation effect. The present study of female sexual arousal was designed to assess whether dishabituation as well as habituation occurs. Habituation was assessed by determining whether physiological and subjective sexual arousal declines over 18 uniform presentations of a film segment or a structured fantasy within I session. The content of the film segment or the structured fantasy was changed on the 19th and 20th trials within the session in order to test for dishabituation. Vividness of imagery was monitored on a trial-by-trial basis in the fantasy session in order to establish whether habituation and dishabituation in sexual arousal were associated with systematic changes in the cognitive saliency of the erotic stimuli. METHOD Subjects Eight undergraduate women reporting exclusive heterosexual orientation were tested. All eight women had participated in earlier psychophysiological research in the same laboratory. It was decided to use experienced Ss to ensure that response decrements over repeated trials reflected habituation to the erotic stimuli rather than processes such as reduction in anxiety or adjustment

Habituation

and dishabituation

of female sexual arousal

219

to a novel situation. The mean age of Ss was 28.75 yr (SD 9.02). As indicated by a mean score of 18.75 (SD 2.87) on the Sexual Behavior Inventory-Female (Bentler, 1968), the women were sexually experienced-5 had a current sexual partner. On a scale ranging from 1 (‘never’) to 6 (‘always’), the mean rated use of sexual fantasy outside sexual activity was 3.25 (SD 0.46). Level of enjoyment from sexual activities received a mean rating of 4.25 (SD 0.87) on a scale from 1 (‘low’) to 5 (‘high’), while satisfaction with sex life on 7 point scale O-6 was 4.25 (SD 1.77). None of the women were using oral contraceptives at the time of testing. Prior to participation each S gave informed consent, and stated that she had no medical or health problems or a history of sexually transmitted disease. Ss were paid $25 on completion of the two test sessions, but the contract allowed a woman to terminate her involvement in the experiment at any time. Procedure

The test sessions, each lasting 65-80 min, were carried out in a dimly lit, sound-attenuated room, which was maintained at 23°C. Communication between the S and the experimenter, who was monitoring equipment in the adjacent room, was through an intercom system. Visual contact was not possible. An infrared vaginal photoplethysmograph (VPPG), a Grass polygraph (model 79D), and a Grass compatible coupler were used in measuring physiological sexual arousal. Construction and calibration of the VPPG and coupler followed the procedures recommended by Hoon, Murphy, Laughter and Abel (1984) except that a rectangular piece of perspex (14 x 5 cm) enclosed the VPPG at a distance 4 cm from the centre of the phototransistor. This modification provided constant depth of placement and consistent orientation of the device in the vagina. The VPPG was sterilized between each session in a solution of activated gluteraldehyde (Cidex) for at least 20 min. The DC (pooled vaginal blood volume, a cumulative measure) and the AC (vaginal pulse amplitude, a rate measure) of the VPPG output were recorded using a low-level DC preamplifier (model 7PI) and drive amplifier (model 7DA) and an AC preamplifier and integrator (model 7P3) and associated drive amplifier (model 7DA). Polygraph settings during recording were those recommended by Hoon et al. (1984). The woman positioned the VPPG in privacy with the aid of written instructions, and during testing she remained seated semisupine in a comfortable recliner chair. At the start of each session prerecorded preparation and relaxation instructions were delivered through headphones. Classical music was played during an initial baseline period, which continued until there was stable recording of vaginal blood volume over an interval of 2 min. Arousal levels were then recorded in one session for 20 film segments and in another session for 20 fantasy segments. Each woman was tested on film and fantasy, and the order of the 2 sessions was counterbalanced between women. Test sessions were scheduled for the follicular phase (612 days after the start of menses) of consecutive menstrual cycles to control for effects within and between Ss that menstrual cycle might have on sexual arousal. In the session in which film-induced arousal was studied a woman viewed the same film segment on 18 occasions (habituation stimulus) and was then shown two novel film segments (dishabituation stimuli). Each segment was displayed on a television monitor in front of the S for 1 min. The interstimulus interval of 90 set included the time required by the S to rate how sexually aroused she had felt during the preceding presentation. This rating, which was given through the intercom system. was on a scale ranging from 1 (‘not sexually aroused’) to 9 (‘highly sexually aroused’). The three film segments (one used on habituation trials and two on dishabituation trials) had been assessed as comparable in sexual arousal through ratings given by 12 women drawn from the same population as the women tested in the study. The habituation stimulus demonstrated intercourse with the man on top, and one dishabituation stimulus portrayed rear entry intercourse and the other stimulus intercourse with the woman on top. The actors were different for the three segments, each of which was shown without sound. In the session involving fantasy a woman engaged in the same structured fantasy for 18 trials (habituation stimulus) and on the 19th and 20th trials she engaged in other nominated fantasies (dishabituation stimuli). Slides were displayed to show the theme the woman was to employ in fantasy. Each descriptive slide (e.g. ‘intercourse with you on top’) was presented for 30 set and followed by a blank red slide for 30 sec. The woman was to engage in the nominated fantasy throughout this period. and in the interstimulus interval of 90sec rate not only how sexually

220

INGRIDMEUWISSENand

RAY OVER

aroused she had been during fantasy (on a 9-point scale ranging from ‘not sexually aroused’ to ‘highly sexually aroused’). but how vivid were the images she formed during fantasy (also on a 9-point scale). Prior to participation in the study each woman rated 15 themes from the Female Sexual Fantasy Questionnaire (Meuwissen & Over, 1990) in terms of how sexually arousing she found each theme. Of the three themes that the woman found most arousing, one was used as the habituation stimulus and the other two as the dishabituation stimuli. The women were not told that the study was concerned with habituation or that novel stimuli were to be presented on the 19th and 20th trials in the session. The instructions given prior to the film session advised a woman that she would see the same erotic videotape segment a number of times. She was to give full attention to the segment on each occasion, and she was not to engage in any sexual fantasy during the entire session. Prior to the fantasy session a woman was instructed that she would engage in the same erotic fantasy a number of times. She was to read the slide before engaging in fantasy, employ the nominated fantasy throughout the 1 min trial. but not engage in sexual fantasy during the interstimulus interval. It was emphasised in the instructions that with repetition of a fantasy theme the content of fantasy was to remain constant without change in imagined partner or behaviors. The general instructions emphasised that as movement would produce artifacts in the polygraph recordings. the woman was to remain as still as possible throughout the session. In particular, she was not to tense abdominal. pelvic. or vaginal muscles. At the end of each session each S rated on a 1O-point scale (ranging from ‘not at all’ to ‘completely’) the extent to which she had complied with experimental instructions. In addition, after the film session she rated on a 10 point scale ranging from ‘not at all’ to ‘very often’ the frequency with which she had engaged in sexual fantasy during the session. The rating on a 10 point scale made after the fantasy session assessed how frequently the woman had varied the content of the repeated fantasy during the session. The Ss were debriefed at the end of the second session. Data reduction

The maximum pen deflection from the initial 2 min baseline was measured in each session for blood volume. The average integrated pulse amplitude change from baseline during each segment in a session was also calculated by scoring at 20-see intervals. The pen deflection change scores and baseline balance voltages were transformed into reflectance unit values using the formula given by Hoon et al. ( 1984). The dependent variables in data analysis were average pulse amplitude, maximum blood volume, subjective sexual arousal. and (for the fantasy condition, but not for film) rated vividness of imagery. In the case of the physiological measures a difference score (arousal level minus baseline level) was calculated for each trial for each S. Whether or not habituation had occurred within the session was assessed for each dependent variable by comparing the mean level of response of Ss across the 18 trials on which there had been constant stimulation. Trials were grouped into blocks of three (trials l-3, 4-6, 7-9, etc.) for purposes of this analysis, and the mean level of response on subsequent blocks was expressed as a percentage of the mean level of response on the first block (trials I-3). In order to assess dishabituation, the mean level of response on trials 19 and 20 (when there had been a change in stimulation) was compared with the mean level of response on trials 16-18. The further interest is in whether the mean response on trials 19 and 20 had recovered to the level found on trials 1-3. RESULTS When completing the questionnaire after the session that had involved film, 1 of the 8 women in the sample indicated low compliance with instructions. She gave a rating of 5 on the O-9 scale. compared with a mean of 8.1 for the remaining Ss, in response to the question, “How well did you comply with instructions. 7” The woman reported that she had frequently engaged in fantasy while watching the film (rating of 7 on the O-9 scale, relative to a mean of 0.6 for the other women). Measures obtained from this woman thus need to be considered separately from data recorded for the other Ss. Data from this same woman in the session involving imagery were also excluded from the analysis of group results. The woman reported compliance with instructions, including

Habituation and dishabituation

of female sexual arousal

221

consistent use of fantasy throughout the session. However, on trials l-3 she gave a mean rating of subjective sexual arousal of only 1.7 (on a O-9 scale) for the fantasy theme (‘sexual intercourse with the same partner’) she had been assigned for the 18 habituation trials. The mean arousal rating for the other seven women on trials 1-3 was 4.76 (SD 1.65). As noted earlier, the themes selected for each woman as the habituation and dishabituation stimuli were the fantasies that the woman herself had rated as the most sexually arousing when she was tested prior to participation in the study. Despite ratings that the anomalous S had earlier given, the fantasy theme assigned to her on trials 1-18 elicited minimal subjective sexual arousal during the test session. Results from this woman need to be excluded from data analysis since habituation cannot be validly assessed when there initially is a floor effect. Figure 1 reports mean levels of sexual arousal (average pulse amplitude, mean blood volume, subjective sexual arousal) across the 18 habituation trials and the two dishabituation trials within a session. For each measure the mean response for successive blocks of three trials (two trials in the case of the dishabituation stimuli) is expressed as a percentage of the mean response levei on trials l-3. Values are shown separately in Fig. 1 for the film and fantasy sessions. Habituation of sexual arousal

The first 18 segments within a session involved exposure to the same erotic stimulus. Habituation demonstrated by showing that there is a significant drop in sexual arousal over segments. In the present case response levels were compared over successive blocks of three trials. Comparisons were is

to2 t ,

,IT_y

--_

Is) r 2 .E $

f Maximum

96.

blood

volume

110,

70

.

60.

I

I

l-3

4-6

7-9

lo-12

Trials

13-15

16-18

--. d ----_ ~

IS-20

Trials

Fig. 1. Mean maximum blood volume, average pulse amplitude, and subjective sexual arousal for film (0) and fantasy (0) on trials i-18 (habituation) and trials 19-20 (dishabituation). Values are given as percentages relative to measures on trials 1-3.

INGRID MEUWISSENand RAY OVER

222

through multivariate analysis of variance with average pulse amplitude, maximum blood volume, and subjective sexual arousal as the dependent variables. The independent variables were made of erotic stimulation (film vs fantasy) and trial blocks. There was a significant difference in level of sexual arousal across blocks of trials, F (15, 198) = 3.57, P < 0.001. Univariate tests showed that the significant trials effect applied for subjective sexual arousal, F (5, 66) = 14.62, P < 0.001, and for average pulse amplitude. F (5, 66) = 2.75, P < 0.05, but not for maximum blood volume, F (5. 66) = 2.19, P > 0.05. It is evident from inspection of Fig. 1 that there was a cumulative decline in subjective sexual arousal over the six blocks of habituation trials. Repeated stimulation also led to a reduction of sexual arousal as assessed by mean pulse amplitude. Although the variation in response level across blocks of trials was not statistically significant in the case of maximum blood volume, 8 of the 10 data points for this measure fell below 100%. Habituation in sexual arousal, as indexed by a significant reduction in response with repeated stimulation, was thus found in the case of two of the three arousal measures employed in the experiment. The interactive influence of mode of stimulation and trial blocks was not significant, F (15, 198) = 0.61. P > 0.05. Habituation was therefore evident to the same degree for film and fantasy. Mean arousal levels for film and fantasy did not differ significantly, F (3, 64) = 2.36, P > 0.05. In considering this result it needs to be kept in mind that the levels of response within each mode were expressed not in absolute units but as a percentage of the response on trials 1-3 in the session. A separate multivariate comparison followed by univariate tests showed that arousal expressed in absolute units was higher for film than for fantasy in the case of all three response measures. Dishahituation

of sexual arousal

Response levels on trials 16-18 and 19-20 were compared to establish whether sexual arousal had increased when novel erotic stimulation was introduced on trials 19-20 following the 18 trials involving constant erotic stimulation. The comparison was through multivariate analysis of variance. The dependent variables were the three measures of sexual arousal, while the independent variables were mode of stimulation (film vs fantasy) and trial block (16-18 vs 19-20). As in the preceding analysis, arousal did not vary significantly with mode of stimulation, F (3, 16) = 0.97, P > 0.05. Consistent with dishabituation, sexual arousal was significantly greater on trials 19-20 than on trials 16-18, F (3, 16) = 11.36, P < 0.001. Univariate tests revealed significant increases in response from trials 16-18 to trials 19-20 in the case of subjective sexual arousal, F (1, 18) = 34.92, P > 0.001, maximum blood volume, F (1. 18) = 22.16, P < 0.001, and average pulse amplitude, F (1. 18) = 7.99, P < 0.01. The interactive influence of mode of stimulation and trial block was not significant, F (3, 16) = 0.44, P > 0.05. Comparable changes between trials 16-18 and 19-20 thus occurred for film and fantasy. The further concern is with whether the recovery on trials 19-20 from the habituation that occurred across trials l-18 was complete. Multivariate analysis of variance showed that mean arousal was higher on trials 19-20 than on trials l-3, F (3, 16) = 3.90, P < 0.05. Univariate tests showed that maximum blood volume was significantly higher on trials 18-20 than on trials 1-3, F (1, 18) = 8.23, P < 0.01. while pre-habituation levels (Trials 1-3) and dishabituation levels (trials 19-20) were similar in the cases of subjective sexual arousal, F (1, 18) = 0.07, P > 0.05, and average pulse amplitude. F ( 1. 18) = 1.84. P > 0.05. Habituation in subjective sexual arousal and average pulse amplitude with repeated stimulation was thus followed by dishabituation to the level of the initial response. Arousal and imagery during fantasy

Immediately after each segment in the fantasy session the S rated not only how sexually aroused she had felt during fantasy, but how vividly she had formed images when engaging in the nominated fantasy. Following the method adopted with the arousal measures, the mean rated vividness of imagery on successive blocks of three trials was expressed as a percentage of the mean rating obtained for the S on trials 1-3. Mean percentage values across the 7 women (excluding the anomalous S) were 106.5 for trials 4-6,95.7 for trials 7-9,91.5 for trials 10-12, 87.5 for trials 13-15, 79.8 for trials 16-l 8, and 98.8 for trials 19-20. Analysis of variance revealed a significant reduction

Habituation and dishabituation of female sexual arousal

223

in vividness of imagery across the habituation trials, F (5, 30) = 2.97, P < 0.05. However, the mean ratings of vividness were not significantly higher on trials 19-20 than on trials 16-18, r (6) = 1.74, P > 0.05, and the values on trials 19-20 did not differ significantly from ratings on trials 1-3, I (6) = 0.16, P > 0.05. The possibility that habituation in sexual arousal over the first 18 segments of the session involving fantasy was mediated by a reduction in vividness of imagery over sessions was assessed through multivariate analysis of covariance. The dependent variables in this analysis were subjective sexual arousal, maximum blood volume, and average pulse amplitude, while the independent variable was trial blocks. The covariate was the mean vividness rating for a S on trials 16-18 relative to her mean rating on trials l-3. Multivariate analysis of covariance showed habituation of sexual arousal even after allowance was made for imagery becoming less vivid over the course of the repeated stimulation, F (12, 60) = 2.98, P < 0.01. Univariate tests showed a significance reduction over trials in subjective sexual arousal and average pulse amplitude, but not maximum blood volume, after allowance had been made for changes in vividness of imagery over trials. InditGduaEdzyerences As noted earlier, one of the eight women in the sample did not comply with instructions during the session in which film segments were viewed. This woman reported that she had engaged in fantasy while viewing the film. All three arousal measures recorded for this woman increased rather than decreased over the course of erotic stimulation. Values for this anomalous S on trials 16-18 (expressed as percentages of measures on trials l-3) were 100.3% for maximum blood volume, 167.8% for average pulse amplitude, and 150.0% for subjective sexual arousal. When the novel film segments were introduced on trials 19-20, ali three arousal measures dropped rather than increased. Values on trials 19-20 were 98.1% for maximum blood volume, 153.3% for average pulse amplitude, and 141.7% for subjective sexual arousal. The extent to which there was uniformity in habituation and dishabituation effects for the remaining seven women can be established from Table 1, which reports response levels (percentages relative to measures on trials l-3) for each S on trials 16-l 8 and 19-20. Values are shown separately for measures taken in the film and fantasy sessions. For fantasy all women reported lower subjective sexual arousal on trials 16-18 than trials 1-3, while there was reduction in maximum blood volume for all but one woman and in average pulse amplitude for all but one woman. Film-induced subjective arousal was lower on trials 1618 than trials 1-3 for six of the seven women, as was maximum blood volume. Five of the seven women had lower values on average pulse amplitude on trials 16--l 8. It is almost uniformly the case that measures on trials 19-20 were higher than on trials 16-18. However, for fantasy two women responded to the novel segments with a reduction in average pulse amplitude, and one of these women also reported less subjective sexual arousal. Table 1. Blood volume. pulse amplitude. subjective arousal. and vividness of imagery values for iodividu~l SC on trials 16-18 (habituation) and 19-20 (dishab~t~tion). Values are expressed as percentages relative to measures obtained for the S on trials l-3 Maximum blood volume

Average plllse amplitude

-.

-

Subjective arousal

Vividness of imagery

S>\Tri~tls

16-18

19-20

16-18

19-20

16-18

19-20

16-18

19-20

(1) (2)

96.9 93.7 95.2 99.9 104.5 94.3 95.3 9x.9 99.3 96.6 96.9 103.0 99.2 91.5 99.6 98.9

101.1 99.3 100.7 100.4 106.9 103.0 99.0 101.5 100.6 100.4 104.8 106.2 102.9 99.8 102.7 102.5

66.3 63.0 103.9 95.5 103.8 98.5 67 8 85.5 97.6 83.7 60.1 77.7 93.2 95.3 110.6 88.3

75.4 95.5 113.7 114.2 120.8 133.9 89.4 106. I III 7 116.5 129.4 100.6 104.9 85.0 102.3 106.9

57. I 62.3 34.6 70.5 100.0 27.2 70.5 60.3 58.3 65.2 36.2 74.9 12.2 61.7 80.0 64. I

71.4 106.3 75.0 97.0 116.0 95.4 88.2 91.3 112.5 91.3 122.6 112.4 133.3 57.4 100.0 104.5

100.0 112.6 36.8 57.1 70.0 81.7 100.0 79.7

122.6 112.6 94.8 85.8 119.9 68.1 87.5 98.8

(3) Fdm (4) (5) (61 (7) .P (1) (1) (3) Fantasy (4) (5) (6) (7) v

224

INGRID MEUWISSENand RAY OVER

DISCUSSION

The study demonstrates habituation and dishabituation in female sexual arousal. An erotic stimulus becomes less sexually arousing with repetition, but with introduction of a novel erotic stimulus there is recovery in arousal. Habituation and dishabituation applied to the same degree to sexual arousal evoked by film and fantasy. Repeated erotic stimulation led to a reduction not only in subjective sexual arousal, but in physiological arousal as indexed by average pulse amplitude. For maximum blood volume there was a trend towards habituation, but the reduction in mean response over blocks of trials was not statistically significant. The reduction in arousal with repeated presentation of the film segment parallels for women the habituation effects that O’Donohue and Geer (1985) established for men. In contrast to the present evidence that sexual arousal habituates during repeated fantasy, Smith and Over (1987b) found no decline in physiological or subjective sexual arousal when men engaged in structured fantasy over repeated trials within a session. As was done in the present study, Smith and Over monitored vividness of imagery during fantasy on a trial-by-trial basis. Whereas their Ss maintained stable arousal and constant vividness of imagery over repeated trials, the women in the present study demonstrated a reduction in vividness of imagery over trials as well as habituation in sexual arousal. The present results could be reconciled with those of Smith and Over (1987b) if it proved to be the case that habituation in arousal during fantasy is mediated by a reduction in vividness of imagery over trials. However, analysis of covariance showed significant habituation effects for the arousal induced by fantasy after allowance was made for the reduction that occurred in vividness of imagery over trials. The present study was designed to allow dishabituation as well as habituation to be assessed. It was found for film and fantasy that women became more sexually aroused when novel erotic stimulation was introduced after a woman had experienced the same stimulus on 18 trials. Such reversibility indicates that the reduction in arousal over repeated trials was not due simply to neural adaptation or fatigue. In the case of subjective sexual arousal and average pulse amplitude the novel stimulus resulted in full recovery from habituation, and for maximum blood volume the level of response to the novel stimulus was above that found prior to the earlier repeated stimulation. The elevation in response level for maximum blood volume is more properly termed a stimulus novelty effect than dishabituation, since the group had not shown a significant decline in arousal during repeated stimulation. Whether habituation has occurred can be established not only through analysis of group results, but by considering data obtained from individual Ss. Although Smith and Over (1987b) found no evidence of habituation when mean levels of arousal were compared across trials, one of their Ss showed a systematic decline in subjective and physiological arousal over repeated trials followed by a recovery in response upon introduction of the novel stimulus. In the present study there was a substantial degree of uniformity in pattern of response among the seven women whose results were included in the analysis of group data. Four women had lower arousal levels on trials 16-18 than on trials 1-3 for ail three sexual arousal measures in the film session and in the fantasy session. For two other women habituation was evident in the case of five of the six comparisons (the exception being a single measure in the fantasy session), and the remaining woman did not show habituation on any of the three arousal measures in the film session. As noted earlier. the anomalous S showed an increase in arousal with repeated display of the film segment, but this woman indicated during post-experimental inquiry that she had disregarded instructions not to employ fantasy while viewing the film. The basis for habituation and dishabituation of sexual arousal when women view erotic film or engage in erotic fantasy needs to be identified. One possibility is that habituation is mediated by changes in cognitive and other attentional processes over the course of repeated stimulation. Cognitive determinants of sexual arousal have been well documented (see Dekker & Everaerd, 1989). Showing the S the same film segment on each trial or requiring the S to engage repeatedly in the same structured fantasy does not guarantee that stimulation has remained constant over the habituation trials. As an example, the S may form progressively less vivid images with repetition of sexual fantasy. Since sexual arousal is correlated with vividness of imagery (Smith & Over. 1987a,c), it may be that habituation of sexual arousal occurs through imagery during fantasy

Habituation

and dishabituation

of female sexual arousal

225

becoming less vivid. It was in order to test for such a possibility that vividness of imagery, and not simply the level of sexual arousal, was monitored throughout the fantasy session in the present experiment. There was a reduction in vividness of imagery over trials. However, habituation of sexual arousal occurred independently of the change in imagery. The possibility that habituation and dishabituation of sexual arousal are mediated by cognitive processes other than vividness of imagery needs to be assessed. Dekker and Everaerd (1988) demonstrated greater sexual arousal for emotion-based than stimulus-based appraisal, and the possibility that Ss become less likely to use emotion-based evaluation when stimulation is repeated should be evaluated. Similarly, sexual arousal is correlated with anxiety (see Barlow, 1986). Ss may become less aroused with repetition of erotic stimulation through becoming less anxious. Again, distraction reduces sexual arousal (Adams, Haynes & Brayer, 1985; Farkas, Sine & Evans, 1979). A stimulus may become less sexually arousing with repetition because the S increasingly engages in non-sexual thoughts. Further, it has been clearly demonstrated that Ss can voluntarily enhance or inhibit sexual arousal (see Dekker & Everaerd, 1989). The demand characteristics implicit in assessment may result in Ss being more motivated to enhance arousal at the beginning than at the end of an experimental session involving repeated exposure to the same stimulus. An objective in future research should be to assess a range of cognitive processes in conjunction with sexual arousal on a trial-by-trial basis. It may prove that habituation and dishabituation are mediated in systematic ways by attentional and other cognitive processes. The study of habituation within this perspective provides a basis for analysis of individual differences. For example, without knowing that the anomalous S in the present study had engaged in fantasy while viewing the film segment it would be impossible to understand why she became more rather than less aroused over the course of the session. It may also be possible to reconcile seemingly conflicting results by reference to processes mediating arousal. Smith and Over (1987b) found no evidence of habituation in male sexual arousal to fantasy, while O’Donohue and Geer (1985) demonstrated habituation with erotic slides. In the present study there was habituation for fantasy and film. The different results could have arisen if the cognitive processes mediating arousal changed over trials in some studies but not in others. In such terms it is possible that there will not be inevitable decline in sexual arousal with repetition of erotic stimulation, and that experimental interventions aimed at regulating attention and information processing can regulate the likelihood of change in response over trials. REFERENCES Adams, A. E., Haynes. S. N. & Brayer. M. A. (1985). Cognitive distraction in female sexual arousal. Psychophysiology. Z, 6899696. Barlow, D. H. (1986). The causes of sexual dysfunction: The role of anxiety and cognitive interference. Journal qf Consulting and Clinical Psychology, 54. 140-148. Bentler. P. (1968). Heterosexual behavior assessment. II. Females. Behavior Research and Therapy. 6, 27-30. Crepault, C. & Couture, M. (1980). Men’s erotic fantasies. Archises of Se.wal Behavior, 9, 565-581. Dekker. J. & Everaerd, W. (1988). Attentional effects on sexual arousal. Psychophysiology, 25. 45-54. Dekker. J. & Everaerd, W. (1989). Psychological determinants of sexual arousal: A review. Behariour Research and Therapy. -77. 353-364. Farkas. G. M., Sine, L. F. & Evans, I. M. (1979). The effects of distraction, performance demand. stimulus explicitness, and personality on objective and subjective measures of male sexual arousal. Behatiour Research and Therapy, 17. 25-32. Heiman. J. (1977). A psychophysiological exploration of sexual arousal patterns in females and males. Psychopbysiolog), 143 266-274. Henson. D. E.. Rubin. H. B. & Henson, C. (1979). Analysis of the consistency of outcome measures of sexual arousal in women. Jourr~al qf Applied Behavioral Analysis, 12. 701-7 1 I. Hoon. P. W.. Bruce. K. & Kinchloe, B. (1982). Does the menstrual cycle play a role in sexual arousal? Psychophysiology, 19. 21-26. Hoon. P. W.. Murphy. W. D.. Laughter, J. S. & Abel, G. E. (1984). Infrared vaginal photoplethysmography: Construction, calibration. and sources of artifact. Behavioral Assessmenf 6, 141-152. Howard. J. L.. Reifler. C. B. & Liptzin. M. B. (1970). Effects of exposure to pornography. In Technical Reports qf the Cnmmission on Ohscenit~ and Pornography (Vol. 8). Washington, D.C.: U.S. Government Printing Office. Julien. E. & Over. R. (1984). Male sexual arousal with repeated exposure to erotic stimuli. Archives qf Sexual Behavior, 131-‘1 l-222. Kelley, K. & Musialowski, D. (1986). Repeated exposure to sexually explicit stimuli: Novelty, sex. and sexual attitudes. Archires qf Sesual Behavior, 15. 487498. Masters. W. H., Johnson, V. E. & Kolodny, R. C. (1982). Human sexuality. Boston: Little Brown. Meuwissen. I. & Over. R. (1990). Five dimensions of female sexual fantasy. In preparation. Morokoff. P. J. & Heiman, J. R. (1980). Effects of erotic stimuli on sexually functional and dysfunctional women: Multiple measures before and after sex therapy. Behariour Research and Therapy, 18. 127-137.

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Morrell. M. J., Dixen, J. M., Carter S. & Davidson. J. M. (1984). The influence of age and cycling status on sexual arousability in women. American Journal of Obstetrics and Gynecology, 148, 66-71. O’Donohue, W. T. & Geer. J. H. (1985). The habituation of sexual arousal. Archives of Sexual Behavior. f4. 233-246. Report of the Effects Panel to the Commission on Obscenity and Pornography (1970) In the Report qf the Commission on Obscenity and Pornography, Part II. The Impact of Erotica. Bantam: New York. Rosen, R. C. (1973). Suppression of penile tumescence by instrumental conditioning. Psychosomatic Medicine. 35. 509-514. Rubin. H. B. & Henson, D. E. (1976). Effects of alcohol on male sexual responding. Psychopharmacology. 47, 123-134. Rubin, H. B., Henson, D. E.. Falvo, R. E. and High. R. W. (1979). The relationship between men’s erogeneous levels of testosterone and their penile responses to erotic stimuli. Behariour Research and Therapy, 17, 305-312. Smith. D. & Over, R. (1978a). Male sexual arousal as a function of the content and the vividness of erotic fantasy. Psychophysiology. 24, 334-339. Smith, D. & Over. R. (1987b). Does fantasy-induced sexual arousal habituate? Behariour Research and Therapy. 2.5. 477485. Smith, D. & Over, R. (1987~). Correlates of fantasy-induced and film-induced male sexual arousal. Archices of Se.uual Behavior. 16, 395-409. Thompson, R. F. & Spencer. W. A. (1966). Habituation: A model phenomenon for the study of neuronal substrates of behavior. Psychological Reriebc. 73. 1643. Wilson, G. T. & Lawson, D. M. (1976). Effect of alcohol on sexual arousal in women. Journal of Abnormal Psychology. 85, 489497. Wincze. J. P., Hoon, E. F. & Hoon, P. W. (1978). Multiple measure analysis of women experiencing low sexual arousal. Behariour Research and Therapy, 16, 4349. Zillman, D. & Bryant. J. (1988). Pornography’s impact on sexual satisfaction. Journal of Applied Social Psychology, 18. 438453.