How do men and women feel? Determinants of subjective experience of sexual arousal

A common finding in psychophysiological research is that correlations between sexual feelings and genital responses are lower in women than in men. Measurement issues, anatomical differences, factors influencing self-report, and the role of attention have all been considered but do not seem sufficient to explain this gender difference. Providing women with feedback about their genital response, or asking them to focus on genital sensations, does not seem to increase response concordance, suggesting that women are less accurate in detecting genital responses. It is proposed that in both men and women, automatic cognitive processing of sexual meaning activates the genital response. Men and women are believed to differ in the degree to which genital feedback contributes to their subjective experience, and in the likelihood that they process other than sexual meanings. For women, more than men, sexual stimuli convey multiple meanings, and their subjective experience seems more strongly influenced by social and situational cues relevant to, for example, physical and emotional safety, intimacy, and commitment. How do men and women feel? 3 According to one of the founding fathers of psychology, William James, bodily responses and emotional experience are two sides of the same emotional coin (James, 1884). In James’ theory, bodily (visceral) changes follow directly the perception of the emotional stimulus, and “our feeling of the same changes as they occur IS the emotion" (1884, p. 190). James’ position implies that, in order for bodily changes to take this central role, they need to be consciously perceived and processed. What is more, without these bodily changes, “a cold and neutral state of intellectual perception is all that remains” (1884, p. 193). Recent cognitive neuroscience perspectives acknowledge that bodily changes are an apparent aspect of emotional response. According to Damasio (2003), feelings consist, among other things, of “the perception of a certain state of the body ” (2003, p. 86). The question is, however, to what extent bodily changes contribute to emotional experience, and whether this contribution is similar in men and women. James’ theory appears less appropriate for women than for men with respect to the experience of sexual emotions. A review of the literature on female sexual arousal reveals that there is little agreement between reported genital sensations and changes in genital vasocongestion (Laan & Everaerd, 1995a). Across studies, correlations between changes in genital vasocongestion and subjective sexual arousal range from significantly negative, to nonsignificant, to significantly positive. In contrast, correlations between genital and subjective sexual arousal in men are usually significantly positive, despite differences in methodology and procedures. Studies designed to compare female and male sexual arousal patterns in one experimental design, thus precluding methodological variation, consistently report higher correlations in men than in women (cf. Dekker & Everaerd, 1988; Heiman, 1977; Wincze, Venditti, Barlow, & Mavissakalian, 1980; Steinman, How do men and women feel? 4 Wincze, Sakheim, Barlow, & Mavissakalian, 1981). A very recent study found that the association between genital and subjective sexual arousal was lower for women than for men and postoperative male-to-female transsexuals (Chivers, Rieger, Latty, & Bailey, in press). Anecdotal evidence suggests that discrepancies between genital response and sexual feelings are not limited to laboratory situations. According to reports of subjects, therapists and patients, women may notice that they have increased vaginal lubrication, but in such instances often do not experience any feelings of sexual arousal, nor any inclination to engage in sexual activity. Other anecdotal evidence suggests that during rape or other types of sexual abuse women may notice increased vaginal lubrication even though they find the situation highly aversive. There have even been reports of women having had an orgasm during such situations (personal communication R.L. Levin, May 2003 and need to add relevant reference). This paper reviews possible explanations for the observed gender differences in agreement between genital response and sexual feelings, and offers some tentative answers to the question of what, if not genital response, determines the experience of sexual arousal in women. Measurement artefacts A number of explanations have been forwarded to explain the low correlations between genital response and sexual feelings in women. The most obvious one is measurement error of instruments designed to assess vaginal vasocongestion. However, low correlations between genital response and sexual feelings are not restricted to a single How do men and women feel? 5 measure of genital response (e.g., Slob, Bax, Hop, Rowland, & van der Werff ten Bosch, 1996). Heiman and colleagues compared the most often used instrument to assess vaginal vasocongestion, the vaginal photoplethysmograph, with pelvic MRI during erotic film (Heiman, Maravilla, Hackbert, Delinganis, Heard, Garland, Carter, Weisskoff, & Peterson, 2001). They found that correlations with MRI were even lower than with the vaginal photoplethysmograph. The discrepancy between genital arousal and sexual feelings in women is not affected by the way in which sexual feelings are assessed (by Likert scales to be filled out directly after exposure to an erotic stimulus or by continuous measures with which the intensity of feelings can be measured concurrent with erotic stimulus exposure) or which sexual feelings are measured (from a single item about sexual or genital sensations to extensive emotion questionnaires with a wide range of possible sexual feelings). Anatomy and sensitivity Anatomy or sensitivity? Many men seem to infer their sexual feelings from changes that take place in their genitals (Sakheim, Barlow, Beck, & Abrahamson, 1984), which is what William James suggested we all do. When it comes to sexual arousal, men are likely to have more cues they can use to detect genital response than women do. Think, for instance, of visual feedback, or tactile feedback when an erect penis is pressing against clothing. It is therefore possible that women can detect their genital responses less easily than men can, for reasons related to the anatomy of the genitals. Even though such cues can aid in making inferences about feelings, the data from Chivers and colleagues (in press) suggest How do men and women feel? 6 that they are not strictly necessary. Postoperative male-to-female transsexuals, who lack visual and tactile genital feedback from a penis, showed associations between genital arousal and sexual feelings that were as high as in men. While processes relevant to memory and learning may need to be considered, these findings indicate that direct feedback from the genitalia may not be sufficient in explaining gender differences. According to Damasio’s ‘somatic marker’ hypothesis of consciousness, feelings require the participation of brain regions that are involved in the mapping and/ or regulation of our continuously changing internal states (Damasio, Grabowski, Bechara, Damasio, Ponto, Parvizi, & Hichwa, 2000). Perhaps the gender differences in associations between genital arousal and sexual feelings can be explained by gender differences in the somatosensing regions of the brain, i.e. the insula and the anterior cingulate, reflecting stronger proprioceptive genital feedback to the brain in men than in women. One of the most robust findings from imaging studies of sexual arousal is bilateral activation of the insula (Sumich, Kumari, & Sharma, 2003). One of the few studies comparing brain activity between genders during erotic stimulus exposure using functional magnetic resonance imaging found significant increases in the insula and anterior cingulate, indicating that the mapping of body states had been significantly modified during the process of feeling (Damasio, 2003), but no gender differences in activity in these regions were found (Karama, Lecours, Leroux, Bourgouin, Bedoin, Joubert, & Beauregard, 2002). The same study showed that in male subjects only, processing of the erotic cues was also associated with significant activation in the hypothalamus and thalamus. The authors assert that the greater hypothalamic activation found in male subjects implies that How do men and women feel? 7 they were more physiologically aroused than the female subjects, and that the greater thalamic activation, mirroring the higher reports of sexual arousal in men, suggests that this region is implicated in the cognitive dimension of sexual arousal. There was a positive correlation between the intensity of sexual feelings and the magnitude of hypothalamic activation in men, but not in women. These findings may suggest that women are less sensitive to sexual stimuli than men are, and that women would need stronger stimuli to reach a comparable level of genital arousal. There is evidence that still pictures evoke genital response in most men (O’Donohue & Geer, 1985) but hardly any in women (Laan & Everaerd, 1995b). It is not clear, however, which visual stimuli would be most arousing for most men, and which visual stimuli would be most arousing to most women. The erotic stimuli used in the study of Karama et al. (2002) were preselected so as to evoke lowest disgust ratings in women, but they were not selected based on their sexually arousing qualities for women. It can therefore not be ruled out that the erotic film excerpts used in this study were less effective in generating sexual arousal in the female subjects, which may have explained the differences in thalamic and hypothalamic activity. Because we cannot directly compare genital responses in men and women it is as yet impossible to say which of the two explanations, the anatomy explanation or the sensitivity (of brain or genitals) explanation, is m