Although he offers a detailed technical description of female sexual response during intercourse his account includes some perplexing features. He notes that the extra thickness of the human male penis is designed to help stimulate the woman; and results in the female’s external genitals going through much more pulling and pushing during pelvic thrusts. This along with pressure from the pubic region of the male would translate to virtual masturbation - if she were a male. According to Lloyd (2005), Morris is evidently using Masters and Johnson’s model of indirect clitoral stimulation caused by thrusting. As the penis moves back and forth, it pulls the labia minora, which are attached to the skin covering the clitoris, back and forth with it indirectly causing movement around over the clitoral glands (Hite, 1976). Broadly speaking, the clitoris is supposed to be stimulated by friction from its own hood. It is difficult to give credit to this account, because Masters and Johnson (1966) developed their model specifically with women who were selected “only if they could consistently and easily have orgasms during unassisted intercourse” (Lloyd, 2005 p.53, her emphasis). Lloyd cites evidence from studies over 70 years claiming that this would only be about 20% of the women therefore cannot be considered representative. Her argument continues when she draws out a contradiction, if the woman was masturbating herself, unless she was among the small percentage of women who masturbate by vaginal insertion alone, she would stimulate her clitoris directly (Kinsey, Pomeroy, Martin, and Gebhard, 1953). The problem that Morris does not address is this: if this indirect stimulation mechanism works so efficiently, and is “virtually masturbatory” (Morris, 1967 p.80) then why the low frequency of female orgasm during unassisted intercourse? Also, why don’t women imitate intercourse while they masturbate (Lloyd, 2005)? So far, Morris’s pair bond account conflicts with the available sex research in significant ways. Firstly, the sex literature about timing to orgasm is grossly misinterpreted. Secondly, his work assumes in several places that female response is like male response to the same sexual situation, particularly to the friction from intercourse and he also neglects the available work on female masturbation.
The next part of the paper will briefly review the Intermittent Reinforcement theory offered by Milton Diamond (1980) and Sarah Blaffer Hrdy (1979) which claims to explain the evolution of the female orgasm based on experimental psychology. One of their fundamental beliefs is that the wide variability in female orgasmic response during intercourse is itself an adaptation. Diamond begins by noting that even among healthy Americans, one in eight couples have infertility problems many of which are because of a deficiency in sperm quality, quantity or transport (Hrdy, 1979 cited in Lloyd, 2005). Thus, more acts of intercourse would allow more successful fertilization; based on operant learning theory, human females could be driven harder by irregular reward (orgasm) to seek sexual gratification. This is under the assumption that partial reinforcement produces more persistent behaviour than 100 per cent reinforcement (reward). Hence frustration might be reduced by engaging in additional coitus or different partners ensuring a more regular or varied supply of sperm to ensure conception (Diamond, 1980, p. 184). Therefore, the argument is, even the highly variable female orgasm could act as an effective reward system for engaging in sexual intercourse.
This contention however has a flaw in the way intermittent reinforcement has been applied. Intermittent reinforcement schedules are only effective if a schedule or regular or constant reward was already setup, wherein the subject is rewarded every time it exhibits the behaviour (Lloyd, 2005). It is not possible to train a rat to hit the lever 15 times to be rewarded with a food pellet unless it is first rewarded each time it does anything like lever pressing (see Domjan, 1998, my emphasis). Among women, they would not repeat the behaviour of intercourse an increased number of times without experiencing orgasm, unless they were first under a schedule in which each act of intercourse was rewarded by orgasm (claim already contradicted by Kinsey et al., 1953). Of course, there are many other rewards for women engaging in intercourse besides orgasm, but the hypothesis in question is proposing that orgasm is the reward for intercourse. In addition to this crucial problem, Lloyd (2005) draws attention to another ambiguity. When the authors say that the female orgasm is highly variable, it could mean that individual females vary widely in whether they experience orgasm on a particular occasion of intercourse, or it could mean that different females vary in whether they tend to experience orgasm with intercourse or not. Evident from the sexology literature both of these variations are widespread but in order for the reinforcement theory to function; it is only the first interpretation that can be considered. Simply speaking, this hypothesis must concentrate on those females who sometimes do and sometimes do not have orgasm during intercourse (Lloyd, 2005). However, according to Kinsey et al. (1953), such women only make up 36% to 44% of the population. Thus, it seems that although the hypothesis may be applied to a sizable percentage of women (and the intermittent reinforcement mechanism may be applied to them) it does not apply to the majority of women therefore may not be the best way to explain orgasm in general.
Having evaluated the above accounts and drawn out their various discrepancies, it is important to present a non-adaptive account which was originally put forward by Donald Symons (1979). Instead of acknowledging the female orgasm as an adaptation, Symons quoted that “human female orgasm is best regarded as a potential” (1979, p.89). He holds that the female orgasm is a capacity among all mammals but is activated in only a few of the species. This section will explicate and defend Symons’s hypothesis.
According to his theory, the female orgasm is a by-product of embryological development. In the early stages of human embryo development, both male and female share the same physical characteristics, the exception being different chromosomes – they are not dissimilar by any other sexual characteristics. This stage continues until the male embryo has hormones released into its body after which the embryo starts to develop different sexual features from the basic female form (Symons, 1979). For the first 8 weeks of gestation, the male and female embryos are indistinguishable except at the level of chromosomes (Hamburg 1978a). It is important to note that the penis and clitoris are the “same” organ in men and women; there is an organ in the under developed embryo that turns into a penis if it receives a dose of particular hormones; otherwise it matures into a clitoris. Similarly, the nervous and erectile tissues involved in the organs (which are then involved in orgasm) share a common embryological source (Kinsey et al. 1953). Nevertheless there is a noteworthy difference, according to Symons, between the male and female orgasm, and it lies in the traits past facilitation of reproductive success (Lloyd, 2005). Symons chooses the example of the male nipples (which are present in female mammals for obvious reasons) to substantiate his claim. The male mammal gets nipples due to sharing the same embryological form with female mammals, thus his nipples are a by-product of selection on the female mammal.
Symons asserts that female orgasm evolved in a similar manner where orgasm and ejaculation are strongly selected in men since they use the contractile pulses of orgasm as a sperm delivery system (Bancroft, 1989). Similar to the male nipple case, the opposite sex gathers the apparatus in virtue of an early embryological commitment. Females get the erectile and nervous tissue for orgasm in virtue of the strong, ongoing selective pressure on males for the sperm delivery system of male orgasm and ejaculation (Lloyd, 2005). At this point it is necessary to review some mysteries of female sexual response. One of these mysteries is the apparently odd data on female masturbation techniques. The most common female masturbation technique as reported by Gebhard et al. (1970) is the manual stimulation of the clitoris which accounts for 84% of all acts of masturbation among the women Kinsey team surveyed (Kinsey et al., 1953). Hite (1976) supported this evidence by finding that only 1.5% of women masturbate by vaginal insertion. Moreover, women’s preferences for clitoral and labial stimulation are commonly known; Kinsey cites 16 pieces of American and European literature dating back to 1885 (Kinsey, 1953, p.158).
From the above, it is safe to conclude that the data available makes it difficult to account for the female orgasm through evolutionary explanation relating it in some way to heterosexual intercourse. On the contrary, according to Lloyd (2005) the fact that almost no women masturbate by mimicking the act of intercourse is quite reasonable because “there is no theoretical commitment to holding that the clitoris’s function is somehow to be stimulated during intercourse” (2005, p.111). In the same line of argument, if placed within the framework of the by-product account, this reasoning enables research to make sense of the otherwise puzzling data on the relative infrequency with which women experience orgasm with intercourse.
Perhaps adaptationist accounts will retort that these hypotheses are misrepresenting the degree to which female orgasm and intercourse generally go together. Admittedly, the statistics from the sex research do differ considerably, but among those studies which find a significant correlation between orgasm and intercourse there is one omnipresent confounding variable: these studies do not claim whether they are considering all orgasms with intercourse or only those “unassisted by direct manual clitoral stimulation” (Lloyd, 2005, p. 112). This is important because such stimulation ensures a higher chance that the female will experience orgasm during an episode of intercourse. There is also no specific study of how widespread this practice is around the world, the cross cultural data suggests that it is not common in other parts of the world, regardless of how common it may be in western societies. This raises an interesting issue which leads the paper into section three outlining the cultural variability of the female orgasm through different social practices.
There are a number of writers who contend that the orgasm rate among women from non western societies is higher than women from western societies (see Allen and Lemmon, 1981) thus claiming that low orgasm rates are pathological but the pathology is due to modern western culture. It is therefore important to consider cross-cultural evidence. Cross cultural variability in the occurrence of female orgasm is remarkable: among some cultural groups, all women are said to experience orgasm and to expect it during intercourse (Marshall, 1971, Davenport, 1977) whereas among other groups women do not experience orgasm or even its concept is absent (Mead, 1967, Messenger, 1971 cited in Symons, 1979). The absence of severe sexual repression appears to be a prerequisite but not sufficient enough condition for the occurrence of regular female orgasm: another requirement is male interest and skill. Marshall’s data on the Mangaian Island in Polynesia reports that all women experience orgasm during intercourse. At the age of 13 or 14, young boys are instructed on sexual matters by the elder members where they emphasize the techniques of coitus, cunnilingus, kissing and sucking the breasts, and bringing the partner to orgasm several times even before the male allows himself to ejaculate. According to Marshall, Mangaian knowledge of sexual anatomy is far more extensive than most western physicians. The young boy is also involved in a practical exercise where he engages in intercourse with an older experienced woman who coaches the neophyte in applying the information he has learned, especially techniques of delaying his ejaculation to suit the time that his partner reaches orgasm (Marshall, 1971). Girls of the same age are instructed in sexual matters as Mangaians believe that “orgasm must be ‘learned’ by a woman and that this learning process is achieved through the efforts of a good man” (p.122). Although Mangains indulge in only 5 minutes of foreplay, Marshall emphasizes that considerable skill is applied during that time which precedes the 15 to 30 minutes of intercourse with continuous thrusting and active participation by the woman. At ‘East Bay’ a Melanesian island, female orgasm is regularly experienced by extended mutual heterosexual masturbation with penetration just before mutual orgasm (Davenport, 1977). However these practices of some Pacific cultures seem to be the exception rather than the rule. The above examples show immense cultural variability in the occurrence of the female orgasm and substantiate the claim that biological and physiological explanations cannot explain its occurrence independently.
While contributing enormously to our understanding of the orgasm as a physiological response, the biological perspective has been inadequate for explaining orgasm as a sexual experience (Mah and Binik, 2001; their emphasis). The latter requires not only physiological involvement but subjective awareness/labelling of the physiological response as “sexual” (Rosen & Beck, 1988). Events such as ejaculation and pelvic contractions need to be perceived as erotically pleasurable for them to be “orgasmic”, otherwise their value and desirability may not exceed that of a mere sneeze. Only recently has the psychology of orgasm received some attention; in some cases by researchers primarily with biological perspective (see Kinsey et al. 1948 who distinguished between physiological and psychic orgasm). Although the literature remains largely under developed in comparison to the biological literature there is still some credible work carried out on the psychological basis for the human orgasm.
Despite the biological orientation of Masters and Johnson (1966) model they stated that “[f]emale orgasm… remains a potpourri of psychophysiological conditions and social influence” (p.133). As a matter of fact, some researchers have claimed that psychological mechanisms alone can induce female orgasm. In one laboratory based observation study, there were no significant differences in heart rate, pupil diameter, and systolic blood pressure between orgasm induced by genital stimulation as opposed to imagery (Whipple, Ogden, and Komisaruk, 1992). Nonetheless, all subjects were first asked to reach orgasm through genital stimulation and then through imagery hence the carry-over residual arousal may have confounded the imagery condition (Mah and Binik, 2001). Studies have also shown women to have reported nocturnal orgasm (Henton, 1976; Wells, 1986) similar to waking orgasm (Wells, 1983) but occurring without any apparent genital stimulation. Following examination of psychological correlates of female orgasm some examples of studies of the orgasm where the role of early experiences and demographic factors affect the female orgasm are mentioned below.
Mead (1955 cited in Mah and Binik, 2001) theorized that sociocultural differences in female orgasm capacity indicate a potential for orgasm dependent on sociocultural learning. She suggests that in sexually liberated cultures, highly varied, diffuse foreplay develops this potential by encouraging bodily receptivity to sexual stimulation. However, no published empirical evaluation of this theory has been conducted. On the contrary, cross cultural differences could demonstrate cultural willingness to report intimate behaviour and the psychosexual impact of internalized norms which dictate appropriate sexual behaviour (Mah and Binik, 2001). Parental influences and childhood experiences have been found to have a relationship with female orgasm (Fisher, 1973). Fisher suggested that because women with low orgasm responsiveness may have difficulties with separation/loss, orgasm could be threatening because it involves a brief loss of object attachments. Certain demographic factors may also influence the occurrence of the orgasm.
Demographic factors such as sex, age (e.g. Laumann, Gagnon, Michael and Michaels, 1994), decade of birth (Kinsey et al. 1948), religion, ethnicity, marital status (Laumann et al., 1994) educational and social standing have been shown to have a correlation with frequency of orgasm during masturbation and sex with a partner. Despite the popular belief of men achieving orgasm more consistently than women, only 75% of men reported to always achieving orgasm whereas 29% of women reported the same (Laumann et al., 1994). Higher orgasm rates have generally been observed with older age and higher educational standing. Black compared to white and Hispanic samples and religious conservative samples compared to those without religious affiliations reported lower rates. Sexual attitudes and traditions associated with social-desirability effects may partly explain findings, i.e. those who report higher orgasm rates may generally have more liberal views of sexuality and sexual behaviour (Mah and Binik, 2001). Despite the above studies, psychologically based research thus far has been relatively unsystematic especially compared to the extensive research done from a biological perspective.
This paper claims to have addressed the following: first, that there are serious debilitating evidential flaws with all but one of the available evolutionary explanations for female orgasm; second, that certain presumptions, especially adaptationism (belief that every human trait has an adaptive function) and androcentrism (for the purpose of this essay: belief that male sexuality is like female sexuality) are at the centre of the scientific failures incurred so far; and third, that the various psychological and sociocultural explanations that have been put forward, despite their under researched models, provide logical arguments for the existence and variance of the female orgasm. In conclusion, there are numerous research questions still open for exploration. One field of research includes pursuing a proposition of the by-product view (Symons, 1967) where cross-species comparisons could be carried out to determine whether those species have highly sexual males also have females who are capable of having orgasm. Also, as suggested by Lloyd (2005) cross species studies of the female anatomy to determine the placement of the clitoris, would help elucidate the question of whether direct clitoral stimulation is experienced by any of our close relatives (a line of research closely supported by Hrdy). The evolutionary, psychological and cultural explanations of the female orgasm still requires years of scientific research and a model encompassing the various explanations could prove useful in many ways.
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