CHAPTER 9
Pleasure Happens
In Greek mythology, the divine, reigning couple of creation—Zeus and Hera—had a difficult marriage. Zeus was always running around looking for new ways to seduce beautiful young women and father more children, and Hera was naturally in a constant state of jealous rage over Zeus’s frequent infidelities. Because Hera’s many titles included the goddess of marriage, her husband’s unwillingness to be true to her caused her not only personal pain but very public embarrassment. It was in the context of this ongoing tension between them that Zeus and Hera had an argument over which sex experiences greater sexual pleasure—men or women. They both tried to defend their respective moral positions on marital fidelity by claiming that the opposite sex experienced greater sexual pleasure than their own. They decided to settle the dispute by consulting the only authoritative source they knew—a wise man named Tiresias.
Tiresias was what biologists today would call a sequential hermaphrodite—an individual who changes sex during its lifetime (as happens in certain plants and animals). Tiresias was born male and grew up in the land of Thebes. One day he was walking in the countryside when he came upon two snakes copulating. He hit them with his staff and was instantly transformed into a woman. Seven years later, Tiresias the woman was walking down this same path, when she observed the same pair of snakes copulating. Perhaps in the hope that the magical power would work in reverse, she hit the snakes with her walking stick again and was instantly transformed back into a man.
Hera and Zeus reasoned that Tiresias was the only human who had firsthand experience of the relative sexual pleasure of both man and woman. So they turned to him to resolve their debate. When Hera and Zeus popped their comparative pleasure question to Tiresias, he immediately responded that woman experiences nine times the sexual pleasure of man.
Why nine times the sexual pleasure? To the geometry-obsessed Greeks, the number 9 was a very special number indeed. Nine is 32. The number 9 tells us poetically that woman’s sexual pleasure is not only greater in magnitude than man’s but also greater in dimension. With a single symbolic number, Tiresias communicated that woman’s sexual pleasure is a nonlinear, exponential increase over man’s.
The myth of Tiresias reminds us that woman’s sexual pleasure is possibly the most central and enduring mystery about sex. What is its purpose, and why does it exist? Yet even while attempting to deal with the evolution of female pleasure—including the female orgasm—the contemporary science of mate choice has been mute about the subjective experience of sexual pleasure. The theory of aesthetic evolution, however, has plenty to say about it, as do I, in this chapter. Viewing pleasure as the central, organizing force in mate choice, and mate choice as a major dynamic in evolutionary change, the aesthetic theory holds that women’s pursuit of pleasure is at the very heart of the evolution of human beauty and sexuality.
The theory of aesthetic coevolution predicts that behind every elaborate sexual ornament, there is an equally elaborate, coevolved sexual preference. If the size and shape of the human penis evolved to fulfill an ornamental function, for example, then there must be a set of female preferences that coevolved with the evolutionary changes that occurred to the penis. As I proposed in the preceding chapter, those preferences had to do with the sensory experiences of enhanced sexual pleasure. And that leads us directly to the question of the female orgasm—its origins, its purpose—and finally to elaborate on the answer Tiresias supplied to Zeus and Hera, why it may be a more powerful and profound experience than the male orgasm.
Perhaps no topic in human sexual evolution has stimulated more scientific excitement and heated debate in recent decades than the origin of the female orgasm. The evolutionary explanation of the male orgasm has always seemed obvious; because the male orgasm is directly connected to the ejaculation of sperm, male sexual pleasure must have evolved, through natural selection, to motivate males to pursue reproductive opportunities. All in all, the male orgasm is a very tidy solution to the problem of how to keep the species going and in perfect keeping with the adaptationist point of view. In contrast, the origin and function of the female orgasm have been highly contested, with an abundance of theorists eager to supply possible explanations. What is surprising about these explanations of sexual pleasure, however, is how anhedonic they are.
In the early twentieth century, Sigmund Freud proposed a scientifically influential account of the female orgasm. He identified the clitoris as the location of infantile female sexual pleasure and the vagina as the appropriate location of mature female sexual pleasure. According to Freud, “normal” female sexual development required transitioning from the clitoral, masturbatory orgasm to vaginal orgasm achieved through heterosexual intercourse without clitoral stimulation. Women who failed to achieve the mythological transition were labeled as “frigid”—that is, sexually deficient, emotionally immature, not fully realized as “feminine.”
Freud’s hypothesis was influenced by the same autonomy-denying, anti-aesthetic intellectual tradition of Mivart and Wallace (see chapter 1), which viewed female sexual pleasure as merely an adaptive physiological stimulus to encourage and coordinate sexual behavior between the sexes and thereby ensure propagation of the species. Freud, Mivart, and Wallace all precluded the possibility that female sexual pleasure could be a goal in and of itself. As we have seen, Mivart was explicit in his antagonism toward female sexual autonomy. He was appalled by the very idea that “vicious feminine caprice” could have any evolutionary effects. Interestingly, Freud’s failed theory of female orgasm might have been rooted in a similar anxiety about the consequences of recognizing the autonomy of women’s sexual desires.
The modern scientific debate on the evolution of female orgasm began with Donald Symons’s 1979 book, The Evolution of Human Sexuality, which proposed that the human female orgasm, like male nipples, evolved as a by-product of natural selection on sexual function in the opposite sex. The by-product theory holds that male nipples exist only because nipples are under strong natural selection in females; that is, they are necessary for nursing offspring. Similarly, the capacity for orgasm in females exists solely because orgasm is under strong natural selection in males; that is, it provides a mechanism for the delivery of sperm during copulation. Such by-products are able to arise because there is incomplete genetic and developmental differentiation between the sexes. Just as male nipples have the same evolutionary origin as female nipples, the female clitoris is homologous to the penis of males. So, Symons hypothesized, the female capacity for orgasmic sexual response is basically a happy accident—a by-product of natural selection for male sexual response.
Symons’s by-product hypothesis was subsequently championed by the evolutionary biologist Stephen Jay Gould and the philosopher of science Elisabeth Lloyd. As Lloyd explained in an interview with the Guardian, “Male and female both have the same anatomical structure for two months in the embryo stage of growth, before the differences set in. The female gets the orgasm because the male will later need it, just as the male gets the nipples because the female will later need them.”
The most persuasive evidence in favor of the by-product account is the simple fact that human copulation is by itself so ill-suited to eliciting female orgasm. There’s also the fact that female orgasm is completely unrelated to female fertility. Women who have never had an orgasm during intercourse manage to produce babies just fine, as the by-product folks maintain, so orgasm cannot be seen as an adaptation to assist reproduction. The by-product account is further supported by the observation that female orgasm is broadly distributed in nonhuman primates—including stump-tailed macaques, chimpanzees, and bonobos. According to this model, there is nothing to explain evolutionarily in women. They come by their orgasmic capacity in exactly the same accidental way that other female primates do, and it has nothing to do with “adaptation.”
Not surprisingly, the adaptationist sociobiologists of the 1980s and 1990s found the by-product account very unsatisfactory. In response, they proposed that female orgasm is an adaptation; that is, female orgasm has evolved by natural selection, its purpose being to support pair-bonding maintenance. Basically, this is the “good sex makes a happy marriage” hypothesis. However, pair-bonding hypotheses fell out of favor in the late 1980s when it was recognized that a female capacity for orgasm could be just as powerful a motivator for sexual liaisons outside the pair bond as within. This intellectual shift coincided with the discovery that many apparently “monogamous” birds are merely “socially monogamous”; that is, while they do form stable social pairs for parenting duties, they also mate extensively outside their social pairs. During the mid-1990s, this discovery led many of the members of an early generation of evolutionary psychologists to focus on the role of sperm competition in sexual evolution, which they eventually connected to theories about human female orgasm.
Positing that female orgasm has an important role to play in these “extra-pair” mating scenarios, they proposed that the uterine contractions that are part of the female orgasm are an adaptive mechanism that evolved in order to “upsuck [sic]” the sperm of genetically higher-quality males, making it more likely that the sperm of these superior males ends up fertilizing the ovum.
Who, then, are these higher-quality males whose sperm is so desirable? According to the standard evolutionary psychology scenario, this evolutionary mechanism acts because women are strategically and deceptively promiscuous; the woman’s “social” mate is not the higher-quality male. Rather, the social mate is the one the female has chosen because he can provide the best direct benefits to her offspring in the form of resources, care, protection, and so on; he’s the good ole reliable, but not very sexy, guy. It’s the extra-pair mate she seeks out during her fertile period who is the higher-quality male—higher quality meaning that he’s the sexy one and, being more attractive, the one she wants to father her children, because he can provide them with indirect benefits, that is, good genes. So the adaptationist theory is that a woman will have an orgasm only during sex with the more attractive, higher-genetic-quality man, because the upsucking mechanism of orgasm will give the advantage to his sperm and make it more likely that he will be the one to fertilize her eggs.
Elisabeth Lloyd presents a devastating case against the upsuck hypothesis in her book The Case of the Female Orgasm. She provides a comprehensive history of the contentious debate over female orgasm evolution, a review of the scientific and human sexology literature on human orgasm, and reams of data that make it clear that there is absolutely no support for the idea that female orgasm influences fertilization. Nor is there any evidence to suggest that males who induce women to orgasm are any more successful than other males at fertilizing the ova or that they are in any way genetically superior. If female orgasm has no effect on fertility or fecundity, and there’s no correlation between male genetic quality and a man’s ability to bring a woman to orgasm, then it is impossible to maintain that orgasm is a sperm-sorting adaptation to fine-tune the genetic quality of offspring. Lloyd goes on to document that critical papers in the upsuck literature rest on fundamentally flawed statistical methods and unjustifiable data manipulation and that many aspects of these studies have been influenced by the sexual biases of the researchers.
An important feature of the debate between the by-product and the upsuck accounts of female orgasm evolution is the way in which the variability of female orgasm is used as evidence by both schools of thought. In defending the by-product theory, Lloyd proposes that the extreme variation among women in orgasmability during intercourse—with some women never having orgasms, others nearly always, and many others somewhere between these poles of experience—is profound evidence that orgasm is not under natural selection. If it were, natural selection would achieve more consistent results. If orgasm is not the result of evolved design, she proposes, then it should be viewed as an accident—albeit a very fortuitous one.
In contrast, the upsuck advocates maintain that variation is the very raison d’être of female orgasmic response—evidence in and of itself of female orgasm’s adaptive function. As the evolutionary psychologist David Puts has written, the variation in women’s orgasmability is a reflection of the variability in the “propitiousness of [their] mating circumstances.” In other words, the higher the woman’s mating value—that is, how sexually attractive she is—the higher the genetic quality of the male partners she can attract, and the more likely she is to orgasm during sex. More attractive females, who are of better genetic quality and condition, will attract more attractive males, who are also of better genetic quality, and these attractive males will more frequently induce those females to have orgasms, upsucking their higher-quality sperm to fertilize their higher-quality eggs. Thus, not only are beautiful women necessarily better (because they have better genes, health, status, and condition), but also they will be rewarded with greater sexual pleasure because of the higher genetic quality of the males they can attract as mates.
It would be hard to come up with an idea that would better reinforce the impression of a male bias in evolutionary psychology. The upsuck theory enshrines the fantasy of the superior male as the proximate and ultimate causal explanation of female orgasm itself.
A fundamental problem with the upsuck hypothesis is that it cannot explain why women vary in their intrinsic capacity to experience orgasm during intercourse—regardless of the attractiveness of the males they’re having sex with. Recently, Kim Wallen and Elisabeth Lloyd published an article citing evidence for the possibility that frequency of orgasm during copulation may be related to women’s genital anatomy. Based on their statistical analysis of historical data sets from the 1920s and 1940s—which, alas, are the only data available on this subject—Wallen and Lloyd propose that the closer the clitoris is to the vaginal opening, the greater a woman’s capacity for orgasm during intercourse. This intrinsic, anatomical variability in women’s capacity for orgasm during intercourse is congruent not just with the data they reviewed but with men’s unscientific, anecdotal, personal experiences. After all, an individual man does not vary in genetic quality over time, but the frequency and ease with which the different women he has sex with over time experience orgasm during copulation do vary (no matter what he may say to the contrary). The upsuck hypothesis fails to explain this variation.
Another fundamental flaw in the upsuck theory is that it rests on the assumption of the importance of sperm competition which takes place only within a context of strategic female sexual promiscuity and deception. Upsuck theorists maintain that the female orgasm has evolved to meet the challenge of obtaining “good genes” when a woman is mating with multiple males of different genetic quality during her small window of fertility. If sperm competition does play a critical role in the evolution of female orgasm, as they posit, then the evolutionary elaboration of the female orgasm that has occurred in humans should be associated with increases in sperm competition. But this prediction is precisely the opposite of the story revealed by the comparative data. Testes size—the most reliable index of the evolutionary history of sperm competition—has significantly decreased in humans since our shared ancestry with chimpanzees, while the role of female orgasm in human sexuality has increased in importance. In contrast, chimpanzees have very large testes and strong sperm competition, and although chimpanzee females are capable of orgasm (as indicated by increased heart rate and rapid vaginal and uterine contractions), female orgasm apparently rarely occurs during sexual intercourse. Yet according to the upsuck theory, because female chimps mate with multiple males that vary in genetic quality, we should see female orgasm occurring as a sperm-sorting mechanism during chimpanzee copulations. But it does not.
Last, advocates of the upsuck hypothesis have surprisingly failed to think through the adaptive implications of their own model. If human female orgasm has evolved to mechanically increase the probability of fertilization, then human males should have evolved adaptive counterstrategies to induce these sperm-sucking orgasms during each and every copulation. What is human intelligence useful for if it cannot be applied by males to further their reproductive success? As a counterstrategy to female orgasmic sperm sorting, men should have evolved a universal, assiduous interest in women’s sexual climaxes. As many a woman can attest, this has not happened. But the evidence goes beyond the anecdotal. Anthropological data from a range of cultures document that there are plenty of men who take little interest in women’s sexual pleasure and orgasm. In many societies, men initiate sex with minimal foreplay and proceed to climax without ever concerning themselves with the woman’s pleasure. In fact, in many cultures, men aren’t even aware that it’s possible for a woman to have an orgasm (or at least such knowledge was rare prior to the Internet). A 2000 survey found that 42 percent of college-educated Pakistani men did not know that women were capable of orgasm. Furthermore, many patriarchal cultures actively suppress women’s capacity for orgasm through clitorectomy and other forms of female genital mutilation. The overwhelming indifference (not to mention frequent hostility) toward female sexual pleasure and orgasm by men in many of the world’s cultures is a glaring explanatory failure of the upsuck theory.
There is still no resolution to the debate about the evolution of the female orgasm. The upsuck hypothesis has been thoroughly discredited. However, even though the fundamental data supporting the by-product account—that is, the genital homology between the sexes and the physiological similarities of male and female orgasmic response—are completely accurate, the question remains whether there is more evolution to be explained than the by-product account provides. Has human female orgasm evolved in its own right?
Interestingly, this issue has been raised by feminists who have argued that the by-product hypothesis marginalizes and trivializes the sexual agency of women, and I think they’re onto something. Is the central place of sexual pleasure in many women’s lives to be attributed to mere historical accident? Don’t the prodigious qualities and potentials of female orgasm and sexual pleasure require a more substantial explanation than the by-product theory?
What has been missing from the debate is a genuinely Darwinian, aesthetic evolutionary perspective. There has been no direct intellectual engagement with the fundamental issue to be explained—women’s subjective experiences of sexual pleasure. Both theories, in their different ways, marginalize and ignore female sexual pleasure as irrelevant to the historical, causal explanation of female orgasm.
It should not come as a surprise that science does such a poor job of explaining pleasure, because, as I discussed in the book’s introduction, it’s left the actual experience of pleasure out of the equation. The modern science of mate choice, in humans and other animals, has not been designed to address the question of sexual pleasure directly. Having grown out of the study of mate choice in other animal species, it simply can’t. There is no way it can capture the pleasure that a female lyrebird experiences while listening to a male lyrebird’s unremitting cascade of mimetic songs from his display mound or while watching the quivering veil of his gauzy tail feathers as he unfolds them over his body like half an umbrella. It cannot understand the aesthetic experience of a female Guianan Cock-of-the-Rock as she stands next to a screaming orange male sitting motionless on the bare dirt floor of his lek territory, the two of them surrounded by other screaming males lending their raucous cacophony to the courtship scene. The only thing we scientists can assess in these instances is the outcome—which mate did the female end up choosing? But by focusing solely on outcomes, biologists have obscured and ignored the richly pleasurable sensory and cognitive criteria that went into making the choice.
When it’s our own human pleasures that we’re investigating, however, we have an opportunity to understand sexual pleasure much more fully, because humans, unlike other animals, can tell us what they’re experiencing. This ability to communicate can transform our analysis of the evolution of orgasm. It’s time for evolutionary biology to embrace this opportunity. Fortunately, the theory of aesthetic evolution is uniquely well equipped to help us do so.
Aesthetic evolution explicitly addresses the subjective experience of the pleasure of mating preference. To understand the evolution of sexual pleasure, we need to create a corollary of the Beauty Happens hypothesis, which I will call the Pleasure Happens mechanism. In the Beauty Happens mechanism, the focus is on the coevolution of desire in one sex and the physical objects of desire in the other sex—in other words, the display traits. In the Pleasure Happens mechanism, we must focus on the coevolution of the subjective experience of pleasure with the features that elicit that pleasure. This means recognizing that the experience of mate choice is, in and of itself, pleasurable, something that is still rarely acknowledged in the scientific literature on mate choice. Darwin, however, proposed it.
Although Darwin was too proper, shy, or fearful of his audience’s responses to explicitly discuss the sexual pleasure of humans in The Descent of Man, he did discuss sexual pleasure in animals, proposing that the sexual displays of animals evolve precisely because of the profound sensory pleasures they elicit. By the same reasoning, because female sexual pleasure and orgasm are fundamental components of the experience of mate choice in action—including all the physical interactions involved in sexual behavior—the exercise of sexual evaluation is inherently pleasurable. The pleasures that are part of it, including and especially the experience of orgasm, are the data upon which mate choice, or more to the point remating choice (see chapter 8), is made. Which leads us back to the question of how these pleasures evolved.
According to the Pleasure Happens hypothesis, female sexual pleasure and orgasm have evolved (that is, expanded in capacity and intensity since common ancestry with chimpanzees; evolutionary context 2) through indirect selection by women’s mating preferences for those male traits and behaviors that they find sexually pleasurable. Because human mating preferences are largely remating preferences, based on repeated sexual encounters, female mate choice can encompass aesthetic evaluation of the physiological, sensory, and cognitive experiences of sex itself. As selection by female mating preferences gradually transformed male mating behavior, females’ own capacity for subjective pleasure coevolved and expanded to become more complex, intense, and satisfying. To be as explicit as possible, the aesthetic proposal is that human female sexual pleasure and orgasm have evolved because females have preferred to mate, and remate, with males who stimulated their own sexual pleasure; females have thereby also selected indirectly for those genetic variations that contributed to the expansion of their own pleasure. By selecting on male traits and behavior that elicit orgasm more frequently, female mate choice has evolutionarily transformed the nature of female pleasure.
In the Pleasure Happens scenario, female orgasm is not an adaptation to accomplish any extrinsic, naturally selected function—sperm upsuck or anything else that adaptationists might come up with in their search for rhyme and reason. Nor is female orgasm merely a historical accident, second fiddle to male sexual pleasure. Rather, female sexual pleasure and orgasm are the evolutionary consequences of female desire and choice, and they are ends unto themselves.
The Pleasure Happens hypothesis of orgasm evolution is consistent with much of the evidence on female sexuality and sexual response—for example, its inherent variability. I agree with Elisabeth Lloyd’s suggestion that the variability in female capacity for orgasm is an indicator that orgasm did not evolve by adaptive natural selection, because natural selection should result in much more reliable, highly functioning, and consistent experience. However, I disagree with the conclusion Lloyd then draws—that this means orgasm is simply a historical (but fortunate) accident. I think that human female orgasm is a highly evolved experience that is about something and has evolved for something. That “something” is pleasure, which evolves through the evolutionary action of their mate choices.
Although there is not yet enough comparative evidence about orgasm in various female monkeys and apes to support the conclusion that female orgasm has evolved or expanded in pleasure in humans since common ancestry with chimpanzees, I hope that proposing the Pleasure Happens hypothesis will lead to further investigations to test it. Until then, we can see that the Pleasure Happens hypothesis is congruent with lots of the current data. For example, the indirect sexual selection that drives the Pleasure Happens mechanism will be less efficient at evolutionary design than direct natural selection can be. In addition, female choice is not the only source of sexual selection in humans, so this mechanism may not predominate in determining the evolution of female sexuality. Thus, the Pleasure Happens mechanism is congruent with the fundamental variability of human female orgasm.
The hypothesis, furthermore, is supported by the existence of many evolved features of human sexuality that are different from our ape relatives and that can only be explained as expansions of sexual pleasure. For example, copulation duration in gorillas and chimpanzees is measured in seconds. On average, human copulation lasts for several minutes and of course can continue for far longer than that. (Much to the frustration of many women, however, the extensive variation in male copulation duration skews toward the short, chimpanzee end of the continuum.) These longer bouts of intercourse would enhance female stimulation and create greater likelihood of orgasm, but they would serve no adaptive function, because extending copulation duration cannot by itself increase fertilization success or make a male a winner at sperm competition. Any evolutionary explanation for longer copulation times in humans is inherently about enhancing the pleasurable sensory experience of sex.
Another piece of evidence that seems to suggest the primacy of female pleasure as the driving force in much of human sexual evolution is the diversity of copulatory positions. Male gorillas and chimpanzees generally mount the females from behind. Men and women are much more creative in their couplings, which is consistent with the aesthetic hypothesis that the evolution of our sexual repertoire is in service to the goal of expanding opportunities for clitoral stimulation and female pleasure. Likewise, the evolution of increases in copulation frequency, concealed ovulation, and the decoupling of sexuality from periods of female fertility all contributed to the expansion of the role of sexual behavior and sexual pleasure in the lives of human beings.
The aesthetic account is also completely consistent with the observation that female orgasm is unnecessary for procreation. Orgasm has no effect on female fecundity because it did not evolve for any adaptive purpose. The very fact that female orgasm is not required for anything is likely to explain both its variability and why it is so pleasurable. The female orgasm might have evolved to be so expansive and prodigious because it has no evolved function. It is sexual pleasure for its own sake, which has evolved purely as a consequence of women’s pursuit of pleasure. In men, however, orgasm almost always occurs with ejaculation and is thus required for sexual reproduction. Consequently, the subjective experience of male orgasm is constrained by natural selection for a peristaltic pumping of semi-viscous seminal fluids up and down the vas deferens and out the urethra. Essentially, male orgasm is all about plumbing—moving stuff through tubes. And because of this ejaculation-orgasm connection, men need to replenish the seminal fluids produced by the prostate, the seminal vesicles, and the Cowper’s gland before they can orgasm again. (Younger male readers may be alarmed to learn that this recovery period gets longer and longer with age.) Thus, the naturally selected physiological function of male orgasm places limits on the magnitude, frequency, and duration of male orgasmic pleasure.
By contrast, female orgasms are not constrained by design for any ancillary physiological function. Female orgasms do not need to deliver any goods or perform any task. The contractions of the vaginal, uterine, perineal, and abdominal muscles are all enlisted purely in the service of pleasure without the compromising constraints of fulfilling any other function. This helps to explain why many women are capable of rapidly repeated, multiple orgasms. Because women’s orgasms do not need to accomplish anything beyond pleasure itself, women require no recovery period and have no limits on repeating the experience other than their own desire.
Thus, the aesthetic theory supports Tiresias’s pronouncement. Because the female orgasm has evolved through a purely aesthetic evolutionary process of mate choice, women actually do have the capacity for greater sexual pleasure than men, and women’s sexual pleasure is more expansive in quality as well as extent. When Beauty Happens, Pleasure Happens too.
The elaboration of the female orgasm in humans may be the greatest testament to the power of aesthetic evolution. And it may also be the premier example of the irrational exuberance of an aesthetic evolutionary bubble—evolution for no purpose other than the arbitrary pleasure of it. Fortunately, human orgasmic pleasure has not yet evolved to be so extreme that it has been countered by natural selection against having too much fun.
All this focus on women’s sexual pleasure might have left the guys feeling left out, diminished, the magnitude of their own pleasure compared unfavorably with that of women, their orgasms denigrated to mere plumbing. But that doesn’t mean that men don’t have terrific sex. So why are men’s orgasms so pleasurable? Recall that the male orgasm has always been explained as an adaptation to encourage males to pursue sexual opportunities. Natural selection for any behavior will often result in the evolution of physiological pleasure in that act. Animals need to eat, so eating when hungry has evolved to be rewarding, satisfying, and pleasurable. However, most men would agree, I think, that the pleasure of orgasm is far greater, more intense, and more rewarding than the pleasure of eating. So, I think it’s fair to conclude that male orgasm is more pleasurable than it needs to be in order simply to ensure reproduction—that is, more pleasurable than natural selection alone can account for. This leads me to the conclusion that natural selection is not the only mechanism involved in the evolution of the human male orgasm and that aesthetic evolution has also played a significant role.
Although this is pretty speculative, I think it is clear that male orgasmic pleasure in humans has undergone an evolutionary expansion since the time of our shared ancestry with gorillas and chimpanzees. While other male apes pursue sexual opportunities with a fervor similar to men’s, they certainly don’t seem to enjoy sex as much as men do. The orgasms of male gorillas and chimpanzees do not appear to pack the same punch as those of human males. There is little foreplay, minimal touching, or even eye contact. After a brief moment of rapid thrusting, it’s over and both male and female go back to sifting through the leaf litter. Consider also the fact that the length of time to orgasm in chimpanzees averages around seven seconds versus a few minutes in men. If the quality of orgasmic pleasure is correlated at all with the amount of time it takes to get there—a not unreasonable physiological conjecture—then men certainly experience more sexual pleasure than male chimpanzees.
If this is true, then we have to wonder why human male orgasmic pleasure evolved and how. The answer, again, is likely to be through aesthetic mate choice. Male chimps and gorillas are not sexually choosy, and they pounce on any sexual opportunity that arises. Without the involvement of mate choice, all evolutionary influence on sexual pleasure will be limited to the effects of natural selection alone. Humans, however, have evolved to be highly choosy. The history of mate choice in women and men, the evolutionary expansion of sexual behavior, copulatory frequency and duration, and so on have all created opportunities for the aesthetic coevolution and elaboration of male orgasmic pleasure as well. The evolutionary enhancement of men’s sexual pleasure is a likely consequence of the fact that human males deviate from the evolutionary psychology stereotype of them as profligate purveyors of cheap sperm. It is only by eschewing some sexual opportunities in favor of others they prefer—in other words, it is only through the operation of mate choice—that human male sexual pleasure has been able to aesthetically coevolve beyond the baseline necessary for reproductive function.
The primary difference between the sexes may be that the evolution of male pleasure has been constrained by natural selection for plumbing functions, while female pleasure has not. In summary, human males and females are both a lot more sexually choosy than our close ape relatives, and the very fortunate evolutionary consequence of the choosiness we exercise in mate choice appears to be that we have evolved to experience a lot more sexual pleasure than they do.
Men and women are in this together, of course, and it seems probable to me that mutual mate choice, acting on many of the same pleasure-extending and pleasure-enhancing sexual interactions, has led to the elaboration of orgasm in both sexes. In his 2000 book, The Mating Mind, the evolutionary psychologist Geoffrey Miller also proposed a role for a Fisherian “runaway process” in the evolution of human orgasm. Perhaps out of discomfort with aesthetic thinking, however, Miller imagined the process as “a stimulatory arms race” between the penis and the clitoris. This unfortunately competitive and martial analogy obfuscates the expansive, pleasurable, sensory dimension of orgasm for both sexes. The changes in penis morphology and sexual behavior that have been driven by female desire have in no way diminished male sexual pleasure. Quite the opposite. Orgasm evolution is not the result of a war between the sexes; rather, it would be better compared to an aesthetic, coevolutionary lovefest.
Another way to describe the mechanism of mate choice is to say that aesthetic coevolution proceeds through the sexual agency of individuals. Thus, in a delightful and unexpectedly feminist fashion, the Pleasure Happens hypothesis identifies women as the active agents in the evolution of their own capacity for orgasmic pleasure. Women’s orgasms are both the direct experiences and the evolved consequences of women getting what they want. In this way, every woman’s orgasm is a celebration of the evolutionary history of woman’s capacity to fulfill her expansive, and expanding, sexual desires.
Women’s own sexual experiences might lead them to ask, “How could it be otherwise?”