Why do people have sex the way they do? There are lots of puzzling things about that, but three really stand out. Sex between two chimpanzees takes a few seconds, but sex between humans can take hours. Why are we so different from them? Men can only have a few orgasms, but women can have lots of orgasms, separated by long intervals of high arousal. Why are we so different from each other? And finally, surveys done by people like Shere Hite and Alfred Kinsey have consistently shown that intercourse isn't really the easiest way for many women to have an orgasm.  Oral sex and masturbation often work better. But why wouldn't the activity that leads to fertilization be the most reliably pleasurable one? And why do we humans engage in so many other sexual activities, from anal sex to zoophilia, that also have nothing to do with reproduction?
To answer these questions, we'd need to know how our human way of having sex evolved. But there's no generally accepted theory. Ten years ago, Elizabeth Lloyd's explanation of the female orgasm looked pretty plausible . She argued that women can have many orgasms simply because there never was any reason for a limit to evolve. They have nothing to do with reproduction. They're just an evolutionary accident.
But our story about human evolution has changed since then. Now that the idea of cultural learning has become more central to that story, does sex look any different?
I could be wrong about this, but Lloyd's "evolutionary accident" theory doesn't really seem right to me anymore. Instead, I'm starting to suspect that the multiple orgasm may have helped make us what we are today. If people everywhere really understood why humans have sex the way they do, if they really understood the competitive obstacle course Nature has laid out for them, I think they might be happier themselves, and more useful to their partners.
To explain why things look so different to me now, I have to tell you how our theories about human evolution are changing. The easiest way for me to do that is by pointing out one last biologically surprising feature of human sex, one that might not have seemed that important to us 10 or 15 years ago.
Anybody who was ever a teenager can probably remember a few moments of sexual awkwardness. Hopefully things got better later on. If they did, that's an example of learning. Googling "sexual techniques" brings up trendy terms like "karezza" and "coital alignment." Those are also things people have to work pretty hard to learn how to do. People in different cultures learn to have sex in very different ways. In some cultures a man without a pierced penis is considered inadequate. In others the female orgasm is completely ignored. The ancient Egyptians masturbated in public, but in one small Irish community in the 1950s, couples kept their clothes on so sex wouldn't become too enjoyable. Same-sex interactions may be taboo, or obligatory. That's very weird. In every other animal, sexual behavior seems to be completely instinctive. How can it be so wildly variable in humans? And why would evolution ever want to put an extra hurdle -- learning -- between us and reproduction?
Of course, sex isn't the only thing humans have to learn how to do. A chimpanzee is pretty smart, but it doesn't learn that much about sex, or anything else, from other chimpanzees. Humans, uniquely, have to learn how to be human from other humans. Everything we learn from others -- how to make a fire, how to keep a promise, how to speak English, how to kiss -- is "culture." It's now becoming clear to us that cultural learning is the really distinctive thing about the human animal. In the older "social intelligence" model, the human mind evolved so we could outwit others in a competition for scarce resources. But chimpanzees already compete for resources. What they don't do is teach. The hero of Kim Sterelny's new "cultural learning" story about human evolution isn't the successful schemer, it's the person who is good at teaching new skills, and learning new skills from other people.  If we humans have to learn to have sex, too, then that fact must fit into this new story somehow.
And it does fit, perfectly. The fact that we have to learn how to have sex, and can get better at it over time, actually looks like a pretty crucial missing piece. Human sex seems to select us for the ability to learn from our sex partners. Learning from others is what we humans specialize in, so it makes perfect evolutionary sense to find this exact kind of obstacle course playing a role in our sexual behavior. It would be more surprising if it wasn't there.
Let me explain all that. Human lovers, in having sex, are learning to collaborate on a project that's something like jazz improvisation. (Darwin argued, in The Descent of Man, that music was originally a form of sexual display.) They're learning to participate in a particular kind of creative performance, and contribute something unique to it that makes it better. Attention is being shared. Roles are assumed and reversed. There are solos and duets. There's a lot of direct eye contact, as the two lovers simultaneously try to see themselves through each other's eyes, like Narcissus peering into the reflecting pool. When things are going well, they share an almost telepathic connection. Most of our learning about sex is nonverbal, so this learning situation is actually quite a lot like the one we encounter when we're babies and toddlers, and are first trying to learn how to interact with other people, and talk.
If we've learned to play our role really well, then many of the performances we're involved in are going to be enjoyable ones. The way we have sex mostly seems to convey information about our creativity and teachability. Humans are creatures who compete with each other in trying to master complex cultural skills like hunting elephants, and playing the piano, and public speaking. If our kids inherit our ability to learn from others, and use the learned skills creatively, they'll have an advantage in that competition. So if the sex was enjoyable, it makes perfect biological sense for our partner to have sex with us again tomorrow. We've just demonstrated, in a way that can't be faked, that we're good at learning from other people. A small difference in the probability that they'll stay, depending on how well things ended up going last night, is enough. Apply this same filter again and again over hundreds of thousands of years, and natural selection will shape us all into finely engineered collaborative learning machines. Which is what we humans actually are, so I suspect that must be exactly what really happened.
If that's how sex fits into the new evolutionary picture, now that we know that, it should be possible to answer my opening questions. Why are men and women so different? Why isn't intercourse the easiest way for a woman to have an orgasm? Why does human sex sometimes last so long? Why does it often involve cultural practices that have nothing to do with fertilization?
Pregnancy and nursing are biologically expensive. Women have every reason to be more choosey than men, to screen their partners more carefully for the teachability and creativity their children will need to get by in a human society. Men make these choices too, but they're not as crucial to their survival. If human sex consisted of intercourse and nothing else, this asymmetry in the value of information to the two sexes makes it seem likely that it just wouldn't last long enough to provide women with all of the information they might require. Since there are other ways of pleasing them, however, men who are good learners can learn to provide the additional information.
Both men and women are beautiful, sing, dance, tell jokes, etc., so we're clearly one of the species in which both sexes display. Still, I might be wrong about this, it's easy to see how I could be, but I think men have the more complex learning task when it comes to sex. They have to figure out that what comes most easily isn't always best. They have to develop a set of physical skills not unlike those required to play a musical instrument, and they have to learn to control themselves, and delay gratification. It seems to me that women must have the ability to have multiple orgasms separated by long intervals of high arousal simply because that leaves more room for different degrees of sexual satisfaction. Their sexuality is set up to give them more information about their partners, because they need information more. The competition to please them that would have resulted from this general way of arranging things could have produced our complicated human kind of sex in the same way competition to attract peahens produced the complex tail of the peacock.
Because it involves culture, human sex is open-ended. Nature doesn't try to guess what we'll invent. It just sets out this huge blank canvas, and lets us collaboratively paint whatever we can think of onto it. The standard of success isn't biologically fixed. It's just a matter of what our competitors have come up with. There's no hard upper limit on the number of orgasms a human woman can have because there's no hard upper limit on human creativity.
So unlike Lloyd's story, this one has a moral. If we'd all just kept on having hasty, boring, completely instinctive sex, like chimpanzees, I'm not sure human intelligence itself could ever have evolved. But in fact, we're lucky enough be human beings and not chimpanzees, so we should learn to enjoy it. Be eager to learn, and easy to teach. Take pleasure in your work. Be creative, take your time, become a good ensemble player. You'll put thousands of hours into learning how to do much less important things like playing the guitar. Why on Earth wouldn't a human male put a similar effort into learning to be really good at oral sex? Whether you know it or not, you're participating in a contest. The palm is likely to go to someone who knows he's competing.
A young man, in particular, should practice this skill at every opportunity. There's a useful book by Ian Kerner called She Comes First, for those of us who want to improve ourselves (as all men should). But personally I love the classics; decades after its original publication, The Joy of Sex is still a good place to start.
Since Christmas is approaching, I'm tempted to say that these books might make good stocking stuffers. But the male ego is so fragile that some delicacy is required on the part of the giver, who must somehow insinuate that she's just trying to improve an already awesome performance, whether that's true or not.
To be offended by such a gift would be extremely stupid. No matter how good you think you already are, it's the very nature of human sexuality that we can always learn to do more. That's what's so fun about it. We don't know how people will be having sex a hundred, or a hundred thousand years from now, but there's one thing I'm sure of: it will always be an endlessly exciting challenge. Learning to participate in a pleasing manner isn't an unimportant, marginal task. It's a central part of the whole human adaptation, something we couldn't have become what we are without, and our lives would be better if male human beings, in particular, took the challenge more seriously.
So to my fellow men, as Yuletide approaches, I can only repeat the immortal words of Bullwinkle J. Moose: "Excelsior! Excelsior!" You're not a chimpanzee. In the year that's coming, and all the years after that, try to learn how to not make love like one.
Daniel Cloud teaches philosophy at Princeton University. He is the author of The Domestication of Language, available on Amazon at:
1. Comfort, A. The Joy of Sex. New York: Crown Publishing.
2. "Excelsior." The Bullwinkle Show. NBC, June 4 1962.
3. Hite, S. 2003. The Hite Report: A National Study of Female Sexuality. New York: Seven Stories.
4. Kerner. I. 2010. She Comes First. New York: William Morrow Paperbacks.
5. Lloyd, E. 2005. The Case of the Female Orgasm. Cambridge, Massachusetts: Harvard University Press.
6. Sterelny, K. 2012. The Evolved Apprentice: How Evolution Made Humans Unique. Cambridge, MA: MIT Press.