What's the Big Idea?

If asked to imagine what prehistoric human sex was like, according to psychologist Christopher Ryan, most of us would conjure "the hackneyed image of the caveman, dragging a dazed woman by her hair with one hand, a club in the other..." Ryan says this image is mistaken in every detail. A much more likely picture of how it went down in prehistoric times was this: a caveman would quietly sit in the corner and watch another caveman have sex with a woman, patiently waiting his turn.

Apparently, prehistoric women were extraordinarily promiscuous, and like our primate ancestors, women are hard-wired to behave like chimps in the bedroom. In his book, Sex at Dawn: The Prehistoric Origin of Modern Sexuality, Ryan offers a biological explanation for why we find monogamy so difficult today. A male is interested in sex with one woman up until the point of orgasm, at which point he will immediately lose interest, fall asleep, or perhaps wonder off to find more action.

In other words, human males are in important ways sexually incompatible with human females, who are capable of multiple orgasms. So what is the evolutionary advantage of this? Take monogamy out of the equation, and the evolutionary logic becomes more evident. A woman can have multiple sexual partners. This may increase her chances of reproducing, and she needs to try it a lot to be successful. Compared to other animals, humans have an incredibly low rate of conception, based on the number of sexual acts we partake in. And so it is well that sex is so much fun for humans, because if that were not the case, we wouldn't have made it this far.

So just what does it mean to make love like a caveman? It means have a lot of sex, partaking in, as Ryan describes it, the "seven million years of primate promiscuity" that our ancestors so heartily embraced as a species. That's a lot of sex.

Watch Christopher Ryan explain the evolution of human sexuality here:

What's the Significance?

According to Ryan, if we took an honest look at our dysfunctional sexual lives today, this is what we would find: we are all victims of a well-intentioned inquisition. American society has responded to this crisis by inventing a 'marital-industrial complex' of couples therapy, "pharmaceutical hard-ons," sex advice columnists, and "creepy father-daughter purity cults.” Viagra breaks sales records every year. Pornography worldwide is a $100 billion business. Ryan says we spend all of this money to compensate for a fundamental disconnect we have with our nature.

For instance, why is monogamy so difficult? According to Ryan, we are biologically programmed against it. It was not until the advent of agriculture that man developed a notion of private property, and had reason to feel jealous of a promiscuous mate. Culture invented monogamy, and with it marriage, cheating, and a sense of shame that surrounds our sexual selves. Ryan is anything but a home-wrecker. His book offers no prescriptions for curing our disconnect with nature. What he does recommend, however, is that we lose this sense of shame we have when we feel or act certain ways that contradict our culture, but which are in perfect harmony with our sexual nature.

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