Sex at Dawn: The Prehistoric Origins of Modern Sexuality (31 page)

If we really did evolve in a Hobbesian ordeal of constant terror and anxiety, if our ancestors’ lives truly
were
solitary, poor, nasty, brutish, and short, why, then, are we still so vulnerable to stress?22

Who You Calling a Starry-Eyed

Romantic, Pal?

Many otherwise reasonable people seem to have a burning need to locate the roots of war deep in our primal past, to see self-sufficient foragers as
poor,
and to spread the misbegotten gospel that three or four decades was a
ripe old age
for a human being in pre-agricultural times. But this vision of our past is demonstrably false.
¿Que pasa?

If prehistoric life
was
a perpetual struggle that ended in early death, if ours
is
a species motivated almost exclusively by self-interest, if war
is
an ancient, biologically embedded tendency, then one can soothingly argue, as Steven Pinker does, that things are getting better all the time—that, in his Panglossian view, “we are probably living in the most peaceful moment of our species’ time on Earth.” That would be encouraging news, indeed, which is what most audiences want to hear, after all. We all want to believe things are getting better, that our species is learning, growing, and prospering. Who refuses congratulations for having the good sense to be alive here and now?

But just as “patriotism is the conviction that your country is superior to all others because you were born in it” (G. B.

Shaw), the notion that we live in our species’ “most peaceful moment” is as intellectually baseless as it is emotionally comforting. Journalist Louis Menand noted how science can fulfill a conservative, essentially political function by providing “an explanation for the way things are that does not threaten the way things are.” “Why,” he asks rhetorically,

“should someone feel unhappy or engage in anti-social behavior when that person is living in the freest and most prosperous nation on Earth? It can’t be the system!”23 What’s your problem? Everything’s just fine. Life’s great and getting better! Less war! Longer life! New and improved human existence!

This Madison Avenue vision of the super-duper new and improved present is framed by an utterly fictional, blood-smeared Hobbesian past. Yet it’s marketed to the public as the “clear-eyed realist” position, and those who question its founding assumptions risk being dismissed as delusional romantics still grieving over the death of Janis Joplin and the demise of bell-bottoms. But that “realistic” argument is riddled with misunderstood data, mistaken interpretations, and misleading calculations. A dispassionate review of the relevant science clearly demonstrates that the tens of thousands of years before the advent of agriculture, while certainly not a time of uninterrupted utopian bliss, was for the most part characterized by robust health, peace between individuals and groups, low levels of chronic stress and high levels of overall satisfaction for most of our ancestors.

Having made this argument, have we outed ourselves as card-carrying comrades in the Delusional Utopian Movement (DUM)? Is it Rousseauian fantasy to assert that prehistory was
not
an unending nightmare? That human nature leans no more toward violence, selfishness, and exploitation than toward peace, generosity, and cooperation? That most of our ancient ancestors probably experienced a sense of communal belonging few of us can imagine today? That human sexuality probably evolved and functioned as a social bonding device and a pleasurable way to avoid and neutralize conflict? Is it silly romanticism to point out that ancient humans who survived their first few years often lived as long as the richest and luckiest of us do today, even with our high-tech coronary stents, diabetes medication, and titanium hips?

No. If you think about it, the neo-Hobbesian vision is far sunnier than ours. To have concluded, as we have, that our species has an innate capacity for love and generosity
at least
equal to our taste for destruction, for peaceful cooperation as much as coordinated attack, for an open, relaxed sexuality as much as for jealous, passion-smothering possessiveness … to see that both these worlds were open to us, but that around ten thousand years ago a few of our ancestors wandered off the path they’d been on forever into a garden of toil, disease, and conflict where our species has been trapped ever since …

well, this is not exactly a rose-colored view of the overall trajectory of humankind. Who are the naïve romantics here, anyway?

P A R T IV

Bodies in Motion

Love’s mysteries in souls do grow, But yet the body is his
book.

JOHN DONNE (1572–1631)

Everybody has a story to tell. So does every
body,
and the story told by the human body is rated XXX.

Like any narrative of prehistory, ours rests on two types of evidence: circumstantial and material. We’ve already covered a good bit of the circumstantial evidence. As for more tangible material evidence, the song says, “What goes up must come down,” but unfortunately for archaeologists and those of us who rely on their findings, what goes down rarely comes back up. And even when it does, ancient social behavior is hard to see reflected in bits of bone, flint, and pottery—fragments that represent only a fraction of what once existed.

At a conference not long ago, the subject of our research came up over breakfast. Upon hearing that we were investigating human sexual behavior in prehistory, the professor sitting across the table from us scoffed and asked (rhetorically), “So what do you do, close your eyes and dream?” While one should never scoff with a mouthful of scone, he had a point. As social behavior presumably doesn’t leave physical artifacts, any theorizing must amount to little but “dreaming.”

Paleontologist Stephen Jay Gould was an early scoffer at the notion of evolutionary psychology, asking, “How can we possibly know in detail what small bands of hunter-gatherers did in Africa two million years ago?”1 Richard Potts, director of the Smithsonian’s Human Origins Program, agrees, warning, “Many characteristics of early human behaviour are

… difficult to reconstruct, as no appropriate material evidence is available. Mating patterns and language are obvious examples … [they] leave no traces in the fossil record.” But he then adds, as if under his breath, “Questions of social life

… may be accessible from studies of ancient environments, or from certain aspects of anatomy and behaviour that leave material evidence.”2

Certain aspects of anatomy and behaviour that leave material
evidence….
Can we glean reliable information about the contours of ancient social life—even sexual behavior—from present-day human anatomy?

Yes we can.

CHAPTER FIFTEEN

Little Big Man

Every creature’s body tells a detailed story about the environment in which its ancestors evolved. Its fur, fat, and feathers suggest the temperatures of ancient environments. Its teeth and digestive system contain information about primordial diet. Its eyes, legs, and feet show how its ancestors got around. The relative sizes of males and females and the particulars of their genitalia say a lot about reproduction. In fact, male sexual ornaments (such as peacock’s tails or lions’

manes) and genitals offer the best way to differentiate between closely related species. Evolutionary psychologist Geoffrey F. Miller goes so far as to say that “evolutionary innovation seems focused on the details of penis shape.”1

Leaving aside for the moment the disturbingly Freudian notion that even Mother Nature is obsessed with the penis, our bodies certainly contain a wealth of information about the sexual behavior of our species over the millennia. There are clues encoded in skeletal remains millions of years old and pulsing in our own living bodies. It’s all right there—and here. Rather than closing our eyes and dreaming, let’s open them and learn to read the hieroglyphics of the sexual body.

We

begin

with

body-size

dimorphism.

This

technical-sounding term simply refers to the average difference in size between adult males and females in a given species. Among apes for example, male gorillas and orangutans average about twice the size of females, while male chimps, bonobos, and humans are from 10 to 20 percent bigger and heavier than females. Male and female gibbons are of equal stature.

Among mammals generally and particularly among primates, body-size dimorphism is correlated with male competition over mating.2 In winner-take-all mating systems where males compete

with

each

other

over

infrequent

mating

opportunities, the larger, stronger males tend to win … and take all. The biggest, baddest gorillas, for example, will pass genes for bigness and badness into the next generation, thus leading to ever bigger, badder male gorillas—until the increased size eventually runs into another factor limiting this growth.

On the other hand, in species with little struggle over females, there is less biological imperative for the males to evolve larger, stronger bodies, so they generally don’t. That’s why the sexually monogamous gibbons are virtually identical in size.

Looking at our modest body-size dimorphism, it’s a good bet that males haven’t been fighting much over females in the past few million years. As mentioned above, men’s bodies are from 10 to 20 percent bigger and heavier than women’s on average, a ratio that appears to have held steady for at least several million years.3

Owen Lovejoy has long argued that this ratio is evidence of the ancient origins of monogamy. In an article he published in
Science
in 1981, Lovejoy argued that both the accelerated brain development of our ancestors and their use of tools

resulted from an “already established hominid character system,” that featured “intensified parenting and social relationships,

monogamous

pair

bonding,

specialized

sexual-reproductive behavior, and bipedality.” Thus, Lovejoy argued, “The nuclear family and human sexual behavior may have their ultimate origin long before the dawn of the Pleistocene.” In fact, he concluded with a flourish, the

“unique sexual and reproductive behavior of man may be the sine qua non of human origin.” Almost three decades later, Lovejoy is still pushing the same argument as this book goes to press. He argues—again in
Science
—that
Ardipithecus
ramidus’
fragmentary skeletal and dental remains dated to 4.4

million years ago reinforce this view of pair bonding as
the
defining human characteristic—predating, even, our uniquely large neocortex.4

Like many theorists, Matt Ridley agrees with this ancient origin of monogamy, writing, “Long pair-bonds shackled each ape-man to its mate for much of its reproductive life.” Four million years is an awful lot of monogamy. Shouldn’t these “shackles” be more comfortable by now?

Without access to the skeletal data on body-size dimorphism we have today, Darwin speculated that early humans may have lived in a harem-based system. But we now know that if Darwin’s conjecture were correct, contemporary men would be twice the size of women, on average. And, as we’ll discuss in the next section, another sure sign of a gorilla-like human past would be an embarrassing case of genital shrinkage.

Still, some continue to insist that humans are naturally polygynous harem-builders, despite the paucity of evidence supporting this argument. For example, Alan S. Miller and Satoshi Kanazawa claim that, “We know that humans have been polygynous throughout most of history because men are taller than women.” These authors go on to conclude that because “human males are 10 percent taller and 20 percent heavier than females, this suggests that, throughout history, humans have been mildly polygynous.”5

Their analysis ignores the fact that the cultural conditions necessary for some males to accumulate sufficient political power and wealth to support multiple wives and their children
simply did not exist before agriculture.
And males being moderately taller and heavier than females indicates reduced competition among males, but not necessarily “mild polygyny.” After all, those promiscuous cousins of ours, chimps and bonobos, reflect
precisely the same range of
male/female size difference while shamelessly enjoying
uncounted sexual encounters with as many partners as they
can drum up.
No one claims the 10 to 20 percent body-size dimorphism seen in chimps and bonobos is evidence of “mild polygyny.” The assertion that the
same
physical evidence correlates to promiscuity in chimps and bonobos but indicates mild polygyny or monogamy in humans shows just how shaky the standard model really is.

For various reasons, prehistoric harems were unlikely for our species. The famed sexual appetites of Ismail the Bloodthirsty, Genghis Khan, Brigham Young, and Wilt Chamberlain notwithstanding, our bodies argue strongly against it. Harems result from the common male hunger for sexual variety and the post-agricultural concentration of