I am an identical twin. By the time I was four or five, I had begun to notice grown-ups staring at my twin sister and me as they asked us questions. Did I know when Lorna was in trouble? Did we like the same toys? Did I ever think I was Lorna? I remember sitting in the backseat of the family car and comparing hands. We laughed alike and still do. We both like risk, although we display it very differently. She is a hot-air-balloon pilot in Colorado, whereas I discuss emotionally charged issues such as adultery and divorce on television and the podium. She is also an artist. She paints large canvases with tiny bruslistrokes, whereas I move tiny words across hundreds of manuscript pages. Both are jobs that require patience and attention to details. And we both work alone.
So as a child I started, quite unconsciously, to weigh my behavior: How much of it was inherited? How much of it was learned?
Then, in graduate school, I discovered the "nature/nurture" debate. John Locke's concept of the "tabula rasa," or empty tablet, was particularly troubling. Was every infant really a blank sheet of paper on which culture inscribed personality? I didn't believe it.
Then I read Jane Goodall's book In the Shadow of Man, about the wild chimpanzees of Tanzania. These creatures bad different personalities, and they made friends, held hands, kissed, gave one another gifts of leaves and twigs, and mourned when a companion died. I was overcome by the emotional continuity between man and beast. And I became convinced that some of my behavior was biological in origin. So this book is about the innate aspects of sex and love and marriage, those mating traits and tendencies that we inherited from our past. Human behavior is a complex mixture of environmental and hereditary forces and I do not wish to minimize the power of culture in influencing human action. But it is the genetic contributions to behavior that have always intrigued me.
The book began on a New York subway. I was pouring over American marriage statistics and I noticed some peculiar patterns to divorce. I wondered if these same patterns might appear in other cultures. So I looked at divorce data on sixty-two societies contained in the demographic yearbooks of the United Nations; there I found some similar curious designs. Then I examined data on adultery in forty-two cultures. And when I compared these worldwide figures on human bonding with patterns of monogamy, "cheating," and desertion in birds and nonhuman mammals, I found some similarities so compelling that they led me to a general theory for the evolution of human sex and family life.
Why do we marry? Why are some of us adulterous? Why do human beings divorce? Why do we remarry and try our luck again? The book begins with chapters on the nature of courting, infatuation, monogamy, adultery, and divorce. Then, starting in chapter 6, I dial back to the beginning of human social life and trace the evolution of our sexuality from its inception on the grasslands of East Africa some four million years ago, through life among the cave painters of Ice Age Europe and on into contemporary times, both in the West and more "exotic" places.
In the course of presenting my theories, I examine why we fall in love with one person rather than another, the experience of love at first sight, the physiology of attachment and philandering, why men have large penises and women display permanently enlarged breasts, gender differences in the brain, the evolution of "women, men, and power," the genesis of teenage, the origin of our conscience, and many other creations of our human sexual impulse. Finally, in the last chapter, I use all these data to make some predictions about "relationships" tomorrow and, if we survive as a species, millennia from now.
But first a few caveats. Along the way I make many generalizations. Neither your behavior nor mine fits all of the patterns I will describe. Why should it? There is no reason to expect a tight correlation between all human actions and general rules of human nature. I focus on the predominant patterns, rather than on the exceptions.
Moreover, I make no effort to be "politically correct." Nature designed men and women to work together. But I cannot pretend that they are alike. They are not alike. And I have given evolutionary and biological explanations for their differences where I find them appropriate.
I have also resisted some fads in anthropology. It is at present unpopular, for example, to use the !Kung Bushmen of southern Africa as a model for reconstructing life in our hunting-gathering past. My reasons for continuing to use their society as a model are laid out in one of many endnotes that I hope you will have time to read.
Most alarming to some readers, I discuss the possible genetic components and adaptive features of complicated, controversial, and often highly painful social behaviors such as adultery and divorce. I am certainly not advocating infidelity or desertion; rather, I am trying to understand these disturbing facts of human life.
Last, I am an ethologist, one who is interested in the genetic aspects of behavior. Ethologists have, as Margaret Mead once said of the anthropological perspective, a "way of seeing." In my view, human beings have a common nature, a set of shared unconscious tendencies or potentialities that are encoded in our DNA and that evolved because they were of use to our forebears millions of years ago. We are not aware of these predispositions, but they still motivate our actions.
I do not think, however, that we are puppets of our genes, that our DNA determines our behavior. On the contrary, culture sculpts innumerable and diverse traditions from our common human genetic material; then individuals respond to their environment and heredity in idiosyncratic ways that philosophers have long attributed to "free will."
In our drive to understand ourselves, we first studied the sun and moon and stars, then the plants and animals around us. Only in the past two centuries have we scientifically examined our social networks and our minds. Victorians put books by male and female authors on separate shelves. Sex researcher Alfred Kinsey made his pioneering studies of American sexuality as recently as the 1950s. And academics have only just begun to inspect the genetic undercurrents of human mating practices. So this book is an attempt to explore the nature of our romantic lives.
There is magic to love—as poets and sweethearts know. I don't pretend to penetrate this sanctum. But our sexual imperatives are tangible, knowable. And I firmly believe that the better we come to understand our human heritage, the greater will be our power over it and the stronger our free will.
No I'm not far from it. I thought I had clearly defined the role of civil unions. Am I missing a point you are making here?
