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We are who we are, or are we? The idea that we are driven by biology isn't sitting well

By Kim Painter
Special for USA TODAY

Girls like to play house. Boys like to play war. Some people are shy, others gregarious; some are especially smart, others especially brave. But in many ways, humans are alike: We fall in love, worry about status and know joy, jealousy and rage.

That's human nature. And according to psychologist Steven Pinker, nature -- not nurture, culture or learning -- is the key.

Girls don't play with dolls because we dress them in pink; young men don't develop violent urges because they read comic books; and it is not just a cultural coincidence that societies everywhere wage war, frown on incest and celebrate fertility.

We are who we are, collectively and individually, because of our brains, he says. And our brains, no less than our livers or kidneys, are products of evolution, Pinker argues in his new book, The Blank Slate: The Modern Denial of Human Nature (Viking, $27.95).

''The emotions and drives and ways of thinking and learning that are uniform across the human species are part of our inheritance,'' he says. In other words, a baby's brain is not a blank slate; it is inscribed with the genetic history of humankind, with the traits that allowed earlier humans to survive -- and with many of the quirks that make individuals themselves, Pinker says. ''Evolution feeds on variation.''

If science and politics feed on controversy, Pinker's book provides plenty. The Canadian native, 48, a language and cognition researcher at the Massachusetts Institute of Technology, is picking a fight with those who deny that the mind is biological and much human behavior innate. That group includes many religious thinkers and evolution skeptics.

But even some scholars and defenders of evolutionary theory reject many of the ideas Pinker endorses, which range from the notion that there is an innate set of emotions to the idea that men crave multiple sex partners because promiscuous male ancestors left the most offspring. The late evolutionary biologist Stephen Jay Gould called the whole field, known broadly as sociobiology, ''foolish,'' ''pathetic'' and ''egregiously simplistic,'' among other things.

Many feminists, of course, reject the idea that sexual differences are largely unlearned and unchangeable. Any discussion of innate genetic differences raises the question of whether minds vary by race (Pinker says innate race differences in IQ ''are possible,'' but ''the evidence we have today doesn't demonstrate that they exist''). And the whole industry of child-rearing advice is based on the idea that parents can mold the minds of children.

Certainly, no one denies that some mental characteristics are innate. ''Human nature exists,'' says sociobiology critic Jonathan Marks, an anthropology professor at the University of North Carolina-Charlotte. ''It's different from chimp nature and cow nature. . . . But I don't know of any reliable way of establishing that any particular trait is human nature.

''When you start talking about behavioral genetics and the influence on personality, you are getting into a real nasty field. . . . There is a political advantage to the right wing in telling you that there is no chance to better yourself, that social hierarchies are rooted in natural differences and therefore there is nothing you can do about them.''

But Pinker, who has written several books on language and the mind, argues in his book that the idea of a truly biological mind is neither unscientific nor dangerous. If anything, he says, the idea of the blank slate is dangerous. ''If you believe in a blank slate, you better make sure the right thing gets written on the slate,'' he says, adding that's just what totalitarian and Marxist governments attempt. As he notes, Mao Tse-tung once said: ''It is on a blank page that the most beautiful poems are written.''

Pinker concedes that some of the ideas of sociobiology can be unsettling. Take gender. Talk about differences in men's and women's brains immediately raises the specter of justifiable discrimination, he says. But, he says, ''People confuse two questions. One is, 'Are men and women indistinguishable?' And the answer is no. The other is, 'Should we bring back discrimination?' And the answer is no again.''

Pinker envisions a world in which individual men and women have the same opportunities even while people acknowledge that average men and women are different -- that, for example, women tend to feel more attached to children and men tend to feel more competitive about job success. Even in a world with perfect equality of opportunity, he says, ''I don't think as many women would figure out how to build a better dishwasher and I don't think as many men would write doctoral theses on the writings of Sylvia Plath.''

On another hot-button issue -- children -- Pinker says parents should be relieved that they can't mold their children's intellects and personalities with the right toys, books and experiences. ''There is a tendency to blame mothers for everything that goes wrong with their children,'' he says. But, he adds, research suggests that within a culture, ''about half the variation among people's personalities is caused by differences in their genes; little is caused by the homes and parents they grew up with; and half is caused by something else.''

That something else could be peer group experiences, he says, as proposed by researcher Judith Rich Harris in her 1998 book The Nurture Assumption, or even ''chance events in the wiring of the brain in utero and early life.'' But, he says, that doesn't mean that parenting doesn't matter.

''Parents affect which peer group a child falls into,'' he says. ''They teach their children skills such as sports, musical instruments and school skills.'' And, at least during childhood, parents ''strongly affect their children's happiness and well-being.''

Nothing about a belief in biological human nature robs life of its meaning or humans of their freedom, Pinker says. Our brains are complex enough to allow moral thinking, and humans are not just gene-carrying robots programmed to reproduce and die.

Of his own decision not to have children, Pinker once wrote, ''If my genes don't like it they can jump in the lake.'' The point, he says, was to ''underscore that the metaphorical motives of the genes (to reproduce themselves) is different from the real motives of people.''

Many questions remain unanswered, Pinker says. ''We know a lot of things at a general level . . . but we don't know much about how, in detail, the child's innate endowment allows learning to take place. For example, we don't understand human nature well enough to program a computer with a simulation of human mental abilities and expect it to learn what children naturally learn.''

Genetic explanations of behavior ''give a lot of people the heebie-jeebies,'' says Eugenie Scott, executive director of the National Center for Science Education, a group that promotes the teaching of evolution in schools. But, she says, ''there's a continuum of scientific views. Nobody says it's all environment and nobody says it's all genetic.''

Pinker certainly falls on the genetic side of the continuum. But the important message, Scott says, is that genes ''are pretty darn important, and we better understand this interaction if we are going to create societies that are functional and humane . . . which is very different from saying that we are slaves to our genes.''