What Makes Us Do It?

By MICHAEL D. LEMONICK

In one important sense, the argument over nature and nurture has been resolved. For centuries, the nature camp said that personalities are born, not made, that our character is pretty much formed by the time we pop out of the womb. The nurture people countered with the metaphor of the tabula rasa: our mind starts out as a blank slate, and it's how we are reared that determines what gets written on it. Modern science, though--especially our fast-growing understanding of the human genome--makes it clear that both sides are partly right. Nature endows us with inborn abilities and personality traits; nurture takes these raw materials and molds them as we learn and mature.

But if you think this compromise has stopped the arguments, think again. Scientists and philosophers are still getting steamed up over the issue, but now they're fighting over percentages, over how much of human character is shaped by genes and how much by environment. And according to Steven Pinker, a professor of psychology at the Massachusetts Institute of Technology, we continue to give far too much credit to the latter. In a series of articles, a lecture tour and especially in a new book, The Blank Slate: The Modern Denial of Human Nature (Viking), Pinker argues that ignorance, prejudice and political correctness have kept scientists and the public from appreciating the power of our genes.

Anyone who has read Pinker's earlier books--including How the Mind Works and The Language Instinct--will rightly guess that his latest effort is similarly sweeping, erudite, sharply argued, richly footnoted and fun to read. It's also highly persuasive. The view that environment is paramount began, he says, with the philosophers of the Enlightenment: John Locke, Jean-Jacques Rousseau, Rene Descartes and John Stuart Mill. And it was reinforced in the 1950s by Harvard psychologist B.F. Skinner, who said that all human behavior was simply a set of conditioned responses.

That jibed nicely with 20th century liberal social theory: violence, crime and poverty were not the fault of the violent, the lawless and the poor but of society. Improve living conditions and you will cure the problems. Even mental illness and homosexuality were the result of family dynamics, went this line of reasoning. These notions, of course, flew in the face of everything conservatives held dear--the idea that the lower classes were inherently stupid and lazy, for example, and that rehabilitating lawbreakers was an exercise in futility--which may have been part of their appeal.

Then, in the 1970s, science began to show that the nurture-only view was indeed too simplistic--which triggered a backlash from the left. When researchers like Richard Herrnstein and E.O. Wilson demonstrated that genes do play a significant role in human intelligence and behavior, for example, they were vilified by many of their colleagues. And just a few years ago, a conference designed to explore the genetic roots of violence had to be canceled in the face of widespread condemnation.

The backlash was understandable, says Pinker. Once you suggest that human nature is in any way hardwired, it's easier for the unscrupulous to write off entire groups as genetically inferior--as the Nazis did with Jews, Poles, Gypsies and gays. If have-nots are genetically lacking in drive or intelligence or ambition, what's the point of fighting poverty?

Plenty, says Pinker. Compassion and altruism (which he thinks also are at least partly hardwired) are good reasons to make life better for those who start out at a disadvantage. And while he's cranky about society's unwillingness to accept scientific discoveries about the roots of human behavior, Pinker also admits, albeit in a less strident voice, that environment plays a significant part in how we turn out. It's just not the whole story.

But those nuances are generally lost in Pinker's all-out assault on those who insist that nurture explains everything--as if anybody still believes that anymore. And his evidence for the power of our genes is, at best, a work in progress. Are liberal and conservative political attitudes really, as Pinker confidently asserts, "largely, though far from completely, heritable"? Are art and literature "in trouble" because they've drifted away from what our genes would prefer to see and hear? Maybe. Yet as with any polemic, this one is delivered with more certainty than it merits. The book is hugely entertaining and highly informative. But readers would be wise to apply some skepticism, whether it's native or nurtured.