MIDDLETOWN, N.J.--She appeared before several hundred members of the American Psychological Association at its annual meeting this summer, a tiny woman in unfashionable eyeglasses and a whorl of gray hair, and told them how grateful she was to be receiving the George A. Miller Award.

After all, Judith Rich Harris acknowledged, she wasn't a PhD, had no university affiliation, wasn't a researcher or a clinician, didn't even belong to the APA. In fact, she informed her audience with a certain glee, a brusque letter ejecting her from Harvard's graduate psych program 38 years earlier had been signed by the acting department chairman -- the very same George A. Miller. Nevertheless, here she was, an unknown textbook writer from New Jersey, receiving the award for a provocative journal article and about to detonate a bomblet that's still reverberating through the profession and the culture.

"I have looked long and hard at the evidence, and the conclusion I came to is that parents have no long-term effects on the personality or intelligence or mental health of their children," Harris told her audience, assaulting a nearly universally held belief about families and human development.

She went on to explain her theory that the greatest influence on kids, aside from the often-underestimated contribution of heredity, is their peer groups -- an idea elaborated on in her jarring new book, "The Nurture Assumption: Why Children Turn Out the Way They Do."

After her talk, recalls Temple University psychologist Frank Farley, a former APA president, several members came up to him in outrage, wondering how such notions had found their way onto the program. Harvard psychologist Jerome Kagan heard similar mutterings, "a lot of gossip over coffee or cocktails: 'How could this book be published?' 'How could it be hyped?' 'How could the APA give her an award?' " Though other psychologists were cheering her on -- "My great hope is that her book will be a kick in the tail for my profession," said Donald Lykken, professor emeritus at the University of Minnesota -- Harris had proposed something so unorthodox that a number of experts have felt compelled to point out publicly how wrong they think she is.

If the pros disagree, as Harris's arguments circulate courtesy of a major media blitz, what are ordinary parents to think? Could it really be true that all their ritualized devotion to their children -- the latest toilet-training techniques, the endless bedtime stories, the careful blend of praise and correction derived from reading and rereading T. Berry Brazelton and Penelope Leach -- has nothing much to do with the adults they'll become?

Instinctively, parents seem to recoil from this latest volley in the nature-nurture battle, and Harris isn't surprised. "They're very upset at the idea that they can't control their children's destiny," she says. But she hopes her theories will have a different, more comforting effect: If parents have less influence than genes and peers, they can afford to lighten up. " 'If you do something wrong, you can ruin your kid forever,' " she intones. "That's the kind of anxiety I'd like to relieve."

In her 60 years, Harris has come to know a lot about parental angst and also about personal tribulations. A promising young woman, she knows, can be bounced from the nation's most prestigious university, suffer years of devastating health problems and still savor, decades later, the delightful vindication of publishing a much-debated book. She can watch, feeling impotent, as her own children struggle and stumble.

Harris's perspective on development is scholarly but not solely academic, which doesn't always bolster her scientific credibility but does help explain her willingness to be a contrarian. "I'm just glad," her daughter Nomi says, "that heretics aren't hanged these days."

'The Scales Fell'

The outlines of what Harris calls "group socialization theory" came to her as she was sifting through reams of research, preparing to revise a textbook on child development she had co-authored through three editions. "The Child: A Contemporary View of Development" was a standard work, well within the professional mainstream, and Harris is now so mortified by its acceptance of the prevailing ideology that in her new book, she buries its title in the bibliography. "I don't want people to go and buy it," she says. "I wrote it before the scales fell from my eyes."

She's sitting at her kitchen table here in Anysuburb USA, an unpretentious Jersey grandmother increasingly unwilling to be dismissed as such. And she's explaining what has historically been one of life's mysteries, convinced that she's got it figured out.

Her book relies heavily on work by behavioral geneticists, who've lately found a partly biological basis for a wide variety of human characteristics. Shyness, risk-taking, intelligence, criminality, alcoholism -- the current consensus is that roughly half the variation in personalities can be attributed to heredity. Harris's emphasizing those findings to parents may be important in itself. As psychiatrist Harold Koplewicz, director of the Child Study Center at New York University Medical Center, observes, "People come in all the time who'd never blame themselves for their children's diabetes, but they'll blame themselves for their children's psychiatric illnesses, or for their aggressive behavior" -- both shown to have significant genetic components.

But that's not new, or even very controversial. Harris's big idea is to look at the other source of human personality, the half that's not inherited: the environment. That's the sphere, experts have long believed, in which parents can produce future book lovers by reading aloud, or batterers by being abusive. But Harris, weaving together reports from anthropology and evolutionary psychology and primate research, constructs a case that Mom and Dad are not paramount, that the other kids on the playground matter more. That's why the children of immigrant parents swiftly learn the language of their adopted country and speak it without an accent, she says. That's why studies show that adopted children raised in the same home are no more alike in personality than any two strangers.

"Most psychologists look at humans as individuals and ignore the fact that they are also members of a group," she says. While parents can influence their kids' behavior at home, once the tykes leave their back yards, "they tailor their behavior to the group. . . . The child who's too aggressive learns to become more moderate. The child, especially the boy, who's timid and fearful learns to be -- or at least pretends to be -- more confident." Peer group dynamics, she claims, influence everything from smoking to gender roles.

Over several months, Harris honed her thinking and then submitted a paper to the prestigious journal Psychological Review. "A real long shot," she recalls. "They accept maybe 15 percent of the manuscripts submitted."

In truth, Harris was an unlikely candidate to create a scholarly stir; that letter from Harvard in 1960 had left her with a lingering sense that she was scarcely a scholar at all.

Her ability to handle the course work was not in question, George A. Miller had written, but "we are in considerable doubt that you will develop into our professional stereotype of what an experimental psychologist should be." He was more accurate than he could have known.

Harris likes to joke about this, but acknowledges that "it was devastating. . . . I gave up the idea of an academic life." She and her classmate husband, Charlie, moved to New Jersey, where he worked for Bell Labs (he's now an AT&T consultant) and she didn't work at all. "Women in my era didn't have to have careers," she notes. "For 10 years I did nothing but be a housewife and mother."

Then, when her two daughters were school-aged and Harris might have resumed work toward a PhD, she was beset by an autoimmune illness, eventually diagnosed as lupus and systemic sclerosis. "It started with my joints, went on to my digestive system, damaged the nervous system -- I have no sense of smell," she recites. She endured multiple hospitalizations, a small stroke and heart and lung problems, turning to textbook writing largely because it allowed her to work at home. Though her health has since stabilized somewhat, extreme fatigue made it difficult even to get to a university library to research her article.

Despite all that, her submission caught the eye of Daniel Wegner, a University of Virginia professor then serving as Psychological Review's associate editor. "She definitely found important holes in the current literature," he says. "Harris stepped in and said, 'We've missed something. We've missed peer influences.' " Wegner sent the paper to "what I'd consider the top experts in the world in this area. Their responses were very positive."

The article was published in 1995, a happy ending to the saga of a once-scorned grad student, but not enough of one to suit Harris. "Nobody paid attention -- this was not what they wanted to hear," she complains. Though she'd mapped out an audacious new explanation for human development, most psychologists and child-rearing experts seemed to go right on thinking that what parents did was central. "I wrote the book hoping to give them something they couldn't ignore," she says. She succeeded.

'This Book Is Wrong'

"The only point worth paying attention to -- which she exaggerates -- is that parents are not the only influence on children," fumes Kagan, researcher, author and one of Harris's most vocal critics. "That's absolutely right. But to claim that their influence is minimal, that's severely wrong."

There are thousands of studies that show parents' impact on children, Kagan says. Indeed, Harris spends a good portion of her book trying to debunk them, arguing that they mistake cause for effect, fail to take genetics into account, or fall prey to various methodological blunders. But she fails to persuade Kagan, who compares her conclusions to a once-ballyhooed discovery in physics that fizzled. "It's like cold fusion, remember that, a few years ago?" he asks. "There is no cold fusion, and this book is wrong."

She's also angered people in the field by taking a bold, almost absolutist stance. "The Nurture Assumption" isn't full of possiblys and maybes -- it makes predictions like "children would develop into the same sort of adults if we left their lives outside the home unchanged -- left them in their schools and their neighborhoods -- but switched all the parents around." She's unapologetic about her tone -- "after 50 years of cobwebs, a stiff broom was needed" -- but it's cost her the support of experts like Koplewicz, who's also written a book about heredity and children's temperaments. Parents can't determine the genetic hand their kids are dealt, he maintains, but the way they respond can be critical.

Take the commonly diagnosed attention deficit disorder. "We know it's biologically determined," Koplewicz says, "but if you have parents who say, 'I'm going to make sure this kid gets skills training, I'm going to get him Ritalin if he needs it, I'm going to get him tutors,' they will have changed the trajectory of this kid's life. They make the difference between the ADD kids who go to jail and the ones who go to medical school."

Psychology is still too young a field, and its ability to measure influences too primitive, to be able to make definitive statements about what produces adults' personalities, such experts insist. "It's premature -- we don't have enough of the right kind of research," former APA president Farley says.

Of course, believing that leaves open the possibility that Harris is on to something. Not a researcher herself, she can't take on the task of verifying or knocking down her own arguments about parental limitations. She does, however, have some firsthand experience.

'Relax a Little'

Scientists trying to disentangle the effects of nature and nurture often study groups of identical twins raised apart (same genes, different environment) or adopted children raised together (different genes, same environment). The Harrises' suburban home approximated the latter: The elder daughter, Nomi, now 32, is their biological child, and 29-year-old Elaine was adopted when she was 2 months old. Their parents, Nomi says in an e-mail interview, "were as fair as possible and tried to set the same rules for both of us."

But the attempt, Judith Harris acknowledges in her book, failed because the girls were very different. Nomi was quiet and reflective. As a baby, "she'd crawl off to some part of the house and content herself by finding something to study," her mother recalls. "She'd open a drawer and examine the contents carefully, without disturbing them."

Elaine -- "a marvelous child," Harris hastens to say -- was more social, more active, and drew complaints from her teachers as early as first grade.

Despite her parents' attempts at strict discipline -- never necessary with Nomi -- by high school Elaine fell in with the proverbial bad crowd. "We always had problems seeing eye to eye," she says of her parents. "I wanted to be who I was and not who they wanted me to be."

The contrast could not be more stark: Nomi went to MIT and Elaine dropped out of high school. She lived with various friends, traveled around, lost touch with her family. "My parents were very upset at how Elaine was behaving, but didn't seem to be able to come up with any good way of controlling her," remembers Nomi, who's now a computer scientist at Lawrence Berkeley Labs in California. "I didn't have any ideas, either."

As some teenagers do, Elaine "matured out of it," she says. She earned a high school equivalency diploma and became a licensed practical nurse and CPR instructor. Now married and expecting her second child, Elaine Valk is close to her parents again.

To Harris, who introduces this bit of personal history in her book to show how children can affect parents' behavior as well as the reverse, her daughters' differences were genetic; they had little to do with the development of group socialization theory. She resents critics who suggest her work merely reflects her own family's struggle. "It simply taught me that child-rearing is more complicated than I'd been led to believe," she says.

She will be pleased if she can induce parents -- including Elaine, whose daughter is 2 1/2 -- to feel less guilt-ridden about every choice from teething rings to day-care centers. "She's always trying to tell me, 'Relax a little,' " Valk says. " 'You don't have to worry about every little thing you do or say; you're not going to make or break her.' "

But Harris will not be pleased if skeptics write her off. She's had enough of that. She used to fear that researchers wouldn't send her reprints of journal articles because she didn't have an academic address. Worried that her status as "a nobody" would doom her chances for publication in Psychological Review, she opted for what's called a blind review: The scientists who were asked to evaluate her work wouldn't know who the author was. This was a woman, after all, who assumed for decades that Harvard had been right to send her away.

That was then. Now Harris revels in the fuss she's created. She's particularly delighted that several textbook writers say they'll include her ideas in future editions.

"I feel like I'm involved in teaching the next generation," she exults, "even if 90 percent of current psychologists reject what I'm saying -- which could well be true." No matter, she says with a sweet smile. "They're not going to live forever."