In Angela's Ashes, Frank McCourt graphically describes the trouble an Irish child was likely to get into by asking questions adults didn't want to answer. The cruelty he experienced as a child made him a survivor, a condition that he celebrates. Lots of us identify with this, as the sales of Angela's Ashes showed.

But Alice Miller, the renowned psychotherapist, finds this attitude "fatalistic". We shouldn't feel sentimental about cruelty, we should rebel against it and do our bit to ensure that it will cease to exist, she says.

Scotland recently banned the smacking of children under the age of three. (Why not all children?) In the Republic, we haven't even talked about the possibility. I'd love to see politicians in the Seanad and Dβil debate smacking; it would tell us a lot about them - because if you smack your children, the only place you're going to find answers is in your own denial of emotion.

The trauma of being smacked is encoded in the brain and stunts children's abilities to develop into psychologically healthy adults, according to Miller in her latest book, The Truth Will Set You Free: Overcoming Emotional Blindness and Finding Your True Adult Self (Perseus Press, £17.99 sterling.) Parents who smack often say, "it didn't harm me", but the fact that they cannot see how they were harmed shows how deeply harmed they were.

An alarming number of parents and teachers consider it normal to smack children. One Irish study found that 90 per cent of adults approved of children being smacked.

These same adults have no awareness of the disastrous long-term consequences of smacking. "Our bodies retain memories of childhood humiliation, causing us to inflict on the next generation what we endured," writes Miller.

Half of the 50 US states allow teachers to smack children in school. Many Irish adults have memories of corporal punishment in school. In Rwanda, where children are carried on their mothers' backs, children are repeatedly smacked for fouling them with their excrement.

Miller argues that the endurance of childhood pain, which results from being physically hurt by parents, makes children grow up to be emotionally blind adults.

She draws on the latest research on brain development to build the case that smacking and other disciplinary traumas are encoded in the brain. Our bodies retain memories of humiliation, resulting in physical illnesses and psychological denial. So the children who cried at being hit revisit the abuse on their own children.

"Every parent should read her", is what Edna O'Brien says about Alice Miller on the dust-jacket. Having read Alice Miller first as a confused teenager dealing with my own traumas, I can only agree.

Written completely without psychological jargon, The Truth Will Set You Free helps parents to confront the roots of their own pain in childhood and see the ways in which they may be unconsciously revisiting that pain on their own children.

Miller says that parents' view of their job as educators has been warped, so that they think that educating children means making them into obedient subjects. They may contrive to enforce obedience through coercion, manipulation or emotional blackmail - things that most parents won't want to admit to, but do nevertheless.

There are other people who don't engage in these activities - parents, teachers, neighbours, siblings - and try to balance the cruelty of other adults by offering kindness. They can make a difference. Hitler, Stalin and Mao had no "helping witnesses" to save them from glorifying violence, Miller writes. From my observation, for what it's worth, the best parents are people who have come to terms with awful childhoods.