Dr Deborah Prothrow-Stith knows fighting violence among young people is not easy. “We’re asking kids to swim against the tide - like the kids who learned about the dangers of cigarettes at school and then went home and harassed their smoking parents.”

But she doesn’t think it’s a naive aim. An associate dean and professor at Harvard School of Public Health and presidential appointee to the National Commission on Crime Control and Prevention, she has developed an anti-violence curriculum that covers primary and secondary levels. In 10 years it has sold more than 20,000 copies to schools and youth centres. She says the idea behind the curriculum, which she devised with the education development centre in Boston, is to present anger as a normal emotion and to talk to children about what they can do with it, first analysing the cost and benefit of acting on it and then discussing strategies to defuse the situation.

A recent violence prevention session at Wilbur Cross high school in New Haven, Connecticut, illustrates how this works. The improvised role play and discussion took place in a weekly peer education session led by three 18-year-old “senior buddies” working with a class of ninth graders (14-year-olds).

Two 14-year-old girls are fighting over a boy. “What you think you’re doing with him? He’s my boyfriend.”

“Hey, I don’t know what you’re talking about. I’m gonna get my friends to talk to you.”

It’s a potentially explosive situation. But the girls turn it on its head by stopping and thinking about what their conflict is about and finding a strategy to avoid a set-to. They turn on the one-time object of their affections. “What’s he think he’s playing at?” asks one. “He’s not really worth this grief,” says the other.

The discussion moves from there to other scenarios. A ninth-grader asks senior buddy Brendan what he would do if someone pushed him accidentally, but forcefully, in front of everyone. Brendan, who is built like Mike Tyson, thinks for a moment before replying. “Honestly? I’d ask him what his problem was, what he’s pushing me for. I’m not the kind of person to go hit him.”

Then, masterfully, he turns the question back on his questioners. “When’s it a good situation to fight?” Everyone jumps in. As Brendan and his fellow senior buddies Marlena and Carly talk about alternative strategies to fighting - talking, apologising, walking away, calling a peer mediator - you can hear a pin drop.

Dr Prothrow-Stith, whose curriculum was shown in one study, to have cut the suspension rate for violent behaviour by 70 per cent in a school where she taught it, sees her programme as “just one thing we have to do.

“America needs to develop a whole set of strategies for changing attitudes and social norms, for showing that violence doesn’t solve problems.

“We haven’t acknowledged just how much of a role we’ve all had in creating the violent culture in which we exist,” she said.

Reva Klein