Programme Information

The dark side of human nature

THE VIOLENCE SEASON
Horizon – How Violent Are You?

Day and time to be confirmed BBC TWO

• Programme copy

Wearing protective headgear, gloves and some discreet padding, Michael Portillo pushes forward, attempting to land blows on a man of similar age and weight. It's hardly Muhammad Ali versus Joe Frasier, but the former Defence Secretary, who'd never previously had a fight in his life, gives it his best shot and admits breathlessly to a certain satisfaction after knocking his opponent down.

"They were hoping that I would get a chemical rush and enjoy the violence," says Michael, who was taking part in the Tinku, a South American Indian festival in which grievances are resolved through fighting, as part of his investigation for BBC Two's Horizon – How Violent Are You?. "I can't say that I did enjoy it much because I was suffering from altitude sickness and Bolivian tummy. I was more nervous about making a fool of myself and possibly getting hurt. But the point we were trying to get at was that a lot of people do use violence and, possibly, if I did it often enough, things would change."

The Tinku, Michael explains, may be a fairly formalised way of resolving grievances, but the violence can be lethal. "What we saw in a village where there were tourists was not wholly representative of what may happen," he says. "We spoke to a doctor who explained that, in places where we don't go, they sometimes take it to the death. Those who die are regarded as heroes – their blood nourishes the Earth and satisfies the Pachamama, the Earth goddess."

But why do people take violence so far? What are the social and psychological factors that might drive an individual to kill? Is there a darker side to human nature that lies within all of us?

To try to understand those factors, Michael employs an immersive style of presentation in which he is required to undertake some edgy tasks. "I'm very much the layman, investigating a question about which I know nothing," he says.

Hardly a natural fighter, he accepts that his brief fight was unlikely to change him very much after years of education, social conditioning and a lifetime spent engaged in verbal reasoning. "Politics is all about debate and resolving your conflicts through speech," he says. "In the House Of Commons the difference between using words and violence is absolute. You're even controlled about the violence of the words you can use – you're not allowed to call someone a liar, use bad language or impugn their good standing. It's a long way from physical violence."

That kind of peaceful resolution of differences may be the default position for most people, but the programme points out that even many mild-mannered people enjoy contact sports or violent movies. It then goes on to explore the factors that may lead people to commit acts of violence, from street brawls to murder to the horrific extremes of genocide. Scientists and medical specialists explain how violence is a natural instinct, hard-wired into the human brain, and show how frighteningly easy it can be for people to lose control.

"The film shows that we have these tendencies and we control them partly because of the development of our brains and partly because we're socialised," he says. "A road or sporting accident can damage the brain's delicate pre-frontal cortex and cause people to undergo a complete personality change. We hear of one example of a man with no history of violence who, after a road accident, murdered his wife."

Michael also discusses the addictive nature of violence with Danny, a reformed football hooligan, who lived for Saturday fights and disorder of any kind. "Danny talks of the adrenaline rush as being addictive," Michael explains. "We know that the release of dopamine is similar to the process that takes place during sex so, for those of us who've never enjoyed violence, maybe we can understand the sort of addictive quality Danny is talking about."

In an extreme sleep-deprivation test that pits him against two crying babies, Michael tries to find out if his passive personality can be changed when pushed to the limit. "I wanted an insight into how somebody denied sleep over a long period of time and maybe lacking the support mechanisms provided by family and friends might experience a change of behaviour," he says. "Because it interrupts the operation of the pre-frontal cortex, you can see that extreme exhaustion might cause someone to become more violent and why they might, for instance, shake a baby. I'm not in any way approving of that behaviour, but we wanted to understand what happens."

Michael is also invited to observe some of society's most violent members – a group biologically incapable of controlling their aggressive instincts – ordinary three-year-olds. Watching violence erupt when left to their own devices, he learns how socialisation and learned experiences change the make up of the brain and help people control their behaviour as they grow. "Children's pre-frontal cortex develops between the ages of three and six," he says. "At the same time teachers and parents show them how not to be violent and to achieve their aims through negotiation."

In 1961, shortly after the start of the trial of war criminal Adolf Eichmann, scientist Stanley Milgram set up a controversial study to test an argument prevalent at the time – that the Nazis responsible for the holocaust were uniquely evil and that such an event couldn't happen elsewhere. Horizon recreates that experiment, in which ordinary people are asked to harm another human being in pursuit of what they think is a worthwhile idea. Most participants are shown accepting the authority of a (fake) scientist to administer potentially lethal electric shocks to another volunteer (also a fake). "They do this in pursuit of an ideology – they believe that they are helping science," Michael explains. "Milgram's experiment was deeply shocking because it showed that people would obey orders to commit an act of violence. What is extraordinary is that they don't do so after years of conditioning or political propaganda, they do it 10 minutes after they were walking down the street."

If this core violence exists within everyone, isn't it a depressing prospect for society's hopes of tackling it? "I don't think the fact that a few people for complicated reasons, which may be part social and partly medical, are violent should depress us," Michael concludes. "I think it's right that we should be outraged, but not depressed by it. We have to continue to ensure, through our policies and our attitudes to each other, that most people are socialised away from violence."

Testimony to what can be achieved comes from Emmanuel, a former child soldier in war-torn Sudan, who tells a harrowing story of brainwashing and regret at his involvement in the torture and slaughter of the enemies who killed his parents.

"Emmanuel's story is absolutely horrific," Michael says. "I think what happened was that, to them, the ideology justified the act – they were in a situation where they thought it their duty to be violent. They took revenge because of feelings about what happened to their family, but ideology drove them. As a child, Emmanuel was intervened upon at a very formative stage of his life, thank goodness he has been able to undergo a rehabilitation."