So the Tory policy chief Oliver Letwin thinks that his party is making “a shift from an econocentric paradigm to a sociocentric paradigm”. What ridiculous language. How does he expect anyone to understand what he is going on about?

Surely he realises that the real shift for the Conservatives is from being dispositionalists to being situationalists. Simple enough. Why not just come out and say it?

A couple of weeks ago on these pages, Mr Letwin began a discourse on Cameron Conservatism with some words about Karl Marx. I want to begin with two cars parked in the street back in 1968, one in the Bronx in New York and the other near Stanford University in Palo Alto, California.

The cars had their hoods up and their licence plates removed and they were being watched. The social psychologist Philip Zimbardo had parked the vehicles for an experiment and was recording everything that happened to them. It didn’t take long before the Bronx car was a wreck. Almost before the recording equipment was in place, the first vandals appeared. Mum emptied the boot, the son emptied the glove compartment and dad barked orders.

In Palo Alto, nothing. Actually, not quite nothing. A few days after the experiment began, it rained. A kindly man came and closed the bonnet.

The New York car has become famous. Well, OK, not famous like Jade Goody, but a celebrity at policy seminars about crime. The observation that a car with the bonnet up was quickly stripped entirely set thinkers on the path towards “broken windows theory”. The belief that you can reduce crime by alleviating physical disorder – wiping out graffiti, for example – has profoundly changed policing policy in cities all over the world.

But broken windows theory is not what Professor Zimbardo was interested in when he parked those cars. In fact, all these years later, he’s doesn’t even really believe in it. To Zimbardo, the untouched car in Palo Alto was as striking as the stripped one in New York. The experiment was intended to establish that in different situations the same sort of people behave differently. In the anonymous crowded city, respectable families can become thieves. In the pleasant environs of Palo Alto, they shut the bonnet helpfully.

Professor Zimbardo, you see, is a situationalist, not a dispositionist. His latest book, The Lucifer Effect, is subtitled How Good People Turn Evil and his answer is that any one of us is capable of dreadful behaviour depending on the circumstances we find ourselves in. Our concentration on the personality of evil people, on their dispositions, is a mistake. We should think instead of the situation.

At least half of The Lucifer Effect is devoted to an account of one of the most disturbing experiments conducted by a social psychologist – Zimbardo’s Stanford Prison Experiment. In the early 1970s a group of Stanford students was invited to join in a role-playing game. Some of them, selected at random, would be prisoners, the rest would be guards. They would play prisons for a fortnight. Within four days the guards were abusing the prisoners so badly that the organisers had to call a halt. The great social psychologist Stanley Milgram had once wondered if he could find enough people in the whole of America to behave as the Nazis had. Experimental work had persuaded him that he could find all he needed just in New Haven. After the Stanford Prison Experiment, Zimbardo agreed.

But really, you don’t need a lab to discover this, do you? Look at the Hutus in Rwanda. Told repeatedly that the Tutsi minority weren’t human, that they were cockroaches, they took out their machetes and hacked their neighbours to death. They killed the little children first. Or look at the followers of Jim Jones, at how 900 of them persuaded each other to drink poison, shoving their children to the front of the queue. Give us peer pressure or the cloak of anonymity or the need to adhere to a consistent philosophy or a group code, give us the right situation and its amazing what we will do, whatever our disposition.

Despite this compelling evidence, Conservatives have always struggled against situationalism. And for very good reason. They didn’t want to excuse the Nazi guard his crime or try to “understand” the forces that made the Hutus wield their machetes. Conservatives have always adhered to the idea that individuals are responsibile for their acts. And quite right too.

Yet there comes a point where this clear moral position becomes a bias against understanding. It actually became Conservative doctrine “to understand less and condemn more” and it can never be right to advocate ignorance. When Tony Blair first talked about being tough on the causes of crime, Tories argued that the cause of crime was criminals, a pure dispositionalist response.

Margaret Thatcher’s assertion that “there is no such thing as society” is perhaps the best pithy statement of what dispositionalists believe.

Yet over the past 15 years, situationalist thinking has become more common on the Right. And with David Cameron as leader it has become central to Tory thinking.

As with much that it is worthwhile in the Tory party, it began with the MP and thinker David Willetts. In the mid1990s he started to argue that criminal behaviour being concentrated among poorly educated young males in inner-city estates could not properly be regarded as a puzzling coincidence. In the decade and a half since, he has gone on probing the social causes of individual behaviour. Later today, for instance, he will be giving a major lecture about social mobility.

Others have followed suit. Iain Duncan Smith’s explanations of drug abuse and poverty all concern “social breakdown”. The emphasis on the positive role played by stable families is classic situationalism.

Mr Cameron and his key adviser, Steve Hilton, now lead the situationist pack. They want to find out what makes people good. A central plank of their programme will be to reverse the process that made Hutus into murderers – to encourage people to treat strangers as more rather than less human, to use peer pressure for good ends.

So there you have it. A fresh way of thinking on the Right. Dare I call it a new paradigm?

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