From the Economist.com: "The idea that graffiti-spraying and other forms of low-level delinquency promote further bad behaviour has now been tested experimentally

A PLACE that is covered in graffiti and festooned with rubbish makes people feel uneasy. And with good reason, according to a group of researchers in the Netherlands. Kees Keizer and his colleagues at the University of Groningen deliberately created such settings as a part of a series of experiments designed to discover if signs of vandalism, litter and low-level lawbreaking could change the way people behave. They found that they could, by a lot: doubling the number who are prepared to litter and steal.

The idea that observing disorder can have a psychological effect on people has been around for a while. In the late 1980s George Kelling, a former probation officer who now works at Rutgers University, initiated what became a vigorous campaign to remove graffiti from New York City’s subway system, which was followed by a reduction in petty crime. This idea also underpinned the “zero tolerance” which Rudy Giuliani subsequently brought to the city’s streets when he became mayor.

Many cities and communities around the world now try to get on top of anti-social behaviour as a way of deterring crime. But the idea remains a controversial one, not least because it is often difficult to account for other factors that could influence crime reduction, such as changes in poverty levels, housing conditions and sentencing policy—even, some people have argued, the removal of lead from petrol. An experimental test of the “broken windows theory”, as Dr Kelling and his colleague James Wilson later called the idea, is therefore long overdue. And that is what Dr Keizer and his colleagues have provided."

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