It was hailed as a breakthrough in the fight to cut carbon emissions. In 2007, researchers found that heavy electricity users cut their consumption after being told that they used more energy than their neighbours. Almost a million US households have since received similar feedback and have cut electricity use by an average of 2.5 per cent.

But a new study has identified a wrinkle in the plan: the feedback only seems to work with liberals. Conservatives tend to ignore it. Some even respond by using more energy.

The findings come from a study of over 80,000 Californian households, just under half of which received feedback on energy use. Overall, the technique worked: households who got the feedback cut electricity by around 2 per cent, say Dora Costa and Matthew Kahn at the University of California, Los Angeles.

But important difference emerged when Costa and Kahn looked at the political leanings of those in the survey. Homeowners who identified themselves as Republicans cut energy use by just 0.4 per cent on average. And those Republicans who showed no practical interest in environmental causes – people who did not donate to environmental groups and did not choose to pay extra for renewable energy – even increased electricity use by 0.75 per cent.


Act of defiance

Wesley Schultz at California State University in San Marcos, one of the researchers behind the 2007 finding, is not surprised by the result. He says that some Republicans have a negative view of the environmental movement and so might want to distance themselves from a green-themed campaign. Using more electricity could be an act of defiance, whether conscious or subconscious.

The result does not negate the usefulness of such psychological “nudges”, adds Schultz. But it does suggest that feedback needs to be tailored to specific groups. “No one is immune to social pressure,” says Schultz. “Even among those that increased electricity use there is a nudge that would work.”

It is not clear what that nudge would be, however. It could be a focus on the financial savings that come with reduced electricity use, suggests Costa. Or it could be a pitch that equated less energy use with increased self-sufficiency, says Robert Gifford at the University of Victoria in British Columbia, Canada.

But such nudges simply may not work in conservative parts of the US, Costa concludes. She says that other energy-saving schemes will need to implemented as well, such as tougher building codes. Unlike nudges, which do not place a financial burden on homeowners and buyers, these other approaches can drive up the price of homes and so are not always popular. “It may be that we have to do other politically difficult things,” she warns.

Costa and Kahn’s paper was published last month on the website of the National Bureau of Economic Research.