08/22/2009 05:12 am ET Updated May 25, 2011

A Smiley Face (and Your Neighbors' Numbers) are Best Way to Save Energy

Ever wondered if those little placards on your hotel room sink, exhorting you to use less water or fewer towels 'for the environment' actually work?

The answer is, not very well. Robert Cialdini, a professor at Arizona State University, studied these hotel hints and found the following: asking people to conserve energy simply for the environment's sake was just a bit (12 percent) more effective than asking people to do it for the hotel.

But when the placard told current guests that the 'majority' of other guests staying in the same room had reused their towels, guess what? There was a 33 percent increase in 'response behavior' over the simple environmental message.

What Cialdini found, according to a story in this month's Atlantic, is that if people are aware of the social norm they will tend to adhere to it. Peer proof, Cialdini calls it, rather than peer pressure.

The more honest energy information people have, Cialdini says, the better they'll green their energy usage.

As the head scientist at a new company, Positive Energy, Cialdini is drawing on his research into this powerful motivator in order to help people lower their energy use. This is a timely idea, as reducing energy use is infinitely cheaper than building CO2-belching coal plants, but utilities haven't had too much luck in encouraging energy efficiency.

Positive Energy is sending Sacramento consumers reports (the local utility supplies the data and pays the tab) that praises them with smiley faces if they've used less electricity than the neighbors, and tells them exactly how much they've saved compared to neighbors with similarly-sized houses.

In Sacramento, in one year they've saved energy equivalent to taking 30 - 50,000 homes off the grid, Cialdini told NPR.

Cialdini thinks this kind of peer proof is the cheapest form of energy conservation we've got.

Read more about energy efficiency at TreeHugger and Planet Green
::Palin Says No Thanks to Energy Efficiency
::Forget Going Green Because It's the Right Thing to Do--Go Green to Make Your Neighbors Jealous
::Resolve for Energy Efficiency
::Beating the Energy Efficiency Paradox, Part I
::Beating the Energy Efficiency Paradox Part II

Read more from Graham Hill on Huffington Post
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::E-Bike: Car-Free Encouragement or Bike Balkanizer?
::Put Down That CAFO Pork Chop
::Your Ungreen Brain Needs More Nature