InTransition Magazine
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InTransition Magazine : Transportation Planning, Practice & Progress

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Social Nudges

All of us seek the approval of others in large and small ways, often without being conscious of it. Studies have found that people are quick to abandon their best judgment in answering a question if they feel they are out of step with other test takers. It is not surprising therefore that if we are informed about how we compare with others, we can be nudged to change our behavior.

Jani Helle

Social psychologist Robert Cialdini used this insight to start a company, Positive Energy, to help utilities reduce energy use by customers. In one test, Sacramento residents who received mailings about how their energy use compared to their neighbors reduced their annual energy consumption by more than 2 percent—a significant amount, equivalent to the energy use of 700 homes. The simple use of a “smiley face” graphic on the mailings, indicating social approval for those using less energy, boosted cooperation further. (In the U.K., many speed radar signs have been programmed to display a smiley face or frown in the hopes of providing a social nudge to drivers to comply with speed limits.)

Direct peer pressure is the strongest of social nudges. Realizing this, many companies have formed “green teams” to motivate cooperation among employees to cut carbon emissions through recycling, carpooling, use of mass transit and walking/biking. Yahoo and other companies in Silicon Valley have been early adopters. 

Poland Spring used a social nudge to reduce truck idling. Compiling data from onboard computers, it posted a ranking of drivers’ idling times in the break room. A gift card was provided to the 10 lowest idlers. Idle-time dropped by over half in two years, saving thousands of dollars. “Human nature, no one wants to be at the bottom of the list,” a manager explained on

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