"Nudges" can be used to influence people's eating choices, for example. In a recent experiment on Good Morning America, a camera was set up in the break room to observe employees eating from a catered spread of doughnuts and fruit. The first day, the majority went for the doughnuts (only a third went for the fruit).
The next day, the fruit was elevated on a pedestal dish—and more people opted for the fruit. When signs were posted citing that the average American consumes fruit for breakfast, and even more people went for the fruit.
What nudge that made the biggest difference? Mirrors! Mirrors were hung on the wall behind the food, and the group consumed far more fruit than any other day. Hardly any went for the doughnuts. See clip here.