Let’s say you want men to stop accidentally peeing on the floor instead of in urinals in an airport bathroom. (Dubner is fascinated with airport bathrooms, so I’m sure he could think of some incentive schemes.) Or maybe someone could invent a new urinal. The choice architects have an easier solution: paint a fly in the urinal. It turns out with something to aim at, “spillage” is reduced 80 percent.
--Steve Levitt, Freakonomics blog, on a great idea from the new book Nudge