A gym’s locker room had two towel bins. The gray bin was close to the lockers. The black bin was twenty feet away, around the corner, and not very visible to tired athletes.

The management want to keep the locker room clean, so they put a sign on each bin that said, “Please use other bins when this one is full.” Unfortunately, everyone piled their dirty towels on the floor around the gray bin. The black bin was simply harder to reach.

The management eventually moved the black bin next to the gray one. Both bins sat close to the lockers, easy to reach, and everyone put their dirty towels in a bin. Problem solved.

When developing software, we can encourage particular actions by making them easy. Humans often take the path of least resistance, so we as designers and developers should make that path the good one. Every decision requires mental effort, after all.

For example, Twitter wants users to “follow” other users, so they made a prominent “follow” button on every users’ profile. There’s no email confirmation barrier. Just the tap of a button. Easy.

Defaults are another powerful way to encourage behavior. Practically every website puts new users on its mailing list (though they can opt-out). If customers had to actively ask to join a mailing list, there would be far fewer shoppers receiving cookie dough promotions. In this way, defaults can be used for good and bad.

In short, put the towels bins where they’re easy to reach.

Make things easy.