You never know when a casual lunch may make you famous. One day in 1927, the psychologist Kurt Lewin was finishing up a meal with colleagues, and called the waiter over to ask for the bill. The waiter unhesitatingly told them how much they owed. A few minutes later, on a hunch, Lewin called him back and asked how much their bill had been. Now, the waiter had no idea. Intrigued, Lewin’s colleague Bluma Zeigarnik ran some experiments back at her lab.
She got people to perform a batch of little tasks, like solving puzzles, and interrupted some of them halfway through. Then she asked all the subjects which activities they remembered. Her conclusion was that people tend to remember uncompleted or interrupted tasks better than completed ones—an observation now widely known as the Zeigarnik effect.
That may seem a bit obvious once you think about it—a problem we’re still in the process of solving sticks in the mind more than one we are done with—but the Zeigarnik effect is used from academia to advertising. Research on the affect of the effect has been deployed to explain what makes Tetris so addictive, how suspense keeps movie audiences interested, and how commercials can be made more effective. In fact, the notion that leaving something incomplete makes it more memorable has even been known to induce magazine writers to …
