Experiment 09 · Famous experiments
The waiter who remembered only the bills not yet paid
A young psychologist found that people remembered interrupted tasks better than finished ones, an idea that is famous, useful and shakier than most people think.
- Bluma Zeigarnik and Kurt Lewin
- Berlin, Germany
- 1927
- 3 min read
On this page
Before you readWhat would you do?
It is late, and three unfinished jobs keep running through your mind: a report, a reply to a client and a bill to pay. What does the research suggest will help most tonight?
Pick an answer now. The file tells you whether you were right.
01The file in one minute
1Unfinished tasks linger
In Zeigarnik's 1927 study, people recalled interrupted tasks far more often than finished ones.
2Shakier than its fame
Repeats of the memory result have been mixed. The urge to return to an interrupted task holds up better.
3A plan closes the loop
A 2011 study found that writing a concrete plan for an open goal made it intrude on thoughts less.
4One thing to do
End each day by writing the next step for every unfinished task.
02Timeline
1920s
Kurt Lewin's group in Berlin studies how goals and tension shape behaviour.
1927
Bluma Zeigarnik reports that interrupted tasks are remembered better than finished ones.
1928
Maria Ovsiankina shows people tend to go back and finish interrupted tasks.
2011
Masicampo and Baumeister find that making a plan quiets thoughts about unfinished goals.
03The experiment
The story goes that the psychologist Kurt Lewin noticed something in a Berlin café. A waiter remembered every detail of orders that had not been paid, then seemed to forget them once the bill was settled. Lewin's student Bluma Zeigarnik turned that hunch into a study.
She gave volunteers a series of small tasks, such as puzzles, sums and making clay figures. Some tasks they were allowed to finish. Others she interrupted before they were done. Afterwards she asked people to list the tasks they could remember. In her 1927 paper, interrupted tasks were recalled much more often than finished ones, close to twice as often.
A year later another of Lewin's students, Maria Ovsiankina, showed a related effect: people who were interrupted often went back to finish the task when given the chance, even with nobody asking them to.
04What it showed
Lewin's explanation was that starting a goal creates a kind of tension that stays until the goal is met. The unfinished task keeps nagging. That idea fits everyday life well: the email you meant to send and the form half filled in.
The evidence is less tidy than the story. Later attempts to repeat the memory result gave mixed results, and reviews have found weak support for a reliable memory advantage. The urge to go back and finish an interrupted task holds up better. A 2011 study by E. J. Masicampo and Roy Baumeister added a practical twist: writing a specific plan for an unfinished goal reduced how much it intruded on people's thoughts.
For anyone juggling work, the useful part is that last finding. An open task does not need to be finished to stop nagging. It needs a written next step.
The idea behind this caseLesson: Meetings and notes →
05What it means when you use AI
- At the end of the day, write each unfinished task with one concrete next step and when you will do it.
- Keep one trusted list instead of carrying open loops in your head.
- When you stop in the middle of a piece of work, leave yourself a short note on exactly where to restart.
- An AI assistant can turn a messy brain dump into a list of next steps. Read it, fix it and make it yours.
07 — Sources
- Zeigarnik effect · Wikipedia · 2026
- Consider it done! Plan making can eliminate the cognitive effects of unfulfilled goals · Journal of Personality and Social Psychology · 2011