An Overview of the Zeigarnik Effect and Memory

Have you ever found yourself interrupted by intrusive thoughts about unfinished work? Perhaps they were about a partially finished work project keeping you up at night or the plot of a half-read novel that keeps circling your thoughts. There is a reason why it's so hard to stop thinking about uncompleted and interrupted tasks. Psychologists refer to this as the Zeigarnik effect, or the tendency to better remember unfinished tasks than completed ones.

The Zeigarnik Effect

When you start working on something but do not finish it, thoughts of the unfinished work continue to pop into your mind even when you've moved on to other things. Such thoughts urge you to go back and finish the thing you have already begun. It's why you keep thinking about that page-turner. Or why you want to finish playing a video game until you win. Unfinished work continues to exert an influence, even when we try to move on to other things.

Soap operas and serialized dramas also take advantage of this effect. The episode may end, but the story is unfinished. Cliffhangers leave viewers eager to learn more, and thanks to the Zeigarnik effect, they will remember to tune in next time to find out what happens.

You have probably also experienced this effect while in school. Before an exam, you probably had fairly good recall for the information that you were studying. After an exam, however, students often have difficulty remembering all of the things that they studied. Because you no longer have immediate use for it, the information sometimes feels like it has been flushed out of your memory.

How Was It Discovered?

The effect was first observed and described by a Russian psychologist name Bluma Zeigarnik, a student of influential theorist Kurt Lewin. While sitting in a busy restaurant in Vienna, she noted that the waiters had better memories of unpaid orders. Once the bill was paid, however, the waiters had difficulty remembering the exact details of the orders.

Zeigarnik's Research

In a series of experiments, participants were asked to complete simple tasks such as placing beads on a string, putting together puzzles, or solving math problems. Half of the participants were interrupted partway through these tasks.

After an hour-long delay, Zeigarnik asked participants to describe what they had been working on. She discovered that those who had their work interrupted were twice as likely to remember what they had been doing as those who had actually completed the tasks. 

In another version of the experiment, she found that adult participants were able to remember the unfinished tasks 90 percent more often than they did the finished tasks. Zeigarnik's initial studies were described in a paper titled "On Finished and Unfinished Tasks" published in 1927.

Further Research Exploring the Effect

During the 1960s, memory researcher John Baddeley further explored these findings in an experiment. Participants were given a limited period of time to solve a set of anagrams. When they could not solve the anagram before the time was up, they were given the word answer.

When the participants were later asked to recall the word in the anagrams, they showed better memory for the words that they had not solved. This supports Zeigarnik's finding that people have a better memory for unfinished or interrupted information.

Conflicting Research

Not all research has found support for the effect, however. Some studies have failed to show the same effect and other researchers have found that there are a variety of factors that can influence the strength of the effect. For example, studies have shown that motivation can play a major role in how well people remember information.

How Does It Work?

Short-term memory is limited in both capacity and duration. Typically, we can only manage to retain so many things in memory, and even then we need to keep rehearsing the information in order to hold on to it. This requires quite a bit of mental effort. Not surprisingly, the more you are trying to keep in your memory for the short-term, the harder you have to work to get it to stay put.

Waiters, for example, have to remember a lot of details about the tables they are serving. Information about what people ordered as well as what they are drinking needs to remain in their memory until the customers have finished their meals.

To deal with this overload of data, people often rely on a number of mental tricks that allow them to better remember a great deal of information. The Zeigarnik effect is one example of this. We hold on to this information in the short-term by constantly pulling it back into awareness. By thinking of uncompleted tasks often, we better remember them until they are complete.

But this effect does not just impact memory in the short-term. Unfinished tasks such as goals that we still have to reach can continue to intrude in our thoughts over extended periods of time.

The Zeigarnik effect reveals a great deal about how memory works. Once information is perceived, it is often stored in sensory memory for a very brief time. When we pay attention to information, it moves into short-term memory. Many of these short-term memories are forgotten fairly quickly, but through the process of active rehearsal, some of this information is able to move into long-term memory.

Zeigarnik suggested that failing to complete a task creates underlying cognitive tension. This results in greater mental effort and rehearsal in order to keep the task at the forefront of awareness. Once completed, the mind is then able to let go of these efforts.

The Psychology of Forgetting and Why Memory Fails

How to Make the Most of It

More than just being an interesting observation about how the human brain works, the Zeigarnik effect can actually have implications in your day-to-day life. You can even use this psychological phenomenon to your advantage.

Common sense might tell you that finishing a task is the best way to approach a goal. The Zeigarnik effect instead suggests being interrupted during a task is an effective strategy for improving your ability to remember information.

Get More Out of Your Study Sessions

  • If you are studying for an exam, break up your study sessions rather than try to cram it all in the night before the test. By studying information in increments, you will be more likely to remember it until test day.
  • If you are struggling to memorize something important, momentary interruptions might actually work to your advantage. Rather than simply repeat the information over and over again, review it a few times and then take a break. While you are focusing on other things, you will find yourself mentally returning to the information you were studying.

Overcome Procrastination

  • Oftentimes, we put off tasks until the last moment, only completing them in a frenzied rush at the last possible moment in order to meet a deadline. Unfortunately, this tendency can not only lead to a great deal of stress, but it can also result in poor performance.
  • One way to overcome procrastination is to put the Zeigarnik effect to work. Start by taking the first step, no matter how small. Once you've begun—but not finished—your work, you will find yourself thinking of the task until, at last, you finish it. You might not finish it all at once, but each small step you take puts you closer to your final goal.
  • This approach can not only help motivate you to finish, but it can also lead to a sense of accomplishment once you finally finish a job and are able to apply your mental energies elsewhere.
How to Stop Procrastinating

Generate Interest and Attention

  • Advertisers and marketers also utilize the Zeigarnik effect to encourage consumers to purchase products. Filmmakers, for example, create movie trailers designed to attract attention by leaving out critical details. They draw the viewers' attention but leave people wanting more. In order to obtain all the details, people must then venture out to the box office or buy the movie once it comes out on home release.
  • Television programs also make use of this strategy. Episodes often end during a moment of high action, leaving the fate of characters or the outcome of the situation unresolved. In order to resolve the tension created by such cliffhanger endings, viewers have to remember to tune in for the next episode to find out what happens.

Promote Mental Well-Being

  • As you might imagine, the Zeigarnik effect is not necessarily always beneficial. When you fail to complete tasks, they can prey on your mind, intruding on your thoughts and creating stress. These invasive thoughts can lead to feelings of anxiety and contribute to sleep disturbances.
  • However, the effect can also play a role in overcoming such difficulties. Repeated thoughts can motivate people to finish the tasks they have started. Completing these tasks can then lead to feelings of accomplishment, self-esteem, and self-confidence.

A Word From Verywell

The Zeigarnik effect began as a simple observation of how restaurant waiters deal with customer orders. Subsequent research has offered support to the idea that, at least in some instances, we have a tendency to better recall unfinished tasks than completed ones. While there are many factors that can influence the occurrence of the effect and its strength, you can utilize knowledge in a number of ways. By taking deliberate breaks while working on a project, you may find that you are able to better remember important details.

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Article Sources
  • Denmark, FL. Zeigarnik Effect. The Corsini Encyclopedia of Psychology. New York: John Wiley & Sons; 2010.

  • Syrek, CJ & Antoni, CH. Unfinished tasks foster rumination and impair sleeping—Particularly if leaders have high-performance expectations. Journal of Occupational Health Psychology. 2014;19(4):490-499. DOI: 10.1037/a0037127.