How to use the Zeigarnik effect to your advantage

Are you normal, or does it feel like you always have a thousand unfinished tasks bouncing around in your head, every day, all the time? Trim the hedges. Call your family. Don’t forget your niece’s birthday present. Write that report for your boss. Also, you need more yogurt.

Well it’s not you. It’s your brain.

Today, let’s talk about the Zeigarnik effect. I’ve been wrestling with it all month, so this post may be just as much for me as it is for anyone else.

And besides, “the Zeigarnik effect” is really fun to say and it illustrates an aspect of how our brains work that has a deep—but sometimes subtle—effect on our behavior.

Waiters, Soviet psychologists, and clay figurines

In a nutshell: the Zeigarnik effect is a cognitive bias that means unfinished tasks occupy more mental real estate than completed ones.

It’s what makes trying to remember to get yogurt and write your boss’s report so painful.

The effect was first documented by Soviet psychologist Bluma Zeigarnik in the 1920s. According to the—likely apocryphal, but fun to tell anyway—story, Zeigarnik noticed that waiters had an uncanny ability to remember complex orders, until they served them. Once an order was delivered, the details seemed to evaporate from their minds.

In her 1927 paper, “Über das Behalten von erledigten und unerledigten Handlungen” (On Retaining Completed and Unfinished Activities), Zeigarnik asked a bunch of study participants to perform tasks that required at least some mental investment—things like puzzles, math problems, and, oddly, making clay figurines.

She then interrupted some participants, while she left others alone.

Afterwards, she asked them to recall the activities they’d worked on. And what she found was that interrupted tasks were remembered significantly more frequently than the completed ones.

Sixty-four years later, Seifert and Patalano added a bit of nuance to the Zeigarnik effect. They found that if the interruption happened too quickly (15–30 seconds after the task began), then participants didn’t remember the task task as well. But once they’d gotten into it, the Zeigarnik effect stayed strong.

Tension and countertension

Psychologists have postulated that Zeigarnik’s findings suggest a tension system in our brains. The initiation of any task creates a tension (“this thing needs to be done; this thing isn’t done”) that we then need to resolve.

Which we can only do by completing the task.

Until resolution, the tension serves as a cognitive placeholder. We keep the task on file, at the front of our minds, until we finish it.

In other words, keeping the task unfinished takes up space in our working memory—and that has knock-on effects.

Back in med school, one of my professors compared our brains to a pumpkin truck (why? who knows…). He said that once that pumpkin truck got full, any new pumpkin that you put in meant that another pumpkin had to fall out.

Simplistic? Yeah. I mean, if he were right, what would the point of learning be? But a useful metaphor anyway. Those unfinished tasks? They’re bumping other pumpkins out.

Now, from an evolutionary perspective, this makes perfect sense. “Build a shelter” or “Defang the new baby saber-toothed tiger” had to stay at the front of our ancestors’ working memories. It was a matter of survival.

But since we’re no longer sewing animal pelts into clothing or making fire from scratch, the Zeigarnik effect may have outlived its usefulness.

The dark side of Zeigarnik

The pumpkin truck gets even worse in a hyper-connected world. Notifications, tasks, alerts, and assignments constantly compete for our attention. And that means that the tension system we first developed to remember to defang pet tigers now gets triggered by every unread email, every social media interaction, every task someone else adds to your list.

Soon enough, the road around us is littered with discarded pumpkins, and we end up suffering from what I call “completion anxiety.” The constant thrum of accumulated psychological tension from myriad incomplete tasks creates a background, constant, uninterrupted stress.

None of us makes good decisions under duress.

Make the Zeigarnik effect work for you

But all is not lost. Here are ways four ways to use the Zeigarnik effect to your benefit:

1. Starting creates commitment
When we start a task, we’re not just beginning an activity — we’re creating a psychological commitment. We’re creating tension. This is why all the productivity gurus tell you to “just start.” It’s why just waiting for the right time to do the thing is rarely successful. The mere act of beginning creates cognitive tension—and that eventually drives us toward completion.

2. Incomplete tasks consume mental resources
It’s the damn pumpkin truck. Unfinished tasks actively eat up our cognitive resources. This mental overhead can actually hinder our ability to make decisions well, and can reduce our focus on other tasks. That’s why multitasking can feel so mentally draining. We’ll talk about how to manage that tension in the next section.

3. Use interruption to your benefit
You know why athletes and musicians practice in chunks? You know why it’s better to study a little bit a day than to cram all at once? Because deliberately leaving tasks incomplete can actually improve retention. If you’re trying to learn something new, use the Zeigarnik effect to your benefit.

4. Create constant opportunities for tension to resolve
“Tension and countertension,” an old colleague used to say, “the keys to a good life, good marriage, and good surgery.” Tension is good—because resolution feels amazing. Ask any musician to imagine leaving a V7 chord unresolved and they’ll shudder. We. Love. Resolution. So take advantage of that frisson by resolving small tasks every morning.

Your turn: The Zeigarnik Audit

Time to make this practical. Let’s make an audit of your pumpkin truck.

1. Mental Download
—Take out a sheet of paper
—Without consulting any lists or devices, write down every unfinished task that comes to mind, in a list, on the left-hand side of the paper
—Don’t judge or organize. Don’t try to finish any task that comes to mind. Just capture everything

2. Task Analysis
Now, evaluate each pumpkin. Make three columns next to the task list: Frequency, Emotional Energy, and Importance. In each column, rank the task, 1–5, based on:
—How often it pops into your mind uninvited
—The emotional energy it consumes
—How important the task is to your current goals
Now circle any items with a significant mismatch between mental intrusion or emotional energy and actual importance.

3. Strategic Resolution
One last column, call it Action. This is where you’ll write what to do with each task. For each circled item, decide on one of four actions:
—Delete it: this task isn’t important. You have permission to abandon it.
—Delegate it: should this task actually be done by someone else? Then delegate it
—Schedule it: put this task in your system (see step 4)
—Do it: for the moment, only do this for a task that takes less than a minute to complete.

4. System Design
OK, so you’ve dealt with the current pumpkin truck. But how do you keep the stress from coming back? You’ve got to find a way to download the unfinished tasks into a system so that you aren’t constantly trying to remember them. My own personal system is a variant of bullet journalling. It looks like this:

Every morning, I write down the unfinished tasks in my pumpkin truck. By hand and by subject. Then, I tick them off as I go through the day. Any task that doesn’t get done that day gets re-written, by hand, the next day.

This accomplishes three things.

First, I’m constantly “touching” my tasks. I don’t write them in my phone’s to-do list for them to get pushed down by other, more immediate, tasks. Instead, I have to rewrite them every day—meaning I have to evaluate the importance of a task every morning.

Second, it also means I’m not always fighting forgetfulness. So much of the stress from Zeigarnik comes from trying to remember all the tensions that haven’t been resolved. With this system, I don’t have to do that. They’re written down, and they’ll still be there tomorrow. I don’t have to try to remember them.

Third, it means no pumpkins fall off a truck unless I specifically decide they’re no longer needed.

Loving your pumpkin truck

Try this for a week, and pay attention to how your mental energy shifts as you get a handle of your tasks. Remember: The most powerful insights often come from tracking your results over time.

Our brains aren’t perfectly rational computing machines. They’re complex systems shaped by evolutionary pressures and psychological needs. We can use them to our benefit.

Speaking of complex systems, in researching this particular article, I read all sorts of old psychological literature, including a paper from 1944 which included this glorious piece of science.

They don’t make papers the way they used to.

See you next week!

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Remember: Understanding cognitive biases like the Zeigarnik effect is just the first step. The real transformation happens when you apply these insights systematically in your daily life.