Does Multitasking Make You Smarter? What the Research Actually Shows

Does multitasking make you smarter? For almost everyone, no. Doing two demanding things at once makes you worse at both, and the people who multitask the most tend to be the worst at it. But one narrow kind of switching does help: deliberately setting a stuck problem aside, on a schedule, and coming back to it later. Researchers call the payoff reduced fixation. It's a real effect, and it's also the opposite of answering Slack while you write a proposal.

You've probably seen both versions of this argument. One camp says multitasking is ruining your brain. The other says "supertaskers" prove you can train yourself to juggle anything. Both camps cite the same handful of studies, and both get some of them wrong.

This article is the corrected version. An earlier version of this page made the second argument, and it was wrong in ways worth spelling out, because the mistakes are the ones most people make.

What the famous Stanford study actually found

In 2009, Eyal Ophir, Clifford Nass and Anthony Wagner at Stanford split students into heavy and light "media multitaskers," based on how often they used several media streams at once (TV while texting, email while browsing). Then they ran both groups through standard attention tests.

Many people expected the heavy multitaskers to be better at switching. They'd had the most practice, after all.

They weren't. The heavy multitaskers were worse at ignoring irrelevant information, worse at filtering out distractors held in memory, and, most surprising to the researchers, slower at switching between tasks. Nass later summarized the finding bluntly: the people who multitask the most are "suckers for irrelevancy."

The study gets cited both ways online, sometimes as proof that multitaskers have broader attention. There's a sliver of truth in that. Heavy multitaskers took in more of the environment. They just couldn't stop taking it in when it wasn't useful.

Nine years later, Melina Uncapher and Wagner reviewed the research that had piled up since. The picture was messier than the original study suggested: some experiments found no difference, and none could prove that multitasking causes weaker attention rather than people with weaker filtering being drawn to multitask. But where differences showed up, they mostly ran one way. Heavy media multitaskers did worse on working memory and sustained attention.

Translation: practice at multitasking doesn't make you good at multitasking. If anything, the habit and the weakness travel together.

Supertaskers are real, and you're almost certainly not one

The supertasker research is where the old version of this article went most wrong, so it's worth getting right.

In 2010, Jason Watson and David Strayer at the University of Utah put 200 people in a driving simulator and gave them a demanding memory-and-math task over a hands-free phone at the same time. As expected, nearly everyone got worse at both: slower braking, more following-distance errors, lower scores on the mental task.

Five people didn't. About 2.5% of the sample performed just as well on both tasks together as they did on each alone. Watson and Strayer called them supertaskers.

Here's what the old version of this page claimed: that supertaskers aren't outliers, they're people who trained their cognitive flexibility, and so you can become one too. Nothing in the research supports that. A follow-up brain-imaging study in 2015 (Medeiros-Ward, Watson and Strayer) found that supertaskers' prefrontal regions worked more efficiently under heavy load than those of matched controls. That reads as a difference in how they're built, not evidence of a training program anyone else can follow.

And the people who think they're supertaskers almost never are. In a 2013 study of 310 students, Strayer's group (led by David Sanbonmatsu) found that 70% rated their multitasking ability as above average. The students who scored highest on an actual test of juggling two tasks were the least likely to multitask in daily life. The ones who multitasked most were often the worst at it, and also the most impulsive and sensation-seeking.

So when you feel like you're good at doing two things at once, that feeling is not evidence. Ninety-seven or so out of every hundred people are paying a cost they can't detect.

Can you train yourself to multitask?

Partly, and only in a narrow way.

In a 2001 experiment, Eric Schumacher, David Meyer and colleagues at the University of Michigan had people practice two simple reaction tasks at the same time: respond to a tone with your voice, respond to a light with your hand. After several sessions, some participants got close to perfect time-sharing. They could do both tasks together nearly as fast as either alone.

The catch is in the word simple. Practice turned two specific tasks into near-automatic routines, which is the same reason an experienced driver can hold a conversation on an empty highway. It didn't build a general multitasking muscle. A large 2016 review of brain-training research (Simons and colleagues) found the same pattern across dozens of programs: people get better at the exact tasks they practice and show little improvement on anything else.

That's why the "train your switching muscle" pitch fails. You can automate a familiar pair of tasks. You can't train your way into writing a strategy memo while sitting in a negotiation.

Where switching actually helps: getting unstuck

None of this means you should grind on a single problem until it breaks. The research on when to switch is more interesting than the research on simultaneous multitasking, and it points somewhere useful.

In 2017, Jackson Lu, Modupe Akinola and Malia Mason ran a set of experiments at Columbia on task switching and creativity. Participants worked on two creative problems (for example, generating ideas for two different prompts). Some did one task then the other. Some switched whenever they felt like it. Some were made to alternate back and forth at fixed intervals.

The forced alternators did best. They produced more ideas and more original ones, on both open-ended and single-answer problems. The reason was fixation: once you've started down one line of thinking, it's hard to see another one. Stepping away for a while loosens that grip, and when you come back you notice approaches you'd been blind to. (A 2025 replication of the core result was recorded as successful.)

The most telling part came in later studies. When people were asked to choose a switching strategy, even when they were paid to pick whatever would make them most creative, they rarely chose to alternate. People reliably underrate the value of stepping away from a problem they're stuck on.

This fits a much older body of research on incubation. A 2009 meta-analysis by Ut Na Sio and Thomas Ormerod pooled 117 studies and found that taking a break from an unsolved problem reliably improves the odds of solving it, especially for creative problems, and especially when you've already worked on the problem for a while before stepping away. A 2012 study by Benjamin Baird, Jonathan Schooler and colleagues added a twist: people who spent the break on an undemanding task, one that let their minds wander, improved more on the problems they returned to than people who did something demanding, rested quietly, or took no break.

Related Reading: Breaks don't have to be productive to work. Here's why your most creative breakthroughs happen during "wasted" time.

Look closely at what all these studies have in common. Nobody did two things at once. The benefit came from sequence: work hard on a problem, leave it, come back. That's controlled task switching, and it's a different activity from multitasking, even though they get lumped together.

The cost nobody budgets for: attention residue

Switching helps when you leave a stuck problem. It hurts when you leave a problem you were actively making progress on, and the damage shows up in the next task.

In 2009, Sophie Leroy named this effect attention residue. When you switch away from unfinished work, part of your mind stays behind, still chewing on it. People in her experiments who moved to a new task before finishing the first performed worse on the second, because they were only partly there.

In a 2018 follow-up, Leroy and Theresa Glomb found that the effect gets worse when you expect to be rushed on your return. They also found a cheap fix. Before switching, take a minute to write a "ready-to-resume" note: where you stopped, what comes next, what's still unresolved. People who did this showed less residue and did better on the interrupting task. Writing the plan down let their minds let go.

Ernest Hemingway arrived at a version of the same trick decades earlier. In a 1935 piece for Esquire, he advised writers to stop each day while they were going well and knew what would happen next, so they could pick it up cleanly the next morning. He didn't stop at a dead end. He stopped with the next step already in view.

If you've ever noticed that an unfinished task keeps nagging at you, that's the same machinery. There's a whole body of research on why unfinished tasks stick in your head, and how a concrete plan quiets them.

Switching on purpose vs. switching on impulse

Psychologists have measured the basic cost of switching for decades. Joshua Rubinstein, David Meyer and Jeffrey Evans showed in 2001 that every switch carries a time cost, and that the cost grows as the tasks get more complex. Stephen Monsell's 2003 review found that some of that cost survives even when people know a switch is coming and have time to prepare. You pay something every time. The only question is whether you get something back.

Here's how the two kinds of switching compare:

	Impulsive multitasking	Controlled task switching
Trigger	A notification, boredom, an urge	A timer or a deliberate decision
What you switch from	Whatever you were doing, mid-flow	A problem you're stuck on
What you switch to	Anything that grabbed you	A planned second task, or something undemanding
What it costs	Switch time, plus attention residue on both tasks	Switch time, mostly offset by reduced fixation
What the research says	Worse filtering, worse memory, more errors	More ideas, more original ones, better odds on stuck problems

The worst case is two demanding tasks at the same time that draw on the same mental resources. Strayer's lab found in 2006 that drivers talking on a phone, even hands-free, were about as impaired as drivers at the legal blood-alcohol limit. No study of creative incubation rescues that.

How to use controlled task switching

If you want the benefit without the cost, the rules are short:

1. Work on the hard problem first, properly. Incubation helps most after a real attempt. A break from something you haven't started is just procrastination.
2. Have a second problem ready. The Columbia studies used two meaningful tasks, not one task and your inbox. Pick another piece of real work you can alternate with.
3. Switch on a timer, not on a feeling. People don't switch often enough on their own when they're fixated, and they switch too often when they're bored. A fixed interval takes the decision away from the part of you that's stuck.
4. Write a ready-to-resume note before you leave. One or two lines: where you are, what's next. This is the step that keeps a useful switch from turning into residue.
5. When you just need a break, keep it light. A walk, the dishes, filing. Undemanding tasks gave the biggest incubation boost in Baird's study. Doomscrolling doesn't count, because it's demanding enough to crowd out the background processing you want.
6. Never stack two demanding tasks at once. Writing during a meeting, reading email on a call, texting while driving. That's the multitasking every study above warns about, and feeling good at it is a warning sign.

The one-line version: focus by default, switch on purpose, and never do two hard things at once.

So does multitasking make you smarter?

No. Simultaneous multitasking makes almost everyone slower and more error-prone, the habit goes along with weaker attention, and the rare people who are truly good at it seem to be built that way rather than trained.

What does make you sharper is knowing when to walk away. A stuck problem is often a fixated mind, and the fastest way to unfixate is to work on something else for a while and come back on schedule, with a note telling you where you left off. That's not multitasking. It's using the switch instead of letting the switch use you.

Frequently Asked Questions (FAQ)

Does multitasking make you smarter?

No. Research since Stanford's 2009 study links heavy multitasking with worse filtering of distractions and weaker working memory, and people who multitask most tend to be worst at it. What does help is controlled task switching: deliberately alternating between problems on a schedule, which reduces mental fixation on creative tasks.

What is a supertasker, and can you become one?

Supertaskers are the roughly 2.5% of people in Watson and Strayer's 2010 study who did two demanding tasks at once with no drop in performance. Brain imaging suggests they process heavy load more efficiently than others. No research shows that ordinary people can train themselves into the group, and most people who think they're supertaskers aren't.

Is task switching the same as multitasking?

No. Multitasking means trying to do two things at the same moment, which the brain handles by switching rapidly and paying a cost each time. Controlled task switching means finishing a block of work on one problem, then moving to another on purpose. The research benefits apply only to the second.

How do I reduce attention residue when I have to switch?

Write a short ready-to-resume note before switching: where you stopped and what you'll do next. Sophie Leroy and Theresa Glomb found in 2018 that this one-minute step reduced residue and improved performance on the next task. Stopping at a point where you know the next step helps for the same reason.

Sources

1. Ophir, E., Nass, C., & Wagner, A. D. (2009). Cognitive control in media multitaskers. Proceedings of the National Academy of Sciences, 106(37), 15583–15587. https://doi.org/10.1073/pnas.0903620106
2. Uncapher, M. R., & Wagner, A. D. (2018). Minds and brains of media multitaskers: Current findings and future directions. Proceedings of the National Academy of Sciences, 115(40), 9889–9896. https://doi.org/10.1073/pnas.1611612115
3. Watson, J. M., & Strayer, D. L. (2010). Supertaskers: Profiles in extraordinary multitasking ability. Psychonomic Bulletin & Review, 17(4), 479–485. https://doi.org/10.3758/PBR.17.4.479
4. Medeiros-Ward, N., Watson, J. M., & Strayer, D. L. (2015). On supertaskers and the neural basis of efficient multitasking. Psychonomic Bulletin & Review, 22(3), 876–883. https://doi.org/10.3758/s13423-014-0713-3
5. Sanbonmatsu, D. M., Strayer, D. L., Medeiros-Ward, N., & Watson, J. M. (2013). Who multi-tasks and why? Multi-tasking ability, perceived multi-tasking ability, impulsivity, and sensation seeking. PLoS ONE, 8(1), e54402. https://doi.org/10.1371/journal.pone.0054402
6. Schumacher, E. H., Seymour, T. L., Glass, J. M., Fencsik, D. E., Lauber, E. J., Kieras, D. E., & Meyer, D. E. (2001). Virtually perfect time sharing in dual-task performance: Uncorking the central cognitive bottleneck. Psychological Science, 12(2), 101–108. https://doi.org/10.1111/1467-9280.00318
7. Simons, D. J., Boot, W. R., Charness, N., Gathercole, S. E., Chabris, C. F., Hambrick, D. Z., & Stine-Morrow, E. A. L. (2016). Do "brain-training" programs work? Psychological Science in the Public Interest, 17(3), 103–186. https://doi.org/10.1177/1529100616661983
8. Lu, J. G., Akinola, M., & Mason, M. F. (2017). "Switching On" creativity: Task switching can increase creativity by reducing cognitive fixation. Organizational Behavior and Human Decision Processes, 139, 63–75. https://doi.org/10.1016/j.obhdp.2017.01.005
9. Sio, U. N., & Ormerod, T. C. (2009). Does incubation enhance problem solving? A meta-analytic review. Psychological Bulletin, 135(1), 94–120. https://doi.org/10.1037/a0014212
10. Baird, B., Smallwood, J., Mrazek, M. D., Kam, J. W. Y., Franklin, M. S., & Schooler, J. W. (2012). Inspired by distraction: Mind wandering facilitates creative incubation. Psychological Science, 23(10), 1117–1122. https://doi.org/10.1177/0956797612446024
11. Leroy, S. (2009). Why is it so hard to do my work? The challenge of attention residue when switching between work tasks. Organizational Behavior and Human Decision Processes, 109(2), 168–181. https://doi.org/10.1016/j.obhdp.2009.04.002
12. Leroy, S., & Glomb, T. M. (2018). Tasks interrupted: How anticipating time pressure on resumption of an interrupted task causes attention residue and low performance on interrupting tasks and how a "ready-to-resume" plan mitigates the effects. Organization Science, 29(3), 380–397. https://doi.org/10.1287/orsc.2017.1184
13. Rubinstein, J. S., Meyer, D. E., & Evans, J. E. (2001). Executive control of cognitive processes in task switching. Journal of Experimental Psychology: Human Perception and Performance, 27(4), 763–797. https://doi.org/10.1037/0096-1523.27.4.763
14. Monsell, S. (2003). Task switching. Trends in Cognitive Sciences, 7(3), 134–140. https://doi.org/10.1016/S1364-6613(03)00028-7
15. Strayer, D. L., Drews, F. A., & Crouch, D. J. (2006). A comparison of the cell phone driver and the drunk driver. Human Factors, 48(2), 381–391. https://doi.org/10.1518/001872006777724471
16. Hemingway, E. (1935, October). Monologue to the maestro: A high seas letter. Esquire.

Updated October 2026. An earlier version of this article argued that multitasking builds cognitive flexibility and that supertaskers are trained rather than rare. That isn't what the research shows, and we've rewritten the piece accordingly. It also contained quotes and examples we couldn't verify, which have been removed.