Is Multitasking Limited by a Mental Bottleneck?

Our ability to multitask is limited by the prefrontal cortex

Join Our Community of Science Lovers!


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


Next to the many amazing feats our brain pulls off daily, its inferior ability to juggle a few simple tasks sticks out like a sore thumb. Now research from Vanderbilt University suggests that these limits on multitasking arise from slow processing in the prefrontal cortex, the brain’s central executive. Although the area has been known to be involved in multitasking, its exact role is a matter of debate.

Using functional MRI, the researchers found that when people were juggling two assignments, their prefrontal cortex appeared to deal with the tasks one by one—creating that familiar mental bottleneck—instead of processing them in parallel as do sensory and motor parts of the brain. With training the prefrontal activation time became shorter, cranking up the speed of the mental conveyor belt by about 10 times. Unfor­tunately, the researchers note, the benefits of training might not apply to tasks other than those specifically practiced. “It’s not like you become able to multitask [with drills]; it’s just that you become able to do each task very quickly,” says cognitive neuroscientist Paul Dux, now at the University of Queensland in ­Australia, who conducted the experiment.

SA Mind Vol 20 Issue 6This article was published with the title “Is Multitasking Limited by a Mental Bottleneck?” in SA Mind Vol. 20 No. 6 (), p. 7
doi:10.1038/scientificamericanmind1109-7c

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe