Register for an account

X

Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.

X

Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

Mind

Key Brain Section Never Multitasks—It Just Switches Very Fast

80beatsBy Aline ReynoldsJuly 20, 2009 2:00 PM
brainzerweb.jpg

Newsletter

Sign up for our email newsletter for the latest science news

As much as we humans like to think we can do two things at once, our brains can only process one thing at a time—like the iPhone—but we can get better at switching between the two tasks, according to a study published in Neuron. Previous studies showed that multitasking activates the brain's prefrontal cortex, or PFC. This area has been found to be the "bottleneck" that can limit the speed at which we multitask, and it becomes less active as we practice doing two things at once. The prevailing theory for that decreased activity had been that

when we practise a task, the brain starts to automatically reroute information from the PFC to regions that are more directly involved [Nature News].

To investigate, researchers used fMRI scans to monitor brain activity by tracking blood flow while subjects multitasked, and found evidence that the previous theory was incorrect. The scientists found that a junction in the PFC which passes signals to other brain regions responsible for performing each task

responded earlier and for a shorter duration than before [in volunteers who had practiced multitasking], indicating it was processing information more quickly. "This suggests our brain becomes better at the task with training, not by reducing the dependence on [the PFC] but rather by improving the processing efficiency [of each task] through this bottleneck," says Marois, who acknowledges that other regions are also likely to be involved [Nature News].

The study also contradicted another theory of how we become more efficient multitaskers. That theory predicted that with practice, the brain learns to designate separate clumps of neurons, or brain cells, to perform the different tasks, instead of relying on the same cells to process information for both of them. This study, however, found no evidence of distinct groups of neurons operating in parallel, and instead showed that the same neurons are simply operating faster.

So we’re switching tasks quickly enough to appear to be doing them simultaneously [Scientific American].

Related Content: 80beats: New Theory of Alzheimer’s: Brain’s Memory Center Is “Overworked” 80beats: Researchers Can Find Out Where You Are by Scanning Your Brain 80beats: God on the Brain: Researchers Probe the Neural Circuitry Behind Religious Beliefs

Image: flickr / Liz Henry

    2 Free Articles Left

    Want it all? Get unlimited access when you subscribe.

    Subscribe

    Already a subscriber? Register or Log In

    Want unlimited access?

    Subscribe today and save 70%

    Subscribe

    Already a subscriber? Register or Log In