Multiple behavioral studies have demonstrated our difficulties with multi-tasking. A new study provides the neurological mechanisms for those findings (and more behavioral data, of course!).
From the LiveScience article:
For those who find it tough to juggle more than a couple things at once, don’t despair. The brain is set up to manage two tasks, but not more, a new study suggests.
That’s because, when faced with two tasks, a part of the brain known as the medial prefrontal cortex (MFC) divides so that half of the region focuses on one task and the other half on the other task. This division of labor allows a person to keep track of two tasks pretty readily, but if you throw in a third, things get a bit muddled.
The new work does not, however, show that the brain can actually execute two distinct tasks, such as letter matching, at precisely the same time, Paul Dux a psychology lecturer at the University of Queensland in St. Lucia, Australia, noted in an email to ScientificAmerican.com. The data reveal that though separate goals might be running concurrently in the brain, “there are still large dual-task costs” when people have to switch between two tasks making for “non-efficient multitasking,” cautioned Dux, who was not involved in the new research but has also studied attention in the brain. (Some commonplace activities, such as driving and talking on a cell phone frequently go hand-in-hand, but the brain is likely switching its main focus quickly between the two activities, perhaps a reason the pairing has been so dangerous.)
The tasks in the imaging study were letter and word matching tasks and appeared to require controlled processing. These types of tasks are resource demanding, error prone, and performed serially. I’ll go on record as saying I’d expect different results with more than two tasks trained to automaticity and with non-overlapping resource demands.
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