You can, as the song says, bring home the bacon, fry it up in a pan, do eight things at once (seven more than your man). But as you'll discover, more is not merrier.

"Where's the restaurant we're meeting at?" Your husband's on the phone as you scramble to finish a last-minute client proposal and root around for your lipstick. You give him directions while reading the five e-mails your boss just sent and trying to decipher the "something came up" text message from the babysitter. Multitasking has practically become an Olympic sport. But new science suggests it's not always a winning game.

A recent study in the British Medical Journal, for example, found that people talking on cell phones while driving were four times more likely to have car accidents resulting in hospitalization than other motorists. Road safety may be an extreme example, but it underscores a larger point. Research shows that we consistently perform better and faster when tasks are done successively, rather than all at once. A new study is shedding light on why. "We've identified a kind of bottleneck in the prefrontal cortex of the brain that forces people to address problems one after the other, even if they're doing it so fast it feels simultaneous," says René Marois, PhD, associate professor of psychology and neuroscience at Vanderbilt University and coauthor of the study. "This explains why previous data shows brain activity going down instead of up with each new challenge—it's like a mental traffic jam." Unfortunately, life isn't slowing down.

From the August 2007 issue of O, The Oprah Magazine

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