A 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.
Feeling overwhelmed? Juggle your to-do list like a multitasking pro with this expert advice:
Don't Try to Learn
"Results are always worse when you multitask, but in some areas they're especially compromised," says Russell Poldrack, PhD, associate professor of psychology at UCLA. Learning takes a big hit, for instance. "Our research shows that if you try to master something while splitting your attention, brain activity switches regions—from memory building to short-term habit making," he says.
A good rule of thumb is to multitask what you want to execute, rather than absorb, and choose jobs where mistakes won't matter.
Pair Different Kinds of Task
It may seem counterintuitive, but similarities make multitasking harder, according to Poldrack. Before getting to the bottleneck, mental processes often originate in different parts of the brain. Pick two from the same area and they can become garbled. For example, you may enjoy reading with music on, but if you time yourself, you'll likely turn the pages much faster when there are no lyrics to distract you from the text.
Try to match projects with different modalities—like reviewing a report while on the stationary bike.
Israeli Air Force cadets trained to pay attention to specific aspects of a video game performed better in actual flight than others who just played the game, one study showed. "Focusing on each task's relative importance allows you to allocate your resources for maximum efficiency," says Poldrack.
Make One Job Routine
Tech-dexterous teenagers are probably no better wired to ace computer games than the rest of us; they've just spent more time practicing with their gadgets, says Marois. Researchers believe that if you repeat a set of skills over and over in exactly the same order and way, you will get noticeably better.
Try to make at least one task something you do all the time. This allows you to fit the others into an already established pattern.
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