Why Cell Phones and Driving Don't Mix
Research Shows Brain Has Limits for Multiple, 'Intensive' Tasks
June 29, 2005 ? Years ago a cruel joke suggested that President Ford couldn't chew gum and walk at the same time.
Silly, of course, but it turns out that there was a bit of truth in it. Not just for Mr. Ford, but for all of us.
Any time we try to perform two things at once, one performance suffers, albeit only slightly when it comes to nearly brainless tasks like walking and chewing at the same time. The going gets tough, though, when either task becomes more demanding.
Take talking on a cell phone while driving a car, for example, and this is not part of an anti-cell phone crusade. New research shows, however, that the price we pay for trying to listen intensely comes at the expense of our ability to see clearly.
When we turn the "listening knobs" up, says psychologist Steve Yantis of Johns Hopkins University, we turn the "visual knobs" down.
It doesn't make any difference if the phone is hands-free. It's the listening that makes the difference, not the nature of the instrument.
Made for Multitasking ? to a Point
That may be a tad surprising because we humans pride ourselves on being able to carry out more than one task at once, or multitasking, as they say in the computer biz. In fact, some research suggests we are the only animals that have developed high skills at multitasking.
"People definitely are optimized for handling multiple tasks," says Yantis, who has spent years studying how we control the flow of information into our brains, and what we do with it when we've got it. "We've evolved to be effective multitaskers because it's useful to be able to do multiple things at once to be able to survive. But there are limitations."
Yantis and his team of researchers have been using one of the most effective tools in the field of cognitive science, functional magnetic resonance imaging, to look inside the brains of their subjects during various experiments. Different parts of the brain literally light up, showing such things as increased blood flow, when the subjects are given different tasks.
The evidence shows clearly that when the participants concentrated on listening, the part of the brain that controls vision became less active, and vice versa.
It's as though we have a certain amount of gray matter, and if we're going to put a lot of it in our listening basket, we're going to have to take it from somewhere else.