Brain & Nervous System Health Center

97.5% Can't Drive Safely While Using Cell Phones

March 31, 2010 -- Driving while talking on a cell phone is extremely hazardous for most people, and only a tiny fraction of “supertaskers” can do both simultaneously without any ill effect, a new study says.

University of Utah psychologists found that only 2.5% of people they studied could successfully drive and use a cell phone at the same time. Most people -- 97.5% -- aren’t able to drive like they should if they’re talking on a cell phone, researchers say.

The findings don’t mean that supertaskers are smarter than most folks, but probably that genetic factors are at play, making some people better able to do two or more things at once, one of the study authors, Dave Strayer, PhD, tells WebMD.

“We were excited to find this small group of people with extraordinary multitasking ability,” Strayer says. “We hope comparing them with the rest of us will help us better understand how the brain coordinates multitasking.”

Co-author James Watson, PhD, says they used the term “supertasker” to describe multitasking ability. He says the odds are “overwhelmingly against” most people being multitaskers -- “about as good as your chances of flipping a coin and getting five heads in a row.”

The researchers analyzed the performance of 200 participants over a single task -- driving a simulated car on a virtual freeway. Then the same people got behind the wheel and were assigned a second, demanding activity -- a cell phone conversation that involved them memorizing words and solving math problems.

Watson and Strayer measured performance of the participants in four areas -- braking reaction time, following distance, memory, and ability to solve the math problems.

Results showed that for most people in the group, performance suffered across the board when they drove while talking on a hands-free cell phone.

It took most people 20% longer to hit the brakes and increased following distances 30%, meaning they failed to keep pace in the simulator with virtual traffic. Also, their memory performance dropped 11% and their ability to do the math fell 3%.

But for a few, it was all a snap. They displayed no change in normal braking times, following distances, or math ability, and memory actually improved 3%, the researchers say.

The findings are published in the journal Psychonomic Bulletin and Review.

The researchers say the results were in line with Strayer’s previous studies showing that driving performance routinely declines when people talk on cell phones, even to the point of being on a par with the impairment seen in drunken drivers.

Yet the supertaskers managed just fine.

The Study of Supertaskers

Watson and Strayer have collected brain scan data (by functional magnetic resonance imaging) on all participants and hope to get a better understanding of brain differences that might explain why a few people can multitask while most cannot.