Jan. 24, 2013 -- Next time you see a driver talking on the cell phone and looking confident, you might want to change lanes.
People who often talk on cell phones while driving may think they are experts at such multitasking, but they are typically not, says researcher David Strayer, PhD, professor of psychology at the University of Utah.
In this case, Strayer and his colleagues found practice does not make perfect, or even close to it.
"The people who multitask the most seem to be the worst at it," he says, citing his study results. The study is published in PLOS ONE.
However, another expert who has studied the effects of distraction takes issue with the finding. It may only suggest that people who are more intelligent don't talk and drive, as they are aware of the risks, says Erik Altmann, PhD. He is an associate professor of psychology at Michigan State University.
Multitasking: Who's Good?
Strayer measured the multitasking ability of 277 college students.
He used a test that involves two tasks. The students had to remember a series of two to five letters. Each of the letters was separated by a simple math equation ("Does 2+4=6?") that they had to decide was true or false.
The students also ranked themselves on multitasking ability. They gave themselves a score, from zero to 100, with 50 termed average.
"Eighty percent said they were at or above average at multitasking," Strayer says. That's statistically impossible.
He jokes that it's akin to thinking they live in Lake Wobegon. That is the fictitious town of humorist Garrison Keillor, where the kids are ''all above average."
Students self-reported their multitasking, including cell phone use while driving. They also reported multitasking with media such as word processing and Web surfing.
They completed questionnaires that measured their impulsivity and sensation-seeking behaviors.
Multitasking: Study Results
Students who reported most often talking on the cell phone while driving actually scored 20% lower on the multitasking test than did those drivers who talked on the cell phone the least, Strayer says.
"Those who did the best on the multitasking test tended to talk and drive the least," he says. "They have the self-awareness of their own human limitations to realize it's not safe to talk or text and drive."
Strayer found certain behaviors more common among the frequent multitaskers. "The people doing it the most tend to be impulsive, sensation-seeking, and overconfident in their ability to do that," he says. "It validates your worst nightmare."
Impulsivity was related to overall multitasking, but not to talking and driving. Strayer says that indicates cell phone use in a vehicle is a deliberate choice.
Multitasking: More Perspective
Altmann of Michigan State takes issue with the test used to gauge multitasking. "It is purely a test of working memory capacity that happens to correlate very highly with IQ," he says. "It may or may not reflect multitasking ability."
"They may only show that someone who is smarter doesn't use the cell phone as much when they drive," he says.
Strayer, in response, says that the test is valid, one of many ways to measure multitasking. "It basically does measure the ability to juggle two tasks with different goals at the same time."
The self-reporting of cell phone use is another limitation of the study, Altmann says, as it may not be accurate.