By Bruce Bower
Cell phone users frequently drive themselves to distraction while operating cars, and all too often end up in traffic accidents. But a select few multitask behind the wheel with extraordinary skill, a new study finds.
About one in 40 drivers qualifies as a “supertasker,” able to combine driving and cell phone use without impairing performance of either activity, say psychologists Jason Watson and David Strayer, both of the University of Utah in Salt Lake City. These unusual exceptions to the general rule that performance declines when a person does two things at once (SN: 3/13/10, p. 16) may offer insights into the workings of attention and mental control, Watson and Strayer propose in an upcoming Psychonomic Bulletin & Review.
Laboratory tests of 200 volunteers operating a driving simulator identified five extraordinary individuals. These people were good drivers: They hit the brakes quickly in response to cars that slowed in front of them and maintained a safe distance from other cars. They also excelled at solving simple math problems and remembering words heard over a hands-free cell phone when not driving. Critically, their performance on these tasks stayed just as high while driving and using cell phones at the same time.
“Supertaskers did a phenomenal job of performing several different tasks at once,” Watson says. “We’d all like to think we could do the same, but the odds are overwhelmingly against it.”
Watson and Strayer studied college students, ages 18 to 43. After learning to operate a driving simulator on a virtual highway, participants followed an intermittently braking pace car driving in the right-hand lane. For each volunteer, the researchers measured time needed to depress the brakes when the pace car slowed and distance from the pace car throughout the trip.
In a separate trial, participants listened through hands-free cell phones as an experimenter read two to five words interspersed with simple math problems that had to be immediately labeled as true or false. Volunteers then tried to recall words in the order that they were presented.
As expected, overall group performance declined markedly when driving and the cell-phone task were performed at the same time. Volunteers took an average of 20 percent longer to hit the brakes when needed, and increasingly fell behind the pace car. Word recall fell by 11 percent and math accuracy declined 3 percent.
But the handful of supertaskers maintained their braking times, following distances and math accuracy while multitasking. Their word recall rose 3 percent.
Stanford University sociologist Clifford Nass wonders whether supertaskers in the new study prefer doing many things at once in their daily lives. He and his colleagues have found that young adults who often multitask — say by regularly sending text messages while navigating websites and watching television — perform worse when switching back and forth between two mental tasks than peers who rarely multitask. Frequent multitaskers have difficulty ignoring information irrelevant to a task at hand, Nass argues.
That leads Nass to the somewhat surprising conclusion that supertaskers tend not to juggle multiple duties and don’t need to practice multitasking to be good at it.
Researchers need to explore whether supertaskers jointly simply perform well-learned abilities the same way everyone else does but with far more efficiency, or instead deploy mental resources in distinctive ways, says psychologist Randall Engle of Georgia Tech in Atlanta.
Watson and Strayer plan to do that by comparing various measures of brain activity for people who do and don’t rank as supertaskers.
