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For Safe Driving, Are All Distractions Created Equal?

A new study confirms that texting and driving is incredibly stupid.

By Nathan Collins


(Photo: Jason Weaver/Flickr)

Distracted driving—everything from eating a hamburger to talking on the phone—is the culprit behind thousands of deaths and hundreds of thousands of injuries every year in the United States. But new research suggests that not all distractions are created equal: Our brains can actually compensate somewhat for certain diversions—though texting is not one of them.

“There has been a lot of emphasis, and rightly so, on texting while driving,” says Ioannis Pavlidis, director of the Computational Physiology Laboratory at the University of Houston and lead author of the new study. “But there has not been equal emphasis … on distraction in general.” The question he poses is whether a heated argument or a challenging math problem could present a threat to safety on par with texting—and if not, how come?

To find out, Pavlidis and his colleagues sat 58 people down in a driving simulator and gave them various challenges—math and other questions requiring analytical reasoning, emotionally intrusive questions (“Have you ever lied to a man or woman to get them to go out with you?”), and, of course, requiring that they respond to texts. Meanwhile, Pavlidis and his team tracked the drivers’ stress levels with thermal cameras aimed at their noses—that’s where people sweat when they’re stressed out—while simultaneously tracking their driving.

Only texting led to noticeably worse driving.

Going in to the experiment, the researchers had thought that each of the different distractions would be stressful and therefore bad for driving. That was true to a point. Solving analytical problems, answering emotional questions, and texting all made drivers sweat more, and in turn made their steering more jittery. The stressors, Pavlidis says, “did their job.”

But only texting led to noticeably worse driving, including more swerves into other lanes and a generally diminished ability to keep the car moving in a straight line. Despite the stress, those who faced mental or emotional challenges drove just as well as those who faced no stressors at all.

Some basic features of our physiology may be to blame. A certain, small amount of shaking is actually necessary for normal movement, Pavlidis says, and the brain is set up to compensate for those movements—a little jitter to the left gets quickly corrected by a little jitter to the right. That mechanism appears to be enough to compensate for mental and emotional stresses while driving.

But “if for a moment this mechanism fails … this jitter is left uncorrected,” Pavlidis says, and that’s when people start driving erratically. If drivers are physically distracted—in particular, if they’re focused on typing out messages on a phone and looking away from the road—a small jitter could become an unexpected trip into oncoming traffic.

In fact, the researchers found, it’s a bit worse than that. Even after drivers had stopped texting, they remained more stressed and their steering remained a bit less stable than normal, making them perhaps a bit more prone to accidents. While texting at a stoplight might not be as bad as texting on the highway, it’s still a pretty bad idea, Pavlidis says.

In turn, heated discussions—and math problems—might not be the worst thing for driving, provided your physical resources stay focused on driving.