Driving distracted may push our brains,
and our consciousness, to their physical limits
June 18, 2010
By Rachel Adelson
Welcome to your new home theater. Enjoy the cushy seats, wrap-around speakers, satellite radio, docking station for your smart phone and touch-screen display. Feel free to check e-mail, program the radio, look up restaurants or watch a movie. Just please—don’t kill anybody.
In today’s competitive market, auto makers and portable electronic device makers are providing an increasing array of technologies meant both to support driving and to provide information and even entertainment. The problem is that the “infotainment” isn’t just for back-seaters (i.e., restless kids). Now we can have Internet, including access to things like YouTube, on the dashboard—tempting even the most conscientious drivers.
These little luxuries distract hugely from the job at hand. Evidence is mounting like a 10-car pile-up that eyes off the road, hands off the wheel and minds on text-chatter can make safe drivers dangerous, with sometimes fatal consequences. The problem’s gotten so bad that Oprah Winfrey devoted a show last January to the subject, calling distracted driving “America’s New Deadly Obsession,” and in the spring, she started the “No Phone Zone” campaign.
Your Distracted Brain
One reason distraction-related crashes are growing so fast is that our brains and bodies can only go so far. Additionally, the mental process needed to drive requires several areas of the brain to work together, like dancers in a ballet. Distraction can disrupt this choreography. (Imagine Larry the Cable Guy trotting on stage during The Nutcracker.)
The problem is that when we’re driving, we may not consciously know if we’re distracted. Dr. David Strayer, a psychologist at the University of Utah, and other experts explain this phenomenon by noting that people tend to think they’re better-than-average drivers and multi-taskers, and thus may not recognize the impact of distracting activity.
Another expert, Dr. Linda Angell, points out this is partly because normal, routine driving seems automatic—when it really isn’t.
In fact, “routine driving is inherently multitasking by itself,” says Angell, who’s a professor at Wayne State University and president of Touchstone Evaluations, an independent research lab that evaluates products and their effects on human experience, including distraction and driving. “Driving may be highly practiced, but there’s a lot of unexpected activity going on all the time; it requires more attention than we may be conscious of.”
So, what’s really happening upstairs when you’re behind the wheel?
Highways and Byways of the Brain
Advances in technology, such as functional magnetic resonance imaging (fMRI), have allowed scientists to discover what parts of the brain become more or less active as we perform day-to-day tasks. Neuroscientists studying driving have used this imaging system to capture pictures of “the driving brain.”
Here’s some of what they’ve found:
Driving cranks up the brain’s motor cortex. This section helps control our motor skills. It activates movement of our hands, feet and head during driving.
The visual cortex deep inside the brain lights up. As drivers scan the scene, their eyes transmit sensory input to the brain, which makes sense of the world outside.
Driving activates the parietal lobes. Angell’s colleague, Dr. Li Hsieh, at Wayne State University (and a co-founder of Touchstone Evaluations) explains that these lobes coordinate visual and motor responses—making sure, for example, that you step on the brake for a stop sign.
Driving gooses a central cortical strip. Activations in this strip are associated with how we pay attention.
The frontal lobes serve as the big boss. Right at your forehead, this section coordinates responses and activity among all the different regions. It monitors and conducts your mental traffic, and is important for all behavior, including safe navigation on the road.
“That frontal cortex is responsible for maintaining task goals, updating information, keeping us on task,” Strayer explains.
But, the frontal cortex is like an overworked boss: it hates interruptions and may need longer to catch up after one. That’s why a ringing cell phone or text alert that might make a driver happy can make the big boss inside kind of slow. It’s an interruption of the mental ballet—producing another lane in the mental traffic to manage.
Unfortunately, driving may not always allow time for a slowed-down brain to catch up with changing conditions, such as a sudden stop ahead or a rain-slick road.
“The goal is to minimize distraction effects to allow people to compensate adequately,” says Dr. Richard Young, a professor at Wayne State University School of Medicine and another co-founder of Touchstone Evaluations.
Indeed, the human brain seems able to compensate for low-level demands—listening to soft rock, chatting lightly with passengers, mulling over work, as shown in real-world research on naturalistic driving from Virginia Tech Transportation Institute (VTTI).
But are we pushing it?
The Brain in Overdrive
Because of what happens in the brain—unknowingly to someone who is driving — distraction works a little differently than other dangerous driving mistakes, such as driving while intoxicated. Alcohol and drugs slow the entire nervous system and impair judgment in ways that a driver cannot turn off or compensate for (you cannot decide not to be drunk once you are inebriated). But some drivers may believe distraction is harmless, all the while taking eyes off the road, hands off the wheel and mind off the drive.
But as scientific and statistical studies together have shown, distractions can turn otherwise conscientious drivers into little more than crash-test dummies.
Strayer’s lab, for example, claims that driving and talking on a cell phone may compete for the same neural circuitry.
It could explain why, in simulated driving, cell phone conversations lead to worse driving than talking to a passenger.
Some scientists, such as Strayer, theorize that talking to someone not physically present may ignite your imagination, causing you to picture mental images that interfere with spatial processing, or your ability to size up what’s around you (kind of important in driving).
According to Strayer, eye-tracking studies show that undistracted drivers scan the world from side to side for input, but cell-phone drivers tend to stare straight ahead, not changing their glance patterns when needed. Glazed, somewhat dazed, “they look but don’t see,” he says.
It Goes Beyond Gadgets
It’s also not just cell phones and other “interactive” gadgets that compete for a driver’s attention. Strong emotions can distract. (After a divorce for example, crash rates are known to increase.)
Dr. Marcel Just, a professor at Carnegie Mellon University’s Center for Cognitive Brain Imaging, found that listening to spoken sentences dampened activity in certain parts of the brain. In his laboratory studies, people simulating driving while listening to spoken sentences had more “virtual” crashes and also veered more from the lane, compared to simulated driving with no listening.
“Technology that’s in the car but not related to driving,” Just notes, “is enabling risk that people greatly underestimate.”
Texting, for example, wins the toxic trifecta by taking eyes, hands and minds away from driving all at once. A Virginia Tech study showed that texting is 23 times (that is 2,300 percent) more likely to result in a crash than ordinary baseline driving.
There are other high-risk combinations. Dr. Young points out that if alcohol and drowsiness each make a driver four times more likely to crash than normal, together they raise the odds to 16 times more likely.
What does it all mean? Driving distracted just isn’t worth the risk.
Deterring Distraction Something that seems so simple — keeping eyes on the road, hands on the wheel — still somehow eludes millions of drivers. Here are easy tips on deterring distraction.
Rachel Adelson writes about technology and the science of behavior from her office near Toronto. Within an hour of finishing this story, she found herself driving behind someone putting on mascara at the wheel.