With miles of highway ahead, and not much else to do, the car might seem like an ideal spot to multitask. And of course, you wouldn’t dream of texting and driving—we’ve all heard those warnings. But thanks to your hands-free device, chatting on the phone can still be convenient and safe…right?
Not according to a new study published in Frontiers in Human Neuroscience. Researchers from St. Michael’s Hospital in Toronto, Canada, wanted to find out what our gray matter looks like while we drive under various conditions. To do it, they popped a fake car inside an MRI, complete with a steering wheel, accelerator, and pedals. “We made it as immersive as humanly possible,” says study co-author Tom Schweizer, PhD, director of neuroscience research at St. Michael’s.
As 16 participants took the car for a spin, researchers tracked their brain activity. And while commuting might feel monotonous from the driver’s seat, it’s something of a gymnastic feat for your brain. The MRI results revealed that turning left requires much more brain activation than does turning right, and during traffic, the move is even more difficult. “It was very, very striking,” Schweizer says. “Compared to all the other maneuvers—just driving straight, making a right-hand turn—as soon as you have a left-hand turn at a busy intersection, that’s when a huge amount of brain resources were required.”
Toss in a cell phone conversation, and your brain becomes even more frenzied. In the experiment, participants were asked true/false questions while making a left turn in traffic. During this exercise, their posterior brain region—implicated in vision and alertness—became significantly less activated. Meanwhile, the prefrontal cortex—involved in conversation and decision-making—lit up. “There’s a finite amount of brain resources to go around,” Schweizer says. “At that left-hand turn at a busy intersection, you’re probably as taxed as you can be…and it just so happens that what gives is the visual part of the brain.”
The majority of accidents happen at left-hand turns with traffic, researchers note, so weakened visual abilities during those turns could make them even more dangerous. And the effects might be even worse if you’re not a young adult with an agile brain—which the study participants were. “In normal, healthy aging, the frontal cortex atrophies,” Schweizer says. “If you have that potential brain atrophy going on, what’s going to happen when you tax the system?” That’s precisely the subject of Schweizer’s next experiment, but you might want to ditch the Bluetooth before these results get even freakier.
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