YouÃ¢â‚¬â„¢re driving with both hands on the steering wheel, and your eyes are on the road ahead. All good, right? Not if youÃ¢â‚¬â„¢re on a hands-free cell phone and your route involves a left-hand turn (weÃ¢â‚¬â„¢re guessing it does). According to a new study published in the open access journal Frontiers in Human Neuroscience, making a left-hand turn in a busy intersection requires a huge amount of brain activity, and talking on a hands-free cell phone at the same time is more than the brain can handle.
For the study, researchers put a driving simulatorÃ¢â‚¬”steering wheel, pedals, and allÃ¢â‚¬”inside a high-powered functional MRI. Young adult participants navigated straight roads, right-hand turns, and left-hand turns. During some of the steering, the participants answered simple true or false questions (for example, if a triangle has four sides) by pressing buttons on the steering wheelÃ¢â‚¬”a lot like the way current hands-free phone technology works. When they did so during a left-hand turn at a traffic-filled intersection, something major happened: Ã¢â‚¬Å“Brain power was allocated to the frontal cortex, which allows you to make decisions and hold that conversation,Ã¢â‚¬Â says lead study author Tom Schweizer, PhD, a neuroscientist and the director of the Neuroscience Research Program at St. MichaelÃ¢â‚¬â„¢s Hospital in Toronto. Ã¢â‚¬Å“The visual part of the brainÃ¢â‚¬”the back end of the brainÃ¢â‚¬”started to shut down.Ã¢â‚¬Â
So what exactly makes turning left so complicated? Think about everything you have to process: the traffic light, oncoming cars (which are probably going pretty fast), pedestrian and bicyclists to the left. Ã¢â‚¬Å“You have to take in all of that visual information and then calculate a safe driving maneuver,Ã¢â‚¬Â says Schweizer. Ã¢â‚¬Å“We found that a huge amount of brain is required to pull that off.Ã¢â‚¬Â When you add some chatting to the equation, Ã¢â‚¬Å“something in the brainÃ¢â‚¬â„¢s gotta give,Ã¢â‚¬Â explains Schweizer. Ã¢â‚¬Å“There are only so many brain resources to go around. And it just so happens that what gives is the visual system.Ã¢â‚¬Â
Many states already ban novice drivers and bus drivers from using hands-free devices while driving.
Marcel Just, PhD, director of the Center for Cognitive Brain Imaging at Carnegie Mellon University, was not involved in the study but has done separate research on driving while listening. His 2008 research found that even just listening to a person reduces the brain activity focused on driving by 37 percent. Ã¢â‚¬Å“What people tend to underestimate is the draw on cognitive resources of even having a conversation or listening to someone speak,Ã¢â‚¬Â says Just. Ã¢â‚¬Å“I donÃ¢â‚¬â„¢t want to be crossing the street while a driver is coming towards me and talking on a cell phone, even if itÃ¢â‚¬â„¢s hands-free.Ã¢â‚¬Â
The verdict: Hands-free doesnÃ¢â‚¬â„¢t mean danger-free. DonÃ¢â‚¬â„¢t chat on the phone when youÃ¢â‚¬â„¢re behind the wheel!
photo: Edyta Pawlowska/Shutterstock More from Women's Health:
Alert! You May Be ODing On Sleep Meds
5 Smart Decision-Making Strategies
9 Ways to Drive Safer and Stay Focused
To find out how to suppress your hunger hormone, buy The Belly Fat Fix now!