Study confirms cell phones’ risk to drivers

In today’s demanding lifestyle, not being able to answer a phone call does not simply mean a “missed call.” It can be the source of great personal and professional inconvenience. However, a new study suggests that sometimes a ringing cell phone has to be ignored.

Recent findings by a team of Carnegie Mellon researchers led by professor Marcel Just have shown that merely listening to a person over the cell phone, even with hands-free devices, can hamper a person’s driving ability.

In the past, drivers wishing to talk on their cell phones typically had one hand on the wheel while holding the phone in the other. While hands-free devices allow drivers to keep drive with two hands, recent research suggests the potential danger of cell phones to drivers remains constant.

“We wanted to see how using language during driving affects not just the driving but the brain activity during driving,” Just said.

The researchers recorded activity in the brain of participants using functional magnetic resonance imaging (fMRI) while they navigated a car along a virtual road. According to a Carnegie Mellon press release, activity was measured in 20,000 brain locations.

Timothy Keller, a post-doctoral research associate, explained that brain activity was monitored during two different experiments. In the controlled experiment, subjects were allowed to virtually navigate the car without any distraction. This tested how well people drive when they can focus entirely on the road.

In the next case, the subjects listened to outside input.

“People were asked to navigate a car by using [mice] in their right hands and were asked to respond to simple true or false questions by using [mice] in their left hands,” Keller said. This tested how a listening distraction can affect a driver’s ability.

A comparison between the results showed that during the dual task of listening and driving, the brain activity in the navigation areas of the brain decreased by 37 percent as compared to the task involving just driving.

“If there is language going in your brain, it will consume some resources for its processing,” Just explained.

According to the team’s research paper, titled “A Decrease in Brain Activation Associated With Driving When Listening to Someone Speak,” the dual-faceted act of driving and listening resulted in a reduction in activation mainly in the bilateral parietal and occipital areas of the brain. Since these areas are involved in spatial and visual processing, decreased activation in these areas inevitably leads to poor driving performance.

Just explained that the quality of driving was measured by two aspects: how well the drivers maintained their lanes and how many times they went off the road. Although the program did not let the cars veer completely off the road, the number of times the cars hit the curbs was counted. This number increased by 50 percent when the drivers were listening and driving. The drivers also tended to weave out of their lanes more frequently when they were listening while driving.

As alarming as this sounds, the story in the real world is much worse.

“We didn’t have any other vehicles on our simulated road,” Keller said. He explained that the situation on a real road would be much worse as the driver would have to keep track of many other aspects besides lane maintenance or staying on the road.

More significantly, Just said that most of the subjects who had experience talking on cell phones while driving on a regular basis still committed the same errors on the virtual road. Therefore, it seems that even drivers that are used to talking on cell phones still suffer in their driving abilities.

Of course, novice drivers are likely to have a harder time. “People who haven’t had experience [in talking and driving at the same time] would be worse off,” Just said.
A common belief among drivers is that talking on cell phones is not dangerous because they pay more attention to the road than they do to the conversation. Another experiment by Just and his colleagues helped disprove this idea.

In this experiment, subjects were once again placed in the dual-task situation of driving and conversing on the cell phone, using a computer simulation. However, in one case of the experiment they were asked to completely ignore the language being spoken and focus entirely on the spatial task. The results showed that even then, the brain was not able to disengage attention from what was being spoken.

“When you try to ignore a language you understand you will be completely unsuccessful in trying to ignore it; it completely gets in. It gets processed almost identically to when you are fully attending to it,” Just said.

The bottom line is that although some states have regulations against holding a cell phone and talking while driving, multitasking while driving is a danger to drivers and others on the road.