The brain imaging study by researchers from Carnegie Mellon University has revealed that just listening to the cell phone while driving reduces brain activity of the drivers by 37 percent.
"Drivers need to keep not only their hands on the wheel; they also have to keep their brains on the road," said neuroscientist Marcel Just, lead researcher and director of the Centre for Cognitive Brain Imaging.
The researchers conducted the study on 29 participants who were asked to use a driving simulator while inside an MRI brain scanner where they steered a car along a virtual winding road at a fixed, challenging speed, either while they were undisturbed, or while they were deciding whether a sentence they heard was true or false.
They used state-of-the-art functional magnetic resonance imaging (fMRI) methods to assess the activity in 20,000 brain locations in every second, each about the size of a peppercorn.
The findings revealed that brain activity in parietal lobe, brain area that assimilates sensory information nad playa a crucial role in navigation decreased by 37 percent. The activity in occipital lobe, area that processes visual information was also reduced.
They also found that cell phone use also worsened the quality of driving. The participants were more likely to weave out of their lane and hitting a simulated guardrail.
"The clear implication is that engaging in a demanding conversation could jeopardize judgment and reaction time if an atypical or unusual driving situation arose," said Just.
"Heavy traffic is no place for an involved personal or business discussion, let alone texting.
"Talking on a cell phone has a special social demand, such that not attending to the cell conversation can be interpreted as rude, insulting behaviour," he added.