A recent study indicates people can’t give their full attention simultaneously to sight and sound tasks, which researchers say supports earlier studies that indicate safety concerns over using cell phones while driving.
Directing attention to listening “effectively ‘turns down the volume’ on input to the visual parts of the brain,” said Steven Yantis, a Johns Hopkins University psychologist.
“The evidence we have right now strongly suggests that attention is strictly limited – a zero-sum game,” Yantis said. “When attention is deployed to one modality – say, in this case, talking on a cell phone – it necessarily extracts a cost on another modality – in this case, the visual task of driving.”
His team’s recent study, published in The Journal of Neuroscience, supports earlier research on the hazards of mixing cell phone use and driving.
Researchers asked adults to view a computer display while listening to voices over headphones in a neuroimaging lab. They watched a rapidly changing display of multiple letters and digits, while listening to three voices speaking letters and digits at the same time to simulate the cluttered visual and auditory input people encounter daily.
Using magnetic resonance imaging, Yantis’ team recorded brain activity. When the participants focused on visual tasks, the auditory parts of their brain recorded decreased activity, and vice versa.