As we all know, we shouldn't drive and text—or (God forbid) put on makeup in the rearview mirror. But psychologists say that even having a hands-free conversation is distracting.
Marcel Just, PhD, and Tim Keller, PhD, researchers at the Center for Cognitive Brain Imaging at Carnegie Mellon University, scanned the brains of 29 volunteers as they cruised on a video-simulated road while judging spoken statements as true or false. Compared with a control group, their brains showed a 37 percent drop in activity in the region associated with spatial processing. "When listening to the statements, the subjects' lane maintenance deteriorated substantially," says Just.
Although some cars now offer systems in which the steering wheel vibrates or there's a beep if you drift from your lane, the best safety feature is an alert mind—focused on the road.