Drivers, listen up: Hands-free cell phones are no more likely to cause accidents than a chat with a passenger. But the bad news: Demanding conversations, either by phone or in person, weaken visual perception by as much as 30 percent.
A study published in the Journal of Experimental Psychology: Applied, analyzed motorists as they drove in traffic along a highway north of Madrid. When engaged in complex conversations, drivers spotted obstacles later and spent less time visually engaged with them. As a result, they had less time to react to dangers.
When conversations shift to complex thinking, the mind reallocates mental capacity away from visual processing. During mental calculations—for example, changing Euros to German marks—visual acuity falls significantly. The same was true for drivers engaged in memory recollection.
In the experiment, Recarte Goldaracena, of the Universidad Complutense in Madrid, studied the eye movements of 12 adults who drove for about four hours. To gauge driver distraction, an eye-tracking machine monitored how frequently the drivers checked the mirror and speedometer. A similar driving test was repeated in the lab.
