Distracted driving is a crime in some parts of the world including Canada and while many motorists may believe that hands-free calls are safer and could not be labelled as distracted driving, a new study shows that the act is as distracting as using a handheld mobile phone while driving.
Researchers at University of Sussex have said through a new study published in Transportation Research journal that the notion that hands-free calls are safer than using handheld mobile is rather a misconception and that they are equally distracting because conversations cause the driver to visually imagine what they’re talking about. Researchers found that drivers having conversations which sparked their visual imagination detected fewer road hazards than those who didn’t.
Further, researchers also found that while motorists are conversing while driving, they focused on a smaller area of the road ahead of them and failed to see hazards, even when they looked directly at them. One of the reasons behind this is that conversations may use more of the brain’s visual processing resources than previously understood. And this means that if a motorist is having a conversation which requires him to use their visual imagination, it creates competition for the brain’s processing capacity, which results in drivers missing road hazards that they might otherwise have spotted.
The study, which tracked eye movements, also found that drivers who were distracted suffered from “visual tunnelling.” They tended to focus their eyes on a small central region directly ahead of them. This led them to miss hazards in their peripheral vision. Undistracted participants’ eye movements ranged over a much wider area.
For the study, researchers ran two experiments in which participants performed a video-based hazard-detection task. In the first experiment, participants were either undistracted, or distracted by listening to sentences and deciding whether they were true or false. For half of these distracted participants, the sentences encouraged the use of visual imagery (e.g. “a five pound note is the same size as a ten pound note”) whereas for the other half, the sentences did not (e.g. “Leap years have 366 days”). All of the distracted participants were slower to respond to hazards, detected fewer hazards and made more ‘looked but failed to see’ errors, meaning their eyes focused on a hazard but they didn’t actually see it. These impairments were worse for the participants who were distracted by imagery-inducing statements.
In the second experiment, the researchers compared undistracted participants to ones who were distracted by a different visual imagery task. This involved mentally moving around an imaginary grid in response to verbal instructions. Distracted participants were more likely to miss hazards in their peripheral vision due to the “visual tunnelling.”