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Tuesday, March 19, 2013

Distractions during driving affect brain activity

By now, we all know that talking on the phone can diminish our ability to drive safely. Our brains simply aren’t equipped to do more than one thing well at a time. Researchers, led by Tom Schweizer of the University of Toronto, were interested in capturing that difference between distracted and regular driving at the level of brain activity. Traffic statistics show that distracted driving is particularly problematic while making left turns (right turns for those of you in the United Kingdom, Australia, or other left-driving countries). Therefore, the scientists used complex left turns for their comparison.

The researchers put sixteen volunteers in a virtual reality enhanced driving simulator that was located within a functional magnetic resonance imaging (fMRI) machine. The subjects were given a variety of ‘routes’ ranging from traffic-free right turns to left turns through busy intersections. While ‘driving’, the subjects were given audio tasks designed to mimic either conversing with passengers or talking on a hands-free phone. For example, they were asked true or false questions, which they answered by pressing buttons on the steering wheel.

I’m no cognitive scientist, but even I can see that different parts of the brain are being activated during distracted driving. The top panel shows the regions of the brain activated during normal, non-distracted driving. It’s mostly the posterior of the brain, containing regions critical for visual-spatial orientation that is engaged. This is especially true while making challenging left turns (bottom row). In contrast, the lower panel shows that when distracted, there’s a shift in activation to the anterior of the brain where regions involved in problem solving predominate.


Brain activations from the bottom to the top of the brain (left to right figures) of participants when performing various simulated driving conditions.
(A)         The right-turn condition showed minimal activation in the brain
(B)         Left-turn showed more activation in the posterior brain regions;
(C)         The left-turns with oncoming traffic.
DOI: 10.3389/fnhum.2013.00053.


Brain activations associated with distracted driving.
(A)   Straight driving with a cognitive-distraction, audio task.
(B)   The demanding, left-turn condition with oncoming traffic plus the cognitive distraction.
Despite these changes in brain usage, there were no great performance differences between distracted and undistracted driving. Participants maintained similar speeds and lane positions during both. This is not to say that it’s perfectly safe to talk on the phone and drive. Numerous studies have indicated the opposite, and that even hands-free calling causes people to be less attentive to their surroundings. This study did not evaluate those dangers. Instead, it simply demonstrated the clear changes that occur in brain activity between distracted and non-distracted driving. How these changes correlate with behavior requires another study.

Schweizer, T., Kan, K., Hung, Y., Tam, F., Naglie, G., & Graham, S. (2013). Brain activity during driving with distraction: an immersive fMRI study Frontiers in Human Neuroscience, 7 DOI: 10.3389/fnhum.2013.00053.