A sixth sense protects drivers except when texting

HOUSTON, May 12, 2016 – While much has been made about the dangers of texting and driving, less attention has been focused on the age-old distractions of being absent minded or upset while driving. A team of researchers from the University of Houston (UH) and the Texas A&M Transportation Institute (TTI) focused on all three of these important factors.

Led by Ioannis Pavlidis from UH and Robert Wunderlich of TTI, the research studied how drivers behave when they are absent minded, emotionally charged or engaged in texting. The work was funded, in part, by the Toyota Class Action Settlement Safety Research and Education Program.*

The study looked at 59 volunteers who were asked to drive the same segment of highway four times – under 'normal conditions' of being focused on driving, while distracted with cognitively challenging questions, while distracted with emotionally charged questions and while preoccupied with texting trivialities. To avoid bias, the order of the drives was randomized.

In all three interventions – absent minded, emotional and texting – the researchers found that the drivers' handling of the wheel became jittery with respect to normal driving. This jittery handling resulted in significant lane deviations and unsafe driving only in the case of texting distractions. In the case of absent-minded and emotionally charged distractions, jittery steering resulted in straighter trajectories with respect to a normal drive and safer driving.

"A likely explanation for this paradox is the function performed by a part of the brain called the anterior cingulate cortex, or ACC," Pavlidis said. "ACC is known to automatically intervene as an error corrector when there is conflict. In this case, the conflict comes from the cognitive, emotional and sensorimotor, or texting, stressors. This raises the levels of physiological stress, funneling 'fight or flight' energy to the driver's arms, resulting in jittery handling of the steering wheel."

What happens when the brain's ACC automatically intervenes, Pavlidis said, is that it counterbalances any strong jitter to the left with an instant equally strong jitter to the right and vice versa. The end effect of this forceful action is nullification of any veering to the left or the right of the lane and, thus, very straight driving.

For ACC to perform this corrective function, it needs support from the driver's eye-hand coordination loop. If this loop breaks, which it does when the driver texts, then ACC fails and the jittery handling of the steering wheel is left unchecked, resulting in a significant lane deviation and possible accident.

"The driver's mind can wander and his or her feelings may boil, but a sixth sense keeps a person safe at least in terms of veering off course," Pavlidis said. "What makes texting so dangerous is that it wreaks havoc into this sixth sense. Self-driving cars may bypass this and other problems, but the moral of the story is that humans have their own auto systems that work wonders, until they break."

Pavlidis and Wunderlich think the scientific and manufacturing community can benefit from their team's study. They posit that the question of what happens when self-driving cars experience failures needs to be asked now rather than later. Case in point, their research uncovers the mechanism that makes moderate cognitive and emotional distractions relatively safe, but only as long as the driver's natural tendency to handle multiple tasks is not overwhelmed.

"Following up on the results of our science study, we are currently looking into the development of a car system to monitor outward driving behaviors, such as steering jitter or lane deviation, as well as the internal state of the driver that causes them," Pavlidis said. "This system, which I call 'stressalyzer,' a play on the word breathalyzer, may serve not only as a 'black box' in car accidents, but also as a driver alert and prevention mechanism, since it will continuously sense a driver drifting to distracted mode."

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The findings are described in a paper titled "Dissecting Driver Behaviors Under Cognitive, Emotional, Sensorimotor, and Mixed Stressors," appearing May 12 in Scientific Reports, an online open-access research journal from the Nature Publishing Group. Pavlidis is a computer science professor in the UH Computational Physiology Lab, and Wunderlich is director of TTI's Center for Transportation Safety.

Video clips of Pavlidis explaining the research are available at http://www.tubechop.com/watch/7975966 and http://www.tubechop.com/watch/7975975. A link to the study's data set is available at http://cpl.uh.edu/projects/stress-studies/dds.

*Editor's note: The conclusions being expressed are the authors' only and have not been sponsored, approved or endorsed by Toyota or Plaintiffs' Class Counsel.

About the University of Houston

The University of Houston is a Carnegie-designated Tier One public research university recognized by The Princeton Review as one of the nation's best colleges for undergraduate education. UH serves the globally competitive Houston and Gulf Coast Region by providing world-class faculty, experiential learning and strategic industry partnerships. Located in the nation's fourth-largest city, UH serves more than 42,700 students in the most ethnically and culturally diverse region in the country. For more information about UH, visit the university's newsroom at http://www.uh.edu/news-events/.

About the Texas A&M Transportation Institute

The Texas A&M Transportation Institute is the largest university affiliated transportation research agency in the U.S. and a member of the Texas A&M University System. Since 1950, the institute has been dedicated to saving lives, time and resources by addressing problems related to all modes of transportation. For more information about TTI, visit http://tti.tamu.edu/.

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