Why We Don’t Crash Our Cars While Daydreaming and Driving

Many of us have experienced prolonged stretches of driving where we’re seemingly oblivious to our surroundings, and we’re left dumbfounded that we didn’t get into a serious accident. A new study suggests that a specific brain function protects us from these bouts of absent-minded driving — but that it completely breaks down while texting.

Image: Pixabay

According to Queensland’s Centre for Accident Research & Road Safety, up to 22 per cent of car crashes involve “non-driving related activities” as a contributing factor, with seven per cent of those involving “talking/listening to a handheld device”.

And there are other forms of distracted driving that are worthy of attention, such as absent-minded driving, or driving while upset. In the US, a team of scientists from the University of Houston and the Texas A&M Transportation Institute recently embarked on a project to study the various ways drivers become distracted and how it affects their performance.

Image: Thomas R Machnitzki

Image: Thomas R Machnitzki

Their results, which now appear in Scientific Advances, shows that absent-minded driving, or driving while angry or upset, is not nearly as bad as previously assumed — and in some instances, can actually improve our driving (up to a point). The reason, said the researchers, has to do with a part of our brain that acts like a “sixth sense”, protecting us from distractions.

At the same time, this cognitive process becomes impaired when we’re incessantly looking up and down at our smartphones — an observation that reaffirms just how dangerous texting-and-driving really is.

A study participant sits in a high-fidelity driving simulator. (Image: Malcolm Dcosta)

A study participant sits in a high-fidelity driving simulator. (Image: Malcolm Dcosta)

The purpose of the study, led by Ioannis Pavlidis from UH and Robert Wunderlich of TTI, was to measure the effects of three distinct factors in driving performance. The team wanted to know how drivers behave when they’re absent-minded, emotionally charged, or texting.

The researchers recruited 59 participants and put them in a driving simulator. Each of them was asked to drive the same segment of highway four times, but under varied conditions. These included “normal conditions” and three specific distractions: driving while being asked challenging questions (like annoying maths problems), driving while being asked emotionally charged questions and driving while texting. The order of these driving experiences were randomised to prevent bias.

Thermal imaging was one of several biofeedback measures used to assess the mental state of the drivers. (Image: Jessie Villarreal).

Thermal imaging was one of several biofeedback measures used to assess the mental state of the drivers. (Image: Jessie Villarreal).

Using thermal imaging and other biofeedback instruments, the researchers analysed the mental states of the drivers at every point in time to see how this affected their performance. Unlike previous studies, this research considered variables that related both directly and indirectly to sympathetic nervous system responses, making it one of the most comprehensive studies ever done on distracted driving.

Results showed that all three interventions — absent-minded, emotional and texting — impaired the drivers’ ability to handle the wheel, or what the researchers described as “jittery handling”. But this jittery behaviour only resulted in serious problems, such as clumsy lane deviations and unsafe driving, when the participants were texting.

In the case of absent-minded and emotionally charged instances, the jittery steering actually resulted in slightly straighter trajectories compared to normal driving. The researchers suspect this apparent paradox is likely a function performed by a specific part of the brain called the anterior cingulate cortex, or ACC.

Pavlidis says that the ACC is compensating for our distractions, and it automatically kicks in when the need arises. In the case of driving, the ACC counterbalances a strong jitter to the left with an instant and equally strong jitter to the right, and vice versa. The ACC works to offset all this veering, resulting in exceptionally straight driving. Remarkably, we’re largely unaware that this is even happening.

“This appears to be a sort of ‘auto-pilot’ we are endowed with,” Pavlidis told Gizmodo.

Here’s the thing about the ACC, however. It needs support from the driver’s eye-hand coordination to work. During texting-and-driving, this loop breaks down, and the ACC fails. The jittery handling of the steering wheel is left unchecked, which results in significant lane deviations. The other problem with texting, of course, is that it’s literally diverting a person’s attention away from the primary task of driving.

“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.”

At the same time, Pavlidis said we shouldn’t reach to the glove compartment, or get physically distracted while we’re emotionally engaged or absent-minded. “The ‘corrector’ will fail that moment and because the underlying steering wheel handling is jittery — due to hidden stress — this will lead to a large and dangerous lane deviation,” he said.

This is not to suggest that emotional states don’t affect driving performance — they most certainly do. But until a certain threshold of agitation or annoyance is attained, emotional states don’t really compromise our driving ability. At least that’s what this research suggests.

Pavlidis and Wunderlich next want to take their research outside the lab to test drivers in real world conditions. One of their goals is to create a “stressalyser”, that monitors a driver’s bio-signatures and alerts them when they’re becoming too distracted.

“It’s like you’re boiling something, and you have the lid tight, so it’s safe,” Pavlidis said. “But if at any point in time something should happen, the lid will basically blow up — so we don’t want this to go on. We want to bring things back to a pre-boiling point, and we’re looking into countermeasures and we’re looking at biofeedback to do it.”

[Scientific Advances]