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The Psychology and Biology of Road Rage

And what we might be able to do to calm it down.
(Photo: aleks.k/Shutterstock)

(Photo: aleks.k/Shutterstock)

A recent car fatality in upstate New York, involving a single car that flipped over twice on a highway median, was a mystery to first responders until witness reports came in. Other drivers that had been on the road at the time described two cars that had been engaging in “a deadly road-rage game of cat and mouse,” as cops told a local NBC reporter. One car was aggressively pursuing the other; when one car flipped and crashed, witnesses said, the other one “just kept going.” Police said that the 27-year-old woman’s death was “being treated as a case of road rage.”

Congested roads, busy schedules, and idiots on the road are a fact of life. But road rage can escalate, to fatal extremes, very quickly. Urban planners and neuroscientists alike have studied the external and internal factors that contribute to aggressive, reckless, and vengeful driving. They’ve shown just how complicated and contagious it is, and how there’s no easy answer to such a persistent problem.

Emil Coccaro, a professor and psychiatrist at the University of Chicago, has studied Intermittent Explosive Disorder (IED) for many years. People with this disorder repeatedly respond with violent or verbally aggressive outbursts, disproportionate to any given situation. (Not all road-ragers have IED, but road rage can be a symptom of it.) He says that the psychological root of this behavior is often something called Hostile Attribution Bias—the belief that every accidental injury or threat is purposeful, and personal. People with IED over-personalize every interaction, and then over-react with immediate aggression.

What if we could all just take a pill? Aggression, like depression, has biological roots as well as psychological ones. Having seratonin or dopamine levels that are off-balance have often been linked to impulsive and aggressive behavior in humans and animals.

It’s a dangerous combination when this happens to someone behind the wheel of a car on the road. And it’s also risky to drive carelessly in such a way that could provoke drivers like that in unpredictable ways. Coccaro explains the unique psychological effect of being in the driver’s seat of a car, which can be akin to a state of denial, combined with a heightened sense of power.

“You’re in a car, and it's kind of a weapon, and you're in a protected environment, and you think no one's going to be able to get to you,” Coccaro says. So, if you get cut off by another driver, you might feel that you can give them the finger without any direct consequence. But the problem is, you don’t have any idea how the other person will respond to that provocation. “I say that to people all the time, ‘Don't assume that the other person is you,’” he says. “You don't know how nuts they are. You don't know that they don't have a gun in their glove compartment."

Guns in the glove compartment and altercations on the road can obviously be a deadly combination. Last week, there was a seemingly random car-to-car shooting during Las Vegas rush hour. After some kind of argument, one driver shot and killed another; the victim’s car, which carried two kids in the back, rolled into several other cars as the killer drove away. And cops are still on the hunt for the unknown driver that the media dubbed "the road rage killer." Timothy Davison was chased for 15 miles in Maryland and Pennsylvania by an angry, aggressive driver after some perceived slight on the road. Davison had already made several 911 calls when he was forced off the road and shot to death. Via CNN:

"The acts committed against Mr. Davison were random only to the point of his initial encounter with his assailant," the Pennsylvania state police said in a statement. "Beyond that, the acts against him were very deliberate, calculated, and violent.... The potential for additional incidents of similar nature is anticipated due to the violent nature of this incident."

Everyday road rage rarely escalates to the point of murder, of course, and these killers likely had psychological problems a lot more dire than your typical fast-driving bird-flipper. But it does make you wonder, could these situations have escalated quite so quickly and irreversibly if the perpetrators hadn’t been driving around with guns in their front seats?

As it turns out, research has shown that the presence of a gun in a car might have a catalyzing effect on car-to-car pissing contests, even if the guns don’t ever come out of the glove compartments. A group of researchers from the Harvard School of Public Health found just that, in their study, “Is an Armed Society a Polite Society? Guns and Road Rage,” published in the journal Accident Analysis & Prevention.

David Hemenway, Mary Vriniotis, and Matthew Miller found in their national survey that people who drive with guns in their cars are more likely to “make obscene gestures at other motorists” and “follow aggressively behind” other cars. (The survey asked people a wide range of questions about their lives and worldviews; results found that road rage was most prevalent in “males, young adults, binge drinkers, those who do not believe most people can be trusted, [and] those ever arrested for a non-traffic violation” as well as those driving with guns.)

So, are people who are naturally aggressive—on the road and in life—more likely to own and carry guns? Or, as this study suggests with its title, does the presence of a gun nearby in the car make people drive more aggressively? This study can’t say. But it does explore the particular psychological effect of being in a car. Like Coccaro, the study's authors describe the car as “like a second home,” almost an extension of the driver’s person. Therefore, they write, “motorists tend to respond to perceived threats in a territorial fashion.”

Drivers make little mistakes all the time: timing things incorrectly, for instance, or accidentally going the wrong speed for whatever zone they’re in. And it’s pretty easy for those mistakes to be misinterpreted as purposeful acts of aggression, especially since there’s no type of horn-honk that says “sorry”:

Unfortunately, when another driver makes a mistake, it is often difficult for him to apologize, to signal ‘excuse me’ in a way that can be readily understood. By contrast, cars provide an environment in which individuals may feel safe to display hostility. A car gives the motorist power, protection, easy escape, and anonymity. Not surprisingly, hostile behavior by motorists is relatively common.

So how can we try to prevent road rage, from the perspective of both the ragers and the road-makers? An article in Trauma, Violence, & Abuse attempted to answer that question a few years ago. A group of Canadian researchers proposed several big-picture solutions, which ranged from aggressive-behavior screening tests for new drivers-license seekers, to more innovative design for both city-layout and car technology, to stricter and more specific laws to punish aggressive drivers. (The last of these is already happening in some places, according to the National Highway Traffic Safety Administration.)

Or, we could forget all of those incremental and abstract ideas. What if we could all just take a pill? Aggression, like depression, has biological roots as well as psychological ones. Having seratonin or dopamine levels that are off-balance have often been linked to impulsive and aggressive behavior in humans and animals. Coccaro’s latest study, published last month in the journal JAMA Psychiatry, explored the connections between IED and a few particular markers of systemic inflammation in the blood. He found that these markers were present in a lot of people who exhibited sudden, aggressive behavior, but not in people who had other psychiatric problems. It’s an intriguing initial finding, even though he says he doesn’t know yet whether correlation means causation, and if so, in which direction the causation goes.

“So we don't know if aggressive people, their lymphocytes that make these inflammatory markers are more overreactive to physical stimuli, and that could be the case,” he says. “Or, is it that they're walking around with higher levels, for whatever reason, and those are stimulating those receptors in the brain and are making people more aggressive because of that.”

Either way, Coccaro suggests, because these two things are so closely correlated, it’s very possible that anti-inflammatory drugs could also calm people’s aggressive behavior. He has seen studies in which cognitive behavioral therapy has helped IED, and he’s seen ones in which drug intervention has helped just as well.

After the inflammatory-marker study was published, several news sites picked up on it, but they didn’t exactly draw the right conclusion. Manyofthemdeclared that aspirin could be a “cure” for road rage. When asked what he thought of that oversimplification, Coccaro laughs. “That is absolutely incorrect,” he says. “Not at this point.” That would be just a little too easy.