The Neuroscience of Car Dependence

Why the brain has such a hard time considering all travel options.

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Even for urban households with both a car and transit options, how people get to work in the morning doesn't feel like a "choice." Economists aside, few of us sit down and calculate the differential cost of driving versus riding the bus or train. Most are lucky to have a few minutes left over for family or Internet on their way out the door.

In short, we have very fixed travel habits. The habit of car dependency, in particular, poses a major problem for sustainable cities. As transportation experts push for mobility "carrots" and "sticks" — making alternative modes more attractive while making driving less attractive — they can't forget they're also battling certain aspects of the human brain that nudge us away from considering any changes to our lives at all.

A group of researchers led by Yavor Yalachkov turn to neuroscience to help explain why so many people remain stuck in their mode choice in a recent essay on science and society. Writing in Trends in Cognitive Science, Yalachkov and company survey the latest evidence on habit development in light of car dependency. Much of it comes as no surprise: habits are triggered automatically by learning associations in our environment. We wake up in the morning, we head to the car.

The greater insight recently drawn by cognitive scientists is that a shift in brain activity occurs to facilitate our routines. Rather than use the parts of our brain that evaluate a decision — in short, rather than engage in a true "choice" — we rely in these habitual moments on neural regions that perform an action without much concern for outcome. This shift in cognitive domain makes the power of habits "so great that a behavioral change may be difficult," explain Yalachkov et al:

Given that evaluation processes are of less or no importance for an established habitual pattern of activity, simply providing alternative choices for the individual can be a disappointingly unsuccessful method for reshaping particular behavioral patterns.

The researchers cite recent research on the nature of drug habits: they're suggesting you're addicted to your car. Perhaps more intriguing is recent work on the role that stress plays in shifting cognitive function from flexible parts of the brain (in the hippocampus) to procedural ones (in the striatum). In brain imaging studies, test participants placed under stress rely more on the striatum to determine their behavior — overwhelmed by life, we revert to habit.

That helps explain why choosing to travel by a certain mode in the morning often doesn't feel like a choice at all. Getting ready to leave the house has always been a stressful time, confronted with an annoying commute and a new day at the office, and the stress only increases with the urge to get a head start on work on our phones. (Morning commutes are the clearest example, but the process applies to any trips secondary to their purpose.) In light of this overload, conserving brain power with regard to travel choice is actually the wise move.

Yalachkov and others bleakly conclude:

Therefore, it is unsurprising that simply providing alternative urban transport options or applying penalties for unnecessary car use may not be sufficient to reduce the car dependence of contemporary cities.

So the prognosis is negative, but recognizing why people don't always take a rational approach to travel choice can be instructive, too. It can help sharpen programs that promote trip alternatives and can help target interventions to those moments when travel habits become especially vulnerable to disruption — after major life events, for instance, or significant construction projects. Knowing that people don't think twice about mode choice makes it all the more important to get other options right the first time.

Top image: solarseven/Shutterstock.com

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