How the city hurts your brain

I've just found a fascinating article, published in the Boston Globe in early January. It makes points that I've felt strongly about for some time, but never been able to verbalize as well, or as succinctly, as does the author. Here's an excerpt to whet your appetite.

... scientists have begun to examine how the city affects the brain, and the results are chastening. Just being in an urban environment, they have found, impairs our basic mental processes. After spending a few minutes on a crowded city street, the brain is less able to hold things in memory, and suffers from reduced self-control. While it's long been recognized that city life is exhausting -- that's why Picasso left Paris -- this new research suggests that cities actually dull our thinking, sometimes dramatically so.

"The mind is a limited machine,"says Marc Berman, a psychologist at the University of Michigan and lead author of a new study that measured the cognitive deficits caused by a short urban walk. "And we're beginning to understand the different ways that a city can exceed those limitations."

One of the main forces at work is a stark lack of nature, which is surprisingly beneficial for the brain. Studies have demonstrated, for instance, that hospital patients recover more quickly when they can see trees from their windows, and that women living in public housing are better able to focus when their apartment overlooks a grassy courtyard. Even these fleeting glimpses of nature improve brain performance, it seems, because they provide a mental break from the urban roil.

This research arrives just as humans cross an important milestone: For the first time in history, the majority of people reside in cities. For a species that evolved to live in small, primate tribes on the African savannah, such a migration marks a dramatic shift. Instead of inhabiting wide-open spaces, we're crowded into concrete jungles, surrounded by taxis, traffic, and millions of strangers. In recent years, it's become clear that such unnatural surroundings have important implications for our mental and physical health, and can powerfully alter how we think.

. . .

Consider everything your brain has to keep track of as you walk down a busy thoroughfare like Newbury Street. There are the crowded sidewalks full of distracted pedestrians who have to be avoided; the hazardous crosswalks that require the brain to monitor the flow of traffic. (The brain is a wary machine, always looking out for potential threats.) There's the confusing urban grid, which forces people to think continually about where they're going and how to get there.

The reason such seemingly trivial mental tasks leave us depleted is that they exploit one of the crucial weak spots of the brain. A city is so overstuffed with stimuli that we need to constantly redirect our attention so that we aren't distracted by irrelevant things, like a flashing neon sign or the cellphone conversation of a nearby passenger on the bus. This sort of controlled perception -- we are telling the mind what to pay attention to -- takes energy and effort. The mind is like a powerful supercomputer, but the act of paying attention consumes much of its processing power.

Natural settings, in contrast, don't require the same amount of cognitive effort. This idea is known as attention restoration theory, or ART, and it was first developed by Stephen Kaplan, a psychologist at the University of Michigan. While it's long been known that human attention is a scarce resource -- focusing in the morning makes it harder to focus in the afternoon -- Kaplan hypothesized that immersion in nature might have a restorative effect.

Imagine a walk around Walden Pond, in Concord. The woods surrounding the pond are filled with pitch pine and hickory trees. Chickadees and red-tailed hawks nest in the branches; squirrels and rabbits skirmish in the berry bushes. Natural settings are full of objects that automatically capture our attention, yet without triggering a negative emotional response -- unlike, say, a backfiring car. The mental machinery that directs attention can relax deeply, replenishing itself.

. . .

City life can also lead to loss of emotional control. Kuo and her colleagues found less domestic violence in the apartments with views of greenery. These data build on earlier work that demonstrated how aspects of the urban environment, such as crowding and unpredictable noise, can also lead to increased levels of aggression. A tired brain, run down by the stimuli of city life, is more likely to lose its temper.

. . .

Given the myriad mental problems that are exacerbated by city life, from an inability to pay attention to a lack of self-control, the question remains: Why do cities continue to grow? And why, even in the electronic age, do they endure as wellsprings of intellectual life?

Recent research by scientists at the Santa Fe Institute used a set of complex mathematical algorithms to demonstrate that the very same urban features that trigger lapses in attention and memory -- the crowded streets, the crushing density of people -- also correlate with measures of innovation, as strangers interact with one another in unpredictable ways. It is the "concentration of social interactions" that is largely responsible for urban creativity, according to the scientists. The density of 18th-century London may have triggered outbreaks of disease, but it also led to intellectual breakthroughs, just as the density of Cambridge -- one of the densest cities in America -- contributes to its success as a creative center. One corollary of this research is that less dense urban areas, like Phoenix, may, over time, generate less innovation.

The key, then, is to find ways to mitigate the psychological damage of the metropolis while still preserving its unique benefits.

There's a lot more at the link. Highly recommended reading.

Peter