Jonah Lehrer (Proust Was a Neuroscientist) explains how the city hurts your brain:
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.
“It’s not an accident that Central Park is in the middle of Manhattan,” says Berman. “They needed to put a park there.”
In a study published last month, Berman outfitted undergraduates at the University of Michigan with GPS receivers. Some of the students took a stroll in an arboretum, while others walked around the busy streets of downtown Ann Arbor.
The subjects were then run through a battery of psychological tests. People who had walked through the city were in a worse mood and scored significantly lower on a test of attention and working memory, which involved repeating a series of numbers backwards. In fact, just glancing at a photograph of urban scenes led to measurable impairments, at least when compared with pictures of nature.
Lehrer’s new book is How We Decide.