By Jonah Lehrer
New York, NY (August 19, 2010)- In the late 1990s, Frances Kuo, director of the Landscape and Human Health Laboratory at the University of Illinois, began interviewing female residents in the Robert Taylor Homes, a massive housing project on the South Side of Chicago. Kuo and her colleagues compared women randomly assigned to various apartments. Some had a view of nothing but concrete sprawl, the blacktop of parking lots and basketball courts. Others looked out on grassy courtyards filled with trees and flowerbeds.
Kuo then measured the two groups on a variety of tasks, from basic tests of attention to surveys that looked at how the women were handling major life challenges. She found that living in an apartment with a view of greenery led to significant improvements in every category. What happened? Kuo argues that simply looking at a tree “refreshes the ability to concentrate,” allowing the residents to better deal with their problems. Instead of getting flustered and angry, they could stare out the window and relax. In other words, there is something inherently “restorative” about natural setting – places without people are good for the mind.
To better understand how nature works its psychological magic, let’s look at an important 2008 study led by Marc Berman, at the University of Michigan. (I’ve written about this study before.) Berman and colleagues 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 nature were in a better mood and scored significantly higher on a test of attention and working memory, which involved repeating a series of numbers backwards. In fact, just glancing at a photograph of nature led to measurable improvements, at least when compared with pictures of city streets.
Does this mean we should all flee the city? Of course not. It simply means that it’s a good idea to build a little greenery into our life. This isn’t a particularly new idea. Long before scientists fretted about the cognitive load of city streets, philosophers and landscape architects were warning about the effects of the undiluted city, and looking for ways to integrate nature into modern life. Ralph Waldo Emerson advised people to “adopt the pace of nature,” while the landscape architect Frederick Law Olmsted sought to create vibrant urban parks, such as Central Park in New York and the Emerald Necklace in Boston, that allowed the masses to escape the maelstrom of urban life. (As Berman told me, “It’s not an accident that Central Park is in the middle of Manhattan…They needed to put a park there.”)
Although Olmsted took pains to design parks with a variety of habitats and botanical settings, most urban greenspaces are much less diverse. Instead, the typical city park is little more than an expansive lawn, punctuated by a few trees and playing fields. I’ve got nothing against grass and Little League, but it’s probably worth pointing out that, if you want to maximize the psychological perks of greenspace, this is probably the wrong approach. In a 2007 paper, Richard Fuller, an ecologist at the University of Queensland, demonstrated that the mental benefits of green space are closely linked to the diversity of its plant life. When a city park has a larger variety of trees, subjects that spend time in the park score higher on various measures of psychological well-being, at least when compared with less biodiverse parks.
Over at Scienceline, Ferris Jabr has an excellent article on the recent attempts to turn ecopsychology into a rigorous science. He describes an interesting new experiment led by Peter Kahn:
First, Kahn stressed out his participants by giving them a series of math tests. Then he placed some people in front of a window overlooking a grassy lawn with trees, others in front of a large plasma television screen displaying the lawn in real time, and still others in front of a blank wall. As expected, those in front of the window experienced the quickest drop in stress levels, as measured by their decreasing heart rate. Participants also spent far more time looking out the window and at the plasma screen than at the blank wall. But the researchers found an unexpected result.
“Surprisingly, the blank wall and the plasma screen were no different in terms of stress reduction,” said Ruckert. Their study indicates that gazing at an authentic natural space reduces stress, whereas a digital replica of nature soothes only as well as a boring blank wall.
I sometimes wonder if, when we look back at the mass cognitive mistakes of the 21st century, we’ll worry less about the internet and multitasking – people have been multitasking forever – and instead fret about our turn away from nature. The human species is urbanizing at an unprecedented rate. (In the next century, at least 3 billion people will migrate to cities.) And yet, we’re only beginning to understand how living in dense agglomerations of perfect strangers, surrounded by skyscrapers and concrete, actually affects the brain. This work on ecopsychology is an important start.