Among the sources of Jonah Lehrer, we find two studies, one by Marc Berman, a psychologist at the University of Michigan , another by Frances Kuo, director of the Landscape and Human Health Laboratory at the University of Illinois.

Marc Berman

«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.»

Frances Kuo

«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.»