One of the most memorable posts on Pruned, I think, was written way back in September 2005, when Alex took a look at what he called “litter-free landscapes and the politics of pollen.” He quoted horticulturalist Thomas Leo Ogren at length:
In our urban landscapes we now have the most manipulated kind of city forest ever seen. In the past twenty years landscapers have grown inordinately fond of using male trees. In dioecious species (separate-sexed) there are separate male trees and separate female ones. Female trees and shrubs do not produce any pollen, ever, but they do produce messy seeds, fruits, old flowers, and seedpods. Landscapers and city arborists consider this female byproduct to be “litter”, and they don’t like to see it lying on our sidewalks.
In other words, urban landscapers over-utilize pollen-intensive plantlife—which, in turn, wildly amplifies seasonal allergies. What if you didn’t need more boxes of Claritin, then—you need a more informed city parks department?
And yet, city life isn’t easy. The same London cafes that stimulated Ben Franklin also helped spread cholera; Picasso eventually bought an estate in quiet Provence. While the modern city might be a haven for playwrights, poets, and physicists, it’s also a deeply unnatural and overwhelming place.
Now 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.