The evidence is surprisingly strong, some neuroscientists say.

Attention and self-control are particularly harmed by urban life. The best antidote seems to be a big dose of nature. In particular, humans respond well to the the rich variety of places like New York's Central Park.

In contrast, researchers say, the denuded savanna of, say, the national Mall in downtown Washington does little to soothe the mind or promote sanity.

Could this explain the occasional madness of Congress? If the incoming Obama administration wants to bring sanity to Washington, DC perhaps it should plant some trees as part of that stimulus package...