A Walk In The Park

Writers have been praising the joys of experiencing nature for a while now. Aristotle wrote that “In all things of nature there is something of the marvelous.” More to the focus of today's post, nineteenth-century environmentalist John Muir said that “In every walk with nature one receives far more than he seeks.” Speaking of walks, playwright Noel Coward said “I like long walks, especially when they are taken by people who annoy me.” But now we're wandering off-topic.

OK, so it's not news that a walk out in nature is a pleasure, but a recent New York Times article headlined as How Walking In Nature Changes The Brain tells about some recent efforts by scientists to pin down just why it is that a stroll through the grove can be such a balm for the spirit.

Stanford University graduate student Gregory Bateman and four collaborators recently published an article in the Proceedings of the National Academy of Sciences that describes more precisely what happens in our brains during a “nature experience”, as they call it.

As summarized in the Times article, the key is the mental state we call brooding--- the unhealthy internal fretting over what is wrong with us, with our lives, and so on. Physiologically, brooding is strongly associated with increased activity of a region of the brain called the subgenual prefrontal cortex.

The scientists divided their research subjects into two groups. Each member of the lucky group took a solitary 90-minute walk through a quiet, parklike area of the Stanford campus, with no iPods or other distractions allowed. The others took a similar stroll along a noisy highway.

A post-walk questionnaire showed that the forester hikers were not dwelling as much on the negative aspects of their lives as the road walkers. This was corroborated by a post-walk brain scan showing less blood flow to the subgenual prefrontal cortex in the first group.

The scientists are the first to admit that many questions remain about just what is going on here, let alone about how much walking under what conditions gives the beneficial effect. I do applaud their work, and especially their choice of subject matter, but a description of the brain chemistry that goes on when one walks in the woods--- or eats a mango--- doesn't really get at the experience itself. Let the science proceed, but let's not leave aside the poets.