Do you find yourself ruminating on the all the bad things in life? Psychologists know that's one of the key behaviors that sustains depression, so addressing patterns of rumination is a serious issue. Now, researchers have found a straightforward, if not necessarily easy, way to avoid mulling things over to excess: take a walk, but not down a crowded street; to be effective, it has to be out in nature.
To a psychologist, rumination means going over and over everything that's wrong in a person's life, whether it's a bad job or a stubbed toe. Rumination is closely connected to depression, and it has a habit of alienating people from those who might be able to support them. A 1999 study, for example, found that, while ruminators sought more help after the death of a loved one and would have benefitted more from that help, they were less likely to get it.
"These findings support the view that natural environments may confer psychological benefits to humans."
Mindfulness and cognitive behavioral therapy are two good ways to treat depression, but Gregory Bratman and his colleagues wondered about a rather less formal approach: walking. Bratman is a Ph.D. student at the Stanford University School of Earth, Energy, and Environmental Sciences, but his interest lies in "psychological ecosystem services"—in other words, the ways nature can benefit mental health. Working with a team of environmental scientists and psychologists, Bratman sought to find out whether walking in nature might help ease rumination, and, with it, depression.
The research team first gave 38 healthy people from the Bay Area a survey designed to evaluate how prone they were to mulling over negative thoughts. The researchers then sent half the group down the road for a 90-minute walk in the relatively wild hills just west of the Stanford campus. The other participants marched in the opposite direction, down El Camino Real, a six-lane road that extends the length of the San Francisco Peninsula—about as far as you can get from nature, even if there are some trees along the way.
Afterward, the walkers came back to the lab and took the rumination survey again, allowing the researchers to compare the results. El Camino walkers' rumination scores were the same both before and after the walk, but the nature walkers' scores dropped from 35.4 (out of 60) beforehand to 33.1 afterward.
"These findings support the view that natural environments may confer psychological benefits to humans," Bratman and his team write today in Proceedings of the National Academy of Sciences. And while the effect isn't large, it could become increasingly important as people migrate to cities. Half of us humans already live in urban areas, and the number is expected to increase dramatically over the coming decades. Urban planners may therefore need to be careful to add green space as cities grow—without some contact to nature, more and more of us may find ourselves ruminating, depressed, and alienated.
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