Can trees improve your cognitive capacity?


Artwork by Hallie Bateman.

Apparently nature is the balm that heals all wounds, or at least all bad moods. The New Yorker wrote about a new study from U of Chicago by Marc Berman which showed that increasing the number of trees on the block you live on increases your well-being.

The numbers are pretty stunning:

After controlling for income, education, and age, Berman and his colleagues showed that an additional ten trees on a given block corresponded to a one-per-cent increase in how healthy nearby residents felt. “To get an equivalent increase with money, you’d have to give each household in that neighborhood ten thousand dollars—or make people seven years younger,” Berman told me.

The study goes on to find, incredibly, that more trees also seem to correlate with a lower rate of death in people with serious health conditions:

Are such numbers fanciful? The emerald ash borer, which has killed a hundred million trees across North America in recent years, offers a grim natural experiment. A county-by-county analysis of health records by the U.S. Forest Service, between 1990 and 2007, found that deaths related to cardiovascular and respiratory illnesses rose in places where trees succumbed to the pest, contributing to more than twenty thousand additional deaths during the study period. The Toronto data shows a similar link between tree cover and cardio-metabolic conditions such as heart disease, stroke, and diabetes. For the people suffering from these conditions, an extra eleven trees per block corresponds to an income boost of twenty thousand dollars, or being almost one and a half years younger.

The trees that people see seem to matter most. Trees on the sidewalk and front yards had a huge impact on well-being, while trees in backyards and parks had little impact. Amazingly, even if you don’t really care for nature, being out in it still has a hugely positive effect:

As a doctoral student at the University of Michigan, a decade ago, Berman conducted a study in which he sent volunteers on a fifty-minute walk through either an arboretum or city streets, then gave his subjects a cognitive assessment. Those who had taken the nature walk performed about twenty per cent better than their counterparts on tests of memory and attention. They also tended to be in a better mood, although that didn’t affect their scores.

“What we’re finding is that you don’t have to like the interaction with nature to get the benefits,” Berman said. Some of the walks took place in June, whereas others took place in January; most people didn’t particularly enjoy trudging through the harsh Michigan winter, but their scores jumped just as much as in the summer trials. Not surprisingly, those whose directed attention is most depleted seem to get the biggest benefits: an end-of-workday nature romp probably packs a greater restorative punch than one first thing in the morning, and the boost is five times bigger in people who have been diagnosed with clinical depression…

You can produce an attenuated version of the same effect simply by looking out a window, or (for experimental convenience) at a picture of a nature scene.

This piece made me think of a Richard Wiseman study in which he created “the world’s most relaxing room,” which basically mimics someone laying in a field of grass and staring up at the sky.

It also reminded me of this lovely piece by illustrator Hallie Bateman, whose image I used above, on the best climbing trees in New York City.

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Hi, I'm Jocelyn. I help people find more creativity and meaning in their daily work.

I created the online course RESET, a cosmic tune-up for your workday, and I host Hurry Slowly, a podcast about how you can be more productive, creative, and resilient by slowing down. Occasionally, I write books and give talks too.
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