Nature Makes Us Smarter. OK, Now What?

June 5, 2015

Ring-tailed lemur. Despite the lack of a large brain, it can organize sequences, understand basic arithmetic operations and preferentially select tools based on functional qualities. Credit: bzd1/Flickr through a Creative Commons license.

Nature makes you smarter — that’s what all the research says.

But what does that mean, actually?

One view: Staring for just 40 seconds at a computer screen picture of a green roof will increase your ability to focus, according to one new study.

But another experiment found only mixed cognitive benefits from a 50 minute walk in actual nature

Welcome to the messy, far-from-settled science of smarter-by-nature. A bevy of studies does say that people just emerging from a “nature experience” (the definition of which ranges from a days-long hike to merely looking at an image of a natural landscape) do better than control groups on memory tests or other kinds of cognitive tasks.

But we’re a long way from those results being confirmed, understood or actually making anyone smarter — much less making nature more of a habit for anyone.

“There’s a ton more work to be done,” says Greg Bratman, a Stanford researcher whose project is digging into the mechanisms behind nature’s psychological benefits, both cognitive and affective.

“We’re all measuring differences according to little concentration tests or working memory tests — we’re not being very specific about the causal mechanisms,” Bratman says. “And replication is a huge issue. Nailing all this down is very important to integrating it into ecosystem services like urban design and prescribing length of urban walks, for instance.”

Not to mention the problem of whether people want to think about nature as, say, a quick-fix to boost our productivity, versus just making us feel better.

More Dosage Required?

As I reported two weeks ago on Cool Green Science, Bratman has found that just a 50-minute walk in a natural setting gives people much stronger  affective benefits when compared to the same duration walk along a busy multilane urban boulevard.

But his results were not as compelling for the cognitive benefits of the same nature walk.

The nature walkers were superior to their urban counterparts in a complicated working memory test known as operation span or OSPAN. OSPAN sounds a bit sadistic: Subjects are forced to solve math equations and simultaneously repeat back a chain of letters they were shown for only 800ms at a time. (This is the first time nature’s been looked at as a variable in such a test.)

However, on three other cognitive tests for which Bratman reported results, he found little or no performance difference between nature and urban walkers.

And two of these tests (attention network task and backward digit span) had shown positive results in previously published experiments. (Part of Bratman’s project is to replicate previous study results on nature’s psychological benefits.)

Bratman says there are numerous explanations for his results — chief among them, test-taker fatigue through 70 minutes of intense tests. And a null result, he adds, doesn’t invalidate previous findings.

“If anything, the OSPAN effects are conservative,” Bratman says.

However, Ben Levy, an assistant professor of psychology at the University of San Francisco who studies learning and memory and who was a co-author on Bratman’s new paper, says the results might also reflect the need for larger nature doses to make a difference to memory performance.

“The dosage of nature Greg did was pretty minimal,” says Levy. “Maybe you need to go spend a day or two in nature. I am optimistic that there might be some cognitive changes there, but they are weaker in my assessment than the affective changes.”

Can Cognitive Benefits Ever Be as Appealing as Affective Ones?

The 40-second green-roof-image test, on the other hand, produced very striking benefits for attention — prompting the study’s lead author, Kate Lee of the University of Melbourne, to tell Chris Mooney of the Washington Post that the findings could have immediate impact on workplace productivity.

“Modern work drains attention throughout the day, so providing boosted ‘green micro-breaks’ may provide mental top-ups to offset declining attention,” Mooney quoted an email from Levy.

“Heavy demands are placed on attention in the workplace and this research suggests a simple strategy to enhance concentration,” Lee also told Kate Ashford at Forbes. “Our results suggest attention boosts that could have meaningful implications for any number of vital work tasks that involve executive functioning, such as strategizing, planning, reading and writing.”

Lee’s comments mirror a hunger among many in the environmental community, who have seized on the smarter-by-nature research as a mantra to motivate more outdoors participation.

But larger questions about the implementation and consequences of research such as Lee’s and Bratman’s remain unanswered.

Will people use nature in this way — in essence, to boost their productivity? Instead of, say, a coffee with their colleagues?

Will computerized images of green roofs (or even green roofs themselves) actually strengthen workers’ affinity for nature? Or its conservation?

Might they even come to resent this use of nature as manipulative?

Contrast that with Bratman’s findings on the substantial benefits that 50-minute nature walk can give to your mood and tendency to ruminate — a known precursor to depression.

One in approximately every 20 people worldwide suffers from clinical depression — so interest in a solution to these findings is already high.

In addition, affective benefits are immediately and universally appealing. As Bratman says, there’s much more science to be done to turn them into true ecosystem services — tailored to different groups and different landscapes, and implementable into urban planning. But one can see that path being much more populist.

Bratman argues that more research can overcome that bias.

“The idea that nature makes us feel better is more intuitive than the idea that nature makes us smarter,” he says. “You need to break that down with evidence.”

‘There’s Something Going On Here…Let’s Just Tackle It’

Levy lauds Bratman’s research project for helping to bring rigor to the smarter-by-nature literature.

“Most of this [previous research] is correlational, which I didn’t find that compelling — a kid who has a view of nature outside his window will perform a little bit better than another kid who doesn’t have that view,” Levy says.

“The interesting question is: Why do we get these effects?” he continues. “Is it something about nature per se, or could you get the same benefits from going to a museum — a place that might inspire the same sense of wonder or interest?”

“Experimental research, like what we did here, where we have control over who gets exposed to nature and over other variables — like amount of exercise — is quite rare. Greg was very careful here, he included more measures of affect and cognition to see what is actually influenced.”

Bratman defends the state of the literature, arguing that it is a convincing mix of correlative, experimental and natural studies.

“If these studies are all pointing in the same direction — and they are — then there’s something going on here,” he says.

His next steps are helping to refine that “something” with a series of experiments that he hopes will lead to customized implementation of his findings to different groups and environments.

For instance, he and Heather Tallis, a lead scientist at The Nature Conservancy, are studying how density of trees and shrubs might impact test scores in schools — and whether planting more greenery near those schools might be a low-cost way of boosting average scores.

“It’s just such a data-starved area right now,” Bratman says. “My approach is: Let’s just tackle it.”

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