Let’s say you’re prone to depression — like an estimated one in every 20 people worldwide.
What if there were a pill called “nature” — proven to quickly boost your mood, tailored to give you the maximum dose response, and able to change the way you think about yourself for the better?
Would you get out into nature more than you do now? Help conserve it? Live in cities that have more of it?
That “pill” is the Holy Grail scientist Greg Bratman is chasing through his research. While lots of past studies have argued that being in nature generally makes us feel better and perform better on cognitive tests, they haven’t increased rates of outdoor activity.
So Bratman (a Ph.D. candidate at Stanford) is diving deep to find out which kinds of nature at which lengths of exposure impact which groups of people the most, and for how long.
It’s state-of-the-art stuff, using tools such as MRI machines, skin conductance sensors, and working-memory tests delivered to people via cell phone as they’re on a nature walk. And the research is far from finished — Bratman’s first paper was just published in the journal Landscape and Urban Planning.
But if the data bear out Bratman’s hypothesis, it could open up another new way people would value and use nature: for its psychological benefits to them as individuals.
“A lot of people grasp intuitively that nature makes them feel better, and the research generally shows it,” Bratman says.
“But how do you push them over the tipping point and into action? How do you get cities designed so that more nature is set aside within them? Finding the mechanisms and modeling the benefits on an individual level will make the science much more convincing.”
Stop Brooding about It: More Nature, Less Rumination
But first: Why does being in nature make many people feel better than, say, being in a city?
Evolution offers one explanation: we’ve developed an innate preference for nature experiences — particularly those landscapes (such as savannas) that provided our ancestors with food and refuge from predators.
But Bratman’s new paper suggests another cause: nature is much better than urban environments at defeating our propensity to brood or ruminate (what Bratman calls “engaging in repetitive, negative autobiographical thoughts”).
And that anti-ruminative quality might be key to nature’s psychological benefits, because rumination is highly associated with depressive episodes, says Bratman — both their onset as well as prolonging them.
“I’m very interested in rumination because a shift in this type of attention allocation might help explain what nature experience is doing to the way we think, which could then explain the other mood benefits we see from getting out into nature,” says Bratman.
For the study, Bratman took 60 randomized subjects, gave them cognitive and mood assessments and then sent them either on a nature walk on the Stanford campus (a grassland with occasional trees) or a walk along a Palo Alto boulevard with heavy car traffic.
All the participants took 10 photos of “whatever captured their attention” during the walk, to prove that the walk took place and obscure the true purpose of the study. (They used a phone Bratman provided them, and were told not to use their own.)
Then they underwent 75 minutes of additional testing after the walk — self-assessments about how they felt as well as memory and other cognitive tests.
The self-assessments showed that being in nature does a much better job than city life at decreasing anxiety, rumination and negative emotions while also increasing positive emotions.
But is it just distraction from negative thought patterns, which other environments or experiences might also accomplish?
Or does nature provide something above and beyond distraction that cities or video games or movies can’t?
Reframing a Grunt: Emotion Regulation and Nature Experience
While his research into the mechanisms behind these results is just beginning, Bratman says that nature might be prompting what psychologists call “cognitive reappraisal” of events, thereby changing their emotional meaning.
“If I’m talking to you and you grunt when I say something,” says Bratman, “I could either think you’re grunting because I said something stupid or because you’re clearing your throat. Those interpretations are going to have vastly different kinds of emotional repercussions for me, and that’s just a silly example of what reappraisal can do — reframing an event that changes how I feel.”
“So simple distraction can help people who have high levels of rumination and negative affect,” Bratman adds. “But there’s another type of emotion regulation that is a possibility as well: that nature is encouraging cognitive reappraisal, and that it encourages the ability to engage in this adaptive way of thinking that could help explain affective benefits.”
Again, it’s just a theory, and much more research is needed. But if nature experiences turn out to be particularly good at reappraisal, such findings could have ramifications for global mental health trends, says Bratman.
That’s because numerous studies suggest that recent increases in the levels of mental disorders globally are tied to increasing urbanization and people’s decreasing exposure to nature.
“We’re at 50 percent urbanization worldwide, and we’re headed toward 70 percent in a couple of decades,” says Bratman. “Our hypothesis is that urban life involves a constant stream of stressors that raise the baselines of our cognitive loads and rumination levels, adding to our risk factor for mental illness.”
In the meantime, Bratman has made important steps toward a better understanding of the link between nature and better moods, says Ben Levy, a co-author on the new paper and an assistant professor of psychology at the University of San Francisco.
“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,” says Levy.
“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. It’s clear from these findings you get an affective benefit from nature.”
Finding Your Happy Place: The Long Research Road Ahead
The ultimate goal of Bratman’s research agenda: To build a detailed “map” of which kinds of nature experiences deliver which emotional and cognitive impacts to which kinds of people (as well as most broadly overall).
People who tend to depression, for instance, might search that map to find the precise kind of forest or grassland walk that could best stop them from ruminating.
Or urban planners might use it to create “smart” nature experiences in their cities — oases that could appeal to corporations looking to give their workforces an edge over the competition, say.
Such knowledge could turn the “nature = well-being” narrative from just a vague feel-good story into an amenity — one that citizens might seek out and demand in their communities.
“The field is moving toward figuring out the causal mechanisms behind these effects, and also they differ across cultures and individuals based on personality characteristics,” says Bratman. “What’s the dose-response relationship? How much nature does it take, and what kinds? Do different kinds of nature have different impacts?”
Bratman himself is digging into what he calls the “psycho-physiological impacts of nature experience on rumination” — tracking differences in heart rate, skin conductance, and other measures of bodily responses as people ruminate in both nature and urban settings, and examining if these different environments have different impacts on physiology and rumination.
(By the way, while Bratman’s experiment reaffirms the connection between nature experience and feeling better about yourself, he found only mixed evidence for the long-standing claim that “nature makes you smarter.” More about that in my post next week.)
The science needed to make the hard case for nature as a psychological amenity — one that you could map, administer in self-dosages, or even market — seems vast and painstaking: the work of a decade, perhaps.
But Levy thinks we might not need to wait for all the research to be in to act on the early findings.
“The questions about what exact natural environment provides the greatest benefit to whom are really interesting — but if you know that nature does provide this benefit, it certainly doesn’t hurt to start providing nature to people, right?” Levy says.
“Yeah, you might be able to find something else that’s equivalent, but if nature works, it works. You can take advantage of that observation.”