Is it true that nature is good for our brains?
It would seem that nature is good for what ails us. When many of us were confined to our homes during the pandemic, we collectively became more aware of our environment. Walks in parks, plants in our homes, gardening, and greenery were salves to our wounded psyches. This general belief in nature’s benefits falls under the widely used term biophilia. The term refers to the hypothesis that humans innately seek out connections with nature and other forms of life, a motivation rooted perhaps in our evolutionary history. First proposed by psychoanalyst Eric Fromm (Fromm, 1992), and then popularized by biologist E.O. Wilson in his book, Biophilia (Wilson, 1984), the idea has taken root in the public imagination.
The scientific literature seems to support this view. Attention restoration theory proposes cognitive benefits from exposure to nature (Kaplan & Kaplan, 1989). The idea is that nature is relaxing and does not make the same kinds of demands on our voluntary attention system as urban environments do. Our depleted attentional resources get restored in nature and we are recharged, ready to take on new cognitive challenges.
Stress recovery theory also emphasizes the benefits of nature (Ulrich, 1981); in this case, on our affective, rather than cognitive, systems. According to this view, exposure to nature decreases arousal and negative emotions, like fear. Being in nature can decrease heart rate, blood pressure, and even stress hormones such as cortisol. Consistent with this view, mental health conditions like anxiety, depression, and schizophrenia are more common in urban than in rural environments (Peen et al., 2007).
Brains on nature
Demonstrating the benefits of nature on our brain would be the final capstone to our intuitions, theories, anecdotes, and observations. A very recently published does exactly that.
Sudimac et al., 2022, looked at 63 healthy people exposed to urban and natural environments in Berlin. In the late summer and early fall, participants were randomized into two groups. Both were given specific routes along which to walk, either urban or natural, and were tracked using their mobile phone’s GPS systems. Participants walked for an hour and were instructed not to enter stores or engage with their digital devices during the walk.
In addition to asking questions about stress and attention, the researchers also recorded physiological measures, such as heart rate and galvanic skin responses, and administered a functional magnetic resonance imaging (fMRI) task in which participants viewed fearful faces. The researchers compared subjects’ reactions to fearful or neutral faces to determine the extent to which the stress or threat areas of the brain were engaged. Participants also did a mathematics task in the scanner; a task known to induce stress.
The investigators did not find any differences in the physiological measures recorded. However, they found less neural activity in the amygdala, especially in the right hemisphere, after the walk in nature in both the fearful face condition and the stress-inducing math task. A similar reduction in amygdala activity was not observed after people took the urban walk.
Nature is not nature is not nature
Is the claim that nature is good for our well-being unequivocally true? I don’t think so. I have had the experience of being airlifted out of the Canadian Rockies because of a grizzly; of banging into an alligator on a log in the Okefenokee Swamps; of puzzling how to cross a narrow path in Belize with a poisonous Tommy Goff snake lying in wait; of worrying about getting stuck in a remote section of Death Valley after an unusual deluge washed away roads. Nature can be scary.
Our research suggests that, for most people, the psychological response to the environment boils down to three components: coherence, fascination, and hominess (Weinberger et al., 2021). “Coherence” refers to how organized and legible the space is. “Fascination” refers to our interest in the environment—the extent to which we wish to explore it. “Hominess” refers to how comfortable we feel in a place. We find that in the built environment we are most at home when the imprint of nature is evident. In the natural environment, we are most at home when it is somewhat ordered. That is, we like nature with the imprint of humanity (Weinberger et al, 2021).
Looking ahead
I wish to be clear. I believe in the salutary effects of nature and am heartened by the research that confirms this intuition. It upsets me that my hometown of Philadelphia plans to take a wonderful area called the Meadows, where a golf course was allowed to go feral and attracts birds and butterflies and urban-nature enthusiasts like me, and construct sports fields over this beautiful land.
Sudimac’s brain findings are an early important step, but not the final word. We need a more nuanced approach to nature to identify which natural features appeal and which repulse. We also need to be clear that people differ. Our personalities and experiences powerfully influence our response to nature. Somebody who has only lived in inner cities might find nature daunting rather than comforting.
Much more work needs to be done to understand the nature of nature and its nurturing dimensions.
