The Research on How Nature Affects Mental Health Has a WEIRD Problem

That's WEIRD as in Western-Educated-Industrialized-Rich-Democratic.
Three women sitting in a park, cityscape in the background.
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Twitter can be a negative place, but in 2019, researchers found a simple intervention that could skew people’s tweets in a more positive direction: going to a park. 

Using the “Hedonometer,” a tool that measures the happiness of words, the study found that park-goer’s tweets contained fewer negations like “no,” “not,” or “don’t.” Their tweets went up by about 0.23 points on the Hedonometer scale, equivalent to the increase measured on Christmas Day, and tweets were more positive the more vegetation there was in the park a person went to.


The findings suggested that green urban spaces and exposure to nature have a positive effect on mood. This boost wasn’t limited to only the time spent in the park, but could last for one to four hours later. “Possible explanations for this trend are anticipation for the park visit, meeting friends on the way, or perhaps relief due to leaving work and heading to a more enjoyable location,” the authors wrote. 

This study is part of a growing body of work that shows that nature can have beneficial effects on mental health and well-being. A study from 2019 in the UK found that a minimum of two hours spent in nature per week seemed to be optimal. Another found that people who felt more connected to nature had greater “eudaimonic” well-being—not just happiness, but a sense of a good life. Books like Your Brain on Nature and The Nature Fix have all stressed how being outside could be a balm for mental distress.

But as the Twitter and San Francisco parks study reveals, statements like “nature helps with mental health” come from research done on real people, from specific demographics. In this case: people who use Twitter, who live in an urban area, and who consider “nature” to be public parks, playgrounds, or even civic plazas and squares. 


In a new study in Current Research in Environmental Sustainability, University of Vermont researchers reviewed 10 years of peer-reviewed studies on nature and well-being, from 2010 to 2020, and found that much of what’s available in mainstream academic journals on this topic is based on a small slice of humanity. People in these studies were mostly white, and over 95% of the work they reviewed was done in high-income Western nations. 

Less than 4% of the studies were done in medium-income nations, like India, and there were none in low-income countries. 62% of the studies didn’t say what their participants' ethnicity was at all. Only one study was done in Africa, one in South America (neither of which tracked ethnicity), and only one out of 174 focused on North America’s Indigenous populations. 

This means that a large swath of this research has focused on so-called WEIRD people. In 2010, a seminal paper pointed out that a lot of behavioral science or psychology is based on societies that are Western-Educated-Industrialized-Rich-Democratic, or WEIRD.  “Members of WEIRD societies, including young children, are among the least representative populations one could find for generalizing about humans,” the authors wrote. 


It doesn’t mean these studies are wrong, but making sweeping generalizations about human psychology from just this group probably isn’t capturing variations present in other cultures. 

People’s relationship to nature, and how it makes them feel, are important to know for urban planning, policy making, and even promoting climate change activism. Mental well-being and planetary health are concerns that affect everyone on Earth, and yet by focusing only on a subsection of the population, we could be missing knowledge as to how exactly people and the natural world are connected, how this connection influences mental health, and what it has to do with pro-environmental behaviors. There are other, often rich, relationships to the natural world we may be ignoring with such a narrow focus. 

In 2005, Carlos Andres Gallegos-Riofrío was studying depression in Indigenous communities. As a psychologist trained in the Global South, he learned early on that the measurements used in other parts of the world had to be validated culturally and linguistically before they could be applied to his communities. 

Now a postdoctoral fellow in nature and health at the University of Vermont, and a co-author of the new paper, he said it was this immersion in the cultural differences in mental health that prompted him to want to examine the research on nature and well-being more closely.

“We need to be able to tell what is universal to us as a species and what is culturally specific,” he said. 


It can feel intuitive, or even obvious, that being outside feels good. (Thus the existence of the meme: “touch grass.”) But the way a city park can be a positive influence on a person who lives in an urban environment is likely different than the effects for a rural or Indigenous person who migrates to a city and is disconnected from their home, Gallegos-Riofrío said. 

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“On the one hand, theoretically, nature is expected to benefit most people based on the restorative qualities it has,” said Lisa Nisbet, an environmental psychologist at Trent University who wasn’t involved in the study. But she added that there are disparities in the kinds of natural environments people have access to, and what meaning they hold. 

“There may also be cultural differences in how people value nature or the attitudes that shape how the environment is used, like harvested vs. conserved,” she said. “Less is known about how age, occupations, socio-economic status, and other demographic characteristics affect people’s connection with and enjoyment of nature.” 

There are instances where green spaces could have had adverse effects on people, as scholarship on people of color feeling like natural spaces are not inclusive to them has shown. “There could be negative associations with spaces in marginalized and underprivileged communities,” Gallegos-Riofrío said. 


The WEIRD perspective can also influence study design itself: how “well-being,” “mental health,” or “mental illness” is defined and measured in studies can be reflective of cultural biases. Even the concept of “nature” changes depending on who is defining it.

In the 174 studies that were reviewed, nature was often described “elusively or through colonial categories” like forests. Many of the studies defined nature as “vegetation cover,” and thought of nature as green, and more rarely, blue. “There is a great range of natural elements and types of ecosystems that we know little about in terms of human well-being,” Nisbet said. 

One of Gallegos-Riofrío’s colleagues is from Kuwait; it was striking for him to see nature only described as green, when for him nature is the desert. “People may come from areas that look different,” Gallegos-Riofrío said. “The way they relate to those environments is definitely not captured in this body of science.”

Some studies put forward conceptions of nature that are even narrower. As one example, a study included, “forest, managed grass, and water as dominant land cover types, specific water features (e.g., small ponds, fountains) and built features (e.g., trails, paths).” Some studies use “nature” that was actually virtual reality, three-dimensional models, or cell phone apps that simulated parks, forests, or gardens.


These are “environments as inanimate, secular spaces, often under the control, ownership, or care of human populations and municipal governments,” said Andrew Hatala, an associate professor in community health sciences at the University of Manitoba who studied the effects of nature in Indigenous youth in Canada. “For many Indigenous populations, perspectives of land and nature are much deeper.” 

For different communities, nature and the surrounding environment have different significance. Hatala explained that having a relationship to nature isn’t always about a physical location, but “can often involve symbolic or sacred representations, and spiritual relationships with broader more universalizing notions of ‘Mother Earth,’” he said. 

Or, the land can be an integral part of other concepts, like the concept of time. For the Yupno of Papua New Guinea the passage of time is connected to the topography of the land they live on. Rather than time moving forward or backwards, the past is construed as downhill and the future as uphill, cognitive scientist Kensy Cooperrider and his colleagues have found

As Cheryl Charles and Gregory A. Cajete wrote in 2020, the way that Indigenous people often express their relationship to the natural world is rooted in reciprocity. In New Zealand, the Maori people view themselves as a part of nature, and responsible for guarding and protecting it. “In Australia, Aboriginal culture was founded on the belief that people and nature are created as one, and humans do not have dominion over the natural world,” they wrote.


Rather than this sense of unity, in the West, nature’s benefits can be referred to with externalizing, medical terminology, like when it’s called “a dose” of nature. The book Last Child in the Woods is known for the term “Nature Deficit Disorder.” There’s an organization called Park RXAmerica; their mission is to “decrease the burden of chronic disease…by virtue of prescribing Nature during the routine delivery of healthcare by a diverse group of health care professionals.” A press release from 2015 described one study as researchers finding a “mental health prescription: Nature.”

There’s nothing inherently wrong with this framing, and it may resonate with many Westerners. But it shouldn’t be assumed to be universally relatable, or capture the role nature might play in other people’s lives and well-being. In Indigenous communities, nature isn’t experienced as a transaction.

“It is not that I got to nature, and ‘I receive this,’” Gallegos-Riofrío said. “We are nature. We belong to nature. We have to take care of nature.” 

Frequently it’s the process of urbanization, migration, and climate change that disrupts people’s lives and their connection to their home environments in the first place—which then causes mental health issues. For people in those situations, the better way to address well-being isn’t just access to a public park, but policy or interventions to prevent what caused the disruption in their lives, said Amaya Carrasco, a PhD student at the University of Vermont and a co-author on the paper. 


Carrasco used to be a medical interpreter in Missouri, and she said she often heard stories from people from Latin America, about how they missed the specific natural landscapes of the places they came from. “They would talk about the mountains, the lake close to their houses,” she said. “They would miss those specific landscapes.”

Charles and Cajete described “ensoulment,” writing that “the ensoulment of nature is one of the most ancient foundations of human psychology.” This is why separating Indigenous people from their land and environments, as was done through forced relocation in North America, “constituted, literally, a loss of part of the soul of that whole generation.” This is a profoundly different underlying explanation for the relationship between nature and well-being.

People in Western cultures may not be able to access or embody these cultural representations, but it should be included in the research, and there is a lot of wisdom to learn from them, Hatala said. 

Folding in these perspectives could make an impact on not just how nature makes us feel, but how we treat it in return. “Nature and land are often understood as animate and sentient as one example, which has profound implications for not only individual health and wellness, how we relate, but also in how we treat the land and respecting the ‘rights’ of the land,” Hatala said. “In some places in Canada Indigenous communities are legally getting certain areas of nature, like rivers, to be recognized as a person and to hold the rights and freedoms that persons hold.”


Michael Barnes, a postdoctoral researcher at University of Minnesota Twin Cities, once worked on a review about how nature could benefit learning, and now teaches a course for K-12 educators on how to incorporate nature-based learning. “Every time I teach I get the question, ‘How does this impact the students in my classroom?’” Barnes said. 

It’s tough to give a specific answer, he said, because each teacher’s class comprises a unique population, and the nature-based learning research is based on “mainstream students.” 

Doing this research should come with an awareness that the findings will be most translatable in the specific group they were studied in. “I might be able to point the educator to one or two studies addressing their specific students, but it's not the level of specificity we need to provide actionable information,” he said. “And this really applies to the broader human-nature-well being literature as well.” 

But Hatala said that even if the 174 studies the new paper reviewed are lacking in diversity, there is a rich history of research on this topic within Indigenous communities in Canada, New Zealand, and the U.S. that others can access. It just tends to be more holistic in nature, and not necessarily the kinds of studies that are included in journal reviews. 

“This, in some sense, also reflects a bias in the process of conducting reviews of this kind,  and that you have to look outside the mainstream journals if you want to find this diversity,” Hatala said. “Because of this, this study is also likely a victim to the same bias they are highlighting in other Western focused research.” 

With an expansion both in research, and incorporating what’s already out there, Barnes thinks we’ll better be able to tackle the unanswered question of what kind of nature is most beneficial for which people. “This is critical because if we assume that everyone benefits equally from a trip to a wilderness area for example, but that’s not actually the case for a certain group of people and we end up further alienating people from nature we’ve now gone backwards,” he said. 

Carrasco hopes that more diversity and pluralism, or the inclusion of differing worldviews about health and nature, leads to better understanding of individuals, but also how we might foster new relationships with nature overall. In Ecuador, where she’s from, there was a movement to protect “Mother Earth” through the constitution

“It’s seen as a subject of rights rather than seen as a thing,” she said. “It's very inside of the Ecuadorian mind. Imagine what we could discover if we research about well-being and the effect of nature from that different perspective or understanding of nature.”

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