October 6, 2022

Spending time in the great outdoors is good for your mental health, according to a growing body of research. For example, getting out and about in forests and parks has been shown to increase happiness and alleviate symptoms of depression and anxiety. But are the benefits universal?

A review paper notes that most studies in this field look at rich, white, western populations, and scientists say this results in an incomplete picture of the health benefits.

Carlos Andres Gallegos-Riofrío, of the University of Vermont’s Gund Institute for Environment, whose findings have been published in Current Research in Environmental Sustainability, says indigenous populations like those he studies in South America have different relationships with nature to other people. He says it is important to learn how their mental health is affected by this different rapport.

Gallegos-Riofro and colleagues at the University of Vermont examined 174 peer-reviewed studies from the last decade and found more than 95% of research was conducted in high-income western nations of the US, Europe and east Asia. Only 4% of studies looked at nations of medium income, such as India, and no low-income countries featured in the studies. Only one study took place in Africa and one in South America. Of the participants whose ethnicity was known, most were white.

Rachelle Gould, a researcher at University of Vermont’s Rubenstein School of Environment and Natural Resources, said: “There’s nothing necessarily wrong with the existing findings, those findings are important, but we have reason to believe they may not apply to the entire population. In order to allow this work to influence sustainability action and to move us towards sustainability, we need to know which of these effects are universal and which are culturally specific.”

Making this distinction can lead to fair policy changes, Gould says.

The study builds on the concept of “Weird psychology”, a term coined by the evolutionary biologist Joseph Henrich. The acronym refers to how experiments that focus mainly on college students from western, educated, industrialised, rich and democratic (Weird) parts of the world cannot allow scientists to draw universal conclusions about human behaviour.

“This research strikingly demonstrates a massive bias in the sampling of global populations towards those that are Weird,” said Henrich, who was not involved in the study. “This limits our ability to generalise about the phenomenon under investigation.”

Henrich said it would be useful to expand research to include more diverse populations and use culturally sensitive tools adapted to the people being studied.