We decided to revamp a couple of stories on the benefits of green spaces, for which there is an ever-growing body of evidence. 

NPR’s Aaron Scott recently spoke with environmental psychologist Ming Kuo on green spaces and why we all seem to feel better walking down a city street lined with trees. Time spent in nature lowers our risk of disease, improves our resistance to infection, and happier overall.

Not only that but spending time in nature has also been known to improve cognition in young children and reduce the risk of dementia in adults. 

Keeping our brains green

A study from Boston University included nearly 14,000 women, with an average age of 61, as part of the largest investigations into the risk factors for chronic diseases among women in the United States. Adjusting for age, race, and individual and neighborhood socioeconomic status, the researchers were able to come up with the average psychomotor speed, attention, learning, and working memory of the participants.

They concluded that green spaces are associated with higher overall cognitive function in middle-aged women, as well as better mental processing and attention. Scientists consider cognitive function around this age as a strong predictor of developing dementia later in life.

They also concluded increased time in green spaces, decreased exposure to air pollution, and increased physical activity decreased the risk of depression, another important risk factor for cognitive decline.

“Some of the primary ways that nature may improve health is by helping people recover from psychological stress and by encouraging people to be outside socializing with friends, both of which boost mental health,” says study lead author Marcia Pescador Jimenez.

They continue: “This study is among the few to provide evidence that green space may benefit cognitive function in older ages. Our findings suggest that green space should be investigated as a potential population-level approach to improve cognitive function.” 

Why are we happier in green spaces?

Researchers have tied our sunny dispositions in nature to fractal patterns.

Fractals are essentially self-repeating patterns of different scales. Think of the repeating patterns of veins on a leaf, then the different repeating patterns on a tree’s bark, and then look at the next level of repeating patterns watching all those trees pass by in a forest. 

These differing levels of repeating patterns are something that our human eyes and minds grew very used to evolving in nature, and it’s no surprise that we feel calmer in nature because of this. It’s like we’re looking at our natural home. These patterns are, unfortunately, less common in cities. 

A University of Oregon study showed that it only takes the human brain 50 milliseconds to detect fractals. The team also measured a positive mental response in their subjects, showing up to a 60 percent reduction in stress and mental fatigue. Healing can even be improved in humans observing natural fractals, such as a hospital patient who mends more quickly with a window facing trees. 

These stories were originally published on March 14 and May 12, 2022.