THE DIRT

What many landscape architects and designers know intuitively is increasingly becoming proven scientifically. In fact, more and more exciting research appears showing the cognitive and mental health benefits of being out in nature — in places like parks, or even just meandering down leafy streets. According to The New York Times, a new study from Scotland shows that “brain fatigue” can be eased by simply walking a half-mile through a park.

In The New York Times’ Well blog, Gretchen Reynolds writes that “scientists have known for some time that the human brain’s ability to stay calm and focused is limited and can be overwhelmed by the constant noise and hectic, jangling demands of city living, sometimes resulting in a condition informally known as brain fatigue.”

Green spaces help alleviate brain fatigue because they are “calming” and require “less of our so-called directed mental attention than busy, urban streets do.” Natural settings “invoke ‘soft fascination,’ a beguiling term for quiet contemplation, during which directed attention is barely called upon and the brain can reset those overstretched resources.”

This type of research has been conducted for some time. Dr. Michael Posner and Dr. Marc Berman have explored the cognitive benefits of nature along with its restorative effects. Reynolds writes that it has been proven that people who live near trees and park has lower levels of cortisol, a stress hormone, in their saliva. “Scientists have brought volunteers into a lab, attached electrodes to their heads and shown them photographs of natural or urban scenes, and found that the brain wave readouts show that the volunteers are more calm and meditative when they view the natural scenes.” Dr. William Sullivan, a professor of landscape architecture at the University of Illinois, Urbana-Champaign, has spoken eloquently about all this research and his own in the housing projects of Chicago, which also shows that the presence of trees boost social ties and reduces crime (this must certainly be a result of the cognitive and mood benefits of nature).  Finally, research is proving that children benefit, too. “Children with attention deficits tend to concentrate and perform better on cognitive tests after walking through parks or arboretums.” (This is great news considering The New York Times recently reported that up to 11 percent of children have ADD).

But, what’s new and exciting about this particular study, writes Reynolds, is that the brains of people moving outside moving through the city and parks were actually examined with a “lightweight, portable version of the electroencephalogram, a technology that studies brain wave patterns.” In the past, work was done in labs or before and after exposure to nature.

In this new study, researchers at Heriot-Watt University in Edinburgh and the University of Edinburgh attached “portable EEGs to the scalps of 12 healthy young adults.” The electrodes were hidden beneath an “ordinary-looking fabric cap” and their brainwave readings were sent “wirelessly to a laptop carried in a backpack by each volunteer.” The researchers sent each volunteer out on a short 1.5 mile walk through different sections of Edinburgh.

“The first half mile or so took walkers through an older, historic shopping district, with fine, old buildings and plenty of pedestrians on the sidewalk, but only light vehicle traffic. The walkers then moved onto a path that led through a park-like setting for another half mile. Finally, they ended their walk strolling through a busy, commercial district, with heavy automobile traffic and concrete buildings.”

These amenable guinea pigs, who were allowed to move at their own pace, yielded some fascinating results: “When the volunteers made their way through the urbanized, busy areas, particularly the heavily trafficked commercial district at the end of their walk, their brain wave patterns consistently showed that they were more aroused and frustrated than when they walked through the parkland, where brain-wave readings became more meditative. While traveling through the park, the walkers were mentally quieter.”

Dr. Jenny Roe, a lecturer at Heriot-Watt’s School of the Built Environment, told The New York Times: “Natural environments still engage but the attention demanded is effortless. It’s called involuntary attention in psychology. It holds our attention while at the same time allowing scope for reflection.” She said the results show the value of “taking a break from work” and “going for a walk in a green space or just sitting, or even viewing green spaces from your office window.” This is not just “unproductive lollygagging,” writes Reynolds. There’s a real restorative effect at work that boosts our ability to concentrate and alleviate stress.

Other scientists have explored how being out in nature or even just viewing images of nature can improve our mood and make us nicer, too. Exposure to greenery can even help those in the hospital, with rehabilitation times lower for those lucky ones with views of natural environments.

Much more research is needed to fine-tune our understanding of the most effective forms of nature on stress reduction, cognition, and mood. Here’s hoping mental and public health researchers will partner with more landscape architects to understand how park design can maximize the benefits for busy, smart phone-obsessed people. Which park models work best? Which kind of green streets pack the most benefits? What kind of hospital gardens speed recovery times the fastest? Which relieve stress, boost cognitive function, and improve mood the most? Also, how do we measure the benefits of aesthetics and the subtleties of design? We’d like to know.

Learn more about this fascinating research using portable EEGs, and also check out another recent study in the journal Landscape and Urban Planning that tested cortisol levels to discover the benefits of nature on stress reduction.

Image credit: ASLA 2012 Professional General Design Award. Canada’s Sugar Beach, Toronto. Claude Cormier + Associés Inc., Montréal / Nicola Betts