Photo: Sharpen your memory with a simple walk in nature

Currently a post-doctoral fellow at Baycrest's Rotman Research Institute in Toronto, Dr. Marc Berman is producing groundbreaking research on how spending time in nature affects the human brain. Here, he tells Docs Talk about his findings.

Docs Talk: You've been researching the effects of nature on memory and other cognitive skills, especially in people with major depression. What are some of your findings?

Dr. Berman: We found that a 50-minute walk in nature can improve memory and focus by about 20 per cent, while walking in a busy urban environment doesn't significantly improve memory. The effects were stronger in individuals diagnosed with major depression.

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DT: Did you discover anything that particularly surprised you?

Dr. Berman: One of the more surprising findings was that effects on memory were not driven by changes in mood. We had people walk at different times of the year; some walked in June when it was nice outside and others walked in January, when it was cold. The winter walkers didn't enjoy the walk as much as the summer walkers, but they still received the same memory benefits. So we may not even need to enjoy the walk to receive the benefits.

DT: What is it about the natural environment that has such profound effects on cognitive abilities like short-term memory?

Dr. Berman: We believe that having "softly fascinating" stimulation to look at (such as trees, leaves and water), while not having to concentrate heavily allows a person to de-focus and self-reflect in a natural environment. Sitting in a dark room isn't restorative because it's boring, which is fatiguing even though it doesn't require heavy concentration. Watching television isn't restorative either, because the stimulation is harsh and requires concentration. Other environments, such as museums, could be restorative as well, but we find that the natural environment is one of the most effective at restoring cognitive abilities.

DT: What are the implications of your findings?
Dr. Berman: We have a long way to go, but there are a lot of potential implications. First, our results and those of other researchers suggest a mental/psychological benefit of interacting with nature, which is not typically discussed. Nature seems to have a three-pronged benefit: ecological, physical and psychological. Second, we and others have found that the benefits of nature extend to children with ADHD, older adults, people recovering from surgery and individuals diagnosed with breast cancer. This suggests that a single intervention can improve human health and wellbeing across the board. Our findings could impact how we design cities, schools, workplaces and hospitals, and how we treat many different kinds of illnesses.

DT: What's next for your research?
Dr. Berman: 
First, we want to uncover the features of nature that lead to restorative experiences so we can design and retrofit existing parks and nature areas to optimize those experiences. Second, we want to use MRI technology to pinpoint the exact neural and physiological changes that accompany a restorative experience in nature.
And third, we'll examine how prolonged exposure to nature affects health and wellbeing at a population level, answering questions like, "do neighborhoods that have more tree canopy have healthier residents than neighborhoods that do not?" This will help us quantify the economic value of natural areas from a mental and physical health perspective, which we hope will lead to public policy and societal changes.

October 1, 2012

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