This study builds on previous research indicating a link between urbanization and increased levels of mental illness. The reason for this is not clear. The purpose of this experimental study was to investigate whether decreased nature experience may be a contributing factor.
Thirty-eight young adults were randomly assigned to a 90-minute walk in either a natural or an urban environment in and around Stanford, California. Before and after their walk, participants completed a self-report assessment of levels of rumination (RRQ) and underwent a brain scanning procedure assessing the neural activity in the subgenual prefrontal cortex (sgPFC). Rumination (repetitive thought focused on negative aspects of one's self) is a maladaptive pattern of thinking associated with increased risk for depression and other mental illnesses. Activity in the sgPFC tends to increase with negative self-reflective processes tied to rumination.
The nature walk took place in a grassland with trees and shrubs; the urban walk on a street with a steady stream of traffic. The nature-walk participants showed decreases in both self-reported rumination and neural activity in the sgPFC. The urban-walk participants showed no such effects. These findings reveal a pathway by which nature-related experiences may improve mental well-being and suggest that accessible natural areas in urban environments may be a critical resource for the mental health of city residents.
This research is consistent with other studies documenting affective and cognitive benefits of nature experience but adds to it by identifying decreased sgPFC activity as a possible explanation for such affective benefits. This study indicates that even a relatively brief nature experience can enhance the well-being of people. This, in turn, suggests that investments in access to natural environments could contribute to the “mental capital” of cities and nations.
Some cities are already incorporating the benefits of nature into urban design by locating buildings (especially schools) near green space and increasing opportunities for public access to nature. Further study and related city planning initiatives can potentially provide city residents with nature experience buffers that offset the negative repercussions of urban life.
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