The Relationship Between Surrounding Greenness, Stress and Memory

Evidence suggests that surrounding greenness is associated with multiple health-related benefits, including better cognitive functioning. Underlying mechanisms of the relationship between exposure to natural environments and cognitive functioning have not been widely researched. This study aimed to analyse the relationship between surrounding greenness and memory performance, and to explore the potential mediating role of stress. A sample of 185 adults was recruited in Stoke-on-Trent and Newcastle-under-Lyme (UK). Data were collected on exposure to and use of natural environments, stress, three measures of memory performance (short-term memory, working memory, overall memory), and participant socio-demographics. Linear univariate regression was conducted to investigate the relationship between surrounding greenness, memory performance and stress. Mediation analysis was conducted to investigate the role of stress as mediator of the relationship between surrounding greenness and memory performance. Surrounding greenness was significantly associated with better short-term and overall memory performance and lower levels of stress, and lower levels of stress were significantly associated with better short-term and overall memory performance. Stress was a significant partial mediator of the relationship between surrounding greenness and short-term memory. Results were robust to controls for area deprivation. One explanation for these findings is that stress is a multifaceted reaction to a demand which involves cognitive functioning, so that less stress might lead to improved cognition. These results suggest that cognitive benefits of exposure to surrounding greenness are partially mediated by lower levels of stress. Future research should consider other potential mediators of the relationships between surrounding greenness and cognitive functioning, such as mood, well-being and social relationships.