Exposure to trees, the sky and birdsong in cities is beneficial for the mental wellbeing of people, a study suggests.
Researchers at King's College London found that (i) being outdoors, seeing trees, hearing birdsong, seeing the sky, and feeling in contact with nature were associated with higher levels of mental wellbeing, and that (ii) the beneficial effects of nature were especially evident in those individuals with greater levels of impulsivity who are at greater risk of mental health issues.
The researchers developed a smartphone-based app to examine how exposure to natural features in cities affects a person's mental wellbeing.
The app monitored 108 individuals who collectively completed 3,013 assessments over a one-week period.
In each assessment, participants answered several questions about their current environment and momentary mental wellbeing. GPS-based geotagging was used to monitor their exact location throughout the 1-week trial.
The results showed significant immediate and time lagged associations with mental wellbeing for several natural features: trees, the sky and birdsong. These associations were still evident several hours after exposure to trees, the sky and birdsong had taken place, indicating time-lasting benefits.
The investigators were interested in whether the beneficial effects of nature might vary from one individual to another, depending on their risk of developing poor mental health.
To assess this each participant was rated on "trait impulsivity" - a psychological measure of one's tendency to behave with little forethought or consideration of the consequences, and a predictor of higher risk of developing addictive disorders, attention deficit hyperactivity disorder, antisocial personality disorder and bipolar disorder.
This revealed that the beneficial impact of nature on mental wellbeing was greater in people with higher levels of trait impulsivity and a higher risk of developing mental health issues.
Dr Andrea Mechelli, Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, said, "These findings suggest that short-term exposure to nature has a measurable beneficial impact on mental wellbeing. The interaction of this effect with trait impulsivity is intriguing, as it suggests that nature could be especially beneficial to those individuals who are at risk of poor mental health. From a clinical perspective, we hope this line of research will lead to the development of low-cost scalable interventions aimed at promoting mental health in urban populations."
Johanna Gibbons and Neil Davidson, landscape architects at J & L Gibbons, said, "Right now decisions on urban planning and design aimed at improving mental health tend to be based on "conventional wisdom", due to the lack of robust scientific data. Our findings provide a much-needed evidence base for the benefits of nature within urban centres. From the perspective of urban planning and design, we hope the results will inform future investments and policies, helping build heathier cities".
Michael Smythe, an artist and action-based researcher at Nomad Projects, comments, "This study represents a successful example of how smartphone technologies can be employed as a tool for citizen science. It also demonstrates the value of academic and non-academic researchers coming together to carry out truly cross-disciplinary work with tangible real-world implications".
The findings have been published in the journal BioScience.