|Abstract:||Exposure to urban nature is beneficial to the health and well-being of people from a variety of cultures and across the human lifespan (Hartig et al. 2014; Sullivan, Frumkin, Jackson, & Chang, 2014); Tzoulas et al. 2007). Considerable evidence demonstrates that the design of places in which we live, work and play impact the extent to which we experience mental fatigue and recover from that fatigue. We do not know, however, the precise neurological mechanism that underlies the relationship between exposure to urban settings that vary in the amount of vegetation they contain and attentional performance.
Although previous research has made it clear that looking at, being in or walking through green urban spaces reduces mental fatigue (Li et al. 2019; Li and Sullivan 2016), the neural pathways through which these impacts occur and the other associated psychological implications that underlie their reactions have been entirely unclear. The lack of this information is an important problem because it limits our ability to design urban settings that support healthy neurological functioning for a growing population of humans who live in cities.
I address this gap in our knowledge by conducting two experimental studies designed to answer the following question: “To what extent does walking in urban nature impact the neurological and psychological well-being of people?” To address these issues, this dissertation includes a review of the current literature and reports on two empirical studies: the walking study and resting-state fMRI study.
In the walking study, which focuses on the psychological implications of walking in urban nature versus walking in barren settings, I asked, “To what extent does the greenness of an urban walk impact healthcare workers attentional functioning, affect, and anxiety when they take a walk during their workday?” To answer this question, I conducted a randomized experimental design with healthcare workers. The experiment had two conditions, three, 40-minute walks in either a barren or green urban setting during a 7-day period. We found that walking in the green setting had significant impacts on measures of attention, affect and anxiety. The green setting resulted in higher total attention and affect scores and lower scores on anxiety.
The resting-state fMRI study, which focuses on the neurological implications of walking in urban settings rich in nature versus walking in urban settings that are nearly devoid of nature, I asked: To what extent does exposure to green versus barren urban settings impact brain functional connectivity – a measure of attentional capacity – when ascertained at resting state?”
In this study, 48 healthy adults were randomly assigned to walk three times for 40 minutes in either a green or barren urban setting during a one-week period. Participants in the green group maintained about the same attentional scores after the one-week treatment, but the attentional scores significantly decreased in the barren group. Findings from the fMRI portion of this study revealed that the functional network connectivity at rest was significantly higher in the green treatment compared to the barren treatment.
The studies presented here strongly suggest that walking in green settings can promote psychological and neurological well-being. This research is among the first studies using resting-state fMRI to examine the relationship between walking in different environments and attentional functioning. This results of this work are significant because they help us understand the relationship between urban green infrastructure and human well-being at psychological and neurological levels. The findings should be of interest to designers, policy makers, and public health providers and can be used to pave the way for targeting urban nature interventions to moderate the neurological and psychological outcomes of typical urban environments in support of mental health.