Effects of a Walk in Different Natural Environments on Working Memory and Rumination
Abstract
Living in a city is related to various health issues, including higher risks for developing psychiatric disorders. On the other hand, various studies suggest that spending time in nature has positive effects on both physical health and mental health and cognitive functions. However, it is not clear which specific features of natural environments are causing beneficial effects.
This study attempts to research possible different effects of different natural environments (open green space, covered green space, blue space) on working memory capacity and rumination. Although the definition of green space may differ between various studies, the term typically relates to open areas of vegetation, i.e. parks as well as conservation areas, i.e. forests, but may also extend to backyards, farms or other spaces, which are primarily defined by vegetation. Blue spaces are typically defined as water bodies, i.e. lakes, oceans, and rivers but might also encompass built features, i.e. canals, water fountains. Based on previous findings, the hypothesis is that exposure to all of three natural environments will increase working memory capacity and decrease rumination. Since there is evidence in the literature favoring both open green space [2] and covered green space [1] regarding its impact on well-being and cognitive processes, the hypothesis is two-directional. Additionally, we expect better working memory capacity and rumination levels after exposure to blue spaces [3] because some studies suggest that it is more restorative than green spaces.
A total of 99 healthy participants were randomly allocated to take a one-hour walk in one of the three natural environments. The locations included Grunewald Forest representing covered green space, Tempelhofer Feld representing open green space, and Krumme Lanke lake representing blue space. Before and after the walk, working memory capacity was measured using the Digit Span Backwards (DSB) task and levels of trait rumination and state rumination were measured using the Rumination-Reflection Questionnaire (RRQ) and open questions. Data was analyzed using a mixed three-way robust ANOVA with environment (open green space x covered green space x blue space) as a between-subjects factor and time (pretest vs. posttest) as a within-subject factor. Additionally, posthoc t-tests were conducted to examine pairwise comparisons of the values before and after the walk.
In contrast to our hypothesis, there was no significant time-location interaction on working memory or rumination in any of the conditions. Nevertheless, working memory performance increased after the walk in the locations of open green space and covered green space, while there was no significant change for blue space. One of the reasons for this might be that the path around Krumme Lanke also encompasses canopy, like the one in Grunewald Forest, which often prevents clear view on the water. However, levels of trait rumination and state rumination did not significantly change in any of the conditions. As discussed in previous studies, trait rumination might not be the best suitable measure to capture changes after short-term interventions. Yet, there was also no decrease in state rumination, which was adopted to measure momentary changes, in any of the conditions. One possible explanation for this could be that the chosen study locations enclose mixed landscapes (combination of natural and human built objects), which is the case for most urban green and blue spaces.
Findings of this research could potentially help to inform decision-making processes regarding the design of urban green and blue spaces to enhance cognitive functions and mental health of citizens. They maybe also point towards future research directions regarding health policies, including green prescription as well as being physically active in nature.
References
[1] Astell-Burt, T., Walsan, R., Davis, W., & Feng, X. (2023). What types of green space disrupt a lonelygenic environment? A cohort study. Social Psychiatry and Psychiatric Epidemiology, 58(5), 745–755.
[2] Kühn, S., Schmalen, K., Beijers, R., Tyborowska, A., Roelofs, K., & Weerth, C. de. (2023). Green Is Not the Same as Green: Differentiating Between the Association of Trees and Open Green Spaces With Children’s Brain Structure in the Netherlands. Environment and Behavior, 55(5), 311–334.
[3] Astell-Burt, R. Walsan, W. Davis, and X. Feng. (2022), “What types of green space disrupt a lonelygenicenvironment? A cohort study,” Social Psychiatry and Psychiatric Epidemiology, vol. 58, no. 5, pp. 745–755, Dec. 2022. doi:10.1007/s00127-022-02381-0
