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Category: Project

Description: Interactions with natural environments and nature-related stimuli have been found to be beneficial to cognitive performance, in particular on executive cognitive tasks with high demands on directed attention processes. However, results vary across different studies. The aim of the present study was to perform a meta-analysis of all our published and unpublished studies testing the effect of different interactions with nature versus urban/built control environments, on an executive test with high demands on directed attention: the backwards digit span (BDS) task. Specific aims were to evaluate the effect of nature versus urban environment interactions on BDS across different exposure types (e.g. being in real environments, or viewing videos, images, or listening to sounds) and disentangle the effects of testing order (i.e. practice with repeated testing) and the role of affective changes on BDS performance. We also reviewed the literature and compared and contrasted our meta-analysis with results from other studies. Results from our meta-analysis comprising 12 studies (N=567 participants) showed significant environment-by-time interactions with beneficial effects of nature compared to urban environments on BDS performance. This effect was magnified after parceling out initial practice effects on the BDS. Changes in positive or negative affect did not mediate the beneficial effects of nature on BDS performance. These results mirrored effects that we reviewed from outside of our laboratories. Uncontrolled and confounding order effects may explain some of the inconsistent findings in the literature. In all, these results highlight the robustness of the effects of natural environments on cognition when confounding order effects have been considered, and also provide a more nuanced account of when a nature intervention will be most effective.