The Role of Methodological Choices in the Effects of Experimental Exposure to Simulated Natural Landscapes on Human Health and Cognitive Performance: A Systematic Review

Abstract

We review the methods and findings of experiments that have examined the effects of exposure to simulated natural landscapes on human health and cognitive performance. Keyword searches of PubMed, Scopus, and Web of Science resulted in the inclusion of 175 experiments in 148 research articles. that were published/in press by December 31, 2018. We report how often landscape features and human factors are controlled for within these experiments, thereby—for the first time—recording specifically what elements of “nature” and the built/social environment are used when testing the benefits of green space and blue space exposure. We also document all the simulation methods that are used (e.g., duration, number of exposures, senses engaged, and devices used). Next, to determine what methodological decisions influence study findings, we compare positive versus mixed/null or negative findings across 14 potential moderators. Only study quality and outcome measure influence findings; experiments without control groups or randomized treatments reported more positive findings than expected. Experiments studying perceived restoration also reported more positive findings than expected—remarkably, 95% of such experiments reported simulated nature was indeed restorative. We discuss the possibility that these findings may indicate publication bias in favor of overreporting the salutory impacts of natural landscapes. We conclude our review with a synthesis of best practices for future research studies.

An Actual Natural Setting Improves Mood Better Than Its Virtual Counterpart: A Meta-Analysis of Experimental Data

“…This meta-analysis originated from a systematic review conducted by some of the coauthors here, which is described elsewhere (Browning et al, 2020a ). The review and this meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines (Moher et al, 2009 ).…”

“…We identified the bulk of relevant papers by consulting the results of the former large systematic review by Browning et al ( 2020a ), in which the authors conducted an extensive keyword search in Scopus, PubMed, and Web of Science for articles that were published or in press by January, 2019 and that referenced natural settings and simulations in their titles, abstracts, or keywords (see Table S1 for list of keywords). Articles were included in that review if they met the following criteria: (A) participants had been exposed to at least one simulated natural setting, such as a photograph, slideshow, video, or immersive virtual environment (i.e., 360° video or computer-generated three-dimensional environment); (B) researchers measured at least one human health or cognitive performance outcome; and (C) researchers compared the results of different treatments using inferential statistics.…”

“…The current meta-analysis extends their work by limiting our assessment to studies that directly compared the same (or very similar) settings. We identified 16 studies that have examined this topic but only 6 that have used a cross-cutting, FIGURE 2 | A flowchart of the process by which experiments were selected for inclusion in the systematic review by Browning et al (2020a) as well as the current meta-analysis.…”

“…Ample evidence suggests that nature simulations can, under some conditions, support processes that promote health. More than 100 experiments report that pictures, videos, or immersive virtual environments with natural elements boosted mood, enhanced executive cognitive functions, promoted physiological stress recovery or reduced pain with little to no side effects (Browning et al, 2020a ). Yet, how and to what extent simulations replicate the benefits of actual natural settings remain essentially unknown.…”

“…Here, we employed a meta-analytical approach to compare the effects of actual and simulated natural settings on human health/well-being. Because this approach was applied to an emerging topic (Browning et al, 2020a ), we conducted a review that included the greatest number of studies possible despite the likelihood that the number of eligible studies would be small. Accordingly, we aimed to provide a benchmark for the current state of evidence upon which future research can build, together with an initial framing of the research problem and articulation of relevant methodological issues.…”