School-based nature exposure interventions may restore and improve cognitive functionNature exposure may improve children’s cognitive function by both replenishing mental resources, a “restorative effect,” and by increasing cognitive capacity, an “instorative effect.” Previous research has suggested that nature may play a beneficial role in these processes, although some mixed findings indicate a need for further study. To develop a clearer understanding, this systematic review and meta-analysis provides a synthesis of the existing research on nature’s cognitive benefits for children and youth.
The systematic review and meta-analysis included studies that examined the relationship between exposure to nature and cognitive performance by focusing on correlational, comparison and experimental/quasi-experimental research studies. Included studies involved children (under 10 years of age) or adolescents (10–19 years of age) from neurotypical and/or neurodivergent populations. Correlational studies assessed nature exposure through measurements of surrounding greenness (such as NDVI) while comparative cross-sectional and experimental/quasi-experimental studies involved an actual nature exposure (such as nature walks, outdoor learning, classroom greenery, or virtual nature). Studies in the review were only included if they reported at least one cognitive measure. Researchers identified 52 studies which met these criteria and were included in the review; the meta-analysis included 51 of these studies. The majority of studies were conducted in Europe and North America. To synthesize data on overall cognitive performance across the body of research, studies were categorized by research design—correlational, cross-sectional comparison, or experimental— and then separate meta-analyses were run for each design type. However, only one cross-sectional comparison study was identified by the review, therefore, a meta-analysis could not be performed for this research design. Additionally, separate analyses were performed for specific cognitive functions, such as attention and memory.
The meta-analysis conducted for correlational research, which examined the relationship between greenspace exposure and cognitive function, included 22 studies with a total of 36,941 participants. Green space exposure in correlational studies was assessed near children’s homes (13 studies), broader neighborhoods (2 studies), or a combination of locations that may have included home, school, commute, and neighborhood (6 studies). The studies were focused on neurotypical populations, with only one study including both neurotypical and neurodivergent participants. Effect size for green space exposure on overall cognitive function “was very small and nonsignificant” across studies. Larger effects on cognition were observed for closer nature exposure (0–499 m), although not significantly so. Green space exposure was also not significantly related to any specific cognitive domains (attention, executive function, global cognition, language, memory, processing speed, reasoning, or visuospatial abilities) assessed by correlational studies.
The meta-analysis conducted for experimental research included 34 studies (from 29 articles) involving 3160 total participants. Ninety percent of studies focused on neurotypical populations and ten percent focused on neurodivergent populations. Analysis detected a small, but significant, effect size of nature-based interventions on cognitive function compared to non-nature conditions. A small, significant effect on attention and executive function was also detected. Due to the limited number of studies assessing memory, problem solving, and processing speed, analyses could not be conducted for these outcomes. Effects on cognitive function were significant for both children and adolescents, and also for instorative and restorative effects. Differences among nature interventions were identified. Interventions that significantly impacted cognitive function, as compared to a control group, were focused on nature “immersion (e.g., doing an activity in nature for at least one session), nature school (i.e., integrating nature into daily activities or curriculum), and class/school redesign (incorporating natural features into environment).” Testing in nature and short virtual nature exposures did not significantly impact cognitive function. Analysis of only studies involving neurodivergent children and adolescents did not detect a significant nature effect; however, this is likely influenced by the small number of studies with neurodivergent populations.
This study provides a statistical synthesis of the existing correlational and experimental findings on nature’s role in cognition. In contrast to previous systematic reviews, this meta-analysis did not find a significant relationship between nature exposure, mainly at the residential level, and cognitive outcomes for children or adolescents in correlational studies. While this finding suggests that living near greenspace may not be associated with cognitive restoration or development, the authors propose several explanations for this discrepancy, which may be related to methodological differences across studies. Additionally, measures used to assess greenspace do not reflect actual exposure to nature. On the other hand, meta-analysis of experimental studies indicate that cognitive performance may be improved or restored through exposure to nature, especially regarding attention and executive function. Further research is needed to draw conclusions on memory, problem solving, and processing speed, and also for neurodivergent populations. Findings suggest that schools can use natural environments to restore and enhance attention by integrating natural elements into classrooms and by incorporating outdoor learning and play in the school curriculum.
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