Exposure to nature can enhance cognitive functioning in children and adolescentsTime in nature can be beneficial for children’s academic learning. This review was conducted to explore the effect of nature on the cognitive functioning of children and adolescents documented by experimental and quasi-experimental studies in the existing literature. Identifying the processes involved in nature’s effects on cognitive performance, and their possible links to theoretical models, was a secondary aim of the review. The review also considers if the effects of nature on cognition vary by age.
A systematic search of literature was conducted to identify research that examined children’s and adolescents’ cognitive functioning when participating in school-based nature interventions. Included studies: 1) were written in English; 2) employed a high-quality experimental or quasi experimental research design; 3) involved children’s exposure to nature (such as parks, school playgrounds, neighborhood green areas, window views of nature, or indoor plants); 4) reported a standardized measure of cognitive function (academic records or cognitive tests); and 5) focused on children and adolescents aged 5-18 years. The search yielded 12 studies from 11 journal articles published between 2014 and 2019. The majority of studies were conducted in Europe (75%), with the remainder conducted in the U.S. and Canada. The quality of studies was evaluated using the Effective Public Health Practice Project Quality Assessment Tool (EPHPP). Age of participants varied across studies and sample sizes ranged from 33 to 3,061 participants. There was also wide variation in the duration of exposure to nature. Eight studies considered the effect of short-term nature exposures, ranging from a few to 60 minutes. Four studies investigated long-term nature exposures, ranging from two months to two years. Cognitive tests used by the selected studies focused on attention tests (nine studies) and long-term memory knowledge tests (two studies).
Though studies in the review used an array of cognitive assessments, findings were focused in the areas of working (short-term) memory, selective attention, processing speed, impulse control, and long-term memory knowledge. Overall, studies investigating short-term nature exposures more consistently reported attention benefits than studies assessing long-term nature exposures. Working memory was found to significantly improve as result of active play at a green school playground and when viewing a green landscape through a window, in comparison to control conditions. Selective and sustained attention was found to significantly improve in multiple studies after a 20–30-minute walk or an hour-long break in nature. Similar results were found after play (both structured and free play) in school greenspace. A living plants classroom wall also had a significant positive effect on the sustained/selective attention of primary school children. However, studies exploring the effects of long-term nature exposures on cognition reported mixed findings in regard to sustained/selective attention. Impulse control was only measured by one study, which found no significant positive effect after playtime in a school garden compared with a built playground. Mixed findings were revealed among long-term nature exposure studies investigating processing speed, with one study finding significant improvements while another study did not yield significant results. Long‑term memory and knowledge acquisition in relation to long-term nature exposures were examined by two studies. School gardens were found to enhance science knowledge as compared to classes with no garden intervention. However, while 7<sup>th</sup> graders engaged in outdoor learning demonstrated greater long-term knowledge retention than those participating in an indoor, traditional curriculum, 8<sup>th</sup> graders did not show improvement.
The review also identified three types of theoretical perspectives, which explain why exposure to nature may benefit cognitive functioning. Underlying mechanisms of the “nature-cognitive performance relationship” were mainly attributed to Attention Restoration Theory and Stress Reduction Theory. To a lesser extent studies aligned with the outdoor learning perspective, which views nature-based learning as a practical approach to knowledge acquisition. Finally, regarding the cognitive functioning for children of different ages, results suggest that nature exposure is “generally beneficial for all age groups covered in this review.”
Findings of the review suggest that exposure to nature can enhance cognitive functioning in children and adolescents. Working memory and sustained/selective attention were especially positively impacted by time spent in nature. Less favorable outcomes were identified among studies examining processing speed and impulse control, although the limited number of studies in this area suggest further research is needed. The researchers conclude that “integrating nature interventions with teaching and learning practices can provide welcome cognitive relief” and support academic learning.
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