Washington University: green space linked to better attention in 11,868 US children, cross-sectional data
In the ABCD Study cohort, children with more tree canopy and park cover in their census tracts scored higher on attention and crystallized intelligence tests, in cross-sectional data.
Psychologists at Washington University in St. Louis analysed data from the Adolescent Brain Cognitive Development (ABCD) Study and reported in Environment International that green space exposure is positively associated with directed attention and crystallized intelligence in children doi.org
Environment Internationaldoi.orgOpen source ↗. The sample included 11,868 American children with a mean age of 9.96 years; 52.16% were assigned female
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Environment Internationaldoi.orgOpen source ↗. The lead author is Carina Fowler, a postdoctoral researcher in the lab of Deanna Barch.
Green space measure and study design
The children completed performance-based assessments of directed attention, meaning effortful, top-down driven attention, and of crystallized intelligence, which the authors used as a proxy measure of achievement doi.org
Environment Internationaldoi.orgOpen source ↗. Green space exposure was calculated as the average of the proportion of tree canopy and the proportion of park cover in the child's census tract
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Environment Internationaldoi.orgOpen source ↗. According to the release, this metric allows some differentiation by type of green space.
The authors used linear mixed-effects models with random intercepts for site and family doi.org
Environment Internationaldoi.orgOpen source ↗. The models were adjusted for area deprivation index, assigned sex, ADHD diagnosis, stimulant use, sleep problems, perceived safety, media use, prenatal tobacco exposure, air pollution and physical activity
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Environment Internationaldoi.orgOpen source ↗.
Associations and the role of air quality
Green space was positively associated with directed attention (β = 0.76) and with crystallized intelligence (β = 0.83) doi.org
Environment Internationaldoi.orgOpen source ↗. Particulate air pollution mediated both associations. The indirect effect was β = 0.06 (95% CI from 0.02 to 0.11) for directed attention and β = 0.06 (95% CI from 0.01 to 0.11) for crystallized intelligence
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Environment Internationaldoi.orgOpen source ↗.
Fowler said the team found a connection to air quality but not to physical activity. The authors conclude that the associations may be explained by improved air quality doi.org
Environment Internationaldoi.orgOpen source ↗. The results are cross-sectional, so they describe associations at one point in time.
Previous studies on this question have given mixed results. Proponents of Attention Restoration Theory, which the study tested, say that a person has to feel safe in the green space and that the effect is weaker when the person uses social media there. Fowler also said the kind of green space might matter.
