Trees Near Home Linked To Sharper Childhood Attention

Study of Nearly 12,000 Kids Links Green Space to Attention

Kids who live near more trees and parks tend to score higher on tests of attention, reading, and vocabulary, and cleaner air may be part of the reason. Exercise, an explanation proposed in earlier research, did not account for the pattern.

A team at Washington University in St. Louis reported the results in the journal Environment International after analyzing data on nearly 12,000 American children. The link between greenery and higher scores held up even after the researchers adjusted for neighborhood disadvantage, screen time, and several other factors that can skew results.

Attention problems among American kids are rising, and reading and math scores have hit record lows, according to the authors. Earlier studies on whether greenery helps have disagreed, with some finding benefits and others finding nothing. Those studies largely skipped whether a child feels safe outside, has ADHD, or sleeps poorly, any of which can hide a green space effect. This study accounted for all three, which is why a large, carefully adjusted look matters.

Green Space Is Linked to Better Attention and Reading Scores

Researchers drew on the Adolescent Brain Cognitive Development study, a long-running project that recruited children at 21 sites across the country, mostly through schools, between 2016 and 2018. The final group included 11,868 kids with an average age just under 10, roughly half boys and half girls. About 52 percent were white, 21 percent Hispanic, 15 percent Black, and 2 percent Asian, and household incomes ranged from under $5,000 to over $200,000 a year. Rural children were underrepresented in the sample, since many sites sit in or near cities.

Greenery was measured by averaging two figures for each child’s home census tract, a small neighborhood zone defined by the Census Bureau: the share covered by tree canopy and the share covered by parks. Children then completed hands-on tests rather than relying on parent opinions. Attention scores combined five tasks covering memory, self-control, flexible thinking, and processing speed. Reading and vocabulary came from two achievement tests. Both were scored like IQ tests, where 100 is average.

Each 10 percentage point increase in a neighborhood’s tree and park cover, roughly the gap between a neighborhood with 5 percent coverage and one with 15 percent, was tied to a 0.76 point higher attention score and a 0.83 point higher reading and vocabulary score. Those gaps are small, under one point each. But roughly half the children lived in neighborhoods with less than 10 percent green space, and about 1 in 10 had less than 1 percent, so the authors speculate that even a modest boost in greenery could matter.

Cleaner Air Partly Accounts for the Green Space Link, but Exercise Does Not

Next, the team tested two popular explanations: that kids in greener areas simply move around more, or that they breathe cleaner air. Kids averaged about 3.5 days a week of at least an hour of activity, and more activity was tied to better scores on its own. It did not, however, explain the green space connection. Tiny airborne particles known as PM2.5 did, to a degree. Greener neighborhoods had less of this pollution, and lower pollution went along with higher scores.

That share was small, though. By a calculation from the paper’s reported figures, pollution accounted for about 7 percent of the total link, so most of the connection remained even after air quality was factored in. That leftover link is what Attention Restoration Theory, a decades-old idea, would predict. Phones, TVs, and traffic grab attention completely, the theory says, while natural settings are “softly fascinating,” holding interest without demanding effort and giving the brain’s focus system a chance to rest.

Going in, the team had predicted that neither air quality nor exercise would play a role, and the authors wrote that the pollution result “was surprising to us.” They also noted that exercise may have gone undetected because of the children’s age and the way activity was measured, which relied on kids’ own reports.

A Single Snapshot Cannot Prove Trees Cause Better Focus

All of the data came from one point in time, so the study can show a connection but not that moving a child to a greener block would raise grades or attention. Adding household income to the models, on top of neighborhood disadvantage, cut the attention link roughly in half, to 0.40 points, though it held up. The reading and vocabulary link fell to 0.35 points and was no longer clearly more than chance. The authors raise the possibility that attention responds to greenery quickly while reading skills build slowly, but the data could not test that. Swapping in a satellite-based measure of plant cover produced the same pattern for both outcomes.

This study did not test whether planting trees raises test scores, and the authors say the benefits of greening the areas around schools still need to be tested. If something as fixable as planting more trees and building more parks could help kids focus and learn, that deserves a real experiment, one that follows children as their neighborhoods get greener.

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Disclaimer: This article reports on published research for general informational purposes only. It is not medical, psychological, or educational advice. Parents and caregivers with concerns about a child’s attention, learning, or health should consult a qualified professional.

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