Brain scans shed light on how green space might support children’s cognitive development

A large-scale study of U.S. children has found that exposure to green spaces in urban areas is associated with healthier brain development, fewer emotional and behavioral problems, and improved cognitive performance. The findings, published in the Journal of Environmental Psychology, suggest that different types of green environments may shape children’s mental health and thinking skills in distinct ways.

Cities offer many conveniences, but they often come at the cost of reduced natural surroundings. Past studies have shown that access to parks, trees, and other green spaces can benefit children’s mental health and cognitive abilities. However, it has remained unclear exactly how green space exposure affects the developing brain, particularly during the sensitive period of late childhood and early adolescence. The new study aimed to shed light on this question by linking various indicators of green space to brain imaging data, mental health measures, and cognitive test scores from thousands of children across the United States.

The research team analyzed data from the Adolescent Brain Cognitive Development (ABCD) study, which includes neuroimaging and behavioral information from more than 11,000 children aged 9 to 10. For this particular analysis, the researchers focused on two groups: 8,430 children with complete brain structure data and 8,161 with detailed white matter imaging. To ensure accurate measurement of environmental exposure, they excluded children who had moved recently and those with missing data.

To capture children’s level of exposure to green space, the researchers used nine indicators derived from national land-use and vegetation databases. These included measures such as tree canopy, different types of forest cover, and the Normalized Difference Vegetation Index, a satellite-based estimate of greenery. These data were used to characterize the amount and type of vegetation surrounding each child’s home.

Brain structure was measured using high-resolution MRI scans. The researchers examined several aspects of brain anatomy, including cortical thickness, surface area, subcortical volume, and overall cortical volume. White matter microstructure, which reflects the integrity of the brain’s communication pathways, was assessed using diffusion imaging techniques that measure how water moves through white matter tissue.

To identify patterns linking green space exposure to brain features, the researchers applied a statistical method called Group Factor Analysis. This technique helps detect hidden relationships across large sets of variables—in this case, environmental data and neuroimaging metrics. The resulting factors were then used to predict children’s scores on standardized mental health and cognitive tests, while adjusting for other influences such as household income and parental education.

The analysis revealed several important findings. One of the strongest patterns to emerge—called BSGFA 1—showed that greater exposure to urban greenery, including tree canopy and mixed vegetation, was associated with larger surface area and volume in many parts of the brain. This included areas involved in visual processing and sensorimotor functions, such as the superior parietal lobule and fusiform gyrus.

Children with higher BSGFA 1 scores also had fewer emotional and behavioral problems, as rated by their parents, and scored higher on tests of crystallized intelligence, which reflects accumulated knowledge and language skills.

Another key pattern, called WGFA 1, linked green space exposure to healthier white matter properties. Children with higher WGFA 1 scores had stronger white matter connectivity and lower levels of diffusion in their brain tissue, suggesting more efficient communication between brain regions. These children also showed fewer externalizing behaviors—such as impulsivity and aggression—and performed better on both fluid and crystallized intelligence tasks. Fluid intelligence, which involves reasoning and problem-solving, is thought to depend especially on white matter efficiency.

Interestingly, not all green spaces were associated with positive outcomes. A different pattern, labeled WGFA 2, reflected greater exposure to forest-dense areas and showed a negative relationship with white matter health and fluid intelligence. This finding suggests that forest-heavy environments might offer fewer opportunities for visual, motor, and social engagement compared to more open or community-oriented green spaces like urban parks.

The researchers proposed several explanations for these effects. Natural environments may reduce stress and mental fatigue, which in turn promotes healthier brain development. This idea fits with existing theories like Attention Restoration Theory, which suggests that nature helps people recover from cognitive overload, and Stress Reduction Theory, which proposes that greenery elicits calming emotional responses. The study also expanded on these theories by showing that exposure to green environments might actually shape the physical structure of the brain during a key period of development.

The results held up even after adjusting for neighborhood-level socioeconomic factors such as income, education, and access to health resources. This means that the benefits linked to green space exposure could not be fully explained by broader advantages of living in wealthier or more resource-rich areas. However, some effects—particularly the relationship between greenery and crystallized intelligence—appeared to be partially influenced by these neighborhood conditions.

The study had several strengths, including its large and diverse sample, use of advanced brain imaging, and integration of multiple environmental and biological indicators. It also revealed how different types of green environments may have different effects on the developing brain. For example, while general greenery like tree canopy and urban vegetation was consistently linked to positive outcomes, dense forest cover showed more mixed or even negative associations with brain connectivity and reasoning ability.

At the same time, the study had limitations. Because it was cross-sectional, it could not determine whether green space exposure directly caused changes in brain structure or behavior. Longitudinal and experimental studies will be needed to better establish causal relationships. The study also relied on satellite and census data to estimate environmental exposure, which may not capture the quality of green spaces or how often children actually used them. Future research could benefit from combining objective measures with personal reports of nature experiences and time spent outdoors.

The study, “Associations Among green space exposure, brain, and mental health and cognition in the Adolescent brain cognitive development (ABCD) study,” was authored by Jia Liu, Yumeng Yang, Tianjiao Kong, Ran Liu, and Liang Luo.