Green space is associated with better directed attention and higher crystallized intelligence in middle childhood: Evidence from the ABCD study

In the United States, rising attention problems and falling academic achievement in childhood are a public health concern given the importance of childhood directed attention (e.g., effortful, top-down driven attention) and achievement in predicting long-term outcomes. Guided by Attention Restoration Theory (ART), several papers have tested the hypothesis that greater green space exposure may support improved directed attention and achievement in children, with mixed results. To help clarify the role of green space in supporting childhood directed attention and achievement, we tested this hypothesis in the large, diverse Adolescent Brain Cognitive Development (ABCD) Study. American children ( N = 11,868, M age = 9.96 years; 52.16% assigned female) completed a performance-based assessment of their directed attention and crystallized intelligence (a proxy measure of achievement) and had their green space exposure assessed as the average of the proportion of tree canopy and the proportion of park cover in their census tracts. Linear mixed-effects models with random intercepts for site and family revealed that green space was positively associated with both directed attention ( β = 0.76, p < 0 .001) and crystallized intelligence ( β = 0.83, p < 0 .001), adjusting for area deprivation index (ADI), assigned sex, ADHD diagnosis, stimulant use, sleep problems, perceived safety, media use, prenatal tobacco exposure, air pollution (PM 2.5 ), and physical activity. Additionally, PM 2.5 mediated the association between green space and directed attention (indirect effect: β = 0.06, 95% CI = [0.02, 0.11]) and between green space and crystallized intelligence ( β = 0.06, 95% CI = [0.01, 0.11]). These cross-sectional results indicate that green space is positively associated with childhood attention and crystallized intelligence and that these associations may be explained by improved air quality.