Differences in brain structure development may explain test score gap for poor children

Socioeconomic disparities in school readiness and academic performance are well documented but little is known about the mechanisms underlying the influence of poverty on children's learning and achievement.

Seth D. Pollak, Ph.D., of the University of Wisconsin-Madison, and colleagues analyzed magnetic resonance imaging (MRI) scans of 389 typically developing children and adolescents ages 4 to 22 with complete sociodemographic and neuroimaging data. The authors measured children's scores on cognitive and academic achievement tests and brain tissue, including gray matter of the total brain, frontal lobe, temporal lobe and hippocampus.

The authors found regional gray matter volumes in the brains of children below 150 percent of the federal poverty level to be 3 to 4 percentage points below the developmental norm, while the gap was larger at 8 to 10 percentage points for children below the federal poverty level. On average, children from low-income households scored four to seven points lower on standardized tests, according to the results. The authors estimate as much as 20 percent of the gap in test scores could be explained by developmental lags in the frontal and temporal lobes.

"Development in these brain regions appears sensitive to the child's environment and nurturance. These observations suggest that interventions aimed at improving children's environments may also alter the link between childhood poverty and deficits in cognition and academic achievement," the study concludes.

Poverty's Most Insidious Damage

In a related editorial, Joan L. Luby, M.D., of the Washington University School of Medicine, St. Louis, writes: "Building on a well-established body of behavioral data and a smaller but expanding body of neuroimaging data, Hair et al provide even more powerful evidence of the tangible detrimental effects of growing up in poverty on brain development and related academic outcomes in childhood. ... In developmental science and medicine, it is not often that aspects of a public health problem's etiology and solution become clearly elucidated. It is even less common that feasible and cost-effective solutions to such problems are discovered and within reach. Based on this, scientific literature on the damaging effects of poverty on child brain development and the efficacy of early parenting interventions to support more optimal adaptive outcomes represent a rare roadmap to preserving and supporting our society's most important legacy, the developing brain. This unassailable body of evidence taken as a whole is now actionable for public policy."