It’s well-known that children from lower socioeconomic backgrounds tend to lag behind their better-off peers in academic readiness and school performance.
Now, investigators may be homing in on a biological reason for that difference.
Researchers linked to the University of Wisconsin-Madison found that children and adolescents who tested lower on standardized tests had a lower volume of gray matter in their brains than the norm, and their frontal and temporal lobes developed more slowly.
Those are two critical brain areas, said Barbara Wolfe, an economics professor who co-authored the study published this week in the journal JAMA Pediatrics.
The brain areas are "critical in the sense that they keep developing until individuals are well into their adolescence or early 20s, and critical in the sense that they are important for executive function," Wolfe said. "They are important for cognitive function."
Researchers looked at magnetic resonance images of the brains of nearly 400 children and young adults, ages 4 to 22, matching the scans with the participants' scores on cognitive and academic achievement tests and their socioeconomic status.
In general, participants who were low on the economic scale tended to score between three and four points below what is expected for their age on standardized tests.
Those who were significantly below the poverty line had a gap of between eight and 10 points below the developmental norm.
Wolfe said factors in poorer students’ brain structure and lower test scores could include inadequate nutrition or stimulation, or "stress that parents face in trying to deal with poverty, putting food on the table."
The authors concluded that up to 20 percent of the low-income children’s achievement deficits could be tied to poverty.
Wolfe suggested early intervention may improve poor children’s brain development and, subsequently, their test scores and academic achievement. Once the source of the deficit is identified, "these areas of the brain can be developed," she said. "... It means that policies can be developed that overcome this deficit."
At the same time, Wolfe said improved test scores might be a way to measure the effectiveness of programs designed to boost lower-income children’s academic achievement.