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Brain scans show children living in poverty tend to have less ‘gray matter’ in areas linked to cognitive abilities that are critical for school-readiness.
Poor children are much more likely to struggle in school, partly because of how poverty influences the architecture of the developing brain. Children who grow up in poverty tend to have less “gray matter” in brain structures that govern a number of processes integral to school readiness, a difference that contributes to underachievement.
This new insight into the so-called “income-achievement gap” comes from recent work that analyzed magnetic resonance imaging (MRI) scans of the brains of hundreds of children and adolescents, aged 4 to 22. Our analysis points to clear differences in the development of these crucial brain structures, particularly for the poorest children, that is, those whose families live below the U.S. federal poverty line. “Near poor” children, those who live in households with incomes below 1.5 times the federal poverty line, also had significantly less gray matter volume, though they had more than the poorest children.
“These results highlight the consequences for children and later generations when policy makers fail to take sufficient action to tackle poverty. They also suggest big educational gains from targeting policy at families living on very low levels of income.”
Our research outlines a biological mechanism that can explain some of the gap in achievement between poor and affluent children. It has long been observed that low-income children have disproportionately worse outcomes in school. They are much more likely to struggle to concentrate, remember, understand, control their behaviour and tackle complex areas of learning. Our work suggests that several regions of the brain tied to processes that are critical for learning and academic functioning (such as focusing attention, problem solving, memory and language comprehension) are vulnerable to the environmental circumstances of poverty.
These results highlight the consequences for children and for later generations when policy makers fail to tackle poverty sufficiently. Research has already shown that poor performance at school, which our study shows to be partly rooted in delayed maturing of the brain, undermines future learning and success at work, leading to lower lifetime earnings and, thus, the entrenchment of inequality across generations.
However, the human brain is malleable, particularly in children, and underdevelopment can be tackled effectively. Research suggests that there could be big educational gains from targeting policy at families living on very low levels of income.
Brain scanning of gray matter volume also provides a biomarker for success. This technique could be used to determine which policies for such children are the most effective, letting us allocate resources relatively efficiently. Having such a reliable bio-marker should also encourage innovations to combat the impact of poverty, now that their effectiveness can be tested more easily.
Our results may well understate the consequences for children’s brain development of living in poverty. The group we studied was initially sampled for a study of normal brain development and it excluded children with low birth weight and those with compromised family medical, prenatal, birth and perinatal histories. These issues are common among families living in poverty. Moreover, compared to national averages, families in our sample were highly educated. In short, we studied a group likely to be doing better than most children living in poverty. While we were not able to study a truly representative sample of children on low incomes – we observed only the healthiest, most robust of the poor – the restrictions meant the impact of poverty on their brains could be isolated and not confused with other factors.
Our study focused on regions of the brain known to undergo a protracted period of postnatal development and therefore most likely to be influenced by environmental conditions. The scans identified developmental differences in the frontal lobes which are responsible for controlling attention, inhibition, emotion regulation and complex learning. There were also differences in the temporal lobe which is important for memory and language comprehension, such as identifying words, relating heard sounds with letters of the alphabet, and attaching meaning to words. We estimate that developmental differences in the frontal and temporal lobes, sensitive to the environmental circumstances of poverty, explain 15 to 20 percent of the deficits in the standard test results of low-income children.
Studies of this type which use repeated brain scans of children could be used to study the influence of a variety of targeted programs. These could range from alternative models of schooling to nutritional enrichment programs, to income enhancing programs. The approach could also address whether those programs work best at age 3 or age 7, or are more effective for boys than girls This work is opening up a whole new way to study the consequences of poverty and the effectiveness of policies to reduce its consequences.
Hair NL, Hanson JL, Wolfe BL & Pollak SD (2015), Association of Child Poverty, Brain Development, and Academic Achievement, JAMA Pediatrics, 169.9