Perhaps one of the most ubiquitous and ostensibly insurmountable social issues in the modern world is income inequality: its effects are felt in a number of different arenas — both here in the United States as well as countries around the world. There is an established body of evidence that suggests there are lifelong implications for children raised in poverty, and that there are unequivocal differences in the opportunities afforded to children raised in poor families versus those raised in more affluent families. A study published in Nature Neuroscience demonstrates that children living in poverty are also more likely to have smaller brains.

Dr. Kimberly Noble and colleagues used MRI scans to “investigate relationships between socioeconomic factors and brain morphometry, independently of genetic ancestry, among a cohort of 1,099 typically developing individuals between 3 and 20 years of age.” Morphometry refers to “the measurement of brain structures and changes thereof,” and in this case specifically, the researchers measured cortical surface area. They chose this measurement in particular because “previous research had shown that [cortical surface area] increases throughout childhood and adolescence as the brain develops, thus making it a potentially sensitive indicator of intellectual abilities.”

The results revealed several important findings. As Michael Balter noted in Science: “Parental education — the number of years that parents had gone to school — showed a linear correlation with overall cortical surface area, especially for regions of the brain involved in language, reading, and executive functions.” On the other hand, the trend between income and cortical surface area was logarithmic — in other words, a small increase in income was associated with much greater gains in surface area, but only among those at lower economic strata.

Christopher Wanjek explained on LiveScience that, “Small increases in income among the poor — for example, from $20,000 a year to $30,000 a year — translated to proportionally larger gains in surface area, far greater than the same $10,000 increase for those in the middle- or high-income brackets.”

The study’s authors can’t pinpoint the reasons for this relationship, but they speculate that “diet, healthcare, lack of access to good schools and play areas, and even exposure to polluted areas may lie behind the connection.”

Elizabeth Sowell, a lead researcher on the study, cautioned against assuming that this correlation is immutable or entirely universal. She says, “The message is not ‘if you are poor, your brain will be smaller, and there is nothing that can be done about it’. That is absolutely not the message. Improving access to resources that enrich the developmental environment could potentially change the trajectories of brain development for the better, even in children and adolescents in the age range we studied.” Furthermore, researchers note, “Race and ethnicity had no effect on any of these correlations.”

The findings are in line with research done by Martha Farah, whose team scanned the brains of 44 one-month-old African-American girls from a spectrum of socioeconomic groups. The researchers found that, “Even at this early age … infants in the lower socioeconomic brackets had smaller brains than their wealthier counterparts.”

All of this research serves to reiterate the idea that poverty is global malady that has far-reaching consequences. Imagine the world we could create if every child had access to resources that allowed them to thrive.

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