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How Growing Up Poor Affects the Brain

New research shows poorer and richer kids' brains have physical differences, but there's scope for change.
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(Photo: Sergey Nivens/Shutterstock)

(Photo: Sergey Nivens/Shutterstock)

Growing up poor can leave its mark, but perhaps it doesn't have to be that way.

A new study out today finds that kids who grow up in families near or below the United States' federal poverty level have less gray matter in certain, crucial parts of their brains. The study also links those brain disparities to differences in the kids' performance on tests of language, math ability, and general intelligence. In other words, the study gives us something physical to blame for a pattern researchers have long known—that poorer children tend to get worse grades and to score lower on standardized tests, including IQ tests, compared to their richer peers. Those differences can carry into adulthood, making adults who grew up in poor families likely to earn less money themselves.

This study isn't even the first to find physical differences in the average brains of kids who grow up in poorer and richer families. At first blush, all this sounds like rough news for low-income families. But there's room for change. Unlike eye color or face shape, there's scope for influencing how a kid's brain develops as she grows, whether that means better nutrition or better school programs. Overall, the research on kids' socioeconomic status and their brains underscores how important it is to develop programs that give poorer kids a more level playing field.

Unlike eye color or face shape, there's scope for influencing how a kid's brain develops as she grows.

For this new study, a team of public-health researchers and neuroscientists from various U.S. universities analyzed test scores and MRI scans of almost 400 children and adolescents between the ages of four and 22. The researchers found that low-income children tended to score four to seven points lower on tests than higher-income children. Children living in families with incomes less than the federal poverty level—about $24,000 for a family of four—had seven to 10 percent less gray matter in certain areas of their brains, compared to other kids their age. Children living in families with incomes that were not much higher than the federal poverty income level—about $36,000 for a family of four—had three to four percent less gray matter. Specifically, these low-income children had less gray matter in their frontal lobes, temporal lobes, and hippocampuses, which are brain regions involved in controlling attention, regulating the emotions, learning letters and words, and long-term memory. They're also brain regions whose growth is thought to be highly influenced by kids' environments, and less by their innate genetics.

What can the government and others do about these disparities? Other research offers some ideas. One study found that raising a family's income by $1,000 a year—via a tax credit—raised kids' math and reading scores. Another analysis found that strong preschool programs can help low-income kids feel more motivated to learn and ultimately fare better later in life. It's always painful to see society's inequities borne out in children, but their young age means they're open to interventions for the better, too.

Quick Studies is an award-winning series that sheds light on new research and discoveries that change the way we look at the world.