Growing up poor has long been linked to lower academic test scores. And there’s now mounting evidence that it’s partly because kids can suffer real physical consequences from low family incomes, including brains that are less equipped to learn. An analysis of hundreds of magnetic resonance imaging (MRI) brain scans found that children from poor households had smaller amounts of gray matter in areas of the brain responsible for functions needed for learning, according to a study published last week in JAMA Pediatrics. The anatomical difference could explain as much as 20 percent of the gap in test scores between kids growing up in poverty and their more affluent peers, according to the research.
Children in households below the federal poverty level — an annual income of about $24,000 for a family of four — had gray matter volumes 7 percent to 10 percent lower than what would be expected for normal development. About 20 percent of American children lived at this income level in 2013, according to census data. Smaller gaps were evident for households considered “near poor,” making up to 150 percent of the poverty level, currently about $36,000 for a family of four.
“It was really when we started getting down into real poverty, real abject poverty, that we started seeing a difference,” says Seth Pollak, a professor of psychology at the University of Wisconsin-Madison and co-author of the study. The differences were evident in kids as young as 4, meaning they occur before kindergarten.
The research may understate the size of the effects.
Pollak suspects that poor children “are getting too little of things we need to develop the brain and too much of things that inhibit brain growth.” They may get less stimulation from parents, or lack things like crayons, children’s books, or games. Crowded environments or unstable homes may disrupt their sleep. Poor neighborhoods may not have grocery stores with fresh food, leading to nutritional deficits.
"It's not enough to bring a child into the world, feed them and make sure they don't get injured," said Dr. Joan Luby, director of the Early Emotional Development Programme at the Washington University School of Medicine in St. Louis.
"People will often ask me, 'What should teachers be doing?' Or, 'What should schools be doing?" Pollak said. "What this says to me is, what should we be doing about environments?" For example, he said children from poor families may not be prepared when they get to school, because they are hungry or tired. You can imagine, no matter what the teacher does, these little people are not showing up ready to learn," Pollak said.
For example, he said children from poor families may not be prepared when they get to school, because they are hungry or tired.