How poverty affects young brains

New monthly payments in the pandemic relief package have the potential to lift millions of American children out of poverty. Some scientists believe the payments could change children’s lives even more fundamentally — via their brains.اضافة اعلان

It is well established that growing up in poverty correlates with disparities in educational achievement, health and employment. But an emerging branch of neuroscience asks how poverty affects the developing brain.

Over the past 15 years, dozens of studies have found that children raised in meager circumstances have subtle brain differences compared with children from families of higher means. On average, the surface area of the brain’s outer layer of cells is smaller, especially in areas relating to language and impulse control, as is the volume of a structure called the hippocampus, which is responsible for learning and memory.

These differences do not reflect inherited or inborn traits, research suggests, but rather the circumstances in which the children grew up. Researchers have speculated that specific aspects of poverty — subpar nutrition, elevated stress levels, low-quality education — might influence brain and cognitive development. But almost all the work to date is correlational. And although those factors may be at play to various degrees for different families, poverty is their common root. A continuing study called Baby’s First Years, started in 2018, aims to determine whether reducing poverty can itself promote healthy brain development.

“None of us thinks income is the only answer,” said Dr. Kimberly Noble, a neuroscientist and pediatrician at Columbia University who is co-leading the work. “But with Baby’s First Years, we are moving past correlation to test whether reducing poverty directly causes changes in children’s cognitive, emotional and brain development.”

Noble and her collaborators are examining the effects of giving poor families cash payments in amounts that wound up being comparable to those the Biden administration will distribute as part of an expanded child tax credit.

The researchers randomly assigned 1,000 mothers with newborns living in poverty in New York City, New Orleans, the Twin Cities metro region and Omaha, Nebraska, to receive a debit card every month holding either $20 or $333 that the families could use as they wished. (The Biden plan will provide $300 monthly per child up to age 6, and $250 for children 6-17.) The study tracks cognitive development and brain activity in children over several years using a noninvasive tool called mobile EEG, which measures brain wave patterns using a wearable cap of 20 electrodes.

The study also tracks the mothers’ financial and employment status, maternal health measures such as stress hormone levels, and child care use. In qualitative interviews, the researchers probe how the money affects the family, and with the mothers’ consent, they follow how they spend it.

The study aimed to collect brain activity data from children at age 1 and age 3 in home visits, and researchers managed to obtain the first set of data for around two-thirds of the children before the pandemic struck. Because home visits are still untenable, they extended the study to age 4 and will be collecting the second set of brain data next year instead of this year.

The pandemic, as well as the two stimulus payments most Americans received this past year, undoubtedly affected participating families in different ways, as will this year’s stimulus checks and the new monthly payments. But because the study is randomized, the researchers nonetheless expect to be able to assess the impact of the cash gift, Noble said.

Baby’s First Years is seen as an audacious effort to prove, through a randomized trial, a causal link between poverty reduction and brain development.

“It is definitely one of the first, if not the first” study in this developing field to have direct policy implications, said Martha Farah, a cognitive neuroscientist at the University of Pennsylvania and director of the Center for Neuroscience and Society who studies poverty and the brain.

Farah concedes, however, that social scientists and policymakers often discount the relevance of brain data.

“Are there actionable insights we get by bringing neuroscience to bear, or are people just being snowed by pretty brain images and impressive-sounding words from neuroscience? It’s an important question,” she said.

Skeptics abound. James Heckman, a Nobel Prize-winning economist at the University of Chicago who studies inequality and social mobility, said he did not see “even a hint that a policy would come out of it, other than to say, yes, there’s an imprint of a better economic life.”

“And it still remains a question what the actual mechanism is” through which giving parents cash helps children’s brains, he said, adding that targeting such a mechanism directly might be both cheaper and more effective.

Samuel Hammond, director of poverty and welfare policy at the Niskanen Center, who worked on a child allowance proposal by Sen. Mitt Romney, agrees that tracking the source of any observed cognitive benefits is tricky.

“I have trouble disentangling the interventions that actually help the most,” he said.

For example, policy experts debate whether certain child care programs directly benefit a child’s brain or simply free up her caregiver to get a job and increase the family’s income, he said.

Yet that is exactly why providing disadvantaged families with cash might be the most potent way to test the link to brain development, Noble said.

“It’s quite possible that the particular pathways to children’s outcomes differ across families,” she said. “So by empowering families to use the money as they see fit, it doesn’t presuppose a particular pathway or mechanism that leads to differences in child development.”