Poverty reduction alters infant brain activity

The study adds to growing evidence that interventions to relieve poverty can affect how infants’ brains develop. Juliya Shangarey / Shutterstock

Poverty in early childhood correlates with lower school achievement and reduced earnings as an adult. It is also associated with differences in brain structure and electrical brain activity. Brain activity exhibits repetitive patterns at various frequencies. More low-frequency activity has been associated with behavioral, attention, and learning problems. Higher-frequency activity has been associated with better language, cognitive, and social-emotional scores.

Some evidence suggests that children from lower-income families tend to have more low-frequency activity and less high-frequency activity than those from higher-income families. But it’s not clear whether poverty causes these changes in brain activity or is merely associated with other factors that cause them.

To find out, researchers created the Baby’s First Years study, a randomized controlled trial of poverty reduction in early childhood. In this study, 1,000 low-income mothers of newborns received a cash gift for the first several years of their children’s lives. The size of the gift was randomly chosen to be either $333 or $20 per month. The mothers could spend the money in ways that made the most sense to them, with no strings attached. 

The ongoing trial is led by Drs. Kimberly Noble of Teachers College, Columbia University, Katherine Magnuson of the University of Wisconsin, Madison, and Greg Duncan of the University of California, Irvine. It is supported in part by NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). The first results from the trial appeared in the February 1, 2022, issue of Proceedings of the National Academy of Sciences.

The team recorded resting brain activity in 435 of the infants at 1 year of age. They found that infants in the high-cash group showed greater high-frequency activity than those in the low-cash group, particularly in frontal and central brain regions. The effect of the payments on brain activity was similar in size to that seen in successful interventions such as class size reductions.

The COVID-19 pandemic forced the team to stop in-person data collection. Thus, the sample ended up being smaller than planned. The significance of the findings varied with different analyses, and the authors couldn’t prove that some of them weren’t due to chance. Repeating the study with a larger sample size, which the team is planning to do when the children reach 4 years of age, will improve confidence in the results.

Even so, these first results suggest that family income may affect infant brain development during the first year of life. They also illustrate how changes to the family environment can change infants’ brain development. Of note, the activity patterns in infants from the high-cash group have been associated with better cognitive skills later in life.

“All healthy brains are shaped by their environments and experiences, and we are not saying that one group has ‘better’ brains,” Noble says. “But, because of the randomized design, we know that the $333 per month must have changed children’s experiences or environments, and that their brains adapted to those changed circumstances.”

The researchers will be directly measuring cognition and behavior in subsequent waves of the study. As the team follows these infants, they will be able to see how stable these differences in brain patterns are, and how they relate to the development of later cognitive skills.

—by Brian Doctrow, Ph.D.