Pablo Flores / Flickr

New research reveals a strong connection between income and the surface area of several key neural regions.

Behavioral scientists have made some truly groundbreaking insights into the cognitive costs of poverty in recent years. We now know, for instance, that scarcity puts a huge strain on our mental resources—the equivalent of stripping 13 points off our IQ, or losing a night’s sleep—making it that much tougher to handle daily tasks or decisions. That’s just one of many findings pointing to the same conclusion: poverty literally alters the way you process the world.

Some notable new work further explores how poverty disrupts the brain from a very early age. The study (spotted by Madeline Ostrander in the New Yorker) comes from a huge research team led by the developmental neuroscientist and pediatrician Kimberly Noble of Columbia University. In the journal Nature Neuroscience, Noble and company call this work “the largest study to date to characterize associations between socioeconomic factors and children’s brain structure.”

What they found doesn’t bode well for disadvantaged youths. The researchers first analyzed brain scans of nearly 1,100 children for possible associations with socioeconomic factors, such as income—controlling for things like age, sex, and most critically, genetic background. What they found is a strong connection between income and the surface area of brain regions related to language and executive functioning, with these variations “steepest” at the low end of the income ladder.

As Noble and collaborators put it, “for every dollar in increased income, the increase in children’s brain surface area was proportionally greater at the lower end of the family income spectrum.” Ostrander sums it up in yet clearer terms:

At the lowest end of the income spectrum, little increases in family earnings could mean larger differences in the brain. At the middle and upper income levels, though, the money-brain curve flattened. In other words, wealth can’t necessarily buy a better brain, but deprivation can result in a weakened one.

The researchers found that family income was “logarithmically” related to neural surface area—with steep variation at the poor end of the spectrum. (Nature Neuroscience)

These structural differences matter far outside the brain scanner. As a follow-up, the researchers gave some of the study participants a battery of cognitive tests. They found that income, via its impacts on brain surface area, had a partial effect on performance for two assessments of executive function. One test (known as the flanker) requires participants to focus attention; the other (a working memory task) asks them to remember a series of items.

The researchers suspect what’s happening is that wealthier parents simply have more tools to nurture a developing brain. They can afford healthier foods or educational games and videos or better child care. They can also move to safer neighborhoods less exposed to environmental pollutants or toxins.

Noble et al. recognize that all sorts of factors, over and above poverty, account for variations in brain structure—hence the huge diversity of brain structures found at every income level in the study, including the disadvantaged end. So it’s not quite right to draw a straight line from low socioeconomic status to poor cognitive development. But insofar as policies that target poverty might also benefit young brains, they’ll help the starting line stay much less crooked.

About the Author

Most Popular

  1. A photo of Andrew Field, the owner of Rockaway Taco, looking out from his store in the Rockaway Beach neighborhood of the Queens borough of New York.
    Life

    Tacos and Transit: Rate Your City

    From taco-rich San Diego to the tortilla wastelands of Boston, we asked you to grade U.S. cities on two critical metrics: Mexican food and public transportation.

  2. A photo of shoppers in the central textile market of downtown Jakarta.
    Design

    How Cities Design Themselves

    Urban planner Alain Bertaud’s new book, Order Without Design, argues that cities are really shaped by market forces, not visionaries.

  3. A photo of low-profile electric fire trucks on display at China's International Import Expo.
    Transportation

    The Fire Trucks Are Too Damn Big

    Smaller heavy-duty emergency vehicles could save a lot of lives, says a new Department of Transportation report.

  4. A photo of a man sitting on a bench in East Baltimore.
    Equity

    Why Is It Legal for Landlords to Refuse Section 8 Renters?

    San Jose and Baltimore are considering bills to prevent landlords from rejecting tenants based on whether they are receiving federal housing aid. Why is that necessary?

  5. A pupil works on a cardboard architectural model at a Hong Kong primary school.
    Design

    The Case for Architecture Classes in Schools

    Through the organization Architecture for Children, Hong Kong architect Vicky Chan has taught urban design and planning to thousands of kids. Here’s why.