A study published in the journal Science found that a child’s socioeconomic environment exerts the strongest influence on brain development, surpassing factors like IQ, parenting style or health history. The researchers analyzed brain scans from nearly 12,000 9- to 10-year-olds, mapping 649 variables across 12 categories. When compared, socioeconomic factors, including family income, home ownership, local poverty rates and access to transportation, accounted for approximately 16 percent of the variability in children’s brain function. Of the top 40 variables linked to brain function, 37 were socioeconomic in nature.

The brain regions most affected by socioeconomic disadvantage were the same areas most susceptible to sleep deprivation and stress, indicating that the brains of children from lower-income households do not reflect diminished cognitive capacity, but rather the consequences of chronic stress and inadequate sleep.

The study also challenges longstanding assumptions regarding IQ and brain structure. When researchers adjusted for socioeconomic status, approximately 70 percent of previously identified brain-IQ associations lost statistical significance, suggesting that earlier studies may have been measuring the impact of circumstance rather than innate intelligence.