What shapes a developing brain more than anything else? A large 2026 study published in Science set out to answer that, screening 649 different variables against brain measures in children aged 9 to 10 from the Adolescent Brain Cognitive Development (ABCD) Study. The standout finding: a cluster of factors tied to socioeconomic status - family income and neighborhood opportunity - showed the strongest associations with how the brain is functionally connected.
The pathway: sleep, stress and arousal
The differences were strongest in brain regions involved in sensory and motor processing - and that is where two everyday factors tied to lower socioeconomic status showed the biggest links: more screen time and less sleep. Because those regions are tied to arousal, and arousal regulates brain activity, the authors propose that socioeconomic stressors may shift arousal patterns over time, producing lasting differences in how the brain works. The same study highlighted stimulant-effect and norepinephrine-related maps, the very systems involved in attention and ADHD.
Environment, not ancestry
Crucially, the team replicated the pattern in a separate UK Biobank sample, and analyses by genetic ancestry pointed the same way: the brain differences linked to socioeconomic factors are not explained by genetic ancestry. In other words, this is about environment and circumstance, not about which group a child belongs to.
Why this matters for you
This is some of the strongest evidence yet that early environment - stress, sleep and daily conditions - leaves a measurable mark on the brain. It connects directly to research on adverse childhood experiences (the ACE test), where chronic early stress predicts adult health. And because the arousal and norepinephrine systems overlap with attention, it adds context to how we think about attention and ADHD.
The hopeful part
Brains are shaped by environment, which means environment can also help. Protecting sleep, lowering chronic stress and improving daily conditions are not small things - they reach all the way to brain function. If you want a private starting point, our free ACE test takes two minutes. It is educational, not a diagnosis.
Sources: Brain-wide association study, Science (2026); Adolescent Brain Cognitive Development (ABCD) Study; UK Biobank replication. Educational summary - not a diagnosis.