The study of normal 9- and 10-year-olds, who differed only in socioeconomic status, showed “detectable differences” in their prefrontal cortex. That is the part of the brain responsible for so-called executive functions, like personality, decision making and social behavior.

Half of the children were from families with low incomes–with mean household income of $27,192–and half from families with high incomes, with mean of $96,157.

“Kids from lower socioeconomic levels show brain physiology patterns similar to someone who actually had damage in the frontal lobe as an adult,” said Robert Knight, director of the institute and a UC Berkeley professor of psychology. “We found that kids are more likely to have a low response if they have low socioeconomic status, though not everyone who is poor has low frontal lobe response.”