Current research has found that there is a relationship between brain size and socioeconomic status in children and adolescents. Researchers have found that certain regions the brain, especially those involved in language and decision making, tend to be smaller in disadvantaged individuals compared to affluent counterparts.
Childhood experiences play a large role in brain development, and it has already been shown that children from disadvantaged backgrounds do not perform as well in school and on cognitive tasks as children from families with more resources. Previous studies examining the neuroanatomical differences in the brains of these groups have been unsuccessful as they did not separate the effects of race and socioeconomic status or of income and education. The current study looks at the effects of family income and parental education on the brains of children and adolescents, all independent of race. Researchers recruited 1,100 participants ages 3-20 and collected data about their socioeconomic status before conducting an MRI and cognitive testing.
The researchers discovered that individuals with higher family income had more brain surface area, especially in brain regions involved in language, reading, and executive functions like problem solving and memory, than those from lower income families. Specifically, individuals from families who made more than $150,000 per year had brains with 6% more surface area than those raised in families making less than $25,000 per year. Not surprisingly, individuals with smaller brain surface areas also tended to perform worse of various cognitive tests. Regarding parental education, participants from highly educated families tended to have larger hippocampi, a brain area important for learning and memory.
The reason for these differences is unknown, but possible explanations include: low income families having less access to resources like healthy food, good health care, good schools, and play areas that affluent families often have access to. Also, family environments in low income homes could be more stressful and low income families may be more likely to live in polluted areas.
This study provides evidence for the importance of appropriate environmental enrichment, especially during development. Recent research has shown that speaking to children and babies and exposing them to as many new words as possible is vital to optimal brain development, and that children of low income or education often hear far fewer words growing up causing them to do worse in school and other cognitive tasks. This could be another reason for the relationship seen between reduced brain tissue and poverty.