Rich and well-educated families are more likely to have children with big brains, according to a new study looking at socioeconomic status and brain structure among young people in the US.
Led by The Saban Research Institute of Children's Hospital Los Angeles and Columbia University Medical Centre, nine universities across the country collaborated to analyse the minds of 1,099 people between three and 20 – the age range during which the brain develops. They carried out MRI scans and found out levels of intelligence using cognitive tests.
A definite correlation became apparent – income and education predicted the surface area of a child's brain, particularly in regions related to language, reading and spatial skills. The results are published in the journal Nature Neuroscience.
Numerous studies have shown how having a bigger brain leads to higher intelligence, and this was no exception – on average, those from wealthier backgrounds did better in the tests.
"Children from lower income families have shown on average more difficulties with language functioning, school performance and other metrics of cognitive development," said Elizabeth Sowell, one of the lead researchers in the study.
She suggested this might be because when a brain is bigger, each nerve has more room for insulation, which in turn leads to signals being fired off more quickly.
The trend was most noticeable at the lower end of the economic spectrum, with large differences in brain size occurring between the children of parents with average and very low incomes. At the higher end, differences were negligible.
Why do the children of wealthy parents have bigger brains?
The existence of a connection is clear, but what causes that connection is still a matter up for debate. The researchers in this study say it's likely to be resources available during development, rather than genetics.
“Not all economically disadvantaged children perform worse than all children with greater financial resources, but it is likely that resources afforded to the more affluent impact the way the brain develops,” said Sowell.
"Family income is linked to factors such as nutrition, health care, schools, play areas and, sometimes, air quality.
"Future research may address the question of whether changing a child's environment - for instance, through social policies aimed at reducing family poverty - could change the trajectory of brain development and cognition for the better."