New research shows that children of poorer backgrounds appear to have ‘smaller’ brains than those of affluent backgrounds, according to neuroscientists of scientific journal Nature Neuroscience.
The study’s researchers assessed the brain scans of 1,100 young children and young adults and found that those in families who earned less than $25,000 a year had 6% less surface area in their brains than those young people of households who earn more than the average income.
The study looked at both girls and boys aging from 3 to 20, and found that those of more deprived, lower socio-economic backgrounds had a smaller cerebral cortex; the part of the brain that handles language, memory, spatial skills and reasoning.
The study, published last month in Nature Neuroscience, is the largest of its kind to date. It was led by Kimberly Noble, who teaches at both Columbia University’s Teachers College and the university’s medical school.
Senior author of the study, Elizabeth Sowell of the Children’s Hospital Los Angeles, says
‘We’ve known for so long that poverty and lack of access to resources to enrich the developmental environment are related to poor school performance’,
“But now we can really tie it to a physical thing in the brain. We realized that this is a big deal.”
This study comes at an important time, as the gap between rich and poor is steadily growing in America. It can provide valuable insight into ways that policy-makers can look at reducing the academic achievement gap between poor and rich children – which is apparent as early as kindergarten.
“It’s only been in the past 20 years that we could have done this with living, developing children,” said Sowell, who published a pioneering 1999 study that found the brain is still developing past adolescence, contrary to earlier beliefs that brain growth was complete by the teen years.
In another study that has been accepted for publication in Psychological Science, a team led by neuroscientist John Gabrieli of the Massachusetts Institute of Technology found differences in the brain’s cortical thickness between low-income and higher-income teens. The study linked that difference for the first time to standardized test scores: 57 per cent of the poor children scored proficient in math and reading tests given annually in Massachusetts, compared with 91 per cent of the higher-income students.
“The thing that really stands out is how powerful the economic influences are on something as fundamental as brain structure,” Gabrieli said. “It’s just very striking.”
“Just as you would expect, there’s a real cost to not living in a supportive environment,”
“To me, it’s a call to action. You want to boost the opportunities for those for whom it doesn’t come easily in their environment.”
The study points to many variables, including the higher amounts of stress those of lower socio-economic backgrounds may have to deal with, hinting that this can be attributed to poor learning and behavioural skills. This may be because they have more limited access to educational resources, and receive less exposure to spoken language early in life. Also, it can be a by-product of poor families leading more chaotic lives.
“Some people feel if you show these brain differences, you’re politically condemning the poor — which is the opposite, I think, of what we need to do.” Gabrieli said. “I think we want to understand adversity and minimize adversity.”
But James Thompson, a psychologist at University College London, has a third theory.
“People who have less ability and marry people with less ability have children who, on balance, on average, have less ability,” he said.
Thompson believes there is a genetic component to intelligence that Noble and Sowell failed to consider.
It is important to note however, that while the study had revealed a statistical significant correlation between income and brain size, the findings weren’t at all that particularly strong. There were still a good amount of those of poorer backgrounds with larger brains, and those of more affluent backgrounds with smaller brains. However, as Noble put it, “You would never be able to look at a child’s family income and from that information alone predict their cortical surface area.” So in other words, poverty is not destiny no matter how small or large the brain.