We are born equal, but some more equal than others, said George Orwell. Children from the higher social classes get better education, nutrition and parental attention than those further down the social ladder and this is reflected in academic achievement.
It’s a fact that children of the rich – or richer sections of society – tend to get higher IQ scores, do better on reading and linguistic tests, and are more able to stay concentrated and focused on a task than the poorer.
Recently, a group of scientists wanted to know whether this difference has a biological basis – not in the genetic or ethnic sense – but in terms of a physical difference in brain development between children of different social classes.
Adverse conditions have always meant that the poor have tended to be shorter in stature, have paler complexions and be more susceptible to illnesses than the rich. So, it seems obvious that this will also have an effect on the brain, just as much as any other part of the body.
Sadly, their findings appear to prove this is true. It seems that differences in environmental conditions lead to smaller and less developed brains in poorer kids compared to those in rich ones, and this begins even before they are born.
“We’ve known for a long time that kids from lower-income or disadvantaged families don’t do as well in school and have more difficulties on standardized tests,” Dr. Elizabeth Sowell, director of the Developmental Cognitive Neuroimaging Laboratory at Children’s Hospital Los Angeles, told the Huffington Post.
“We know that the brain is driving cognition and behavior, so there must be some difference in the brain.”
This has been the largest study to compare things like family income and the size of the brain. Using MRI, the researchers scanned the brains of 1099 children and young adults, ranging from 3 to 20 years old. The subjects underwent cognitive tests and took DNA samples to control for factors of race and genetic ancestry. The results were published this week in Nature Neuroscience
Science Mag says,
“The MRI scans allowed the team to measure the surface area of the subjects’ cerebral cortices, the outer layer of the brain where most advanced cognitive processing takes place, including language, reading, and executive functions. The researchers chose to measure cortical surface area because previous research had shown that it increases throughout childhood and adolescence as the brain develops, thus making it a potentially sensitive indicator of intellectual abilities.”
The results showed that children from families with an income greater than $150,000 had a 6% larger surface area of the brain’s cerebral cortex than those from families earning $25,000 or less. It also showed that children from families of higher social classes had a larger hippocampus, which is key for short term memory and spatial navigation, says the Guardian.
The study wasn’t able to say why exactly this is, but the team puts it down to factors like better nutrition, health care, better schools, opportunities to play and air quality, plus other environmental factors, which are known to play a role in physical development, including the brain.
Generally, poor families, who are often working two jobs or long hours, and for low pay, have less time to invest in their kids’ development or buy toys and educational material, which helps the brain to grow. Therefore, the lack of cognitive stimulation could be playing a major role in holding back the brain’s development, as well as emotional factors like stress in the family environment.
Luckily, the team are not suggesting that this is an hereditary or irreversible thing. Improvements in the child’s circumstances have been shown to counteract this process.
Science Mag says the study showed that,
“At the very lowest income levels, each incremental increase in income led to relatively greater increases in cortical surface area, whereas the influence of income tended to level off at higher levels.”
This tends to suggest that even relatively small improvements in income, environment and opportunities could improve children’s mental development.
Nature.com points out that,
“A study in Mexico….showed that supplementing poor families’ income improved their children’s cognitive and language skills within 18 months.”
Dr Sowell said,
“The implications for public policy are substantial. The brain develops over a very long period, throughout childhood and adolescence,” suggesting that enriching the environment of a child “at any point in development” can make a big difference in his or her abilities.
Kimberly Noble of Columbia University, who was the other leader of the study, stressed that race and ethnicity had no effect on any of their correlations.
“The links between socioeconomic status and brain structure were the same across individuals, regardless of racial background,” she said.
Martha Farah, a cognitive neuroscientist at the University of Pennsylvania, says that the study provides overwhelming support for the idea of alleviating childhood poverty.
“Even without neuroscience, the case for investment in society’s poor children is very strong,” she says. “But if brain imaging helps to focus people’s attention on the problem of childhood poverty, that’s great.”
