Why $75K is significant for memory and language ability

University of Toronto study reveals new insights into how socioeconomic disadvantage affects children's cognitive abilities

Why $75K is significant for memory and language ability
Steve Randall

There have been many studies on why people from low income backgrounds often miss out on the opportunities enjoyed by those from wealthier environments.

But a new study from the University of Toronto has uncovered new insights into the connection between low income families and the cognitive abilities of their children.

It’s not the first study to find that children from low income families score lower on memory and language abilities than higher income peers, but it is the first to establish which part of the brain is affected.

They discovered that the anterior hippocampus – one region of the part of the brain that is vital for memories and learning – is smaller in those from low income families.

While the researchers – led by psychology PsD candidate Alexandra Decker – focused on family income, they also found that stress and other factors also appear to play a negative role in cognitive abilities.

"Parents from families with higher incomes are more able to take time off work and are less likely to be working multiple jobs," says Decker. "They're also generally able to consistently afford enrolment in enriching programs and nutritious meals."

She added that children from low income families are likely to be affected by the stress borne by their parents struggling to pay bills.

Why $75,000 matters
The study, published in Nature Communications, also discovered that there is a limit on how much family income impacts children’s cognitive abilities.

"The relationship between income and the anterior hippocampus seems to be significant up to about an annual family income of about $75,000," says Decker. "There appear to be diminishing benefits at higher levels.”

Decker says that further research is needed on why, but suggests that at that level of income, particular needs may have been met.

Co-senior-author Amy Finn, head of the Learning and Neural Development Lab at U of T, says that research into how family income affects brain development is a key part of addressing inequality.

"Understanding how these factors interact is central to designing means to boost cognitive performance in children from lower income backgrounds, with implications for social mobility, reducing achievement gaps and much more," she said.

Read more at https://www.nature.com/articles/s41467-020-17854-6.