A mother’s perceived social status predicts her child’s brain development and stress levels, according to a new study from Boston Children’s Hospital.
In the study, children whose mothers saw themselves as having a low social status were more likely to have increased cortisol levels, an indicator of stress, and less activation of their hippocampus, a structure in the brain responsible for long-term memory formation, which is required for learning and reducing stress responses.
“We know that there are big disparities among people in income and education,” said Margaret Sheridan, PhD, of the Labs of Cognitive Neuroscience at Boston Children’s Hospital, the study’s first author. “Our results indicate that a mother’s perception of her social status ‘lives’ biologically in her children.”
The research team, led by Sheridan and senior investigator Charles Nelson, PhD, of Boston Children’s Hospital, studied 38 children between the ages of 8 and 11. The children gave saliva samples to measure levels of cortisol, and 19 also underwent functional MRI of the brain, focusing on the hippocampus.
Meanwhile, the mothers were asked to rate their social standing on a scale of 1 to 10, comparing themselves with others in the United States.
The researchers found that — after controlling for gender and age — the mother’s self-perceived social status was a significant predictor of cortisol levels in the child.
This finding is consistent with studies in animals, according to the researchers.
“In animal research, your stress response is related to your relative standing in the hierarchy,” Sheridan explained.
The mother’s perceived social status also significantly predicted the degree of hippocampal activation in their children during a learning task, according to the study’s findings.
Actual maternal education or income-to-needs ratio — the family’s income relative to its size — did not significantly predict cortisol levels or hippocampal activation, the researchers noted.
The findings suggest that while actual socioeconomic status varies, how people perceive and adapt to their situation is an important factor in child development, the researchers said.
Some of this may be culturally determined, according to Sheridan. She is currently participating in a much larger international study of childhood poverty, called the Young Lives Project, that is looking at objective and subjective measures of social status, along with health measures and cognitive function. The study will cover much wider extremes of socioeconomic status than just a U.S.-based study, she said.
The current study did not find evidence that stress alters hippocampal function, Sheridan said, noting that no relationship was found between cortisol and hippocampal function, as has been seen in animals. This may be because of the small number of children in the study that had brain fMRIs, she said.
“This needs further exploration,” she added. “There may be more than one pathway leading to differences in long-term memory, or there may be an effect of stress on the hippocampus that comes out only in adulthood.”
The study was published by the journal Developmental Science.
Source: Boston Children’s Hospital