In the United States a new study of low-income children has found that those with more family instability and an emotionally unavailable mother early in life had higher levels of a stress hormone and more learning delays.
According to lead author, Jennifer H. Suor, insensitive parenting and family instability were the strongest predictors of children’s cortisol profiles (cortisol is the hormone which is released into the bloodstream in times of stress).
She also said “that many low-income children face a variety of social stressors, such as chaotic and unpredictable family environments and problematic parenting practices as economic hardship is known to place considerable burden on the family system,”
Almost all were receiving public assistance and living below the federal poverty line and more than half of the mothers identified themselves as black.
At the first visit, researchers observed the mother-child pairs playing with toys and puzzles for 10 minutes and rated the mother’s “emotional availability.”
They also looked for her awareness of the child’s needs, moods, interests, and capabilities.
The researchers also interviewed the mothers about the frequency, nature, course, and aftermath of parental or partner conflicts the children had witnessed. Researchers then collected 2 saliva samples from the children every year for 3 years to monitor their cortisol levels.
In the end, when the children were 4 years, it was found that the cortisol level of the children remained generally stable over the 3 year period, over a third had low levels of cortisol and 30% had high levels.
Those with higher and lower cortisol levels tended to have poorer mental functioning at age four, those with the higher cortisol pattern generally had more insensitive interactions with their mothers during the observation period at age two.
Children with the moderate cortisol profile had experienced less family adversity at age two and had the highest cognitive performance at age four.
Researchers however noted that their environmental and biological factors may contribute to lower cognitive functioning, noting that poverty tends to limit opportunities for early education, but income does not determine someone’s level of cognitive functioning.
J.J. Cutuli, said “Poverty is undeniably correlated with lower levels of cognitive functioning when you compare groups of low income children to higher income children on average, but many low income children outperform many higher income children.”