Subjects: R and D
Virtually every nation on Earth struggles with endemic poverty.
Children of the poor are at greater risk for underachieving as adults regardless of the system of government where they live and the quantity and quality of both social services and educational systems available to them.
The problem has been poorly understood until, perhaps, now.
Three years ago, Martha Farah at the University of Pennsylvania demonstrated that the working memories of kids raised in poverty are smaller than those of middle-class children.
Working memory is the capacity to hang on to bits of information for current use; the items on a small shopping list, for example. It is required for solving problems and understanding language, and serves as a gateway to permanent memory.
Now, Cornell University’s Gary Evans and Michelle Schamberg have reported that Farah’s findings are almost certainly caused by the adverse effects of stress on brain development in children.
The scientists examined results from a longitudinal study of 195 participants of both sexes.
They assessed stress using a measure known as the allostatic load which combines the values of 6 parameters: systolic and diastolic blood pressure, serum levels of 3 stress-related hormones, and the BMI.
In all cases, higher values indicate more a more stressful life, and indeed poor kids had higher values than those in the middle class for all 6.
The scientists then confirmed Farah’s original finding: kids that had been poor their whole lives were able to retain 8.5 items in their working memories. That was significantly less than kids from the middle class, who could retain 9.4.
After that, the scientists used hierarchical regression techniques to remove the effect of allostatic load on the relation between poverty and memory.
Doing so made the relationship vanish, meaning that stress itself, not another aspect of poverty caused the memory deficit.
These findings held up after controlling for birth weight, maternal age at childbirth, maternal education level, maternal stress level and marital status.
The finding that stress interferes with the working memories of poor children is supported by other studies showing the effects of stress on generation and remodeling of cerebral neurons, and on the volume of the hippocampus and prefrontal cortex, where working memory is located.
Thus, stress associated with poverty makes it harder for children to learn.
Is it any wonder they do poorly at school, end up poor as adults and unwittingly visit the same fate on their kids?
The write-up is in Proceedings of the National Academy of Sciences.