Dr. Pat Levitt, a developmental neuroscientist at Children’s Hospital Los Angeles, he has become interested in another sort of neurotoxin: poverty. As it turns out, the conditions associated with poverty — “overcrowding, noise, substandard housing, separation from parent(s), exposure to violence, family turmoil,” and other forms of extreme stress--can be toxic to the developing brain, just like drug or alcohol abuse. These conditions provoke the body to release hormones such as cortisol, which is produced in the adrenal cortex. Brief bursts of cortisol can help a person manage difficult situations, but high stress over the long term can be disastrous. In a pregnant woman, the hormone can “get through the placenta into the fetus,” Levitt told me, potentially influencing her baby’s brain and tampering with its circuitry. Later, as the same child grows up, cortisol from his own body may continue to sabotage the development of his brain.
A person whose brain has been undermined in this way can suffer long-term behavioral and cognitive difficulties. In a longer-term study published two years ago, neuroscientists at four universities scanned the brains of a group of twenty-four-year-olds and found that, in those who had lived in poverty at age nine, the brain’s centers of negative emotion were more frequently buzzing with activity, whereas the areas that could rein in such emotions were quieter. Over the past decade, the scientific consensus has become clear: poverty perpetuates poverty, generation after generation, by acting on the brain.