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How Childhood Poverty Affects the Brain


The general findings that cognitive neuroscientist Martha J. Farah, PhD, reported at the beginning of her recent talk on Penn’s campus were grim:

  • the poorer you are, the more depressed you are;
  • a child’s IQ is related to family income;
  • psychological well-being and intelligence both depend on the brain;
  • low socioeconomic status (SES) contributes to what Farah called “the vicious cycle of poverty.”

Given this starting point to her presentation -- “Childhood Poverty and Brain Development: From Science to Policy” -- Farah then posed an important question: “Does neuroscience really add anything to this?” Just as critical: are there implications for social policy?

BrainFarah, the Walter H. Annenberg Professor in Natural Sciences and professor of Psychology in Penn’s School of Arts & Sciences, has a secondary appointment in the department of Neurology in the Perelman School of Medicine. She is also the founding director of the interdisciplinary Center for Neuroscience & Society. For her, “Society” is as important as the science: part of the center’s mission is to address the ethical, legal, and social implications of neuroscience.

In the course of her academic career, Farah has studied the neural underpinnings of vision, reading, and face recognition, as well as the function and impact of what has been called “cosmetic neurology,” the use of cognitive-enhancing drugs. More recently, she turned her attention to the connection between socioeconomic status and the brain. The relevance of SES to cognitive neuroscience, she has written, “lies in its strong relationship to cognitive ability, as measured by IQ and school achievement.” In fact, the very beginning of an article that appeared in December in PNAS, the journal of the National Academy of Sciences, relates how Farah became interested in what PNAS called “the neuroscience of poverty.” The babysitters she hired to look after her daughter were often mothers who were struggling to make ends meet. She realized that their children started life “with the same evident potential as my own daughter.” But somehow the paths diverged dramatically.

Neurological studies have demonstrated that poverty takes a toll in three areas: language, executive function (especially cognitive control and working memory); and declarative memory (the ability to consciously recall facts and verbal knowledge). Farah explained that specific parts of the brain are affected, “not in a good way” -- the prefrontal cortex, which is involved in decision-making and self-control, and the hippocampus, which is essential for consolidating memories and information.

Jack P. Shonkoff, MD, a professor of child health and development at Harvard University, has shown the effects of “toxic stress” on children, and children in poverty are likely to encounter much more such stress that children of higher socioeconomic status. Parents who are stressed are likely to be less patient and affectionate with their children; as a result, the children are more stressed as well. The stress contributes to a smaller hippocampus, which then has an impact on a child’s ability to consolidate information.

Farah also noted a valuable neuroscientific clue “from a place you probably never expected”: rats. Research has shown that the young rats whose mothers are more solicitous grow up to have relatively normal memory, better hippocampal development, and better response to stress. Similarly, in the world of low-SES households, where stress is more of a factor, how the parents treat the children makes a notable difference when they are tested for memory. Researchers have studied the signs: is the home environment supportive? Does the mother hit the child? Does she have a friendly nickname for the child? In the end, Farah asserted, “Parental nurturance matters.” In particular, maternal nurturing behavior buffers the hippocampus from stress.

As she ended her presentation, Farah returned to the matter of policy. Poverty’s effects on child development are complex: “We need all hands on deck” to learn more, Farah said, and neuroscience is a useful tool along with the others available. “The science we have now is not useless,” she continued, but nothing so far is “exactly actionable.” More work is needed before researchers can recommend any specific interventions. Future studies may be able to personalize treatments for children whose brains are particularly challenged. Farah did cite a form of parental behavior that is indeed supported by neuroscience: reading to children, engaging them in that way from an early age.

On the other hand, Farah ended by underscoring another important aspect of the neuroscience of poverty. It is “less morally freighted” than many popular views. “A large fraction of Americans believe that people are poor because they’re not working hard.” But neurons, Farah said, “are not good guys or bad guys.” A wider understanding of the neuroscience would help reduce the “blaming” that goes on.

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