Poverty and a child’s brain: new data on the host of bad effects

As a group, children in poverty are more likely to experience developmental delay, perform worse on cognitive and achievement tests, and experience more behavioral and emotional problems than their more advantaged peers. In addition, child socioeconomic status is tied to educational attainment, health, and psychological well-being decades later. Increasingly, research is focused on understanding the extent to which these long-term outcomes are related to changes in the developing brain.

This sobering quotation comes from a recent review article in Pediatrics, the journal of the American Academy of Pediatrics. It highlights an observation we’ve sort of known for many years, but now we have some specific research to support the observation. The article lays it all out.

There are decades of animal studies, research in which they can examine the brain, demonstrating that an enriched environment with things like exposure to new things and social stimulation positively affect brain growth. In contrast, chronic stress is bad for the developing brain. The actual structure of the brain is altered. Environmental exposures such as these affect which genes are expressed.  These observations are tied to the notion of brain plasticity, that the brain is not fully developed at birth. We know this is also true in humans. We also know sensitivity to external stimuli, both positive and negative, is heightened during periods of rapid brain growth, such as early childhood.

Childhood poverty is associated with several things known to affect brain growth and development, all of them negatively. Examples include the following:

1. Cognitive stimulation in the home. Poor children are less likely to be exposed to books, toys, and other stimuli because their parents can’t afford them. There is also evidence poor children are exposed to less complex and stimulating words and speech patterns, possibly because they are more likely to be left alone for extending periods.
2. Nutritional deprivation. Not surprisingly, a child’s brain needs good nutrition to grow to its fullest capacity. Poor children are less likely to get that. They are especially more likely to be deficient in iron.
3. Exposure to stress. The phrase “toxic stress” describes negative effects on brain development. Poor children are more likely to live in chaotic social situations that well describe such a state. The biological basis for this is under study, but increased levels of stress hormones, the body’s natural response to stress, have been implicated.
4. Environmental toxins. Poor children are more likely to be exposed to things that negatively affect brain growth and development. Two examples are exposure to lead and tobacco smoke, both more prevalent in poor households.

If you are interested in the specifics, the article goes on to present the evidence for how these things affect specific areas of the brain, particularly those associated with emotions, learning, memory, and what we call executive functions. The latter refers to higher order planning, reasoning, and decision making. Poor children are more likely to have problems in all of these categories.

But there is hope, as the authors point out:

Although young people are particularly vulnerable to the negative effects of poverty, their systems are also likely more malleable in response to intervention. The success of interventions such as the Perry Preschool Program demonstrate that the impact of poverty may be preventable or reversible at cognitive and behavioral levels.

There are a couple of key points to make with this. Genetics and environment are not destiny. Certainly individual children escape from poverty to achieve normal or even extraordinary things. We are talking about populations here, about averages. And it is clear to me that a crucial part of improving child health in America is directly linked to reducing poverty. The American Academy of Pediatrics has addressed this. The deck is stacked from birth against poor children. Certainly individual efforts are important. But the known effects of poverty on the developing brain make it unfair to demand of poor families that they somehow manage on their own to give their children the same chances at success I had.