February 16, 2018
Economic inequality is a growing concern to Americans. Disparities in wealth and education have a real impact on American lives, especially during childhood. Poverty has deleterious effects on early brain development and even genetics, studies show, in part because toxic stress and adversity increase stress hormones.
Prolonged stress response can negatively impact cognitive functioning and mental health. But there is more to the intertwined story of economics and biology, according to Dima Amso and Andrew Lynn in a new article for Policy Insights from the Behavioral and Brain Sciences (PIBBS). It’s not just that poverty is detrimental, but that wealth is beneficial to development. When the researchers looked across the economic spectrum, they found that socioeconomic status (SES) has an impact of its own, distinct from that of adversity. “Wealth’s advantages, more than poverty, are driving many SES-based differences in brain and cognitive development, and educational achievement outcomes,” claim the authors.
Historically, many social science studies have unintentionally conflated low SES with adversity, because they often co-occur. According to Amso and Lynn’s review of the research, income and adversity actually have independent effects on development. Some studies that have tried to tease them apart have found that adversity, but not low-SES by itself, predicts increased levels of stress hormones and decreased functioning in parts of the brain associated with memory and emotional regulation. Other studies show that, regardless of their family’s income and education level, children with adverse experiences like maternal depression, abuse and neglect, family transitions, and neighborhood violence are at higher risk for mental and physical health problems and low achievement.
SES has its own distinct impacts on life outcomes, especially cognitive achievement, and they aren’t limited to the low end of the income distribution. Children from very wealthy families do better than their peers from middle-income families and so on down the spectrum. The most privileged children have the highest language skills, executive functioning and planning skills, and other cognitive outcomes, in part because they get more parental support and language input and have better neonatal health, studies suggest. There is evidence that this pattern extends all the way down to the neurological level. For example, two studies examining cortical thickness (a rough measure of brain development) found adolescents in the very highest income group experienced maintenance or thickening of the cortex while all other income groups experienced thinning.
By looking across the economic spectrum, Amso and Lynn are not suggesting that policymakers abandon efforts to remediate poverty. Rather, they are advocating for more specificity in the identification and remediation of problems. Although eliminating stressors is the ideal result, that outcome is not always quick or even feasible, so it is worth remembering that “it is the body’s response to the stressor, not the stressor per se, that begins the wear and tear process,” they point out.
To counteract the effects of adversity, studies suggest the best way to dampen the body’s stress response is through social buffering from nurturing relationships. Programs that help new mothers and foster parents regulate their own emotional response and encourage children’s self-regulation have been shown to improve long-term outcomes for kids. Exercise also appears to buffer the stress response, so the authors suggest that schools serving children living with adversity make physical exercise a regular part of the curriculum. When it comes to addressing the consequences of SES differences, the answers aren’t as clear. But science is telling us that income inequality is a problem worth thinking about, because it affects all of us, especially our children.
Drawn from “Distinctive Mechanisms of Adversity and Socioeconomic Inequality in Child Development: A Review and Recommendations for Evidence-Based Policy” by Dima Amso and Andrew Lynn in Policy Insights from the Behavioral and Brain Sciences.
