“The American dream is not a sprint, or even a marathon, but a relay. Our families don’t always cross the finish line in the span of one generation. But each generation passes on to the next the fruits of their labor.”

Julian Castro, Former 2020 Presidential Candidate and 16th United States Secretary of Housing and Urban Development

The American Dream has played a crucial role in the imagination of our perceptions of social mobility, happiness, and well-being since the inception of the United States. To this day, the idea that anyone, regardless of their background, has access to the opportunities for prosperity and success still pervades American society. From celebrities to politicians like Julian Castro, people use the American Dream as an emblem of hope passed on from one generation to the next.

But, does the American Dream still hold true today?

Frankly, it seems quite the contrary. A number of studies by social scientists have shown that intergenerational poverty is extremely prevalent in the United States and is very much the norm. Meaning, children that grow up in poverty are more likely to be poor as adults too (McEwen and McEwen, 2017; Shonkoff et al., 2009). Sociologists have attributed this to one’s family background, institutional and systemic inequalities, and community resources available. However, this is not the case for everyone. There are a handful of adults who grew up poor, but are now more well-off. Sociological approaches that focus on the social structures of society cannot entirely explain this anomaly.

So, then, the real question is: Why is it that poor children are more likely to be poor when they grow up? And, how are some people able to break away from intergenerational poverty?

It was not until recently that developmental neuroscientists began to investigate whether or not the stress of poverty affected the brain development of children. Findings by neuroscientists suggest that forms of early-childhood adversities become a form of toxic stress in which the biological stress system is frequently activated by chronic social conditions like poverty (McEwen and McEwen 2017; Shonkoff et al., 2009).

Typically, when someone is stressed, the body is able to respond effectively in the short run by adapting to the environment and achieving homeostasis through a process called allostasis (McEwen, 1998). However, when the body is exposed to chronic, toxic stress, the body is no longer able to maintain homeostasis and goes into an unbalanced physiological state known as allostatic overload (McEwen, 1998). In the case of allostatic overload, the hypothalamic-pituitary-adrenal (HPA) axis, which is responsible for neuroendocrine regulation stress responses by releasing hormones, becomes dysregulated and cannot successfully manage allostasis (McEwen, 1998).

Neuroscientists have found that early-childhood adversities and forms of toxic stress significantly shape brain development, cognitive performance, self-regulation, and physical and mental health (McEwen and McEwen, 2017). In particular, cumulative toxic stressors in the environment (i.e. household and neighborhood poverty) affect the childhood development of the brain’s frontal lobe and limbic system, regions of the brain that deal with problem-solving, goal-setting, and executive function. Social factors like poverty are thereby direct influences on levels of adversity, and these effects are further magnified in the early development of the brain in children.

McEwen and McEwen’s (2017) article suggests a toxic stress model that integrates the biological components of brain and body development with the greater social structures that pattern life trajectories. Specifically, they suggest that brain development and the vulnerability of children to toxic stressors are remarkably influenced by inherited genes and changes in gene expression.

Their model demonstrates the ways in which biological processes related to brain development are not the cause of social outcomes, namely poverty in this case, but rather part of a system that depends on such social structures found in society. Social circumstances create adversities that, in turn, affect brain development and life trajectories through the form of toxic stress. 

What is more, the model leaves room for individual variation with regards to how people respond to stress and the types of support systems they have in place.  Given the neuroplasticity of the brain, or its ability to change neural pathways and connections, many of the effects of toxic stress can be reversed through social interventions (McEwen and McEwen, 2017). This may explain why some people are able to break the cycle of intergenerational poverty, while others are not. 

So, maybe it is time that we question the American Dream that we idealize, and consider the ways in which our background affects both our neurobiology and our access to social mobility. 

References

McEwen, B. S. (1998). Protective and damaging effects of stress mediators. New England Journal of Medicine, 338(3), 171-179.

McEwen, C. A., McEwen, B. S. (2017). Social structure, adversity, toxic stress, and intergenerational poverty: An early childhood model. Annual Review of Sociology, 43, 445-472.

Shonkoff, J. P., Boyce, W. T., McEwen, B. S. (2009). Neuroscience, molecular biology, and the childhood roots of health disparities: Building a new framework for health promotion and disease prevention. JAMA, 301(21), 2252-2258.