During the first PoRESP summer school, which was organized from July 6th to July 9th 2015 in Brussels, we had the chance to have Martha Wadsworth as one of our keynote speakers. Martha Wadsworth is an Associate Professor of psychology at Penn State University and she is the director of the Coping and Regulation of Environmental Stress (CARES) Lab. She works on the biological and psychological impacts of poverty on children. In particular, her research shows that children that grew up in poverty have a biological response to stress that is different from children who have not experienced poverty.
How do children who DID NOT grow up in poverty react to stress? When a stressful event occurs, the stress response system of the body gets activated and interactions among three endocrine glands (called the Hypothalamic-pituitary-adrenal axis) leads to the secretion of two hormones, the adrenaline and the cortisol. These hormones send signals to the different organs of the body for them to stop working on non-vital activities, so that the entire body focuses on coping with the stress. For example, the secretion of these hormones can cause pupils to dilate for better vision acuity. Once the stress has passed, the secretion of hormones decreases rapidly.
However, recent research shows that children that grew up in poverty have a higher chance to have a malfunctioning stress response system, which comes from a too frequent activation of the stress response. Indeed, these children tend to face a lot of stress due to poverty-related factors such as residential instability, violence, discrimination, neighborhood poverty, etc… The stress response system can malfunction in two ways: there can be a hypoactivation of the stress response system, and in this case the quantity of hormones secreted is too low. There can also be a hyperactivation of the stress response system, which translates into the level of secretion of hormones staying high even once the stress has passed. Both these malfunctionings are very problematic: hypoactivation can lead to unemotional conduct problems and sever depression. Hyperactivation can also lead to depression, anxiety or post-traumatic stress. As a consequence, poor kids face what Martha Wadsworth calls a “triple jeopardy”: they are more exposed to stress, they have a higher propensity of having a damaged stress response system and they are therefore less able to regulate their emotions. Additionally, poverty-related stress damages other components of the brain, such as the hippocampus, the amygdala or the pre-frontal cortex, which also participate in the regulation of stress.
Fortunately, Martha Wadsworth’s research shows that this situation is partially reversible: when poor children are taught how to cope with stressful situations, the regulation of their level of hormone tends to improve. To study this question they designed an experiment in which 45 poor children between the ages of 9 and 12 were selected to be part of an intervention that would help them building a strong identity and coping skills. To measure if the intervention changed anything to their stress response, the researchers put the children in a stressful situation and they measure their level of cortisol at different moment of the stressful situation. Before the intervention these children show a hypoactivation of their stress response system: they have no change in their level of cortisol secretion when facing the stressful situation. After the intervention, although the quantity of secreted cortisol is still lower than the average child, the secretion of cortisol increases during the stress.
Martha Wadsworth’s talk at the summer school gave fascinating insights into the biological consequences of poverty and was particularly relevant for economists interested in understanding poverty. In fact, her work sheds light on one possible reason for the persistence of poverty over generations, by underlying that poverty-related stress faced by individuals in their childhood impacts their capacity to react to stress later in their life. Given that these self-regulation problems are correlated with other type of problems such as inability to delay gratification, difficulties to plan ahead or high risk-taking, they are likely to negatively impact adulthood outcomes.