Cerebrum Winter 2020

Psychologists, sociologists, public health researchers, and, more recently, neuroscientists, are all interested in understanding socioeconomic influences on the brain and body.

S ocioeconomic status (SES)— or one’s annual income, years of education completed, and occupation—has long been appreciated as a critical determinant of longevity. Indeed, there are large gaps in life expectancy for those at the top of the socioeconomic ladder compared to those at the bottom, and at many points in between. But how can a “macro-level” societal factor, like how much money you make or if you graduated from college or not, “get into the skull and under the skin” to influence an individual’s health and well-being? Psychologists, sociologists, public health researchers, and, more recently, neuroscientists, are all interested in understanding socioeconomic influences on the brain and body. It perhaps comes as no surprise that living in poverty, without enough money to meet basic needs like food, water, and shelter, or to go to the doctor when you’re sick, can take a toll on health. But, interestingly, the data show that the relationship between socioeconomic status and health is present even in countries with universal health care, suggesting that there is more to the psychological experience of being lower in SES beyond just access to health care. Further, some intriguing research shows that our subjective perceptions of our standing in the US are a better predictor of health compared to more objective indicators like income and education. Together, data like these have led some to conclude that, in addition to our objective life circumstances, how we perceive our social standing and how we compare to others in our environments can impact our health. Given the robust associations between socioeconomic status and health, more recent research has focused on understanding the

mechanisms, or pathways, through which SES may impact disease processes and health outcomes. Some of this work has utilized advancements in brain imaging technology to explore how SES impacts the functioning of the brain in ways that could lead to poor health outcomes. Other work has focused on the relationship between socioeconomic factors and physiological processes, such as the functioning of the cardiovascular system and the immune system. What follows is an overview of these areas of recent research, all of which are attempting to fill in pieces of the complex puzzle of the relationship between SES and health. Much past research on the effects of SES on the brain has focused on how socioeconomic factors influence the development of brain regions important for academic achievement among children and adolescents. Together, this work suggests that children whose parents’ make less money or have fewer years of education have different trajectories of development in brain structure (i.e., the size and shape of different brain regions) and in brain function (i.e., what brain regions are used to perform a task) that may prevent them from performing to their full potential in school and beyond. This research has been critically important in facilitating our understanding of how SES in early life can shape brain development in ways that may perpetuate economic inequality. But given that most SES-based health disparities don’t develop until much later in life, when adults start to develop chronic diseases like heart disease and diabetes, more recent work has begun to shed light on how SES influences SES Impacts Health-Relevant Brain Functioning

neural activity in brain regions that may contribute to chronic disease development among adults. One brain region that has received a lot of attention for its potential role in contributing to SES-based health disparities is the amygdala. The amygdala is an “infamous” brain region that is often incorrectly characterized as a “fear center” of the brain. Instead, our current understanding of the primary function of the amygdala is that it plays an important role in helping detect salient information in the environment (which could be feared things, like snakes or spiders or angry faces, or could be positive things, like a smiling baby or winning a raffle). The amygdala is important for health because it has strong connections with other brain regions that can start physiological cascades like the “fight or flight” response, which, if chronically activated, can take a toll on the body and put individuals at risk for chronic disease development. Given the amygdala’s importance for health, a number of prior studies have investigated the association between socioeconomic factors and amygdala responses to stressful or threatening stimuli, like angry faces or receiving negative performance feedback. This growing area of work shows that individuals from lower SES backgrounds have greater amygdala activity to stressful, threatening stimuli, compared to higher SES individuals. Although speculative, this suggests the possibility that lower SES individuals are more reactive to stressors, which, over time, could increase risk for poor health outcomes. But of course, it’s not only our initial, “knee jerk” response to a threatening situation that is important for health over time, but also how we cope with the situation. Psychological scientists

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