Poverty shapes people in some hard-wired ways that we're only now beginning to understand. Back in August, we wrote about some provocative new research that found that poverty imposes a kind of tax on the brain. It sucks up so much mental bandwidth – capacity spent wrestling with financial trade-offs, scarce resources, the gap between bills and income – that the poor have fewer cognitive resources left over to succeed at parenting, education, or work. Experiencing poverty is like knocking 13 points off your IQ as you try to navigate everything else. That's like living, perpetually, on a missed night of sleep.
That finding offered a glimpse of what poverty does to a person during a moment in time. Picture a mother trying to accomplish a single task (making dinner) while preoccupied with another (paying the rent on time). But scientists also suspect that poverty's disadvantages – and these moments – accumulate across time. Live in poverty for years, or even generations, and its effects grow more insidious. Live in poverty as a child, and it affects you as an adult, too.
Some new research about the long-term arc of poverty, particularly on the brain, was recently published in the Proceedings of the National Academy of Sciences, and these findings offer a useful complement to the earlier study. In this new paper, researchers from the University of Illinois at Chicago, Cornell, the University of Michigan, and the University of Denver followed children from the age of 9 through their early 20s.
Those who grew up poor later had impaired brain function as adults—a disadvantage researchers could literally see in the activity of the amygdala and prefrontal cortex on an fMRI scan. Children who were poor at age 9 had greater activity in the amygdala and less activity in the prefrontal cortex at age 24 during an experiment when they were asked to manage their emotions while looking at a series of negative photos. This is significant because the two regions of the brain play a critical role in how we detect threats and manage stress and emotions.
Poor children, in effect, had more problems regulating their emotions as adults (regardless of what their income status was at 24). These same patterns of "dysregulation" in the brain have been observed in people with depression, anxiety disorders, aggression and post-traumatic stress disorders.
Over the course of the longitudinal study – which included 49 rural, white children of varying incomes – these same poor children were also exposed to chronic sources of stress like violence and family turmoil, or crowded and low-quality housing. Those kinds of stressors, the researchers theorize, may help explain the link between income status in childhood and how well the brain functions later on. That theory, they write, is consistent with the idea that "early experiences of poverty become embedded within the organism, setting individuals on lifelong trajectories."
To add some of these findings together: Poverty taxes the ability of parents to do all kinds of things, including care for their children. And the developmental challenges that children face in a home full of stressed adults may well influence the adults that they, themselves, become.