The Research Brief is a short story about interesting academic work.
big idea
According to our team’s new study, children growing up in more disadvantaged neighborhoods—that is, with poorer housing, more poverty, and lower levels of employment and education—show a marked increase in brain activity when viewing emotional faces on the screen. But what’s important is that we found that this association was only true when adults in those areas also didn’t have strong general norms about preventing crime and violence.
Our results highlight that where children live and the resources of other people in the neighborhood can influence brain development. But neighbors can help protect children from such brain damage if they can create positive social norms for caring for each other and preventing violence.
To obtain these results, we recruited families from areas of southern Michigan with above-average disadvantage. We used functional magnetic resonance imaging, or fMRI, to measure the brain activity of teenagers as they looked at facial expressions of various emotions. We focused on monitoring activity in the amygdala, the region of the brain responsible for detecting threats and processing emotions.
We used the area’s census data on factors such as home ownership, the percentage of families living below the poverty line, and the percentage of the unemployed to measure the disadvantage of the area. We then asked randomly selected neighbors of each family to answer questions about social norms in their area, especially shared beliefs about preventing crime and violence.
We found that in young people aged 7 to 19 who lived in more disadvantaged areas, the amygdala reacted more strongly to frightened and angry faces. But neighbors who shared strict social norms, such as the belief that adults should do something if children were fighting, seemed to offset this effect. That is, unfavorable neighborhood was associated with amygdala reactivity only when neighbors were more non-intrusive about preventing violence.
Why is it important
In 2020, about 6.4 million children in the United States lived in areas with a poverty rate of 30% or more. Research shows that young people who grow up in poorer neighborhoods are more likely to perform poorly in school and have more severe mental health problems.
Disadvantaged neighborhoods create higher risks for children who go beyond the family’s own resources or the environment. This is because these neighborhoods increase children’s exposure to violent crime and physical hazards such as pollution, toxic substances, and traffic, and they limit access to healthy food and high-quality schools.
Our study, along with other recent studies, highlights how troublesome neighbors can get under the skin. In other words, it can affect a child’s development by shaping the structure and function of the brain, in addition to influencing other body systems such as the stress response system.
Unfortunately, research shows that structural factors such as the location of highways and how neighborhoods are defined can concentrate disadvantage in particular neighborhoods. This, in turn, prevents neighbors from building strong relationships and norms. So while neighbors may work to create a more child-friendly environment, policy changes may be needed to help neighbors and families thrive in more disadvantaged neighborhoods.
What other research is being done
Recent studies by other researchers have attempted to understand why living in a disadvantaged neighborhood affects brain development and to identify additional factors that may protect children.
For example, in a peer-reviewed study that has yet to be published, researchers found that firearm deaths within a half-mile radius of orphanages were associated with connectivity between brain regions important for emotion processing and self-regulation. And, like our study, they found that this effect was offset by positive relationships with neighbors.
Other work shows that exposure to air pollution from vehicular traffic is associated with differences in children’s brain development.
