Childhood exposure to severely disadvantaged communities is linked to decreased verbal ability later in childhood, a lasting negative effect that continues even after moving out of the neighborhood, according to research that will be published this week in the Proceedings of the National Academy of Sciences.
Living in “concentrated disadvantage” decreases later verbal test scores by about four IQ points, which is roughly equivalent to missing a year of school.
The study was led by Robert Sampson, Henry Ford II Professor of the Social Sciences in the Faculty of Arts and Sciences at Harvard University, with Patrick Sharkey of New York University and Stephen Raudenbush of the University of Chicago.
“For children, living in disadvantaged neighborhoods appears to contribute to a detrimental effect on trajectories of verbal ability. This is important because language skills are a proven indicator of success later in life,” says Sampson. “What is surprising is the durability of the effect, continuing even when the child moves out of the neighborhood.”
Over 2,000 children from the lower, middle and upper classes, who were ages 6-12 and lived in Chicago at the beginning of the study, were followed over a seven-year period starting in the mid-1990s as they moved in and out of neighborhoods in Chicago and to other parts of the United States. Extensive interviews with the children and their caretakers were conducted at three different periods and each time the children were also given a vocabulary test and a reading examination.
The researchers focused on the 772 African-Americans in the study because of their unique ecological risk—almost a third of black children were exposed to high concentrated disadvantage compared to virtually no white or Latino children. After incorporating the propensity of families to live in concentrated disadvantage over time, the results showed that, by the end of the study, black children who lived in a disadvantaged neighborhood at the mid-point had fallen behind otherwise identical peers that did not live in disadvantage by about four IQ points, the equivalent of missing one year of schooling.
This negative impact on verbal ability persisted even after a child had moved from a disadvantaged to a non-disadvantaged neighborhood. Further research, not included in this study, has also shown that the youngest children are the most affected, suggesting a developmental process.