CAMBRIDGE, Mass. -- 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.
The short-term negative impact of living in a segregated disadvantaged neighborhood includes increased exposure to violence and reduced access to safe public places for play. However, in addition to the immediate negative influences, children are exposed over time to specific kinds of social interactions that may contribute to a lasting effect on verbal development. For example, in severely disadvantaged neighborhoods, kids are less likely to repeatedly hear spoken academic English, which research has shown contributes to educational and labor market outcomes. Families with children in these environments are also more likely to "hunker down," limiting exposure to the varied communication skills and social exchanges that are rewarded in American society.
The social influences present within disadvantaged neighborhoods impact a child's verbal ability even outside of the effects of the public school system or the poverty of the neighborhood. To look beyond just economic situation, and define a neighborhood as one of "concentrated disadvantage," Sampson and colleagues examined the presence of six social factors in the lives of the children: welfare receipt, poverty, unemployment, female-headed households, segregation, and the number of children per household. The social worlds of black and non-black children are so different that comparable cases across race could not be found to assess the combined effect of disadvantage.
"Even beyond their economic situation, children in neighborhoods of concentrated disadvantage are exposed to a myriad of social factors that can deflect developmental trajectories," says Sampson. "The persistence of the neighborhood effect on verbal ability indicates the importance of timing in any efforts to intervene. Not only do these circumstances have a lasting impact on a child's language skills, it's not easily remedied by taking the child out of the neighborhood. This consideration should be included in discussions of educational policy."
The research was funded by the Robert Wood Johnson Foundation.