Children's Development Depends on Nature, Nurture and the Interplay Between the Two, Study Finds

    • March 1, 2011

Why do some children in “rough neighborhoods” grow up to be happy, healthy adults and others don’t?
The answer to this stubborn nature-vs.-nurture question is not simply environment or biology but rather the complex interplay of the two.

That is the conclusion of a recently published study by Nicole Bush, Ph.D., a child clinical psychologist who is a Robert Wood Johnson Foundation (RWJF) Health & Society Scholar (2009-2011).

In her study, published in the September-October issue of the Journal of Applied Developmental Psychology, Bush and her co-authors found that all children—regardless of their natural disposition, or temperament—who grow up in disadvantaged neighborhoods face higher hurdles to success than children in neighborhoods that are better off.

But more importantly, she took a key step toward defining the cryptic—and understudied—relationship between environment, temperament and development. In what she calls “rough” neighborhoods—the kind with high crime rates, little social connectedness, and few social supports— Bush found that more innately fearful children were more likely to have social and health-related problems than calmer kids.

“For children who grow up in rough neighborhoods, there is a detrimental effect across the board,” Bush says. “But some children in these neighborhoods, because of their temperament, are at particular risk of developmental problems.”

A native of Alaska who spent her early childhood in a trailer park, Bush has devoted her career to examining the effects of poverty and challenging early experiences on children. Some children, she had observed while working in low-income communities, thrived even though they lived in neighborhoods with high rates of crime, gang activity, drug use, and teen pregnancy.

Other children in similar circumstances, however, struggled. “I wanted to know how these kinds of environments affect children’s development.”

Bush began to research the subject and found little empirical data. Sociologists, she said, tended to focus on the effects of environment on children’s development, while psychologists focused on the individual. A psychologist with extensive training in sociology, Bush decided to bridge the two fields and explore the effects of both together.

For the study, Bush conducted scripted 2.5-hour interviews with third- , fourth-, and fifth-grade children and their mothers in family homes in Seattle, Wash. More than 300 mother-child pairs from a variety of racial and economic backgrounds participated in the study.

She found that the effects of environment and temperament taken together are greater than the sum of their parts. “Neighborhoods affect children a little bit, and temperament affects them a little bit, but we don’t just add them together to predict how well children can adjust to their environment. It’s important to look at the two together, and we can’t just assume they all add up normally.”

A good illustration is a young boy with whom Bush worked at an after-school program in a low-income Chicago neighborhood. The boy was anxious and reactive by nature—traits that Bush believes caused him to get into more fights than his less fearful peers. These traits also contributed to mental health problems like depression and anxiety and unhealthy behaviors, she says.

“When he got anxious, he would start to say dumb stuff that drew attention to him,” she says. “He would end up getting pushed around and roughed up. He later picked up smoking to fit in. Other less fearful kids with better social skills were able to avoid conflict or stay calm and just say, ‘No thanks, I’m not interested’ if they were offered cigarettes, for example. They had a better ability to manage that social stress.”

The negative effects of growing up in a disadvantaged neighborhood, in other words, were exacerbated by the boy’s more fearful temperament.

The findings have implications for policy-makers seeking to make best use of limited resources in disadvantaged neighborhoods. “Public dollars are not targeted at kids who are at greatest risk,” she said. “Maybe we need to think about taking both into account when figuring out how to fund social support services.”

The study confirmed the importance of individual differences in children’s temperaments for predicting neighborhood effects on health, but it didn’t address the environmental contributors to temperament. Bush felt there was more to learn about how social factors shape children’s temperament and the biology that underlies those individual differences.

That interest led to Bush’s current work as a Health & Society Scholar. She is now examining how social determinants shape temperament and biology. She plans to publish two papers in the near future that show that young, disadvantaged children have different biological reactions to stress than wealthier children. Over time, these different reactions can contribute to the development of cardiovascular disease, mental health problems, and poor health in general.

“These findings suggest that the environment is actually making these kids sick,” she said.