According to a new study, the genes and warm support received from parents also can buffer these children against many of the cognitive and behavioral problems for which poverty puts them at risk. The findings are published in the May issue of the journal Child Development.
Numerous studies show that economic hardship during childhood elevates a person's risk of developing conduct problems and lower intelligence, says Julia Kim-Cohen, co-author of the recent paper and postdoctoral fellow in psychology at the University of Wisconsin-Madison and the Institute of Psychiatry at King's College London.
But, as she notes, some children overcome these odds and, in fact, perform better on intelligence or behavioral tests than would be expected, given the level of poverty in which they're raised. These children, says Kim-Cohen, are considered to be "resilient" - or capable of doing well despite adversity.
Interested in understanding the factors that contribute to a child's resilience to poverty, Kim-Cohen and her colleagues studied genetic and environmental differences among 1,116 mothers and their five-year-old same-sex twins, part of the E-Risk longitudinal study being conducted in England and Wales.
"Children in our study experienced more than just poverty, as measured by family income level," explains Kim-Cohen, adding that often their parents were poorly educated, owned no car and held menial jobs or no job at all. "Living in the poorest neighborhoods, their homes were rated as being overcrowded, damp or in disrepair," she says.
After determining the economic conditions of each family, the researchers conducted interviews and tests to evaluate the mother's warmth and support toward her children, as well as the children's temperament and intelligence. The children who performed better than expected on behavioral and cognitive tasks, says Kim-Cohen, are the ones more resilient to the poor conditions in which they were raised.
To determine the role of genes in buffering children against poverty, the researchers studied differences among the twins, some who were identical (sharing all genes) and others who were fraternal (sharing half their genes). If identical twins have levels of resilience similar to each other, compared to that between fraternal twins, Kim-Cohen says it would be due, in part, to genetics.
"Genetic endowment is known to influence a variety of children's capabilities, such as how well they use language, how quickly they learn new skills, and how outgoing and cheerful they are," says co-author Terrie Moffitt, a psychology professor at UW-Madison and King's College London. Given these genetically influenced capabilities, Moffitt adds, "We reasoned that they might help poor children in their struggle to overcome their lack of economic advantages."
Results from the study show that genetic makeup does play a part in resilience. According to the statistical analysis, genes explained 70 percent of the variability in children's behavioral resilience and 46 percent of the difference in their cognitive ability.
"This means that when the children in a classroom or neighborhood differ on behavior problems or cognitive achievement," explains Moffitt, "about half of that variation across the group emerges from the fact that every child has his or her own individual genetic endowment."
But as these numbers suggest, genes are only partially responsible for a child's ability to do better than expected in the face of poverty. Environmental factors, such as the mother's warmth and participation in the child's development, also are involved.
The researchers found, for example, that twins who engaged in more stimulating activities with a parent, compared to those who didn't and were from a similar background, generally scored higher on intelligence tests.
Kim-Cohen explains, "The warmth, mental stimulation and interest that parents pay toward their young children can make a big difference in their children's lives." She adds that many of the stimulating activities that were measured, such as taking a long walk or going to the park, cost little or no money.
With the joint role of genes and upbringing - nature and nurturing - on development, the researchers conclude that both children and their parents are agents capable of protecting children against the hardships of growing up poor. This conclusion, they add, may provide an impetus for researchers, as well as policymakers, to seek out the particular genes and non-genetic factors that promote a child's ability to overcome the odds poverty predicts for them.
"The main point of the research is that neither genes nor poverty can determine a child's fate," says Moffitt. "The study showed that many children - and parents - use their natural talents and abilities to turn lemons into lemonade."
- Emily Carlson, (608) 262-9772, firstname.lastname@example.org