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The more hours that toddlers spend in child care, the more likely they are to turn out aggressive, disobedient and defiant by the time they are in kindergarten, according to the largest and most authoritative study of child care and development ever conducted.
Researchers yesterday said this correlation held true regardless of whether the children came from rich or poor homes, were looked after by a relative, a nanny or at a center, and whether they were girls or boys.
What is uncertain, however, is whether the child care actually causes the problem or whether children likely to turn out aggressive happen to be those who spend more hours in child care. It also remains unclear whether reducing the amount of time in child care will reduce the risk that a child will turn into a mean-spirited bully.
Complicating matters further, quality child care is associated with increased skills in intellectual ability such as language and memory, leading some academics to suggest that child care turns out children who are "smart and nasty."
The government-sponsored research, which has tracked more than 1,300 children at 10 sites across the country since 1991, is bound to rekindle the debate over child care, a debate that resonates across every income group and every demographic: How should people balance work and family? And how should parents, especially mothers, resolve the demands that are placed on them to be both breadwinners and Supermoms?
That debate was already on display at a new briefing yesterday, where researchers themselves clashed about the data and its implications.
"There is a constant dose-response relationship between time in care and problem behavior, especially those involving aggression and behavior," said Jay Belsky of Birkbeck College in London, one of the lead investigators of the study who has previously earned the ire of women's groups because of his criticisms of child care.
Children who spend more than 30 hours a week in child care "scored higher on items like 'gets in lots of fights,' 'cruelty,' 'explosive behavior,' as well as 'talking too much,' 'argues a lot,' and 'demands a lot of attention,' " said Belsky. "If more time in all sorts of [child care] arrangements is predicting disconcerting outcomes, then if you want to reduce the probability of those outcomes, you reduce the time in care. Extend parental leave and part-time work."
"On behalf of fathers or mothers?" interrupted Sarah Friedman, a developmental psychologist at the National Institute of Child Health and Human Development (NICHD) and one of the other lead scientists on the study.
"On behalf of parents and families," responded Belsky.
"NICHD is not willing to get into policy recommendations," retorted Friedman, contradicting her colleague. "There are other possibilities that can be entertained. Yes it's a quick solution -- more hours [in child care] is associated with more problems.
The easy solution is to cut the number of hours but that may have implications for the family that may not be beneficial for the development of the children in terms of economics."
In an interview after the briefing, Friedman said that asking parents to work fewer hours and spend more time with their children usually meant a loss of family income, which adversely affects children.
Child advocates also cautioned against a knee-jerk reaction. "One out of three children whose mothers work would be poor if they didn't work," said Helen Blank, director of child care at Washington's Children's Defense Fund, a nonprofit, child-advocacy group.
"Women work for a complex set of reasons, she said. "We had a national [welfare reform] policy in 1996 that required low-income-level women to work. Many women are working to pay the mortgage or health insurance."
Scientists said that the study was highly reliable. Although the findings were about children in kindergarten, the children in the study are actually now in the sixth grade. The lag is because of the time it takes researchers to sort through the data.
The results will be formally presented today at a meeting of the Society for Research in Child Development in Minneapolis.
The researchers found that 17 percent of children who spent over 30 hours a week in child care demonstrated problem behaviors by the time they were between the ages of 4 1/2 and 6. Only 6 percent of those who spent less than 10 hours a week in such care had the same problems. The average time that children spent in child care between the ages of 3 months and 4 1/2 years was 26 hours a week.
While those problems were not resolved by the quality of the child care, such quality improved children's language and memory skills. For example, more hours spent watching TV, rather than in a rich verbal environment, was correlated with lower math scores, smaller vocabularies and more behavior problems.
What could explain the correlation between child care and problem behavior?
"When families have a child in child care, there is always a question of balancing work, family and child care," said Robert Pianta, a professor of education at the University of Virginia and another scientist conducting the study. "The more hours a week in child care, the more that balance gets difficult to achieve. I suspect that's the issue. It may place a little more stress on the family . . . That might have an effect on the child."
The researchers said they had no idea whether the behaviorial difficulties persisted as the children moved to higher grades. They also cautioned about extrapolating too much from the study -- for example, the data did not explain a recent spate of school violence.
"I'm not saying they are the super, hyper violent types," said Belsky. "These kids are more likely to be bullying kids. That's bullying within the normal range. I'm not endorsing bullying, but we are not talking of psychopaths and kids who gets guns and blow away other kids."
-Reprinted from The Washington Post