A new study on preschoolers attending full-day child care in licensed day care homes has found increases in cortisol, a stress hormone, when the children are in child care that exceeds their levels at home. The increases were larger in day care homes where providers were intrusive or overcontrolling.
The study, in the May/June 2010 issue of the journal Child Development, was conducted by researchers at the University of Minnesota, Georgetown University, and the Oregon Social Learning Center.
The researchers looked at about 150 mostly White, largely middle-class 3- and 4-year-olds in 110 different family child care homes, observing the children's behavior at child care as well as the behavior of their care providers, and sampling saliva to measure cortisol levels. Cortisol is a hormone that helps individuals adapt to challenges and stretches their coping skills.
The study found that about 40 percent of the children showed elevations in cortisol that were large enough to indicate that their bodies were stressed. It also found that cortisol increases over the day were larger in settings where care providers were intrusive or overcontrolling. In such settings, children moved frequently between activities, were given relatively little time for free play, and spent long periods of time in structured activities led by the providers. While many of these structured activities seemed designed to help the preschoolers learn letters, numbers, and colors, the activities weren't carried out in a way that allowed the children to learn actively through play, but rather in a rote fashion that required the little ones to sit quietly and respond when called on.
The larger elevations in cortisol meant different things for girls and boys in terms of behavior. Girls with larger increases in the hormone acted more anxious and vigilant at child care, while boys acted more angry and aggressive.
"These findings indicate that the behavior of the care provider is associated with both how well children function at child care, and how much their cortisol is elevated," according to Megan R. Gunnar, Regents Professor of Child Development at the University of Minnesota, who led the study. "They add to our understanding of how children process stressors in child care, highlighting differences between boys and girls in how they express being more physiologically stressed."
The study was supported by the National Institute of Mental Health.