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A child sucking on a cotton dental roll.

A child sucks on a six-inch cotton dental roll as part of the "Tasting Game." University researchers use this highly absorbant device to collect saliva from young children.

How young children manage stress

Published on March 30, 2005

Stress--the emotional and physical impact our bodies experience as we adjust to challenge--is a normal part of life. Whether caused by daily demands or a physical threat, stress triggers a primal physical response, releasing hormones that ready the body to react, then return to normal. Yet today many people suffer from chronic stress, which is linked to heart disease, depression, diabetes, and countless other health problems leading to early death.

Scientists believe our ability to manage stress as adults is formed in childhood through a combination of genes and experiences. For two decades, Megan Gunnar, child development professor and director of the Human Developmental Psychobiology Lab, has pioneered the field of measuring stress in young children as a way to unravel the mysteries of healthy development.

"Some individuals experience stress from minor problems, while others let everything roll off their backs," says Gunnar. "Our research seeks to understand how this range of differences develops and impacts our mental and physical health."

Gunnar's lab assesses children's stress levels by measuring cortisol, a blood-borne hormone that increases under stress. This hormone leaks into and can be measured in saliva. To make saliva collection enjoyable, Gunnar and her students have developed a playful testing method called the Tasting Game, in which children suck on test strips they first get to dip in a sweet substance that increases saliva flow.

Gunnar's research finds that social relationships control cortisol levels in infants and young children. Children with secure attachments to their caregivers--even when emotionally upset--show stable cortisol levels, while even minor challenges raised cortisol levels among those in insecure relationships. She has shown that the key ingredient to buffering stress is sensitive, responsive, individualized care, the type of care that leads to secure attachment relationships.

Stress in day care and preschool settings Since the mid-1990s, Gunnar has studied children who are in group care--day care and preschool--and family-based child care.

In group- or center-based care, the most profound discovery was that 70-80 percent of children show ever-increasing levels of cortisol across the day, with the biggest increases occurring in toddlers. By first grade, children don't show these stress reactions when they are with their peers all day. It's not separation from parents, says Gunnar, but the experiences young children have in child care that triggers their stress responses. In family-based child care, children's stress levels do not rise in settings where they receive a lot of attention, support, and guidance from the care provider, but their stress levels do rise when attention is lacking. This is especially true of children with negative emotional temperaments.

Gunnar is currently studying whether frequent increases in stress hormones at child care affect children's emotional and cognitive development. She is also conducting studies on preschoolers that focus on understanding how a child's temperament, relationships, and social skills impact their stress level.

When her son entered preschool, she began to notice how much preschoolers care about fitting in and making friends. Her findings have shown that stress levels seem to be directly related to relationships with peers, and stress levels decrease as children gain social competence. "Negotiating friendships is very complicated," says Gunnar. "It doesn't appear that the child needs to be popular to maintain low stress, but it seems very important that they not be socially rejected."

Why this research matters With nearly 60 percent of American women working outside the home, most young children spend much of their day in child care, where many first learn to interact with peers, establish relationships with adults other than their parents, and learn social skills like sharing, waiting, and cooperating.

"In the United States, there is no standardized system for maintaining high-quality child care settings," says Gunnar. "My research shows on a physical level--as others have shown on a behavioral level--that children who experience poor-quality care in their early life are at risk for poor developmental outcomes."

Gunnar's ongoing research can provide families and policy makers information vital to making the best care decisions for children, such as standards for low-stress day care settings and guidelines to help parents select the best type of care for their child's temperament. This research continues to shed light on how quality child care directly influences brain development among children.

For more information, see Megan Gunnar's lab.

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