|
Megan Gunnar
Institute of Child Development
|
|
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."
How the research is conducted
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," where children suck
on test strips they first get to dip in a sweet substance that increases
saliva flow.
What the research shows
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 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 cortisol levels when young
children are in group care-day care and preschool. The most profound
discovery was that 70-80 percent of children in center-based care
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 to being with other children all
day.
Gunnar has evidence that it is not separation from parents, but
the experiences young children have in child care that produce these
stress responses. "There is something about managing a complex
peer setting for an extended time that triggers stress in young
children," says Gunnar.
In a study of family-based child care, Gunnar finds that children's
stress levels do not rise in settings where they receive a lot of
attention, support, and guidance from the care provider, but do
rise when they don't. This is especially true of children with negative
emotional temperaments. Gunnar is studying whether frequent increases
in stress hormones at child care affect children's emotional and
cognitive development.
When Gunnar's son entered preschool, she began to notice how much
preschoolers care about fitting in and making friends. Her studies
of preschoolers have shown that stress levels seem to be directly
related to relationships with peers, and decrease as kids 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." Gunnar is conducting ongoing preschool studies that
focus on understanding how a child's temperament, relationships,
and social skills impact their stress level.
Brain development among children
adopted from orphanages and foster care
A major question is whether early neglect has long-term effects
on children's stress, emotion, and cognitive functioning. Through
grants from the National Institutes of Mental Health, Gunnar has
been studying children adopted internationally from foster and orphanage
care. Using a registry of over 3,000 Minnesotan internationally-adopted
children, she and her colleagues are studying whether early deprivation
has long-term effects on specific brain regions involved in emotion
and behavior regulation.
She hopes the project will discover information that could lead
to interventions to help these children reach their full emotional
and intellectual potential.
What others say about this research
W. Thomas Boyce, professor of epidemiology and child development,
University of California-Berkeley, says, "Her research has
been fundamental to an emerging vision of biology-environment interplay
in disorders of early development and behavior, and has deepened
early childhood educators' understanding of and responses to the
differences between young children."
"Megan has taught the fields of developmental neuroscience,
psychology, and psychopathology the importance of examining neurobiological
stress systems in their research," says Dante Cicchetti, psychology
professor at the University of Rochester and director of the Mt.
Hope Family Center, Rochester, NY, who studied stress in maltreated
children with Gunnar. "Her research has shown that differential
experiences can exert varied effects on brain development and child
adaptation."
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 policymakers
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: www.education.umn.edu/ICD/GunnarLab/
Reprinted with permission from ResearchWorks,
an online publication of the College of Education and Human Development.
|
