Neglected Tots: Brain Hormones Lowered
Hormones Linked to Social Bonding, but Healthy Relationships Still Possible
Nov. 21, 2005 -- Neglected babies may have lower levels of brain hormones
tied to social bonding.
But those children can still develop satisfying relationships, researchers
"It's extremely important that people don't think this work implies that
these children are somehow permanently delayed," says researcher Seth
Pollak, PhD, in a news release.
"All we are saying is that in the case of some social problems, here is
a window into understanding the biological basis for why [those problems]
happen and how we might design treatments," he continues.
Pollak is an associate professor of psychology, psychiatry, and pediatrics
at the University of Wisconsin-Madison. He's also a researcher at the
university's Waisman Center for Human Development.
The study appears in the early online edition of Proceedings of the
National Academy of the Sciences.
The study included two small groups of children.
One group consisted of 18 children who had spent the first 16 months of
their lives, on average, in overseas orphanages before being adopted by U.S.
The adopted kids had lived in typical American homes for about three years.
They had been tested for fetal alcohol exposure, birth defects, and
The second group included 21 American children who were being raised by
their biological parents in similar settings.
The researchers compared levels of two brain hormones -- oxytocin and
vasopressin -- which are involved in social bonding.
Play Time With Mom
For the study, the kids played interactive computer games while sitting in
the lap of their mother or a woman they didn't know.
The game included light physical contact, like counting fingers or
whispering in the partner's ear. Afterwards, the kids provided urine samples,
which were checked for oxytocin and vasopressin.
After physical contact with their moms, oxytocin levels rose for children
living with their biological parents. The same wasn't true for children who had
been neglected early in life.
Formerly neglected kids also had lower overall levels of vasopressin, the
No hormonal differences were seen between the two groups after the kids
played the computer game with unfamiliar women.
Nurturing Environment Helps
"Importantly, at the time of testing, children had experienced an
average of three years in rearing in relatively stable, enriched, and nurturing
family environments," write the researchers.
"However, this environmental change does not seem to have completely
overridden all of the effects of early neglect," they continue.
Remember, the study just tracked the two brain hormones, not behavior or
emotions. "It is critical to note that not all children who experience
early neglect develop the same kinds of problems, and children with lower
reactivity may, over time, develop satisfactory relationships," write
"It's exciting that we've taken an area of child development that has
been very descriptive and can now look at it in more mechanistic way," says
researcher Alison Wismer Fries, in a news release. Fries is a psychology
graduate student at the University of Wisconsin.
She and her colleagues note that oxytocin and vasopressin levels varied
among both groups of children.