[Paleopsych] NYT: Exploring a Hormone for Caring
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Wed Nov 30 23:37:12 UTC 2005
Exploring a Hormone for Caring
By NICHOLAS WADE
The lack of emotional care given to infants in some Romanian and
Russian orphanages has provided researchers an opportunity to study
the hormonal basis of the mother-child bond.
Researchers led by Seth D. Pollak of the University of Wisconsin have
found that these children, even three and a half years after adoption
into Wisconsin families, produce two critical hormones in a different
pattern from children with traditional upbringings.
The hormones, oxytocin and vasopressin, are small proteins produced by
the pituitary gland in the center of the brain. Although they
influence bodily functions like giving milk and the water balance,
they also have a range of effects on social behavior, at least in
laboratory rodents and monkeys.
These include fostering positive interactions with other individuals,
notably the social bonds between mother and child and the sexual bonds
between male and female.
In June this year, oxytocin was reported to elevate the level of trust
among people who received a nasal spray of it before playing a game
created to test their tolerance for being betrayed by other players.
The game was created by an economist, Ernst Fehr of the University of
Dr. Pollak and his colleagues have looked at how the two hormones are
involved in shaping the bonds between mother and child. In normally
raised children aged about 4½ years, they found, oxytocin levels rise
after half an hour of physical interaction with their mothers.
But the previously neglected children in their study did not show this
oxytocin jump, Dr. Pollak and his colleagues write in today's
Proceedings of the National Academy of Sciences. The hormone levels
were measured from samples of the children's urine.
Dr. Pollak believes that oxytocin acts through the brain's reward
system and gives infants a positive feeling about social interactions.
The finding that the adopted children in the study apparently get less
of an oxytocin reward could explain why some children from Eastern
Europe, as they grow older, have difficulty forming social
"Tens of thousands of these infants are entering the U.S. every year,
and the children are having problems in social relationships, and we
haven't a clue why," Dr. Pollak said.
Many young children when distressed will accept comfort only from a
parent, not a stranger, but some previously neglected children will
run to the nearest adult, sometimes ignoring their adoptive parents.
The Wisconsin team noted that the adopted children in their study
produced very low levels of vasopressin. This hormone, they say, is
critical for recognizing individuals as familiar, an essential step in
forming social bonds.
Dr. Charles Nelson, a Harvard pediatrician who has studied children in
Romanian orphanages, said the Wisconsin team's method of measuring the
two hormones in urine, if reliable, would be a major advance in
tracking emotional development in infants.
The new finding can be interpreted in several ways. One possibility,
Dr. Nelson said, is that there is a sensitive period in the first two
years of life for developing a strong relationship, and that later
relationships depend on the biological mechanism having been set
correctly, as judged by the oxytocin response.
It could be that the previously neglected children have missed this
critical window of development, Dr. Nelson said. Or, the biological
system may be flexible and it will just take longer for the children
to develop a normal oxytocin response. .
The best possible intervention for neglected orphan children would
seem to be adoption into loving families. But maybe this is not enough
and if so, the oxytocin measurements may point to the need to do
something else, Dr. Nelson said.
It is unclear why humans, a highly social species, are not born with
an innate ability to form social relationships instead of having to
develop the skill in infancy, as is apparently the case. Perhaps the
arrangement is a safeguard against forming bad relationships, Dr.
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