If you're willing to trust musical theater as legitimate evidence, the lives of orphans often turn out pretty well. Oliver Twist might have learned to steal, but he bonds with poor-yet-loving Nancy and walks into the sunset with his biological grandfather. Little Orphan Annie might have developed an ear-splitting belt, but she lives happily into adulthood with (Sugar) Daddy Warbucks and his secretary.
But only the most foolish of fools trusts musical theater. In reality, children who grow up without loving parents are often unable to form relationships with a new caregiver. A team of researchers at the University of Wisconsin-Madison has the hormonal evidence to prove it.
According to a study published on November 21st in the Proceedings of the National Academy of Sciences, children who begin life deprived of close personal care tend to have lower levels of oxytocin and vasopressin, hormones that regulate social functioning.
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"These results suggest that a failure to receive species-typical caregiving disrupts the development of [oxytocin and vasopressin] systems in children," said Alison Wismer Fries, the study's lead author, via email. "They give us a clue as to one possible reason that these adopted children are at increased risk for social and attachment difficulties."
Wismer Fries said that while there have been many studies on rodents and one on monkeys showing similar effects, this is the first study in humans to link childhood neglect to low hormone levels.
"There has been a great deal of research in non-human primates and rodents showing that [oxytocin and vasopressin] are involved in the emergence of social bonding, parental care, stress reduction, social communication and emotional reactivity," Wismer Fries said. "These hormones rise in response to pleasant touch and smell. As these hormones rise, animals increase their positive social interactions and display selective infant-parent attachment."
The team examined 18 children who spent the first months of their lives in Russian and Romanian orphanages before being adopted by parents in Wisconsin. On average, they had lived with their adoptive families for three years. The comparison group consisted of 21 children from Madison who live with their birth parents. The two groups were matched in age and socioeconomic status. All subjects were free of birth defects and developmental disabilities.
To measure oxytocin and vasopressin levels, the researchers used a novel method of urine analysis developed by coauthor Toni Ziegler, senior scientist at the National Primate Research Center at the University of Wisconsin-Madison. They soon noticed that baseline vasopressin levels were significantly higher in the comparison group than in the neglect group.
The researchers had each child play an interactive computer game on separate occasions: once with the child's mother and once with an unfamiliar female adult. The game, which the child played on the adult's lap, encouraged friendly touching between the players. After the children played with their mothers, the kids in the non-neglected group showed much higher levels of oxytocin than the neglected kids.
Wismer Fries emphasized that while the adopted kids had a lower average level of these peptides, researchers observed significant individual variation. She also noted that children may be able to overcome these deficiencies.
"It is not the case that neuropeptides are destiny," she said. "We do not have any evidence that a change in rearing environment cannot, over time, change or that children cannot find other ways to form close relationships."
Apparently, the scientists are not ready to label all adopted children sociopaths or to halt the adoption process for parents who want to raise healthy children.
"We definitely don't want anyone to reach the conclusion that they should not adopt a child from overseas," Wismer Fries said. "If there is one thing we have learned, it is that the best thing we can do for kids is get them out of institutions and into families."