Scientists have already established that the hormone oxytocin is a trigger for love and affection. Now they have discovered that babies raised for their first two years in orphanages do not produce the same levels of oxytocin as children raised by their biological parents.
In a test designed to elicit cuddling and affection, Seth D. Pollak and his colleagues at the University of Wisconsin–Madison recruited 18 toddlers adopted from places such as Russia and Romania and an equal number of children with biological parents. Each toddler sat on his or her mother's lap while playing an interactive game with instructions such as “tickle your partner's tummy” and “hug your partner.” The children completed the same game on the lap of a friendly female stranger. The biological children showed a rise in oxytocin after playing with their own mother but not after playing with the female stranger. Yet the adopted children showed no rise in either case.