Is Hormone 'Trust In A Bottle?'

Scientists Say Findings Could Be Abused By Con Artists, Politicians

(AP) 
For years oxytocin was considered to be a straightforward reproductive hormone found in both sexes. In both humans and animals, this chemical messenger stimulates uterine contractions in labor and induces milk production. In both women and men, oxytocin is released during sex, too.

Then, elevated concentrations of the hormone also were found in cerebrospinal fluid during and after birth, and experiments showed it was involved in the biochemistry of attachment. It's a sensible conclusion, given that babies require years of care and the body needs to motivate mothers for the demanding task of childrearing.

In recent years, scientists have wondered whether oxytocin also is generally involved with other aspects of bonding behavior — and specifically whether it stimulates trust.

In the experiments, the researchers tried to manipulate people's trust by adding more oxytocin to their brains. They used a synthetic version in a nasal spray that was absorbed by mucous membranes and crossed the blood-brain barrier. Researchers say the dose was harmless and altered oxytocin levels only temporarily.

A total of 178 male students from universities in Zurich took part in a pair of experiments. All the volunteers were in their 20s. They got the oxytocin or a placebo.

In the first experiment, they played a game in which an "investor" could choose to hand over to a "trustee" up to 12 units of money that are each equal to .40 Swiss franc, or about 32 cents. The trustee triples the investor's money, then gets to decide how much of the proceeds to share. The trustee can't be certain how much — if anything — he will get in return.

Of 29 subjects who got oxytocin, 45 percent invested the maximum amount of 12 monetary units and, in the researchers' words, showed "maximal trust." Only 21 percent had a lower trust level in which they invested less than 8 monetary units.

In contrast, the placebo group's trust behavior was reversed. Only 21 percent of the placebo subjects invested the maximum, while 45 percent invested at low levels.