CHICAGO — Trust takes time. But if time is short, trust may bloom from a fine mist of hormones sprayed into your nostrils.

That's the remarkable finding of a new study in which people who inhaled a brain chemical called oxytocin became more trusting, allowing a partner to invest more simulated money than people who didn't get the hormone.

It could be a surreal fantasy come true for con men or politicians, though for now neuroscientists are the ones most excited about the report by Swiss and American researchers, to be published today in the journal Nature.

The chemical roots of trust have long eluded biologists even though the capacity for it is one of humanity's defining features, allowing cooperation in everything from intimate friendships to vast projects.

The new research suggests that may stem in part from the brain's selective secretion of oxytocin, a common hormone best known for its role in childbirth and breastfeeding.

"It's a very important study," said Antonio Damasio, head of neurology at the University of Iowa's College of Medicine, who wrote an accompanying commentary on the Nature study.

Although Damasio focused on the meaning for brain science, he conceded he is concerned about the potential for misuse of a chemical that may make people more trusting without their conscious knowledge.

"One has visions of political operatives spraying it at rallies," he said, only half-joking.

A more practical use may be for people with conditions such as autism or social phobias, which involve a breakdown of the normal ability to approach or bond with other people.

Oxytocin — not to be confused with the painkiller OxyContin — seems to work by easing the fear of close contact and betrayal. It is secreted in brain tissue and synthesized by the hypothalamus.

This small, but crucial feature deep in the brain controls biological reactions like hunger, thirst and body temperature, as well as visceral fight-or-flight reactions associated with powerful, basic emotions like fear and anger.

For years, oxytocin was considered to be a straightforward reproductive hormone found in both sexes.

In both humans and animals, this chemical messenger — also known by its trade name, pitocin — also stimulates uterine contractions in labor and induces milk production.

Mother-baby bonding

Later, 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 child-rearing.

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

Trust is the glue of society and human interactions. Erase it, and you compromise everything from love to trade and political order.

"On average, most people do better if they trust others," said Paul Zak, a co-author of the new study and director of the Center for Neuroeconomic Studies at Claremont Graduate University in Southern California.

Zak and his Swiss co-authors at the University of Zurich had 128 college students play a "trust game."

The transaction involved taking a risk: handing over money to a "banker" who had the option of returning the investment with a profit or withholding principal and profit, leaving the investor with nothing. The experiment was a measure of the trust the investors had in the bankers.

Volunteers who inhaled oxytocin were more likely to trust the banker with money and risk larger sums, the researchers said.

The scientists said they made sure the chemical was not merely enhancing risk-taking behavior by substituting bankers with computers. Without the interaction with a human, the hormone had no effect.

Oxytocin did not alter the behavior of the bankers, which strengthened the researchers' belief that the hormone was influencing trust. Bankers did not need to trust investors, because they were taking no risk.

In essence, sniffing oxytocin produced instantly the sort of trust that would normally build through a history of reliable dealings, Zak said.

Potential for misuse?

If it really works, the potential for misuse of a trust drug like oxytocin is almost limitless. Shady car dealers could pump it into their showrooms; casino owners might spike their martinis with it; pickup artists could wear it as a cologne.

Zak thinks none of those abuses is likely to work.

"Sprinkling this in the air is not going to do anything — it has to be sprayed into your nostrils," Zak said. "I'm not too concerned about the misuse of it."

Other experts were less sure, including Zak's co-author Ernst Fehr, director of the Institute for Empirical Research in Economics at the University of Zurich. He said the hormone's power to change behavior without an investor's awareness raised serious concerns.

"Our results have implications for the idea of free will," Fehr said in response to an e-mail.

Compiled from reports by the Chicago Tribune, The Associated Press and

The Washington Post.