It sounds like the stuff of science fiction, but scientists have discovered that a whiff of a certain hormone makes people more willing to trust others with their money.

The hormone is oxytocin, which in nonhuman mammals is associated with social attachment, as well as a number of physiological functions related to reproduction. As such, it is believed to help animals overcome their natural tendency to avoid proximity and allow others to approach them. Hypothesizing that oxytocin might have a comparable role in human prosocial approach behaviors, such as trust, Michael Kosfeld of the University of Zurich and his colleagues devised a double-blind study to compare trusting tendencies in subjects given an oxytocin nasal spray and those given a placebo. After receiving either a single dose of the hormone or the placebo, participants played a trust game in which an investor chooses how much money to fork over to a trustee, who then decides how much to return after the amount is quadrupled. Subjects played the game using monetary units, which were exchanged for real money at the end of the experiment.