Research suggests that, if David Petraeus had been administered a dose of oxytocin, maybe he would still be the head of the Central Intelligence Agency right now.

Oxytocin, nicknamed the "cuddle drug", is a hormone that facilitates sexual attraction, trust, and social bonding. In women, it has been known to be released during childbirth and while breastfeeding, which helps promote a bond between mother and child. It also floods the body during orgasm and in the early stages of a new relationship.

The hormone has remained more mysterious for men, however. Testosterone was thought to inhibit the production of the hormone.

A study published in the Journal of Neuroscience puts that idea into question. The study, conducted by researchers at the University of Bonn and the University of Berlin in Germany and the University of Arizona in the United States, gave heterosexual men a whiff of either oxytocin or a placebo.

Then all of the men were introduced to a female experimenter who they all later described as attractive. The men were asked to demonstrate a comfortable distance; either they would need to move to create space or she would.

For single men, they stationed themselves at a cozy 21 to 24 inches. For men in stable, monogamous relationships, they would move themselves a further 4 to 6 inches.

This effect also was true if men were shown a picture of an attractive woman. Single men would view the picture at a closer distance than their committed counterparts.

This effect disappeared, however, if men were introduced to a new male acquaintance or if they were not given oxytocin.

Interestingly, researchers had thought that oxytocin, which facilitates trust, would make men move closer to an unknown woman, but that was not what they found. The research indicates that oxytocin works more subtly than scientists had thought.

Work on the matter had found that oxytocin promoted monogamy in prairie voles. On a study done on male and female risk takers, the hormone increased empathy and trust. Another study inserted oxytocin into men's spinal fluid, causing spontaneous erections.

New research indicates that oxytocin in humans may have evolved to cause humans to be drawn more toward long-term relationships. "Hugh Hefner is the exception, not the role model for men," said Paul Zak, from the Claremont Graduate University, to the Los Angeles Times.