David Petraeus should have been told earlier: a hormone called oxytocin has been been linked to more monogamous relationships.
Oxytocin's unique ability to promote monogamy was found by researchers in Germany after testing a man's ability to stay away from attractive women.
CBS reported that the study used 86 men near the age of 25 and administered either oxytocin or a placebo.
An attractive female entered the room 45 minutes later and the men were told to sit near her at a distance that felt appropriate and another that made them feel "slightly uncomfortable."
Men in relationships who received the oxytocin stayed on average between 28 and 30 inches away, said the Toronto Star.
Those who received the placebo, both men in committed relationships and single men, stayed between 20 and 24 inches away from the woman.
The same findings were revealed using a woman's photograph.
“Because oxytocin is known to increase trust in people, we expected men under the influence of the hormone to allow the female experimenter to come even closer, but the direct opposite happened,” said study author Rene Hurlemann in a statement, according to Time.
“Previous animal research in prairie voles identified oxytocin as major key for monogamous fidelity in animals. Here, we provide the first evidence that oxytocin may have a similar role for humans.”
Replacing the attractive female with a male research showed no effect at all.
The findings were published in the Journal of Neuroscience.