Men with partners increase the space they feel comfortable with between themselves and an attractive woman if exposed to the bonding hormone oxytocin.

René Hurlemann at the University of Bonn in Germany and colleagues gave men either a sniff of oxytocin or a placebo before asking them to choose the ideal distance for an interaction with a woman. The distance that they felt was comfortable significantly increased after sniffing oxytocin, but only for men in relationships.

The team conclude that oxytocin discourages partnered but not single men from getting close to a female stranger.

Journal reference: Journal of Neuroscience, DOI: 10.1523/jneurosci.2755-12.2012