A new study claiming to be the first of its kind has identified the most effective facial expressions a woman can use to flirt with a man.
Researchers at the University of Kansas have published the paper entitled Identifying a Facial Expression of Flirtation and Its Effect on Men in the Journal of Sex Research.
It found that being romantically or sexually interested in someone can indeed be conveyed to others nonverbally through facial expression, through studies that "support the role of flirtatious expression in communication and mating initiation".
The study reports that a woman's most effective flirting cues include a head turned to one side and tilted down slightly, and a slight smile and eyes turned forward toward the man.
"Our findings support the role of flirtatious expression in communication and mating initiation," said Omri Gillath, professor of psychology and the paper's co-writer.
"For the first time, not only were we able to isolate and identify the expressions that represent flirting, but we were also able to reveal their function - to activate associations related with relationships and sex."
The study found most men were able to distinguish a woman giving a flirty look from them simply expressing happiness or anything else.
However, just as some women in the study were better able to "convey a flirtatious cue", some men were better able to recognise them.
The women included professional actresses and volunteers from the community who were asked either to spontaneously strike a flirty pose similar to what they'd use at a bar, or to follow instructions based on what is already scientifically defined as flirting.
And despite all the studies that have been conducted in the field of sexuality, the University of Kansas researchers say this study's focus on flirting with one's expression is wholly original.
"There are very few scientific articles out there that have systematically studied this well-known phenomenon," said Prof Gillath.
"None of these studies have identified the flirting facial expression and tested its effects."