Smarmy Smiles and Head Tilts

Women give specific facial cues when they're flirting, according to researchers at the University of Kansas.

The team used the Facial Action Coding System (FACS) to identify the most recognizable flirtatious facial expressions.  

The technology, which describes facial movements, showed the most effective flirting cues include a head turned to one side and tilted down slightly, a slight smile, and eyes turned forward toward the target.

Head tilting is a signal that someone is listening and involved -- and a particularly feminine gesture. As such, head tilts can be very positive cues, but they are also subconsciously processed as submission signals.