The human mating process is so systematic that women from around the world flirt with the same sequence of expressions. First the woman smiles at her admirer and lifts her eyebrows in a swift, jerky motion as she opens her eyes wide to gaze at him. Then she drops her eyelids, tilts her head down and to the side, and looks away. Frequently she also covers her face with her hands, giggling nervously as she retreats behind her palms. Eye contact seems to have an immediate effect. The gaze triggers a primitive part of the human brain, calling forth one of two basic emotions—approach or retreat. You cannot ignore the eyes of another fixed on you; you must respond. This sequential flirting pattern is so specific that many researchers are convinced it is innate; a human female courtship strategy that evolved eons ago to signal sexual interest.
With flirting comes the personality factor of attraction. Research has confirmed that a good sense of humor is an important human mate preference worldwide. When people are asked to rate the importance of various traits for romantic relationships, a good sense of humor is consistently at or near the top of their, sometimes outranking physical attractiveness. There is also evidence that the preference for humor may be stronger in seeking romantic partners than in seeking platonic friends (Sprecher & Regan, 2002). Also, the preference for humor seems to increase with the duration of the relationship: we seem to value humor especially in long-term mates.