Women from places as different as the jungles of Amazonia, the salons of Paris, and the highlands of New Guinea apparently 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. This sequential flirting gesture is so distinctive that (German ethologist Irenaus) Eibl-Eibesfeldt was convinced it is innate, a human female courtship ploy that evolved eons ago to signal sexual interest.
Men also employ courting tactics similar to those seen in other species. Have you ever walked into the boss’s office and seen him leaning back in his chair, hands clasped behind his head, elbows high, and chest thrust out? Perhaps he has come from behind his desk, walked up to you, smiled, arched his back, and thrust his upper body in your direction? If so, watch out. He may be subconsciously announcing his dominance over you. If you are a woman, he may be courting you instead.
The “chest thrust” is part of a basic postural message used across the animal kingdom—”standing tall.” Dominant creatures puff up. Codfish bulge their heads and thrust our their pelvic fins. Snakes, frogs, and toads inflate their bodies. Antelope and chameleons turn broadside to emphasize their bulk. Mule deer look askance to show their antlers. Cats bristle. Pigeons swell. Lobsters raise themselves onto the tips of their walking legs and extend their open claws. Gorillas pound their chests. Men just thrust out their chests.
~ Read more on The Biology of Attraction