Helen Fisher, The Biology of Attraction

Psychology Today: The Biology of Attraction

"...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..."


"...Body synchrony is the final and most intriguing component of the pickup. As potential lovers become comfortable, they pivot or swivel until their shoulders become aligned, their bodies face-to-face. This rotation toward each other may start before they begin to talk or hours into conversation, but after a while the man and woman begin to move in tandem. Only briefly at first. When he crosses his legs, she crosses hers; as he leans left, she leans left; when he smoothes his hair, she smoothes hers..."

"...Psychologist Dorothy Tennov measured the duration of romantic love, from the moment infatuation hit to when a "feeling of neutrality" for one's love object began. She concluded, "The most frequent interval, as well as the average, is between approximately 18 months and three years..."

"...Only 16 percent of the 853 cultures on record actually prescribe monogyny, in which a man is permitted only one wife at a time. Western cultures are among them. We are in the minority, however. A whopping 84 percent of all human societies permit a man to take more than one wife at once—polygyny..."