The music swells. On screen, the two main characters' eyes meet. They lean in, and — slowly! — their lips gently press in a romantic kiss. All the teenage girls in the audience exhale audibly.
Such on-screen behavior seems romantic if you were raised in a culture that practices romantic kissing. But that type of culture may not be the majority. In a study published this month in American Anthropologist, researchers propose that romantic kissing isn't something everybody does; in fact, not even half the cultures surveyed lock lips in romance.
Scientists have at least a couple of ideas about why we kiss people we are attracted to. We might be doing it to evaluate a potential mate, evolutionary biologists say, or to maintain a bond, or to arouse the other person. Kissing behaviors have been observed in chimpanzees and bonobos, though how romantic the animals were feeling at the time is unknown.
For a long time it was assumed that, whatever the reason, kissing was something people everywhere did. But, according to study author William Jankowiak, an anthropologist at the University of Nevada, Las Vegas, few people have looked across cultures at romantic kissing.
Jankowiak and his colleagues looked at data compiled from decades of ethnographic studies of all sorts in more than 168 cultures. He and his team searched for mentions or observations of a romantic-sexual kiss, which they defined as "lip-to-lip contact that may or may not be prolonged." The researchers found that in 54 percent of the cultures studied, there was no record of romantic-sexual kissing.