Not only is romantic-kissing not a universal behavior, per a new study published in American Anthropologist, some 54% of the cultures the researchers analyzed didn't share such kisses. Art, literature, and the media present such kisses as widespread; some evolutionary scientists have framed them as a behavior that has evolutionary benefits (providing a way to gain clues to a potential partner's health), and has thus become "near-ubiquitous." But the University of Nevada and Indiana University researchers write that the "relative ubiquity" of the romantic-sexual kiss—which they defined as "lip-to-lip contact that may or may not be prolonged"—from a cross-cultural view has actually received scant study. And so they dug in, with specific focus on nonindustrial societies (meaning, for instance, the indigenous Mehinaku people of Brazil, not New Yorkers).
Data from the Standard Cross-Cultural Sample and electronic Human Relations Area Files World Cultures and interviews with ethnographers gave the researchers a sample set of 168 cultures; they found evidence of such kissing in 77 (46%) cultures, but none in 91. The behavior was varied: The kissing was near-ubiquitous among foragers who live in northern Asia and North America, but not a single one of 10 Central American cultures studied engaged in it. The researchers also observed a "significant association between social complexities," with such kisses more likely in complex societies. What they found "remarkable": such kissing appears to have emerged late in human evolutionary history, and it's unclear how it became so common in some places. "It cannot simply be due to copying the behaviors of the global elites," they write, noting some people react to first observing outsiders kissing as "gross." (It turns out you swap more than spit in a French kiss.)