Jesse Bering in Scientific American:
Most of us are convinced that we excel at being clearheaded, humane thinkers when it comes to sex. We appeal, and admirably so, to notions such as harm and consent. But since most of us aren’t anthropologists, we W.E.I.R.D. people (the anthropologist Joe Henrich’s apt acronym for “Western, Educated, Industrialized, Rich, and Democratic”) often assume a false obviousness along these lines of harm and consent that, interestingly enough, simply isn’t there. Scientists have found that since we would be harmed by a certain sex act,we presume others would be harmed as well.
In fact, cultural relativism is the most glaring sign that the lion’s share of our sexual ethics is arbitrary, given that our intuitive feeling of what’s “normal” and “deviant” hinges largely on our cultural indoctrination. In the past, for instance, a proper Crow gentleman wasn’t expected to simply woo the object of his desire over a slice of homemade juneberry pie. Instead, the tradition for a man so smitten involved his crawling up to the woman’s tent in the middle of the night and fishing around with his hand under the flaps for her body. And female Crow informants explained to the anthropologists inquiring about the tradition that this manual search in the dark for her orifices was an especially romantic first move. “If he is successful,” wrote the researchers Clellan Ford and Frank Beach, “a man may by this device persuade the woman to have intercourse with him later on.” If he were successful in our society, he’d be signing his name to the sex offender registry before dawn, if he still had a hand. But in the cultural context of these Native Americans, most women, presumably, favored this custom.
More here.