My friend was not similarly concerned. “So?” she texted back.

In the line to get into the spa, we saw a crestfallen couple who were apparently expecting something more like a resort, rather than a cross between a gulag and a nude beach.

My friend was, apparently, fine with it. “Ready to get naked?” she asked me cheerily as we tucked our phones and shoes into our lockers.

After my friend and I had stripped, a random stranger, her nipple rings glinting in the fluorescent light, showed us the way to the “bade pool.” The pool, with its cerulean water, mushroom-shaped fountains, and gobs of nude flesh, looked like something out of an adolescent rococo painter’s wet dream. Best friends gossiped while their bare asses got kneaded by underwater jets. The only safe place to gaze was somewhere in the middle distance. One woman stood under a very open-facing showerhead, closed her eyes, and scrubbed her crotch diligently. The Koreans seemed to take it in stride, but at least for the awkward white people, there was a suspension of social norms to a degree that was alarming.

What’s interesting about the spa is that it’s not like people suddenly began to celebrate nudity. Instead, it was proof that social norms can change without people changing their actual attitudes—toward naked butts, in this case. It’s enough simply to plant the idea that something is normal and suggest that it’s the right thing to do. How you, personally, feel about it doesn’t matter; you’ll do it anyway.

Princeton University professor Betsy Levy Paluck discovered28 a similar phenomenon in a study on a far more tragic topic a few years ago. For her work, she focused on Rwanda, where a genocide against the Tutsi ethnic group by the Hutu-majority government in 1994 resulted in the death of three-quarters of the Tutsi population.

After the genocide ended, but trauma remained, Paluck traveled to the country to examine the effects of a radio program called, in English, New Dawn. It was produced by a nonviolence nonprofit, and it aimed to ease ethnic tensions. The program portrayed two ethnic groups who worked together and spoke out against violence, and even included a Romeo-and-Juliet-like story line about two lovers from different communities. Over the course of a year, Paluck studied groups of Rwandans who were exposed either to the New Dawn program or to a control program about an unrelated topic.

Her results were either disappointing or uplifting, depending on how you look at it. The New Dawn program didn’t change the community’s beliefs about violence, trauma, or war. The people who had listened to the “correct” messages about violence were still just as likely to believe that “evil people” cause violence, rather than more practical factors like passive bystanders or a lack of open dissent and intergroup connections. They still thought traumatized people are just crazy and can’t recover.