So Dr. Kupfer along with Sonia Alas and Tiffany Hwang, then undergraduate students at UCLA, pored through YouTube. They followed and debated for hours to choose the most ranked rankings. Many options were too weak, such as footage of “mildly moldy food,” said Dr. Copper. “We wanted feces, we wanted a kind of infection,” he clarified.
Dr. Kupfer’s dream came true. The final ectoparasite clips contained a kitten full of fleas, a nightmare attack and a beauty image of a mosquito sucking blood. The last pathogen clips included flesh pulsing with maggots, an infected arm lesion oozing with pus – Dr. Fessler called it the “pus volcano” – and a lump of earwax as dark as an asteroid.
The meat was Dr. Kupfer’s own creation; unable to find a sufficiently disgusting video of rotten food, he left a meat plate in his garden for two weeks and returned as it “seemed maximally disgusting,” he said.
The video that the researchers found most disgusting – titled “Dirty festival toilets” in the newspaper’s supplementary information – has since been removed from YouTube. This is perhaps the best. I tried to watch every video used in the experiment. I did not vomit, but I experienced palpitations and had to sit in my bathroom with the light off for several minutes until I stopped to see the pus volcano. Missing out on the dirty festival toilets seemed to be an act of self-care.
The researchers conducted roughly the same experiment three times, twice in the United States and once in China, and examined a total of more than 1,000 people. In all three studies, participants had different reactions to the ectoparasite videos compared to the pathogen videos. When they saw ectoparasites, participants reported several calls for itching and scratching, which theoretically protects the surface of their skin from danger. And when looking at pathogens, participants reported more nausea and urges to vomit.
The researchers plan to expand this project internationally to see how ectoparasite-disgusting responses vary in different countries and in different languages. Understanding the nuances of disgust, they say, could inform our understanding of disorders such as misguided parasitosis, the mistaken belief that parasites have invaded the body.
Bunmi O. Olatunji, a psychologist at Vanderbilt University who was not involved in the research, said he considered the results of the new paper too preliminary to draw conclusions about clinical conditions. But it provides “interesting opportunities to think about the mechanism by which disgust can contribute to the development and maintenance of skin picking disorder.”