The pop of a ripe whitehead. The forceful spray of a cyst. The drip-drip-drip of a draining abscess. These are just some of the sounds that fill the pages of r/popping, a Reddit community dedicated to the perverse pleasures of popping pimples.

While r/popping might seem like a small and terrible corner of the internet, it’s actually about 100,000 members strong. The similarly minded dermatologist Dr. Sandra Lee, better known as Dr. Pimple Popper, has almost 3 million YouTube subscribers and over 1 billion views. In the 2011 YouTube video featured below, the highest-rated in the genre, a thick stream of what looks like Easy Cheese sprays from a stranger’s back. This video, which requires viewers to agree that they wish to proceed, has 36 million views.

While some might deny their love of popping pimples, the urge to squeeze is, clearly, hardly niche. To some scientists, this is hardly surprising: the near ubiquity of this urge to poke, pop, and tweeze, they argue, is likely rooted in fundamental primate behaviors, developed over the course of our gross evolutionary history.

Robin Dunbar, the British evolutionary psychologist famous for his work on human social bonds, tells Inverse that our pimple popping tendency could be a vestige of evolution.

Dunbar, whose observations of primate societies have revealed the benefits of gossip and the limits of our social networks, has found that our chimpanzee cousins and orangutan aunties spend a lot of time physically grooming each other. Pimple popping, he suggests, is just another part of that process.

“They’re removing debris — vegetational leaves and burrs that get caught in the fur — so a lot of grooming is just removing that kind of junk,” he says. “But they’ll also pick scabs and the like. So anything that’s on the skin’s surface or in the fur attracts their attention and they’ll try and remove it.”

In addition to keeping loved ones clean, grooming has another, arguably more important function: communication. While we humans can communicate our emotions and social bonds through complex verbal language, Dunbar says, we also continue to value touch — whether we actually do it or watch it on YouTube — as a means to do so, just like our ancestors.

Let me take you down.... Does this GET you every time?! 👉🏼❤️👈🏼#strawberryfieldsforever #drpimplepopper ✌🏼❤️💥

A post shared by Sandra Lee, MD Dermatology (@drpimplepopper) on

“We still do use those classic primate grooming actions,” he says. “We really do see it very commonly with mothers sort of fiddling with the hair of their children… And they’ll be kind of flicking through it, and so on. And, of course, more extensively beyond that, it does get into pimple popping.”

Dunbar’s famous “social brain hypothesis” argues that the human brain evolved to facilitate survival in big social groups. Pimple popping, he argues, soothes us because the evolution of the “social brain,” which valued touch as a means of communication, created a special neural pathway between our skin and our brain. It was especially important in primates, whose fur required plenty of grooming, but it’s still very relevant in humans.

“Of course, we lack the hair over most of the body,” he says. (“Well, some people don’t,” he adds.) But interpersonal touch, he explains, still triggers the release of pain-relieving endorphins and the “love hormone,” oxytocin, just as it does in our hairy cousins. It may seem socially taboo, but when a mom picks at her child’s blemishes or a teenager pops his own pimples in the bathroom, everyone involved is left feeling downright tingly.

It's all about touch.

Dunbar’s theory lines up well with the explanation provided by Dr. Pimple Popper herself. A dermatologist in California, Dr. Sandra Lee posts viral videos of her clinical encounters with a host of subcutaneous atrocities. She thinks her videos provoke a “cerebral orgasm,” telling The Guardian in 2015 that her own videos sometimes put her in a “hypnotic” hold.

Her “cerebral orgasm” hypothesis has never been tested scientifically (strangely, there seems to be a dearth of grant money for pimple popping science), but it is consistent with the implications of Dunbar’s touch-centered hypothesis.

It may be that watching pimple popping videos releases some of the endorphins and oxycontin you’d get from actual physical touch. Some studies have shown that mirror neurons in the brain allow primates to feel what others feel, and it could be that the positive feelings associated with seeing someone else experience touch encourages our mimicry and social behavior. This makes sense, given that many Dr. Pimple Popper fans self-identify as having autonomous sensory meridian response (ASMR), a phenomenon that purportedly causes tingling skin in response to videos of things like whispering, food preparation, and skin picking. ASMR hasn’t been validated by scientists, but its implications are similar to those of Dunbar’s social brain hypothesis.

Positive associations with touch aside, some fans of pimple popping, might simply be delighted by disgust. In his book The Anatomy of Disgust, law professor William Ian Miller traces how humans are hardwired by millennia of evolutionary forces and cultural practices to feel fear, disgust, or other negative emotions toward things that could cause us harm. That means we avoid vomit, blood, and, yes, acne.

But when we watch these small, orgasmic horrors unfold on a computer screen, we know we can’t be hurt, and therein lies the thrill.

Photos via Giphy, YouTube