In the video below, a young woman picks up a brown leather wallet, rubs it between her hands, then shakes it. The zipper pull trembles against the rows of linking teeth with a tinny sound. These sounds and sights have one goal: to make the viewer feel "tingles." This reaction is called ASMR, or autonomous sensory meridian response. The sensation is usually described as electrostatic-like tingles that travel across the scalp and back of the neck, occasionally extending to additional areas of the body. They occur in response to certain triggers—usually sounds and images, but sometimes touch as well. Videos like the one above have exploded in popularity on YouTube over the past few years, as have online communities on Reddit and other social media, where people create videos, share triggers, and commune over the unusual sensations. Some have more than 100,000 members [PDF]. But while hundreds of thousands of people claim to have ASMR, science has only begun to investigate the phenomenon. Here's what we know so far.

1. THE TERM ASMR IS LESS THAN A DECADE OLD.

It was coined by Jennifer Allen, the creator of the first ASMR Facebook group, in 2010. As Vice reported in 2012:

“Autonomous” refers to the “individualistic nature of the triggers, and the capacity in many to facilitate or completely create the sensation at will,” Jenn told me in an email. “Sensory” and “response” are fairly obvious, and “meridian,” Jenn said, is a more polite term for “orgasm.”

She further clarified in 2016, "I wanted to use a word that would replace the word 'orgasm,' and referenced the dictionary definition, for which entries included the noun form, 'a point or period of highest development, greatest prosperity, or the like.'" Allen isn't a scientist—she's a cybersecurity expert who has played a pivotal role in the organization of online ASMR communities for the last decade, and is a founder of ASMR University. Other names people use to refer to ASMR include “head tingles,” “brain tingles,” and “brain orgasm.” The experience is portrayed as pleasant without being sexual, and as accompanied by feelings of relaxation and well-being. “My favorite way to describe it,” one popular "ASMRist" says, “is when you get that negative, horrible feeling of nails down a chalkboard—ASMR is the complete opposite."

2. ASMR HAS MANY TRIGGERS.

ASMR triggers are likely as varied as the individuals experiencing "the tingles," but there are recurrent themes. Soft, calm whispering, slow hand motions, and sounds made by objects are frequent triggers. A recent study found that sounds were more critical to having an ASMR response than sights, but it's not just any sounds—background music, for instance, prevented many viewers from experiencing tingles. Many ASMR videos are centered on handling objects in a very deliberate and focused manner. Favorites include unhurriedly folding towels, unpacking mail, or sorting baseball cards. Personal care and close attention are common themes: Some of the most watched ASMR videos include role-playing situations, in which the host simulates the act of giving a haircut, a beauty treatment, or a health checkup to the viewer.

3. PEOPLE DON'T NEED VIDEOS TO GET THE TINGLES.

The experience is not restricted to watching videos, though. "Soft voices are something that's very triggering for people with ASMR, as is whispering, or any socially intimate—not sexually intimate—acts," says Beverly Fredborg, author of two influential studies on ASMR at the University of Winnipeg. Many people experience the tingles for the first time in real life while feeling cared for by somebody kind and attentive, or while getting a manicure or foot massage: "They'll feel warm, and they'll feel calm and at peace, while they are experiencing these stimuli." The Whisperlodge spa, in New York City, offers “an immersive sensory journey of live ASMR” in which customers are lightly touched with brushes or gentle steam, and lay down while people whisper in their ears. People seem to have a range of sensitivity, with the least sensitive people feeling ASMR only when they're being physically cared for in some way, while the most sensitive feel tingly from audio and visual cues alone.

4. THOSE WHO GET ASMR MAY BE MORE OPEN TO NEW EXPERIENCES …

The number of people among the general population who are what researchers call "ASMR-capable" is currently unknown, but research has started to produce some tantalizing clues about those who are. A 2017 study found that individuals who said they experienced ASMR had higher levels of openness-to-experience and neuroticism on the "big five" personality traits test (a standard metric of mental health used by psychologists) than those who do not—and the higher their scores, the more intense their ASMR responses were.

5. … AND THEIR BRAINS MAY BE WIRED DIFFERENTLY.

Another 2017 study used fMRI to scan the brains of 11 ASMR-capable participants and 11 non-ASMR-capable controls. The researchers found that people with ASMR had reduced functional connectivity between the frontal lobes—where much of our complex thought occurs—and sensory regions of the brain. But they had greater connectivity in some cortical regions that take part in executive control (goal-oriented behavior that relies on cognitive processes such as working memory) and resting state networks (the brain regions that are active by default, when we’re not trying to accomplish an explicit task). The scientists hypothesized that this “blending” of neural networks could give rise to the sensations that people experience during ASMR.

6. IF CERTAIN SOUNDS BOTHER YOU, YOU MAY HAVE ASMR.

Mouth sounds such as clicking, kissing, and eating are some of the most divisive triggers: They can induce strong ASMR in some people and an intense negative response in others. Some investigators have proposed that ASMR and misophonia, where triggering sounds cause anger and aversion, are the two extremes of the same sensory continuum. A 2018 study found that 50 percent of people suffering from misophonia also experience ASMR.

7. ASMR ISN'T THE SAME THING AS THE CHILLS YOU CAN GET FROM LISTENING TO MUSIC ...

It shares some characteristics with frisson (the chills that some people feel when listening to great music) and flow (the complete absorption and altered passage of time that people can feel when they are immersed in an activity). It also overlaps with synesthesia (a condition where stimulation in one sensory modality produces a perception in another one, such as hearing shapes, or tasting colors). But there are important differences too. For example, while ASMR’s tingles occur in response to relaxing situations, frisson usually happens when listening to exciting, rousing music. And as Frebourg notes, frisson tends to course through the entire body for just a few moments, while ASMR is localized to the head and neck, and can last 30 minutes or longer.

8. … AND EVIDENCE IS MOUNTING THAT IT'S A UNIQUE PHENOMENON.

Because of its connections to other sensory experiences, ASMR has lacked scientific recognition as a distinct experience, but that is changing. One 2018 study found that ASMR increased pleasurable feelings (such as tingles) in those who experienced it and reduced their heart rate. In contrast, frisson is known to produce higher heart rates.

9. ADVERTISERS WANT TO USE ASMR TO SELL YOU STUFF …

ASMR has gotten the attention of some food and drink advertisers, who are beginning to use recording and mixing technology to emphasize sounds—such as the crinkling of packages, or even an actor’s noisy chewing—that would normally be edited out from commercial ads. In 2016, KFC released a video in which actor George Hamilton, dressed as Colonel Sanders, folded handkerchiefs into pocket squares and noisily chomped on fried chicken, hitting two ASMR favorites at once. The brand’s chief marketing officer, Kevin Hochman, told the Washington Post: “This is a community that is absolutely infatuated and enthusiastic about the sensorial experience of sound. ... To me, it makes a lot of sense, why we would at least try to enter this space in a small way. There’s a lot of comfort that’s associated with ASMR, and that’s what our food delivers.”

10. … AND ARTISTS ARE USING IT TO HEIGHTEN YOUR RESPONSE.

ASMR could make going to the movies a richer experience. In the 2017 movie Battle of the Sexes, directors Valerie Faris and Jonathan Dayton designed one of the scenes, set in a hair salon, to provoke ASMR. “People work to make videos that elicit this response,” Dayton told Fast Company, “and we were wondering, ‘Could we get that response in a theater full of people?'” (Anecdotal reports suggest it worked.) Some ASMRtists have started to explored the potential of the tingles in erotica, and others are mixing customary triggers with horror and gore content to generate even greater shivers down viewers’ spines. "There's absolutely a subset of video creators doing more quirky and strange, experimental stuff," ASMR horror star Phoenician Sailor said in a 2016 Motherboard interview. "I really like that people are trying out the crazier things. There's only so many ways you can tap on a piece of plastic.”

11. BOB ROSS IS AN ASMR FAVORITE.

All the characteristics The Joy of Painting host was famous for—soothing voice, calm actions, a gentle affect, the tap-tap-tap sound he made on the canvas as he painted his "happy little trees"—make him a natural ASMR star. As one Redditer recently noted, the 19th most popular post on the Reddit ASMR channel is an announcement from 2016 that Bob Ross videos were going to be livestreamed for nine days straight.