We’re about to tell you something that will blow your mind: when a movie character gets hurt, most people don’t feel the pain themselves.

Oh, you already knew that? You must be in the 98 percent of people who don’t experience mirror-touch synesthesia. But for the other 2 percent out there who just learned that they’re unusual, read on.

What is mirror-touch synesthesia?

If you’ve heard of synesthesia before, you may associate it with the ability to see sounds or taste words. In fact, there are at least 80 different types of synesthesia, most with similarly paradoxical descriptions: there’s one type that makes people see dates and times in the physical space around them, for instance, or another that endows numbers with personalities and gender.

Mirror-touch synesthesia, on the face of it, sounds comparatively normal: it’s the experience of feeling what other people feel. But this goes way past normal empathy – it’s a real, physical sensation, and for some people, it can be completely overwhelming.

“If I see somebody with a pair of glasses, I’ll feel a sensation of the glasses on my nose as if they were on my face,” Joel Salinas, a neurologist at Massachusetts’ General Hospital and mirror-touch synesthete, told the BBC.

But the experience “can be a little distressing,” he added, noting that one former patient who had self-mutilating tics – he would “chew on the inside of his lips” and “grind his teeth” – would unwittingly cause “this painful buzzing shooting through my own cheek.”

What causes mirror-touch synesthesia?

This is a tricky one. See, in a way, almost everyone has a bit of mirror-touch synesthesia – it’s part of what makes us human.

“We do kind of automatically slip into the shoes of other people, even if we're not consciously aware of that,” neuroscientist and expert in synesthesia Michael Banissy told NPR.

For most people, that feeling is limited to things like crying at a weepie movie, or crossing your legs when you read about why the chainsaw was invented. But for the one in 50 of us with mirror-touch synesthesia, Banissy explained, this normal empathetic response kind of gets turned up to 11.

“They hyper-activate their system. It's over-excitable. It's much more excitable than when you or I activate the system,” he explained.

“So what they're doing is potentially activating the system past threshold to the extent that they can actually reach the level of a conscious experience … [they’re] literally having a physical sensation or tactile response when observing these experiences in other people.”

At least, that’s one theory. Another suggests that mirror-touch synesthetes have a problem with their “self/other representation” – that is, how your brain distinguishes between yourself and other people. If that’s the case, then people with mirror-touch synesthesia are literally “treat[ing] others as if they are themselves,” Banissy explained.

“Mirror-touch synesthetes appear to have less gray matter … [in the] temporoparietal junction,” he told NPR.

“[It suggests] that there might be some breakdown in terms of the way the brain is activating when it's trying to distinguish between the self and somebody else,” he explained. “And it's actually this blurring between the self and other that might lead to them treating other people's bodies as if it's their own.”

Is mirror-touch synesthesia dangerous?

It’s not dangerous, per se, but for those who experience it very strongly, it can be totally debilitating.

“[A kid was] standing up in the cart, I think,” recalled synesthete Amanda on NPR. “And he fell backwards and hit his head – just smack. And I went to run. And all of a sudden, my eyes went blurry, and I was down on my knees on the thing before I could get to this kid. And I'm just like, this child, he needs help. And my head hurt so bad that I basically, you know, was like crawling to try to get to the kid. Like, it was bad.”

For Amanda, her synesthesia is so bad that she basically became a recluse – going out and seeing other people was simply too much for her. She couldn’t even eat with her family: it “feels like they're shoving food in my mouth,” she said. “It's terrible.”

And mirror-touch synesthesia can have more existential impacts too. We probably all know someone who changed a bit after they met a new partner, but for people with mirror-touch synesthesia, that inability to distinguish between themselves and others can mean that a new relationship, friend, or even just a random acquaintance on the street can result in a full-blown crisis of identity.

“I remember looking in the mirror, and I – I was just staring at myself in the mirror, like, what am I doing here?” Amanda said.

“Is this who I am? Or is this who I am because of the people around me? Am I taking them on, you know? Are they affecting me so badly – so overwhelming me – their personalities, their movements, their this and that? Am I myself?”

What do I do if I have mirror-touch synesthesia?

If you think you have mirror-touch synesthesia, the first thing you should do is ask yourself a question: is it causing me a problem?

"If you have mirror-touch synesthesia, there's nothing wrong with you,” said Jared Medina, assistant professor in the University of Delaware's Department of Psychological and Brain Sciences. “It's just an interesting difference, like being double-jointed.”

Two percent of the population may not sound like a lot, but it translates to hundreds of millions of mirror-touch synesthetes across the world – and for most of them, the condition isn’t as extreme as Amanda’s. Some feel others’ sensations and emotions only lightly – a tickle instead of a slap, for instance. Or, as Salinas put it in a profile for Pacific Standard: “an echo of pain.”

For others, the experience only occurs at all under specific circumstances. In a 2017 study, for example, some people with mirror-touch synesthesia found that the experience would lessen or even disappear if they simply changed position.

“[The] phantom sensations were more frequent when the participants' hand position matched the video hand's,” explained Medina, who was the lead researcher on the study. “Our findings suggest that the brain is matching the video hand to their own hand, as if asking 'could that be my hand?'”

For Salinas, the key was learning to redirect his attention away from the emotions of those around him – focusing instead on the task at hand, or a physical object, or perhaps the calmest person in the room.

“Once I was able to harness the trait, I felt like it helped me become a better doctor,” he told the BBC.

And of course, there’s always the possibility that you might actually like being a synesthete.

“When I see people hug, I feel like my body is getting hugged,” mirror-touch synesthete CC Hart told the BBC.

“It feels good for them, but it feels good for me as well.”