How Psychology Can Explain the Deadly Medieval Dancing Plagues

How Psychology Can Explain the Deadly Medieval Dancing Plagues

♪♪♪ In the year 1518, the city of Strasbourg was
struck by a dancing plague. Yes, a dancing plague. And it was deadly. It started with a single woman, but within
a month, there were over 400 people dancing in the streets—wildly, uncontrollably, and
often to their deaths. Some sources claim that, for at least some portion of the outbreak, as many as 15 people were dying a day. And if it’s not already obvious, the dancers
weren’t having fun. They screamed and begged for mercy. There were literally hundreds of people, miserable
and in pain… because they were dancing for no reason. Even more strange is the fact that 1518 was
neither the first nor the last time this happened. There are other documented incidents from the 1200s through the 1600s from all along the Rhine River. And while it’s unclear why these plagues
happened, psychologists think they can explain it through a combination of two phenomena:
dissociative trance disorder and social contagion. Now, there are other possible explanations, from it being some kind of extreme religious ritual to sleep deprivation. Researchers have even suggested the dancers might’ve been poisoned with ergot, a mold
that grows on rye and causes spasms and hallucinations. But that seems unlikely, since rye wasn’t
eaten everywhere that the dancing plagues happened. And dissociative trance disorder plus social
contagion would explain quite a lot. Dissociative trances could be responsible
for the dancing, while the social contagion bit could explain how it “spread” like the plague. Dissociative trance disorder or DTD is currently
included in the DSM-5 under “other specified dissociative disorders.” That’s a group of disorders which all involve
experiencing a disconnect between what’s happening in your thoughts and memories and
your surroundings and actions. And DTD is essentially when people experience
dissociation as a kind of trance: a temporary state of mind where the person loses their
usual sense of identity, their awareness narrows, and their movements and speech become limited. Now, it’s kind of hard to measure how many
people experience DTD, because unless things get really bad, people might not want to talk about feeling possessed or disconnected from themselves. Plus, a 2011 survey which identified 402 cases worldwide suggested that it might be underdiagnosed in places like the U.S. due to cultural biases. And the low number of documented cases has made it kind of hard to study what exactly goes on in people’s brains during a DTD trance. But we know from people who’ve voluntarily entered a trance state that trances tend to involve different patterns of activity in
the brain like, a shift from more activity in the analytical left hemisphere to the more
experiential right one. That may explain why the dancers felt they were compelled to act, rather than in control of their own bodies. Also of note: during trances, natural opioids are released. Those could have dulled the dancers’ pain, which would help explain why they were able to keep dancing for so long even though they were literally killing themselves. Trances would also make sense because what a person experiences during a trance is influenced by their culture and beliefs. For example, a 1996 study looked at 10 people who had contacted the official Exorcist of the Rome diocese because they felt they were possessed by demons or the devil They were all ultimately diagnosed with having
experienced at least one dissociative trance, and the researchers argued that the commonalities of the cases showed how their culture and Catholic community had provided them a lens to express their trauma. Oh yeah, because that’s another thing: while there are lots of kinds of trances, it’s widely accepted that dissociative trances,
like other dissociative disorders, are triggered by trauma. Which brings us back to those plagued dancers. You see, the two biggest outbreaks happened
in 1374 and 1518, which researchers have called “bitterly harsh years… even by the gruelling
standards of the Middle Ages.” In 1374, people living along the Rhine River got hit by a really bad flood, plus that bout of Black Death that killed half of Europe
was still within living memory. And in 1518, they got treated to bad harvests,
high grain prices, and the arrival of syphilis. Huzzah! So they were pretty miserable, and dancing
plagues weren’t unheard of. In fact, paintings from the time suggest that
people were kind of scared of them happening again. And generally speaking, people are more susceptible
to trance states if they expect them… so maybe uncontrollable dancing isn’t that
strange a way for their trauma to have manifested. But how did it spread from one woman to 400 people dancing in the streets? That’s where what’s known as social or
behavioral contagion comes in. Behavioral contagion is the tendency to repeat
a behavior after seeing others perform it. Now, this is different from conformity. That’s where you see someone else do something
and then experience a conflict about it, because you want to do or say what everyone else is
doing to fit in, but it’s not something you would normally do. Contagion happens when you’re already experiencing
conflict about something. Then, seeing someone do the thing you kind
of already want to do becomes enough to make you do it— even if you don’t think about
it like that. Say, for instance, you have a neighbor who
always leaves trash scattered around their yard, and you’re not really sure what to
do about it. And then, one day, you see another neighbor
confronting your terrible neighbor. Next thing you know, you’re up in their
face yelling at them, too. Come on, Jim! Take out the trash! Studies tracking thousands of people over
time have found evidence for behavioral contagion for everything from happiness and cooperative
behavior to obesity and divorce. Even memories can be spread by contagion. People who think they maybe remember something
one way can become convinced of it when someone else also remembers it that way—Berenstein
bears-style. There never was a Berenstein bears! It always had an A at the end. I promise. And sadly, the spread of terrible behaviors
by contagion is also well-documented, including violence to others and self-harm. So… why not deadly dancing? Seeing that woman in her dancing trance, combined
with the cultural fear of dancing plagues, could have been just enough for others to
manifest their trauma in a dissociated dance, too. And at the time, it was believed that dancing
it out was the best way to rid yourself a dancing curse. So officials actually made room for the dancers
in a public space where they were sure to be seen by everyone. And the rest, as they say, is history. A lot of this is still speculation, of course. We can never really know why hundreds of people
took to the streets to dance themselves to death. But! These two ideas do cobble together a pretty
decent explanation. And they can begin to help us understand why
humans sometimes do wild, hard-to-believe things. Thanks for watching this episode of SciShow
Psych! I hope you learned something—that’s what
we here at SciShow are all about. So tell us in the comments what part of this
video you found most surprising! And if you just can’t get enough about the
psychology of dancing, you might like our episode on what your moves say about you. You can watch that one next! And let’s be honest—you know you’re
curious now.



  • Brains Applied - Unraveling The Human Mind

    Oh wow, nice!
    I once wanted to search for an explanation, but I couldn't really find it that well.
    Guess I did something wrong in my research :O

  • MissSagittarian

    I love learning about all the theories for these events. So wild.

  • Titanic

    Will you guys be able to do a video on how the brain reacts to a situation like a Sinking Ship?


    “It started with a single woman” – nuff said!

  • Karl Marxs' Goldfish


  • Gaia Builder

    "Dance, dance, dance till you're dead"

  • seasong

    Back then they still had good music

  • scorpiss9

    anyone's up for a dance?

  • Honey

    You can dance if you want to. Leave your friends behind.

  • David Buschhorn

    Brain worms.

  • Drumpad 24

    Wow they were so sad and traumatised that they tried to overplay it by dancing (selfharm) crazy !

  • clxwncrxwn

    There is also a reported case of a covenant of nuns meowing all day everyday, until soldiers were sent to stop it, with orders to beat them back into people.

  • Dakota Brown

    I thought the left and right brain was a dead theory

  • Spencer Dokes


  • Assaf Wodeslavsky

    Reminds me of global warming hysteria. But what do I know?

  • Natalia

    But how do you dance so hard that you die? Dance for days, too harsh? Can’t wrap my mind around that idea 🤔🤔🤔

  • CaramelLeek

    Idk I'm more interested in what this "dance" actually was. Like was it actually dancing? Or was it just weird movements that could be likened to dancing?

  • vsmash2

    Left-brain-right-brain differences, really, sci-show? You have videos that debunk that and now you are perpetuating it?

  • Jessrassic_Snark

    "there was always an a at the end" ….in THIS dimension!

  • David Jameson

    Just gonna say…
    Weak minds are easily swayed by religion.

  • inevitabletraitor

    It's obviously the dancing demon from "Once More With Feeling," the musical episode of "Buffy."

  • New Message

    They had the fever… Dance Fever!

  • Mystic Mind Analysis

    I don't wanna end like this
    There's a sting in the way you kiss me
    Something within your eyes
    And it could be the last time
    'Fore it's over!

    I just wanna be
    Wanna bewitch you
    In the Moonlight
    I just wanna be
    I wanna bewitch you
    All night

  • La Sphynge

    It's important to note that no contemporary source actually mentions deaths from the dancing plague. Such accounts are only found in later texts from authors who did not witness it themselves. Although that is not proof that nobody died either, it's a piece of information we should be cautious with.

  • Cheese Monger

    What do you guys think about the idea that being transgender is a product of social contagion?

  • TwoBears Highfiving

    Well they can dance if they want to. They can leave their friends behind. Cause their friends don't dance, and if they don't dance? Tsh, well they're no friends of mine.

  • vealck

    Those dancing plagues are still prevalent in present day Bollywood.

  • Ginny Jolly

    Yes, the Berenstain Bears. By Jan and Stan Berenstain. They also wrote, The Berenstain Baby Book, or What Dr. Spock Didn't Tell You
    (not to be confused with Star Trek's Mr. Spock, Science Officer on the Enterprise.)

  • Plurpee

    Old-skool flash-mobs…

  • Throttle Kitty

    Takes "Dancing in the streets" to a whole new level

  • threeMetreJim

    Could they have ingested some sort of neurotoxin or maybe suffering some sort of vitamin/mineral deficiency? (vitamin B12 deficiency?)

  • EV Belluche

    Pretty sure it was the Sanderson Sisters actually

  • krellen d20

    Screaming and begging for mercy do not sound like things caused by social contagion. It sounds a lot more like a (possibly now extinct) river-borne parasite to me.

  • CPTAZ Studios

    Didn’t they already do this?

  • a.i. c.

    Fairies did it

  • Chelsey Abbott

    I love videos lile these. Its so interesting how so many people can be convinced of something even if its not true

  • John Opalko

    "Huzzah!" indeed.

  • Ty

    You can sleep when you're dead~

  • Mac Jerick Castillo

    They might have had symptoms of a certain disease and then a prominent person told them that the only cure is to dance it out

  • Existential Error

    Hate it when PRofeSsIOnaL daNCErS enter our reality like this.

  • Jackson Stein

    Sam o Nella academy covered this also.

  • US

    So how many degrees of Kevin Bacon and Footloose does it take to connect to this

  • Deebo Molina

    I only know about this plague because of Legion and I thought it was fake!

  • Lemanic89

    ”Dissociative Trance Disorder” is my Psy-Trance DJ Name.

  • Brandon Hale

    Your hair looks nice

  • Aaeren A

    "We've been screwed in so many different ways guys… With luck like ours, I would bet that eventually, we might even experience some troll job from Satan himself, where he makes us dance to death. We should be the first ones to do the death dance as a psychological preemptive strike against the devil's evil manipulations."
    Psychology lol.

    They did it to themselves, with hysteria lol.

  • Lucid Moses

    I'm going to go with Occam's razor on this and go with a root cause that got wildly exaggerated. Like say look for cause of contagious itching.

  • Scotty Gilmer

    Somebody alert the BuzzFeed Unsolved guys.

  • Chester Liwosz

    yeah but ergotamine can make entering that dissociative trance a LOT easier, so I wouldn't count it out entirely as a contributing factor

  • FrozenRoxas

    This is so inaccurate. This is obviously the aftermath of a particularly powerful Tarantellegra spell.

  • Cognitively Absurd

    My social contagion wouldn't have been to confront that guy about the trash but to generate lots of trash on the lawn myself.

  • Plipp the First

    All this talk about trances makes me wonder if all these videos floating around on YouTube purporting to hypnotise you into a trance have any merit. Also, where is the line between a trance and a deep meditative state?

  • Real Human Being

    this is really fascinating in a morbid way

  • Vince85

    Lol @ Catholic

  • Aluminium Dose

    Could it be late-stage syphilis? I read somewhere it causes mental derangement

  • Rossco The Red Roo

    What about Mercury poisoning, Like the dancing cats of Japan?

  • Dave Toms

    Dancing Hank at 6:38 is the best thing to happen to me today.

  • Jes The Red

    All along the Rhine… something blooming in the water maybe?

  • George Indestructible

    Sheep, sheep everywhere. 🥴

  • casesandcapitals

    Oh my god it's those people in France who danced until they died
    Shane was right

  • Infectedstyles_Chris

    Best scishow host here.

  • undertakersarmpit

    two things come to mind, the late 1200s pied piper story and the planking fad of 2010/2011

  • veryberry39

    The Sanderson Sisters have been busy throughout history…

  • shadwo xii

    Black magic

  • Goth Girl

    "You can dance if you want to, You can leave your friends behind,"
    "Cause if your friends don't dance and if they don't dance, well the're no friends of mine!"
    "you can go where we want to, if your not I'm sure we will,"
    "You can act real cold and act a little bold, you can act like an imbecil!"
    "We can dance, we can dance everybody taking the chance!"
    "We can dance we can dance, doing the safety dance aaance! Its a saftey dance!"

  • John Matthias

    No mention of the documentary Saturday Night Fever?

  • Claudia

    we think the dancing plague was weird when in our current time we had hundreds of people around the world attempting to plank

  • John Bradley Evans

    I recently watched a Black Death online course (Great Course Plus – Prof. Dorsey Armstrong). She said the towns people would sometimes all dance to ward off bubonic plague. People were trying all sorts of weird stuff. Perhaps this affected the Dance Plagues which occurred within some of the same peoples' lifetimes.

  • Chloe Pekel

    How I want to go. It's like an L.M.F.A.O. music video.

  • CelesteofOz

    One thing here doesn't make sense. If trauma and social contagion are likely causes, why doesn't it happen now? – All the conditions for that still exist – there's plenty of people exposed to trauma from wars, natural disasters etc. Places are even more crowded, and there's viral video sharing. Why not now?

  • MisterCynic18

    Silly psychologists, this is obviously the result of people not giving proper tribute to the local fae lords

  • Liss

    Dark ages= not dark economically or artistically

  • Ms. Blackcat

    You noticed this phenomenon happened around the Rhine River. I think it might have been something in the waster.

  • MakeMeThinkAgain

    Or this was like Once More With Feeling. Where we see if there is an overlap of Buffy and CrashCourse fans.

  • Imperiused

    I think this would make for really good movie or miniseries potential as historical horror/drama. The dancing plague might seem funny at first, but as it progresses it would become gradually more and more horrifying. And to take that journey with the residents, with all the confusion and horror and helplessness that people felt, it could be incredible.

  • UncleBibby

    speaking of The Berenst(a/e)in Bears Effect, there’s a video of the actor Pierce Brosnan being asked by an interviewer about the scene in Ms.Doubtfire where Robin Williams yells “It was a run-by fruiting!” at him, and Pierce offhandedly corrects the interviewer, saying the line was actually “It was a drive-by fruiting!” however, Pierce is miraculously wrong about his own movie… if you go watch the scene in question, Robin Williams’ character Ms.Doubtfire says “It was a run-by fruiting!” despite that seeming like a worse punchline

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