If you find your­self think­ing you aren’t a vic­tim of fash­ion, maybe take anoth­er look. Yes, we can con­scious­ly train our­selves to resist trends through force of habit. We can declare our pref­er­ences and stand on prin­ci­ple. But we aren’t con­scious­ly aware of what’s hap­pen­ing in the hid­den turn­ings of our brains. Maybe what we call the uncon­scious has more con­trol over us than we would like to think.

Inex­plic­a­ble episodes of mass obses­sion and com­pul­sion serve as dis­qui­et­ing exam­ples. Mass pan­ics and delu­sions tend to occur, argues author John Waller, “in peo­ple who are under extreme psy­cho­log­i­cal dis­tress, and who believe in the pos­si­bil­i­ty of spir­it pos­ses­sion. All of these con­di­tions were sat­is­fied in Stras­bourg in 1518,” the year the Danc­ing Plague came to the town in Alsace—an invol­un­tary com­mu­nal dance fes­ti­val with dead­ly out­comes.

The event began with one per­son, as you’ll learn in the almost jaun­ty ani­mat­ed BBC video below, a woman known as Frau Trof­fea. One day she began danc­ing in the street. Peo­ple came out of their hous­es and gawked, laughed, and clapped. Then she didn’t stop. She “con­tin­ued to dance, with­out rest­ing, morn­ing, after­noon, and night for six whole days.” Then her neigh­bors joined in. With­in a month, 400 peo­ple were “danc­ing relent­less­ly with­out music or song.”

We might expect that town lead­ers in this late-Medieval peri­od would have declared it a mass pos­ses­sion event and com­menced with exor­cisms or witch burn­ings. Instead, it was said to be a nat­ur­al phe­nom­e­non. Draw­ing on humoral the­o­ry, “local physi­cians blamed it on ‘hot blood,’” History.com’s Evan Andrews writes. They “sug­gest­ed the afflict­ed sim­ply gyrate the fever away. A stage was con­struct­ed and pro­fes­sion­al dancers were brought in. The town even hired a band to pro­vide back­ing music.”

Soon, how­ev­er, bloody and exhaust­ed, peo­ple began dying from strokes and heart attacks. The danc­ing went on for months. It was not a fad. No one was enjoy­ing them­selves. On the con­trary, Waller writes, “con­tem­po­raries were cer­tain that the afflict­ed did not want to dance and the dancers them­selves, when they could, expressed their mis­ery and need for help.” This con­tra­dicts sug­ges­tions they were will­ing mem­bers of a cult, and paints an even dark­er pic­ture of the event.

Cer­tain psy­cho­nauts might see in the 1518 Danc­ing Plague a shared uncon­scious, work­ing some­thing out while drag­ging the poor Stras­bour­gians along behind it. Oth­er, more or less plau­si­ble expla­na­tions have includ­ed ergo­tism, or poi­son­ing “from a psy­chotrop­ic mould that grows on stalks of rye.” How­ev­er, Waller points out, ergot “typ­i­cal­ly cuts off blood sup­ply to the extrem­i­ties mak­ing coor­di­nat­ed move­ment very dif­fi­cult.”

He sug­gests the danc­ing mania came about through the meet­ing of two pri­or con­di­tions: “The city’s poor were suf­fer­ing from severe famine and dis­ease,” and many peo­ple in the region believed they could obtain good health by danc­ing before a stat­ue of Saint Vitus. They also believed, he writes, that “St. Vitus… had the pow­er to take over their minds and inflict a ter­ri­ble, com­pul­sive dance. Once these high­ly vul­ner­a­ble peo­ple began to antic­i­pate the St. Vitus curse they increased the like­li­hood that they’d enter the trance state.”

The mys­tery can­not be defin­i­tive­ly solved, but it does seem that what Waller calls “fer­vent super­nat­u­ral­ism” played a key role, as it has in many mass hys­te­rias, includ­ing “ten such con­ta­gions which had bro­ken out along the Rhine and Moselle rivers since 1374,” as the Pub­lic Domain Review notes. Fur­ther up, see a 1642 engrav­ing based on a 1564 draw­ing by Peter Breughel of anoth­er danc­ing epi­dem­ic which occurred that year in Molen­beek. The 17th cen­tu­ry Ger­man engrav­ing above of a danc­ing epi­dem­ic in a church­yard fea­tures a man hold­ing a sev­ered arm.

We see mass pan­ics and delu­sions around the world, for rea­sons that are rarely clear to schol­ars, psy­chi­a­trists, his­to­ri­ans, anthro­pol­o­gists, and physi­cians dur­ing or after the fact. What is med­ical­ly known as Saint Vitus dance, or Sydenham’s Chorea, has rec­og­nized phys­i­cal caus­es like rheumat­ic fever and occurs in a spe­cif­ic sub­set of the pop­u­la­tion. The his­tor­i­cal Saint Vitus Dance, or Danc­ing Plague, how­ev­er, affect­ed peo­ple indis­crim­i­nate­ly and seems to have been a phe­nom­e­non of mass sug­ges­tion, like many oth­er social-psy­cho­log­i­cal events around the world.

Episodes of epi­dem­ic manias relat­ed to out­mod­ed super­nat­ur­al beliefs can seem espe­cial­ly bizarre, but the mass psy­chol­o­gy of 21st cen­tu­ry west­ern cul­ture includes many episodes of social con­ta­gion and com­pul­sion no less strange, and per­haps no less wide­spread or dead­ly, espe­cial­ly dur­ing times of extreme stress.

via Pub­lic Domain Review

Relat­ed Con­tent:

Oliv­er Sacks Explains the Biol­o­gy of Hal­lu­ci­na­tions: “We See with the Eyes, But with the Brain as Well”

Behold the Mys­te­ri­ous Voyn­ich Man­u­script: The 15th-Cen­tu­ry Text That Lin­guists & Code-Break­ers Can’t Under­stand

A Free Yale Course on Medieval His­to­ry: 700 Years in 22 Lec­tures

Josh Jones is a writer and musi­cian based in Durham, NC. Fol­low him at @jdmagness