Mass hysteria

Attention, zoo patrons! Clamu the Giant Oyster is on an emotional rampage! Please scream and run around in circles! Mass hysteria, a.k.a. "hysterical contagion", or more generally "psychogenic epidemic", is the phenomenon of multiple people experiencing some of the same symptoms of hysteria. Hysteria is the designation for a malady in which sufferers may present an extraordinary and shifting range of physical symptoms. It is also a colloquial label for mass delusions, where large groups of people all claim to have seen impossible events, such as floating saints or the like. Despite all appearances, the World Cup is not an example.

Female hysteria
The word "hysteria" comes from the Greek word for uterus. Among other things, it was believed that the movement of the uterus could cause mental or physical illness in women. And we're not just talking about cramps.

Mass hysteria
Strictly speaking, mass hysteria consists of a large number of people being influenced by a feeling of panic to the point that they begin to experience physical symptoms. These symptoms often mimic the well-documented state of hysteria, but are characterized by their rapid remission and frequent dependence on immersion in the atmosphere of panic.

Mass hysteria occurs most often among the youth, especially preadolescents and adolescents.

People have been susceptible to mass hysteria throughout history; German physician Johann Weyer reported an outbreak in Amsterdam in 1566:

Mass delusions
While more properly classified as something quite different from mass hysteria, that label is often used to refer to what are actually mass delusions, or "collective delusions". On rare occasions, and often in a manner inspired by religious belief or common myths such as UFOs, large groups of people will all witness events that probably did not occur. Witnesses and their believers will often accuse godless skeptics of using the mass delusion explanation to conveniently ignore "evidence" that they find inconvenient, but the prevalence of mass delusions in so many places and on so many contradictory topics makes it hard to work out exactly whose mass hallucination was accurate.

It is possible, of course, that the Virgin Mary did appear to thousands in Egypt, such as was reported by many advocates of Our Lady of Zeitoun. But it is equally possible that any other mass delusion was real, such as in 1995 when all manner of Hindu statues apparently began drinking the offered milk of devotees.

Misdiagnosis
One of the archetypal examples of mass delusion was the a bizarre collection of stories about residents of a small town reporting a phantom home intruder while falling ill from a "sickly-sweet" gas. The police eventually concluded the case was due to mass hysteria, possibly coupled with pollution from a nearby industrial plant.

In 2003, a former resident of the area released a book that hypothesized that there was a real perpetrator: a brilliant, mentally disturbed chemist who was later institutionalized and wanted to exact revenge against former schoolmates and teachers. Interviews in 2006 revealed that older members of the town had known this all along, but allowed the mass hysteria label to stand as a way of protecting the Gasser's father's reputation as a beloved benefactor of the town.

Misuse
The term is also frequently misused hyperbolically to refer to any large group of people being wrong or upset about something. For instance, one would be wrong (although reasonable) to say that the strong readership of WorldNetDaily is an example of mass hysteria. On the other side of the coin, you have certain right-wing pundits such as Dennis Prager (who, coincidentally enough, is a WND columnist) who abuse the word like no tommorow, usually by characterizing anything "the left" is upset at as "hysteria", even on subjects that are of genuine importance, such as global warming, or characterizing a relatively fringe figure/movement as "mass hysteria".

Charles Mackey, a Scottish journalist, made this mistake when he wrote in his 1841 book Extraordinary Popular Delusions and the Madness of Crowds, about the tulip frenzy of the seventeenth century:

However, while the behavior of "tulip speculators" might have been irrational and foolish on a wide scale, it was neither a mass delusion nor mass hysteria.