History is filled with moments of shared delusion and madness, from silly fads and popular crazes to the more extreme forms of collective panic and cult paranoia.
They're examples of what has come to be called ‘mass hysteria'
Hilary Evans and Robert Bartholomew – who have spent many years exploring and cataloguing just such anomalies – have produced, in their new book, Outbreak! The Encyclopedia of Extraordinary Social Behaviour, what will undoubtedly remain the definitive reference work on collective delusions, mass panics and other strange forms of group behaviour for the foreseeable future.
Underlying all these diverse manifestations, they argue, are two chief vectors: a negative one involving exaggerated fear and uncertainty, and a positive one driven by hope and expectation. In both cases, these emotions of fear and hope can multiply to such an extent that they shape society for better or worse… mostly, it has to be said, for the worse.
There have been many attempts to account for the kinds of outlandish collective behaviour that so fascinate forteans – the book provides entries on many of these related theories and explanations, from Altered States of Consciousness and Anxiety to False Memory Syndrome, Hysteria and Psychosomatic Phenomena. Many once-favoured ideas don't really stand up to much scrutiny: consider the fad among 19th-century physicians for ‘curing' masturbators with bizarre surgical ‘intervention' and for terrifying their hapless patients with the prospect of bodily ruin and eternal damnation. It could be argued that none of the theories that have been put forward – even the more promising ones – actually applies in all cases.
Source (no longer available): Fortean Times