Mandela Effect
False Memory Effect · Berenstain Bears Effect
A phenomenon in which large groups of people share the same false memory — such as many recalling Nelson Mandela dying in prison in the 1980s, when he was actually released in 1990 and died in 2013.
Origin
American paranormal researcher Fiona Broome coined the term in 2009 after a conversation at Dragon Con in Atlanta, where she discovered that many others shared her vivid but incorrect memory of Nelson Mandela dying in a South African prison during the 1980s. Mandela had in fact been released in 1990 and went on to serve as president. Broome launched the website MandelaEffect.com in 2010, and the concept gained mainstream attention as thousands reported similar collective false memories about pop-culture details. Psychologists attribute the phenomenon to confabulation, suggestibility, and source-monitoring errors rather than Broome's preferred parallel-reality explanations.