The reason for the "Mandela Effect" term

When Nelson Mandela's death in 2013 was announced some people were surprised. This is because they were sure he'd already died, and they even seem to remember where and when - in prison in the late 1980s. Individual people would have normally just dismissed this as something they didn't quite remember correctly. Maybe they misheard it wrong, or maybe it was someone else who died and for some reason they were sure it was Nelson.

Then - somehow - this notion started getting discussed on the internet and this began a stream of "me, too!" type responses. Once this number became too big to ignore, and those experiencing it were not just dismissing it as faulty memory, we had what became known as The Mandela Effect. 

Mass Memory Discrepancy

The Mandela Effect is one of many which comes under the broader classification of the "Mass Memory Discrepancy Effect", characterised by a significant number of people remembering something having been different in the past to all the evidence related to the incident available today. This disconnect is absolute, so Googling, reading old books, watching the old movies and so on, all show the same thing, and that is definitely not what the people experiencing the effect remember.

Here is President Barack Obama speaking after President Nelson Mandelas 2013 death:

Whatever the reason, it now seems Nelson Mandela has left another legacy besides the one his struggle in Africa did.