Today, millennials call it 'Mandella Effect' which is a fancy word for collective false memories. Now, we've all heard about repressed memories or things we forgot that happened but it's less common to remember things that didn't happen. Of course there's the ever so elusive Sinbad movie Shazaam and the fruit loops, peanut butter and Oreos hokey pokey but what is really the deal here? Was it simply I can imagine it happening so I thought it was true or was it a case that occurred after the Internet? Everybody always says 'Don't believe what you hear on the Internet' so is this just a case of mass effect? Or is there an alternate universe where things happen differently than on this one? I thought it'd be a nice little topic for you fellow writers.. Perhaps we can nibble at it a bit.
The Mandela Effect is rather frustrating. The human mind is not infallible, and in fact can be led astray quite easily. Memories are not like videos that we play back perfectly; instead we recreate them afterwards and can get things wrong quite easily. Add into that pareidolia, seeing patterns where none exist, and the human brain can be tricked pretty easily. The Mandela Effect is basically ignorance made meme. Not that I'm calling you ignorant OP.
I would SWEAR the popular children's books about bears was spelled "Berenstein Bears". But look it up.
The Mamas & Papas were actually The Mamas & The Papas. Well, not for me. And gets worse, they didn't sing it even [see evidence below].
I thought it was Bearstein. I think the issue from that was because at one point, it was spelled one way, then it was spelled another and the authors never came up to say, "Hey, dumbasses! This is how to spell our last names!!" I don't think it's a case of 'alternate universes', but rather a case of our brain remembering it wrong and convincing us that it is fact.
Every last memory we have is false. Our brains only approximate reality, and only so much as we need to survive long enough to procreate. That's how evolution works.
Literally the first lesson in any science class: Don't trust your own experience. Your memories are way less accurate than you think they are. Memory is a vague impression that your brain has some knowledge of and works out the rest on the fly. Once a mind worm is planted, there is no way to remove it. I'm certain that Donald Trump absolutely remembers Muslims celebrating on 9/11, I'm also certain that it never happened.
Or, the effect could be indicative of something rather interesting. The quantum eraser experiment suggests that information can be retroactively erased and replaced.