Are you living in an alternate reality? Welcome to the wacky world of the 'Mandela Effect'

It wasn’t one of those casual misconceptions that we all have that a certain person must be dead simply because we haven’t heard about them for years. Broome vividly recalled the media coverage of Mandela’s funeral and subsequent riots. And that was in 2010, when he was still alive, so it wasn’t that she remembered footage from 2013 and had simply mixed up the dates.

When Broome started mandelaeffect.com, she quickly discovered that there were groups of people who remembered other periods of history differently, such as insisting that the protester who defied the tanks in Tiananmen Square in 1989 was run over by them. Some claim they were taught that in school.

According to the theory, such memories are accounted for by something such as a time traveller (or, to blame those meddling scientists, a quantum ripple created by CERN’s Large Hedron Collider) changing history and creating sci-fi-style alternate realities. Moreover, that some of us have moved between those realities, hence remembering things that have been written out of our current timeline.

It sounds far-fetched, but it’s the claimed changes to small details, such as the spelling of well-remembered brand names and the subtle "altering" of familiar logos that has convinced believers history has been tampered with during our lifetimes.

Take a look at the Ford badge, for example. Do you remember it ever having that unusual little pigtail on the end of the bar that passes through the "F"? Despite the logo being one of the most recognised in the world, many will swear they’ve never seen that little loop before, and moreover that it just doesn’t look right. It’s not an updated logo, however – the loop’s been there since at least 1912, so throughout the entire lifetime of most who claim the bar never had a flourish on the end.

Some alleged examples of the Mandela Effect are easily debunked. If you grew up reciting a line in the Lord’s Prayer as “forgive us our trespasses,” you may be momentarily taken in by a YouTube conspiracy theorist’s claim that such a familiar text has changed overnight to “forgive us our debts.” Check with Wikipedia and – my god! – it is “debts” – how did that happen? Scroll down, though, and you’ll find there have always been different versions favoured by different denominations.

Similarly, there’s nothing wrong with the memories of those who say La-Z-Boy chairs used to be spelt Lay-Z-Boy. Whether misprints or otherwise, plenty of old adverts exist with the Lay-Z-Boy spelling.

The case that most excites believers, however, is that of the Berenstain Bears, a children’s book series that hundreds or even thousands of online commenters remember as the Berenstein Bears. According to Mike Berenstain, whose father Stan created the series, the spelling has always been "stain." And although there are old press clippings with the "stein" spelling – it’s an easy typing error – no misprinted versions of the books have surfaced to explain why so many people would be so convinced their treasured childhood reading once had Berenstein on the cover.

False memory experts explain the Mandela Effect as confabulation, where different memories get mixed together to create something that a person comes to believe is true. Berenstain would therefore be remembered as "stein" simply because readers have grown up seeing far more names ending in "stein," such as Einstein.

Psychology, meanwhile, offers a number of reasons why memes like the Mandela Effect can quickly gain a following.

The first is another ME – the Misinformation Effect. If someone tells you the Ford logo looks different to what it did, there’s a natural tendency to believe them if you’ve never looked closely at it before. That effect would be doubled if the theorist began – as they often do – by showing you a photoshopped version and fed you the suggestion that “this is what we all remember the Ford logo to look like, don’t we?”

If the doctored version looks plausible, because you have no firm memory to check it against, it’s a short step to accepting that the real badge is the impostor.

For those who have always misremembered a particular spelling, meanwhile, cognitive dissonance describes the difficulty of accepting evidence that contradicts a deeply held belief. Basically, we’re more likely to trust our fond (if faulty) memories of the Berenstein Bears and believe that Berenstain must be wrong.

Confirmation bias then plays its part: converts to a belief tend to seek out evidence that confirms their belief and disregard evidence to the contrary.

Of course, one reason conspiracy theories catch on may simply be that they’re fun. You don’t have to actually believe in the Mandela Effect to be entertained by the notion of how cool it would be if time travel and alternate universes were real. A hunger for the uncanny has always drawn an audience to science fiction, so why not to YouTube, where countless flat Earth proponents and ufologists are waiting to convince you that their far-fetched stories are true?

Then again, it could be that every Mandela Effect convert was once a sceptic, chuckling at those who believe in alternate universes, until they each had that sudden WTF moment when they came across an example like Looney Toons, which they personally knew with absolute certainly was never, ever Looney Tunes.