The Mandela effect

This is the one where the ordinary explanation is strongest

Every category on this site gets the ordinary explanation checked first. This is the one where it does the most work, and pretending otherwise would be dishonest.

Memory is reconstructive rather than recorded. It fills gaps with what usually happens, it regularises the odd toward the expected, which is exactly how an unusual spelling drifts toward a familiar one, and it is highly suggestible: once a group discusses a memory, their accounts converge on each other rather than on the event. Between them those three mechanisms account for most famous examples, and they are not fringe theories, they are the well-evidenced mainstream of memory research.

What is genuinely less settled is why convergence lands so precisely. Ordinary error predicts people being wrong in scattered directions. A great many of these have people wrong in the same direction, with the same substituted detail. Some of that is the regularising pressure above, and some of it is contamination from having read the claim before recalling it. Separating those two is a measurable question and almost nobody measures it.

What this record could actually contribute

Not another list of examples. Those exist everywhere.

The engine already scores every group of accounts for how independently they are worded, because reports that follow news coverage echo each other and look like corroboration when they are not. Pointed at collective memory, that becomes the useful question: of the people who report a given memory, how many describe it in their own words rather than the phrasing already circulating? A high independence score on a memory would mean something. A low one would mean the internet taught people the memory, and saying so would be a genuine result rather than a debunk.