Countless people have watched the "Star Wars" movies, and most of them will tell you that the bumbling droid named C-3PO is gold all over. But did you know that C-3PO actually has one silver leg? And what's that immortal line Darth Vader uttered in the movie "The Empire Strikes Back": "Luke, I am your father"? Nope, he actually said, "No, I am your father."
Both are widespread examples of what's called the Mandela effect, false memories that are shared among a large population of people – a collective misremembering of sorts. The phrase was coined around 2009 by self-described paranormal consultant Fiona Broome, who used it to explain the phenomenon where many people around the world believed that the South African leader died in prison in the 1980s. In fact he was released in 1990, later served as president of the country and died in 2013 at the age of 95.
Broome's theory is that at all times there are multiple realities of each universe (the multiverse), and that within each universe there are variations of objects, events and people. So, memories of those "incorrect" shared moments are not really false – they are just instances where parallel universes crossed paths for an instant. (The multiverse theory is usually advanced for physics concepts.)
Science has other explanations for how the Mandela effect happens. Much of it boils down to the fact that human memory is notoriously unreliable. In this age of digital technologies, we often equate our brains with computer hard drives, organic storage bins for our experiences. However, our prefrontal cortices, where many memories are stored, don't work with the same precision as a hard drive.
UCLA Ph.D. candidate in neuroscience Caitlin Aamodt says that based on what we know about the brain, we can make inferences about what contributes to the Mandela effect. "Memories are organized in the brain so that similar memories are stored in nearby neurons. When a memory is recalled, those cells are able to change their connections, which allows for the addition of new information," she says via email. "But because 'neurons that fire together wire together,' sometimes false memories can emerge from erroneous connections."
While we might think of recalling memories as solidifying them in our brains, science seems to suggest otherwise. Recalling a memory often triggers other memories in the process, often intertwining various scenarios and people in new ways, a sort of "reconsolidating" of the information in our brains.
Human beings are also vulnerable to the concept of confabulation, an error or misinterpretation regarding a memory without a conscious attempt to mislead. Confabulation occurs when the brain is attempting to fill in the blanks for incomplete memories. The speaker may mix and match similar experiences and information in order to complete the story in his or her mind, complete with details and emotional responses, certain that the tale is true. This kind of behavior happens in people suffering from neurological issues, such as brain damage or Alzheimer's, but healthy individuals confabulate, too.