Our expectation that memory is consistent and reliable is ubiquitous. It is taken for granted in day-to-day interactions and determines countless decisions. We do not acknowledge often enough how unstable our memories are, how susceptible they are to change, and how serious the implications of those changes are when we rely on memory to determine the fates of real human beings. In this way, memory provides a lens through which to view the release of former Ferguson officer Darren Wilson’s testimony of how and why he shot Michael Brown, the deterioration of Rolling Stone’s story, and the popularity of the Serial podcast.

This has been underlined by recent events. The image of Michael Brown being shot with his hands up has become a protest meme. But it's an image in our minds alone: While some (not all) witnesses described the shooting this way, we have no video or photographic evidence. In his grand jury testimony, Wilson did not deny that the gesture happened, but he interpreted it differently: “The only way I can describe it, it looks like a demon, that’s how angry he looked. He comes back towards me again with his hands up.” Wilson also described Brown as “Hulk Hogan” and “like he was almost bulking up to run through the shots.” If Wilson told the truth as he remembers it, then needless to say, he felt threatened when he shot Brown.

But it’s possible that every time Wilson recalled shooting Brown, his memory changed in small ways. He must have known immediately that he would need to explain why he used force on Brown. Whether consciously or not, Wilson might have remembered Brown as more threatening each time he recalled the shooting.

A memory’s potential to change each time it is recalled was discovered by Dr. Karim Nader in 2000, when he argued that “[memory] consolidation is not a one-time event, but instead is reiterated with subsequent activation of the memories.” Since then, Nader and others studying memory and neuroscience have also discovered that false memories can be implanted, and traumatic memories can be erased. While we don’t know how often these tricks of memory can occur in a person’s day-to-day life, we occasionally see them acknowledged in the way personal accounts are framed.