In the hazy cloud that comprises your childhood memories, several scenes may appear as clear as a film unfolding behind your eyes. Like when you learned how to ride a bike or when you forgot a line in your Christmas play. Or your first kiss. For High School student Jonah Lehrer, it was drinking Coca-Cola from those characteristically slender, vintage bottles at his high school football game. However, glass containers were actually banned from his school. So how exactly did this improbable scene etch itself into his autobiography? He saw it in a Coke ad. When your life flashes before your eyes, one would hope it resembles a documentary, rather than being merely ‘based on a true story’.

Memories are the heartwarming souvenirs from that one trip through our childhood that we show off to our friends. They are the stories that help build our identity, the stories we cherish – and the more vivid and detailed, the better. Unfortunately, memories are easily distorted and sometimes even completely fabricated. Encoding a memory is less like taking a video than it is scribbling down bullet points on a notepad, which renders them susceptible to distortions by our biases, emotions, ambiguities and time.

Psychologist Elizabeth Loftus’ work focuses on the reliably unreliable nature of memory. In one study, Loftus demonstrates how easily memories can be altered by simply changing a single word in her question, which led participants to different recollections of the same car accident (e.g. the speed of the vehicle and if there was broken glass). But we don’t just change minor details – we embellish whole scenes. Loftus also misled witnesses of a 1999 terrorist attack in Moscow to believe they had seen wounded animals at the scene, despite there being no animals present. “One recalled an ‘absolutely crazy dog, barking and rushing around police officers’. Two others described ‘a lost parrot in a cage’ and ‘a bleeding cat, lying in the dust’.”

Loftus’ studies demonstrated that even emotionally laden, vividly remembered events were subject to manipulation. In fact, research has shown that confidence ratings are not correlated with the accuracy of recall. Thus, if distorted memories can be vividly remembered as real, entirely falsified memories can be remembered as real too. In another study, researchers Rajagopal and Montgomery demonstrated this by showing individuals an ‘imagery-evoking’ popcorn advertisement and asking them one week later to rate how delicious the popcorn was. Of course, the participants did not try the popcorn, so they wouldn’t know how delicious it is – except for the fact that thought they did. They rated the popcorn similarly in taste to individuals who actually tried the popcorn. Like Jonah, these participants had a ‘false experience effect’, leading researchers to believe that imagining a situation can lead individuals to vividly remember it as real events.

Scientists have yet to pinpoint why exactly this happens but they have made several guesses. Research using fMRI has suggested that areas of the brain relating to perceiving an object and imagining an object overlap. Furthermore, real memories and false memories use near-identical brain mechanisms, which could explain why an imagined event could be remembered as an experienced one.

This harbours major implications for us and the wider community, especially criminal proceedings. Anyone familiar with Netflix’s Making a Murderer would know that in 1985, Penny Beernsten plucked Steven Avery from an eyewitness lineup and subjected the 23-year-old to a 32-year sentence for a crime he did not commit. Avery was exonerated of his crime, 18 years into his sentence, due to new DNA results incriminating Gregory Allen instead. Beernsten later disclosed that she was shown two lineups and Avery was the only person present in both. Perhaps this was what nudged her to choose Avery. Perhaps it was also because her true perpetrator was absent from both lineups. Yet, despite acknowledging her mistake and despite DNA evidence, her response to being shown a photo of Gregory Allen was surprising, stating “I would swear I’ve never seen him before in my life.”

Prosecutors understand that eyewitness testimonies are notoriously unreliable. But can, or should, we completely discard eyewitness testimonies from legal proceedings? Is it justified to ignore eyewitness accounts and reports of childhood abuse on the basis that the victims could have – albeit unintentionally – ‘made it up’? According to Loftus, probably. Other studies also show that trauma can contribute to forgetfulness and further distort memories.

However, we can’t reject the evidence supporting improved recall for emotionally arousing events. It remains unclear how trauma, or conditions such as post-traumatic stress, can affect memories. There is no known method of disentangling enhanced memories due to emotional arousal, from falsified ones due to suppression or memory degradation. The American Psychological Association recognises that the issue of how to disentangle real from false memories is a scientific mystery, and until then, will acknowledge that children who were sexually abused can remember those traumatic events.

The idea that the veracity of our memories, and with it all that we know about our past, could be undermined is not a comforting thought. But our memories don’t always betray us. Only 12.5 per cent of the witnesses of the Moscow terrorist attack bought researchers’ suggestion of dead animals being present and the study also attempted to misinform 9/11 witnesses, none of whom believed there were dead animals nearby. So our memories aren’t entirely bogus. After all, it was an evolutionary tool necessary for our proliferation as a species.

So before you call your family members in a desperate attempt to verify childhood events, take solace in the fact that what we remember may tell us more about ourselves than the memories themselves. According to research, we may be more likely to recall memories that correspond with our self-perception and identity.  The main takeaway is: your memory is a tool, but don’t depend on it. Simply maintain a healthy amount of skepticism and if that doesn’t make you feel better, well… think of a happy memory.