How Much Can You Trust Your Own Memory?

How Much Can You Trust Your Own Memory?

When reality is stripped back to basics, the only thing we can truly be sure of is our own mind. Right? The human brain can hold an estimated 2.5 petabytes of information, which is the equivalent of one million gigabytes. With so much storage space, you might assume that everything would run smoothly, without any errors – but you’d be wrong.

Despite the brain’s incredible capacity, relying solely on your memory – as in your recollections of past experiences, situations, conversations or anything else – can often prove a mistake. Memories are fickle and fragile things, and one person’s account of an event is rarely any more valid than another person’s remembrance of the same thing.

Arguing with one of your friends about something that happened a few years ago won’t really get you any closer to the truth, though… unless one of you happens to have a detailed and incorruptible record; like video footage – but the human race hasn’t quite yet installed itself with round-the-clock surveillance cameras as standard. Or perhaps you, or your friend, can boast a photographic memory. But even then, photographic memories aren’t usually taken as gospel, because true, 100% reliable memories have never been conclusively proven.

What makes our memories so unreliable is a neurological phenomenon known as distortion. When we remember something, we’re not actually remembering that event, we’re remembering the memory. Every time we recall this memory it changes – either subtly or significantly – and therefore becomes less and less accurate as it distorts. It’s like when you use an appliance so much that it eventually breaks. Unfortunately, this means that our favorite memories – those which have been ‘replayed’ over and over – are actually often the most inaccurate. Beloved childhood moments as we see them in our mind could (quite disappointingly) be a far cry from the mundane reality in which they originally played out. Or worse, the times we’re remembering may not have existed to begin with.

As well as the sheer act of remembering something, there are other factors in our lives which affect our recollections. For example, sleep deprivation. Studies have found that people who get less sleep will struggle to remember things correctly. One notable experiment, published in “Psychological Science”, revolved around getting participants to read an article about the September 11th attacks. The article said that video footage existed of the plane crash in Pennsylvania, but in fact no such footage was ever captured. However, the following day, when the sleep deprived people were interviewed, many claimed to have seen the non-existent footage.

It’s a pretty significant error, based on just one line of information in an article and only one bad night wherein they slept for less than five hours. Contrast it alongside our everyday, ‘real’ memories, and it becomes more and more believable that the various things we tell ourselves could have very little basis in fact.

Besides distortion, the other big issue for memory validity is forgetting things altogether. Forgetfulness is a huge shortcoming in humanity as a species. We constantly need to set reminders or write things down so that we remain aware of everything we have to do, have done, or even are currently doing.

Of course, the main issue with forgetting things is that we don’t know we’ve forgotten them. We often have absolutely no idea that there’s any lapse in our mind at all; it’s not like we’re knowingly faced with a big, blank space in our past. It’s a blind-spot that we’re utterly oblivious to, which leaves us over-confident that the version of events we do remember is without question the right one.

Memory and its many problems have been the subject of more psychological studies than most other neurological features, mainly because of the important role our memories play in law, order and criminal convictions. Witness statements are the crux of many court proceedings, with witnesses made to swear not to lie. But, given that memory is easily manipulated, even ‘the truth, the whole truth, and nothing but the truth’ could be incorrect.

Famed psychologist Dr Elizabeth Loftus, whose work on false memories has inspired much of modern memory research, has also highlighted the problem. She says that there have been hundreds of cases of innocent people who were convicted based on eyewitness testimony, but later exonerated thanks to improved DNA testing. Similarly, forensic psychologist Scott Fraser has also cited the wrongful imprisonment of Francisco Carrillo for a drive-by shooting, as evidence of why eyewitnesses sometimes get it wrong.

Some studies have shown that often, and especially with eyewitness testimony, inaccuracies come about partly because of the circumstances in which the information was gathered. In the midst of an active crime scene, for example, your thoughts and reactions could be quicker and more frantic than usual – which could inspire an especially reliable account, or otherwise an especially unreliable one.

Suggestive questioning could be another reason for sketchy recollections in the courtroom, or under police investigation – with interviewers creating a false narrative, and essentially implanting false memories into the minds of interviewees. Elizabeth Loftus has again proven a pioneer here, with various studies showing that the words, body language and sentence types used when recalling the past can influence how anything is remembered. And then there’s the question of perspective, as in where you were when you saw, heard or sensed in any way that something was happening. No two people can ever experience anything in exactly the same way, so problems arise there, too.

While all of these issues seem especially relevant within the legal system, they influence our everyday memories just as much. While one person may place themselves at the centre of a memory, another may recall it as though watching from afar. Recollections of moments that you found especially funny might feel vivid, because of the emotions they evoke; but if someone else was unamused or bored, they might not recall it with such affection – meaning their memory of it could actually be more reliable. Loftus’ work on leading questions also proves that memory faults can happen over pretty much anything – with her experiments including the fooling of multiple subjects into fabricating a memory about getting lost at the shopping mall, as well as memories involving them having a bad experience with certain foods or even witnessing a demonic possession.

Dr. Loftus’s career hasn’t been completely free of memory-related controversy, though. More recently, she’s investigated the relatively modern phenomenon of repressed memories. She looked into cases where, after psychotherapy, people regain memories that they had previously lost – often of extreme trauma or abuse. But, Loftus has at times questioned the validity of these cases – leading to widespread criticism, and suggestions that even therapists can influence incorrect memories in their patients. If nothing else, it shows how delicately poised our powers of recollection are.

Ultimately, what really happened and what we remember happening are two separate things. And while they seem to match up most of the time, it can be difficult to separate fact from fiction – especially as you’re usually unaware whenever fiction has infiltrated fact. The more we replay cherished memories, the more nostalgic and rose-tinted they can become. The more we dwell on past mistakes, the bigger and more destructive they can seem. It’s accuracy suffering in the face of fondness, or fear. Throw into the mix that memory can be manipulated by anyone we share it with, either purposefully or accidentally, and the potential for problems widens even further still. All of this isn’t to say that you can’t trust your own memories, but keep in mind that not everything you remember will always be 100% true!