The Memory Illusion: Remembering, Forgetting, and the Science of False Memory

by Julia Shaw

Semantic memory, also called generic memory, refers to the memory of meanings, concepts and facts.

Semantic memory works alongside episodic memory, or autobiographical memory.

Any event, no matter how important, emotional or traumatic it may seem, can be forgotten, misremembered, or even be entirely fictitious.

Research has long established that as adults we cannot accurately retrieve memories from our infancy and early childhood. To put it simply, the brains of babies are not yet physiologically capable of forming and storing long-term memories.

Two of the main processes during which this occurs are known as confabulation and source confusion.

‘Confabulation denotes the emergence of memories of experiences and events which never took place.’

we generally remember things better if we are in the same state during the recall of a memory as during the encoding of it.

Sometimes referred to as the fourth dimension – an extension of our 3D physical reality – time is something that could be considered a primarily internal phenomenon. It is characterised by linearity, sequentiality and change; by growth or destruction. Our subjective perception of time is known as chronesthesia,13 and it is studied by researchers from fields as diverse as neurophysiology, psychology and philosophy. And what all of these scientific disciplines have demonstrated is that, perhaps unsurprisingly, memory is vital for our ability to perceive time. One line of research argues that the way we perceive the passage of time is through our sense of chronology. In other words, we remember the order in which events happened, which then allows us to infer when and for how long an event took place. Obviously to do this, we need to remember what things happened, and in which order. Time is memory; memory is time.

Further, according to Roger’s own research from 1994,16 and the review of the literature by him and his colleagues in 2010, we only think of ourselves as future-time superheroes. When estimating the efficiency of others we are actually comparatively pessimistic, overestimating how long it will take them to complete tasks, and often predicting that they will run into problems that will delay their completion of the task. Researchers in this area have found that this effect applies across different kinds of task estimation, suggesting that our prospective memory abilities as they relate to other people are equally bad in work or personal contexts – we overestimate how much time our friends are going to need to get work done, and how long it will take them to meet us for coffee.

the overwhelming majority of participants engaged in what is referred to as temporal displacement, or ‘telescoping’, which means moving things around in time. We have a tendency to do this. In particular, we often remember things that happened more recently as having happened longer ago than they actually did. Conversely, we often remember things from long ago ‘as if it were yesterday’.

While telescoping is due to a complex interplay of memory biases, one reason we might particularly think that things happened more recently than they actually did (forward telescoping) is because landmark memories are often very accessible. We can recall these important life events easily and with a lot of detail, just like memories of things that happened much more recently. We thus interpret this easy access and high vividness of the memory as indicating that it must have happened fairly recently.

This is a phenomenon called the reminiscence bump, and may help explain ‘the good old days’ and the ‘when I was your age’ comments. The reminiscence bump means that we do not remember all ages in our life equally.

So we seem to retain the most memories of our teens and twenties.

One explanation for the reminiscence bump may be that it is related to our emergence of a real sense of self, which seems to be a largely universal phenomenon. At what age did you form a stable identity? The chances are that if you are a woman, your you-ness first really shone through when you were between 13 and 14, and if you are a man, you probably settled into yourself a bit later, between the ages of 15 and 18. This age range also happens to be the peak of the bump, at least according Steve Janssen’s research team.

the ability to muddle up memories is the by-product of a brain that can change, learn and reason. Occasional memory mistakes are but a small price to pay for that.

This adaptive quality of our brain is called neuronal plasticity, and it is only due to neuronal plasticity that we can have any memories at all.

This leads us to one of today’s most en vogue biochemical theories of memory: retrieval-induced forgetting. This theory states that whenever we remember we also forget.

This is how retrieval, if interrupted, can actually induce forgetting in a number of ways. It makes every event, every time it is recalled, physiologically vulnerable to distortion and forgetting.

In order to contextualise all of this, it is important to emphasise the fundamental principle of memory – association is everything. It is the association between the individual memory fragments in different parts of the brain that

makes what we think of as a whole memory.

Associative activation thus implies that false memories are the downside of being able to form powerful associations. The upside is that these associations allow us to have memories in the first place, along with the ability to creatively rewire ideas to respond to our environment and come up with complex solutions to problems.

Through our brains experimentally combining memories and ideas in novel ways, we get new associations – it is this that forms the foundations for our ability to be creative and artistic, to birth new ideas and solve complex problems. However, this same tendency can also lead to memory illusions when engrams become connected in ways that are inaccurate.

Building on the strong verbatim trace, the individual may

extrapolate and generate a false memory about why they were there.

To summarise, fuzzy trace theory proposes that memory illusions are possible because each of our experiences is stored as multiple fragments, and these fragments can be recombined in ways that never actually happened.

It really is quite amazing that although by the late 1970s researchers essentially considered the existence of photographic or eidetic

memory a myth (except as an incredibly short-lived and rare occurrence in children), the idea is still such a frequent misconception in society today.

On my first day in the first memory class I ever took at university I remember the professor picking up a piece of paper. He waited for the eager class of 150 students to settle down, then held up the unfolded sheet of paper and proclaimed: ‘This is what happens in the world around us.’ He then folded the paper in half. ‘This is what you perceive.’ He folded the paper in half again. ‘This is what you pay attention to.’ He folded the paper in half again. ‘This is what you are interested in.’ Another fold. ‘This is what the brain makes into engrams. And this …’ (he folded the paper one final time; it was now a fraction of its original size) ‘is what you are able to access and recall later on.’

attention is a prerequisite for memory formation. Put simply, attention is the glue between reality and memory. If we do not pay attention to a stimulus in our environment, we cannot remember it.

So I hope this chapter has demonstrated that we need some form of attention to be able to create memories, and

that sleep is crucial for the consolidation and strengthening of those memories. I also hope that it has shown that intelligence-enhancing baby videos, sleep learning, and hypnosis or subliminal messaging as ways to influence ourselves or others, are all best considered creative fictions.

The problem is so persistent that in a 2011 article published in Nature, social scientists Dominic Johnson at the University of Edinburgh and James Fowler at the University of California4 argued that ‘Humans exhibit many psychological biases, but one of the most consistent, powerful, and widespread is overconfidence.’

explanation: our memory is selfish. We are less likely to remember something done by someone else than something we did ourselves.

Besides the superiority illusion, we also suffer from survivorship bias. This is an error whereby we tend to focus on successes and overlook failures, literally focusing on people or things that survived a process.

They found that liberals and conservatives both claimed to know the other side better than the other side knew them, as did those on either side of the abortion debate. Asymmetric insight helps explain why in arguments and debates we may believe that the other side will never understand our point of view. We may also think we perfectly understand their point of view, perhaps also bolstered by the superiority illusion that we are smarter and more informed than our opponents.

So, we are already bad at estimating how much we will remember in the near future, and seem to be even worse at estimating how much we will remember in the distant future.

It turns out that our ability to recognise faces is actually the responsibility of a specific part of the brain, which has been named the fusiform face area. It is located approximately above your ears, relatively close to the surface of your brain.

‘Photo-ID is widely used in security settings, despite research showing that viewers find it very difficult to match unfamiliar faces. Here we … ask officers to compare photos to live ID-card bearers, and observe high error rates, including 14 per cent false acceptance of fraudulent photos.’

In other words, we remember new faces in relation to our database of faces that we already have: How similar is this new face to old faces?

This so-called exemplar-based model of remembering faces means that our existing memory bank matters. It allows us to optimise the way we analyse faces, minimising the time and effort we must invest in learning a new face.

So, while eyewitness identification is at the core of most legal trials, research shows that there are fundamental memory characteristics that make any such identification a whirlwind of possible errors. In such cases, independent pieces of corroborating evidence are needed if we are to feel at all confident that an identification is correct. The Dutch have a great saying that applies here: one witness is no witness.

There is a tendency when a crime has been committed, especially a particularly horrific one, to assume guilt of an accused party. While of course it would be terrible for someone guilty of a terrible crime to go unpunished, it is surely equally terrible to end up punishing the innocent as a result of poor practice or inadequate understanding.

To me, high confidence is often instead a warning sign. WARNING, this person may not fully appreciate their biases. WARNING, this person may not be aware of memory illusions and shortcomings. WARNING this memory is too good to be true. I approach high levels of confidence with high levels of caution because if it is overconfidence, it can be incredibly destructive.

be left if a seal were stamped on running water.’ This view assumes that our memories of traumatic events are thus stored as fragmented images, emotions and sensations without a coherent structure. A soldier might remember the smell of the battlefield, the sound of gunshots and the taste of blood, but not remember any particular events. Proponents of the traumatic memory argument claim this is why PTSD sufferers sometimes experience powerful flashbacks – they are remembering little fragments of traumatic memories rather than whole events.

It is also unlikely that there is such a thing as repression, hiding emotional memories from direct access, but we will get back to that in a later chapter.

Regarding trauma memories, there is also potential for the integration of grossly false information about events that we have, or think we have, experienced ourselves. Even our highly emotional memories can be totally false. How do I know this? Because it’s part of my job as a researcher to show that even our most vivid memories may be up to no good.

We would expect that the more often we verbally rehearse and reinforce the appearance of a face, the better we should retain the image of it in our memory. However, it seems that the opposite is true. The researchers found that those who wrote down the description of the perpetrator’s face actually performed significantly worse at identifying the correct person out of the line-up than those who did not.

Putting pictures into words always makes our memories for those pictures worse.

It seems that whenever something is difficult to put into words, verbalisation of it generally diminishes performance. Try to describe a colour, taste or music, and you make your memory of it worse.

This does not mean that verbalising is always a bad idea. Schooler’s research also shows21 that verbalising our memories