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

by Julia Shaw

Picking up the memory-braincam analogy from earlier, in the 21st century digital photos, like our memories, can be quite easily shared and edited by ourselves and others. Even if photographic memory were to exist – and it seems doubtful that it truly does – it appears that memory Photoshop would exist right beside it. Along with advances in actual photography, our memory-photo analogy may need a similar upgrade. We no longer use Polaroid cameras, and we should no longer be calling memories photographic, at least not in a way that implies perfection and permanence.

In a review of the science on this topic, neuroscientist Dorit Shalom from Ben Gurion University in Israel proposed in 200922 that in autism there is damage to part of the brain most often associated with episodic remembering of personal events, the limbic-prefrontal system, but other types of memory remain spared. This means that people with autism are going to more generally have worse memories of their own lives. This is different from what we would usually classify as amnesia, as it is not a complete lack of ability to form these memories, just a deficit.

It seems that the memories of savants are essentially the reverse of the memories of HSAMs. While HSAMs have incredibly enhanced memory of their own lives, but do not display any particular excellence in other kinds of memory, savants appear to lack autobiographical memory, but have an incredible memory for non-autobiographical things – facts and information. The memories of HSAMs are almost exclusively personal, while the memories of savants are almost exclusively impersonal.

As the researchers put it, ‘These findings indicate that, although forgetting can be frustrating, memory might be adaptive because forgetting confers neural processing benefits.’ We become more efficient rememberers if we filter out the less relevant information. It allows us to become better at remembering the important stuff in life.

PTSD sufferers showed an increased deficit in the inhibitory processes associated with memory compared to the rest of us; that is, they were less efficient rememberers because their brains were bogged down with parts of their past they were unable to forget. Causally, it is difficult to say whether these individuals had PTSD in the first place because they were already worse at forgetting things, or whether experiencing a trauma rewired their brains.

And when talking about attention in babies we often refer to just one thing – how long a baby looks at something, known by researchers as attentional gaze. As we know from our own lives, simply looking at something for a period of time by no means guarantees that we are giving it our full attention; we also need to be internally focused on the information that we want to encode and remember, we need to recognise patterns, and we need to be able to filter out all the other unimportant information that we may be taking in at the same time.

results. Live presentations of language, and of tasks, have been shown to be far more effective for developing babies’ memories than any kind of media simulation.

in 2011 the American Academy of Pediatrics (AAP)5 clearly said that children under two should have no screen time at all, meaning no iPads, iPhones, laptops or TVs. Instead, parents should use play and live interaction if they want to give their babies the best possible developmental help. This may be bad news for the 90 per cent of parents who let their babies regularly interact with screens, and in practical terms may not be possible, but an effort can be made to limit screen exposure as much as possible.

Paying attention to something requires you to be blind to the overwhelming majority of the information you are receiving from both your external and internal environment.

Change blindness is a function of two bottlenecked processes, processes that need to filter a great deal of information and can only do so much at once. The first is our limited ability to perceive the world through our senses. The second is our limited short-term memory capacity. As mentioned in Chapter 1, our short-term memory really is super-short-term, lasting only about 30 seconds, and has a very limited capacity. That means that when we experience a complex scene we cannot possibly remember all of the details in it.

So it seems that our facility for paying attention overwhelmingly works to make us notice only a small amount of information so that we have a chance of actually processing it, and, in certain situations, remembering it for the future. Memory feeds into attention to tell it what ‘important’ information is, based on past experience, and attention feeds back into memory to update our internal representations of the world.

day. In particular they claim that something called ‘active system consolidation theory’ can help us understand the association between memory and sleep. This theory suggests that during a type of sleep called slow wave sleep, the memories that we just formed while we were awake are strengthened. This, they argue, is how sleep helps to consolidate memories: by repeating the connections between neurons, and replaying our experiences, which makes some of our memories last.

Glutamate is the most common neurotransmitter in the brain, and works to open up some of the main channels of communication between cells. These channels allow calcium to flow into cells, which activates them and allows the chemical encoding of engrams, enabling us to generate and access the networks of information required for complex memories. Thus, our brains release glutamate as part of the chemical process that underlies memory formation. This glutamate mainly remains in the brain until it is processed and drained when we sleep. But while we need glutamate to make memories, too much of it is bad for us. An excess of it can cause excitotoxicity, in which brain cells are damaged and killed due to an overactivation of glutamate receptors causing an excess build-up of calcium.

Can we actually learn new complex information, or significantly reinforce memories, while we sleep, as the subliminal learning advocates suggest? The answer is a definitive no. There is no evidence that we can learn words or facts, or benefit from any sort of personality-pumping propaganda, while we sleep – not even when information is delivered in the convenient form of an iPhone app. As Madalina Sucala and her research team reported in 2013, ‘technology has raced ahead of the supporting science’. The only people who get rich from ‘sleep your way to success’ subliminal learning recordings are the people selling them.

there is a set of guidelines for hypnosis research laid out by scientists Peter Sheehan and Campbell Perry, the earliest version dating back to 1976.23 It states that ‘no behaviour following hypnotic induction can be attributed to hypnosis unless the investigator first knows that the response in question is not likely to occur outside of hypnosis in the normal waking state’. In other words, we need to make sure that the effects we see from hypnosis are due to the technique itself, and cannot be due to influences that happen in normal everyday life.

It’s a circular argument that makes it impossible to argue whether hypnosis makes people respond to suggestion, or whether suggestibility makes people respond to hypnosis. People who are hypnotisable, the report goes on to explain, are highly likely to follow suggestions made by another person regardless of whether or not they are actually ‘hypnotised’. This is problematic as it takes us back to your chicken-dancing friend, who may indeed dance like a chicken regardless, making it impossible to study hypnosis independently.

While this is how the test interprets such a response, other psychologists may just call this type of reaction a form of suggestibility or compliance, as both of these have to do with a person’s willingness to follow instructions. Or, as the hypnosis researcher Graham Wagstaff28 put it, ‘there is a strong case for arguing that much of the special status that has been awarded to hypnosis may have resulted from a failure to consider the power of social pressures and the normal capacities of ordinary human beings’.

People who are hypnotised are paying attention to what the hypnotist is saying; they are choosing to be hypnotised and to engage in the resulting behaviour. That means their attention is still engaged and functioning, allowing the possibility of behavioural and psychological consequences from stimuli they encounter. And while there is good scientific evidence that hypnotism can help with some medical and psychological issues, there is no such evidence to suggest that it has any kind of beneficial effect on memory.

occurrences. In a study as far back as 1962, for example, medical scientist Theodore Barber29 from Boston University found that many of those to whom it is suggested that they are being regressed to their early childhood display childlike behaviour and claim they relive their memories. When examined further, however, the responses given by these ‘regressed’ participants does not match what children would actually do, say, feel or perceive. Barber argues that it may feel to patients as if they are reliving their early years, but in actuality such experiences are creative re-enactments rather than rediscovered memories.

In my personal conception of the term, brainwashing refers to changing a person’s ideology or epistemology – changing their ideas about the world and the knowledge they believe they have of it. In certain kinds of false memory research, including my own, scientists have been able to have a small temporary effect on a person’s view of the world – perhaps, for example, making them think they have committed a crime when they have not.

The Innocence Project2, an organisation dedicated to getting innocent people exonerated through DNA testing, has helped to release at least 337 people who were wrongfully convicted. On average, these people served 14 years in prison for a crime they did not commit. Faulty memory played a role in at least 75 per cent of those cases. Those figures are just for the US, and just for cases in which DNA was available, so around the world there are significantly more people who have been wrongfully imprisoned.

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.’ One reason for this may be the superiority illusion, which suggests that we have a tendency to overestimate our positive qualities and to underestimate our negative traits.

We are less likely to remember something done by someone else than something we did ourselves. This is partly because watching a partner do a chore, or having them report to us that they did it, provides us with a far less rich and complex memory trace than if we had performed the task ourselves because there is simply less sensory input. The memory trace being weaker means that we are probably more likely to forget that it happened in the long run. On the other hand, we will always have stronger and more meaningful memories of those occasions when we have done chores.

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.

the illusion of asymmetric insight. In 2001 Emily Pronin at Stanford University and her colleagues published a paper7 on this bizarre bias, appropriately entitled ‘You don’t know me, but I know you’. Over six studies the team demonstrated that we think we know our close friends and roommates better than they know us.

Pronin and her team found that participants believed that their own quintessential qualities, including their intimate thoughts and feelings, were mostly kept internal but that those of others were more likely to be observable. They were more submerged icebergs, while other people were more visible icebergs. This makes sense from a memory perspective because we have direct access to our own thoughts and feelings and so appreciate that they can be complicated and nuanced – which makes them difficult for other people to understand. On the other hand, it can be difficult or even impossible to appreciate the complexity of the thoughts and feelings of others in anything other than a basic ‘surface’ way – we tend towards assuming that is all that there is to understand. Our general outlook is ‘I’m a riddle, but my friend is an open book.’

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.

Even if we wish to be humble and take pains to avoid overconfidence illusions, we may not be able to – they are largely the by-product of selective memory processes we cannot control.

This kind of research, which has been repeated in many other learning contexts, shows that even though all of us know that we can forget things, we seem to systematically underpredict how much we will forget. To make matters worse, this effect seems to increase as time delays increase – in Kornell’s study ‘The results demonstrated long-term overconfidence: Relatively modest immediate overconfidence transformed into enormous overconfidence as the test delay increased.’

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.

Whatever the underlying reason, this research demonstrated that participants had culturally influenced facial search strategies that could lead them astray when looking at or identifying foreign faces.

David Ross and colleagues at Vanderbilt University,20 the reason we are able to recognise faces at all is because we have these face-learning strategies. Ross suggests that it is because we have a strong set of memories of what faces look like that we are able to identify new faces. More specifically, he suggests that faces are represented in our brains by their similarity to exemplars of previously experienced faces. 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?

we are all defective detectives when it comes to identifying real memories or true accounts of events, be they of crimes or everyday occurrences. We are all vulnerable to the same kinds of memory and confidence illusions. And we need to realise that confidence is not key in these kinds of situations. To me, high confidence is often instead a warning sign.

Most memory researchers since the early 2000s argue that while dissociation may be possible, people usually do not dissociate during emotional events, and that there is no evidence to support a special fracturing process of memory in trauma situations.

Porter and Peace found that the memories of the traumatic events were highly consistent over time, remaining virtually unchanged in almost all features. It also turned out that in comparison to the highly positive life experiences, the memories of negative experiences were significantly more stable over time. These findings suggest, as does Porter and Birt’s research, that memories of trauma are special, just not special in the way that many people assume, indeed often being better than other kinds of memories.

Interestingly, this persistence of memory seems to occur not only with traumatic events we directly experienced ourselves, but also indirectly experienced traumatic events that we have heard about repeatedly through the media.

In other words, people could report more correct details with higher confidence for certain kinds of events, with these events having three main characteristics. First, the event needed to generate a high level of surprise. It could not be a trivial or expected event. Second, the event needed to carry important consequences for the person or for people in general – referred to as having a high level of consequentiality. This can be an important consequence for them personally, or for society.

Depending simply on how the participants were asked about their experiences when they returned to the barracks, the presence or absence of these features in their memories underwent marked changes.

In these kinds of situations we are transferring information that was originally encoded visually (or indeed through other senses) into verbal information. We are turning sensory inputs into words. But this process is not flawless; every time we take images, sounds or smells and verbalise them we potentially alter or lose information. There is a limit to the amount of detail we are able to communicate through language, so we have to cut corners. We simplify. This is a process known as verbal overshadowing, a term coined by psychological scientist Jonathan Schooler.

By rehearsing only details that could be readily put into words, the participants had de-emphasised the nuances of their original visual memory, making it harder to access. This effect is incredibly robust, as indicated by quite possibly the biggest replication effort of all time in psychology.19 This was a massive collaborative effort by almost 100 scholars and 33 labs, including Jonathan Schooler and Daniel Simons, and published in 2014. All researchers followed the same protocol, and they found that even when the experiment was conducted by different researchers, in different countries, and with different participants, the verbal overshadowing effect was constant. Putting pictures into words always makes our memories for those pictures worse.

According to Schooler,20 besides losing nuances, verbalising non-verbal things makes us generate competing memories. We put ourselves into a situation where we have both a memory of the time we described the event and a memory of the time we actually experienced the event. This memory of the verbalisation seems to take precedence over our original memory fragment, and we may subsequently remember the verbalisation as the best account of what happened. When faced with an identification task where we need all the original nuances back, such as a photo line-up, it then becomes difficult to think past our verbal description.

Simply seeing photos of completed tasks made it more likely for participants to think that they actually had completed them, even without the researcher making that implication – they thought they had done things simply because they saw photos of them. Seeing a photo made participants about four times more likely to say they had done something they had not done.

It seems that photos can quite severely mislead our memories, especially when coupled with deliberate misinformation. One of the main reasons for this is presumably similar to the cause of verbal overshadowing; when we see a photo we create a new memory of that occasion which can interfere with our memory of actually experiencing (or not experiencing) an event. When we think about the event we may then have trouble distinguishing between our memory of the photo and our actual experience – possibly even entirely replacing a real visual memory with another.

For one thing, group recollection situations like this are the poster child for people’s memories melding into one another’s – for better or worse. Due to verbal overshadowing effects, both our own descriptions and the descriptions of others may now become a permanent part of our memory records. Every new account we hear has the potential to taint and re-taint our memories.

However, by setting up the expectation that everyone who experienced a particular event probably has – or should have – a severe adverse response, critical incident stress debriefing has the potential to adversely homogenise people’s reactions, pushing their memories and responses to be more negative than they naturally would have been.

When we ask people about just how terrible an event must have been, or about how a situation has fundamentally changed them, we are setting up social expectations that they are likely to have a hard time avoiding.

And the consequences are not just limited to diminishing our ability to do the task at hand – they also appear to have an impact on our ability to remember things later. Task-switching also seems to increase stress, diminish people’s ability to manage a work–life balance, and can have negative social consequences.

In their study, Miller and Buschman argue that these brainwaves (or, as they call them, oscillatory brain rhythms) are the key to the communication between the neurons in our brain and our core experience of thinking. They suggest that our brain ‘regulates the flow of neural traffic via rhythmic synchrony between neurons’, meaning that when we have a thought it is because a selection of neurons (which they refer to as an ensemble) are all firing at the same wavelength.

In other words, this may endow ensembles with a critical feature: flexibility in their construction.’ Our brains are able to seamlessly switch from one complex thought to another because neurons can work together by operating on a certain frequency of electrical signal, allowing synchronicity regardless of how they are physically joined together.

In the monkeys the alpha waves helped to quiet down the humming of the brain’s network that was assessing whether a line was vertical or horizontal, so that the brain could hum the line colour identification network instead. This experiment provided hard evidence for the researchers’ hypothesis that these two conflicting tasks had to be switched between and could not be completed at once. As such, we cannot hope to make memories for more than one thought at a time.