The Memory Illusion

by Dr Julia Shaw

  When you stop and think about it, it actually is pretty incredible. How could those people possibly remember any of those things at such a young age?

  Well, they couldn’t.

  Your first memory

  Everyone has an earliest memory – clearly one of our memories must be the oldest. And, barring a belief in past lives, this memory must be of an event that happened within a knowable time frame – some time between now and when our minds first came into existence. But how can we discern whether the earliest memory we think we have is an accurate representation of something that happened?

  When people claim to be able to remember the mobile that hung above their beds when they were a baby, or the hospital room in which they were born, or the warmth they felt inside their mother’s womb, they are recalling what psychologists refer to as impossible memories. 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. And yet many people seem to have such memories anyway, and are often convinced that they are accurate because they can see no other plausible origin for these recollections.

  But actually, it does not take much to think of a few alternative explanations. Is there really no other way we could know what our mobile or crib looked like, or that we got caught in the latch of our crib, or that we had a musical bear? Surely there could be external sources for this information: perhaps old photographs or a parent’s retelling of events. We might even have memories of objects of personal importance because they were still around much later in our lives.

  So we know that at least some of the necessary raw material to build a convincing picture of our earlier childhood can be found elsewhere. When we then place this information into seemingly appropriate contexts, such as a retelling of an early life event, we can unintentionally fill in our memory gaps, and make up details. Our brains piece together information fragments in ways that make sense to us and which can therefore feel like real memories. This is not a conscious decision by the ‘rememberer’, rather something that happens automatically. Two of the main processes during which this occurs are known as confabulation and source confusion.

  As Louis Nahum and his cognitive neuroscience colleagues at the University of Geneva put it, ‘Confabulation denotes the emergence of memories of experiences and events which never took place.’2 This single word describes a complex phenomenon that affects many of our memories, particularly early ones. Of course, in the case of early childhood memories, this definition can fall a bit short: the event may have actually taken place, it is just impossible that our brains were able to store this information at such a young age and present it back to us in a single meaningful memory later on.

  Alternatively, the belief that we have early childhood memories of events like birth may be simply due to misidentifying the sources of information. This is known as source confusion – forgetting the source of information and misattributing it to our own memory or experience. Wanting to remember our lovely childhoods, we may mistake our mother’s stories for our memories. Or we may meld into our personal narratives recollections told to us by our siblings and friends. Or we may mistake our imagination of what our childhood could have been like for a real memory of what it was like. Of course, memory errors can also be due to confabulation and source confusion working in tandem.

  One of the first experiments which demonstrated that we can fiddle with our memories of childhood was conducted by memory scientists Ira Hyman and Joel Pentland at Western Washington University in 1995.3 Their 65 adult participants were told that they were taking part in an experiment investigating how well people could remember early childhood experiences. They were told they would be questioned about a number of events which they had experienced before the age of six, details of which had already been provided by their parents through a questionnaire. Finally, they were told that accuracy of recall was paramount.

  But of course this was no regular childhood memory study. The researchers did not just want to see how well the participants remembered true events – they wanted to see how well they remembered events that had never actually happened. Among the true accounts obtained from the participant’s parents they had hidden a false account they had made up themselves: ‘When you were five you were at the wedding reception of some friends of the family and you were running around with some other kids, when you bumped into the table holding the punchbowl and spilled the punchbowl on the parents of the bride.’ Appropriately, the study is frequently known simply as the ‘spilling the punchbowl’ experiment.

  It is easy to picture this event – it’s both emotional and plausible. We all know what weddings look like in our particular cultures and countries. We all know what a punchbowl looks like, or at least what it might look like. We all know that weddings are generally formal events, so we likely picture the parents of the bride as an older couple dressed up for the occasion. It is easy to picture ourselves running around in this situation at the age of five. And, as it turns out, it is even easier to picture all this if we imagine the event happening for a few minutes.

  Each participant was asked first about two true events which the researchers had learned about from the participants’ parents, and then they were asked about the fake punchbowl incident. After giving participants basic information for each memory, the researchers asked them to try to form a vivid mental image of the event in order to access the memory. They asked them to close their eyes and imagine the event, including trying to picture what the objects, people and locations looked like. The researchers had the participants come back three times, each visit a week apart, and repeat the process.

  What they found will astonish you. Just by repeatedly imagining the event happening, and saying out loud what they were picturing, 25 per cent of participants ended up being classified as having clear false memories of the event. A further 12.5 per cent could elaborate on the information that the experimenters provided, but claimed that they could not remember actually spilling the punch, and were therefore classified as partial rememberers. This means that a large number of people who pictured the event happening thought that it actually did happen after just three short imagination exercises, and that they could remember exactly how it happened. This demonstrates that we can misattribute the source of our childhood memories, thinking that something we imagined actually happened, internalising information that someone suggested to us and spinning it into a part of our personal past. It is an extreme form of confabulation that can be induced by someone else by engaging your imagination.

  As an aside, besides being an amazing researcher who has contributed greatly to our understanding of false memories, Ira Hyman is a complex character, and instantly likeable. While we are talking about him, here is a quick multiple-choice quiz. Complete the sentence: Ira Hyman …

  wrote his first academic publication about the Beatles.

  has danced in a ballet.

  hates pickles.

  All of the above.

  Of course, the answer is ‘all of the above’. And we love him for it.

  Super short-term

  Let’s back up and talk about the neuroscience of memory and exactly why early childhood memories are so prone to distortion in a physiological sense. When scientists talk about memory maturation – how our memories change as we age – they typically talk about changes in short-term memory and long-term memory separately. Short-term memory is a system in the brain that can hold small amounts of information for short periods of time. Really short periods of time – only about 30 seconds or so. For example, when we go to remember a phone number and repeat it to ourselves over and over until we dial it, in what is known as the phonological loop, we are using our short-term memories.

  This system cannot carry much of a memory load. Since a seminal paper published in 1956 by George Miller from Princeton University,4 which also happens to be one of the most
cited psychology papers of all time, the number of items we are said to be able to hold in working memory at once is seven plus or minus two. In other words, depending on our unique memory abilities and our mental state at the time, our capacity can be diminished to only holding five pieces of information or increased to holding nine. This variability is sometimes noticeable: when we get really tired many of us will find our short-term memory seems to all but disappear.

  While Miller’s magic number, seven, has been questioned – according to a 2001 paper by Nelson Cohen from the University of Missouri5 the number of items we are able to hold may really be just four – the same principles remain; we can only keep a few things in short-term memory at any one time, and we can only do so for about 30 seconds.

  A concept that often comes up in discussions of short-term memory is that of ‘working memory’. This term generally refers to a larger theoretical construct that has to do with how we flexibly keep information in mind while we do things like problem-solving – short-term memory is generally considered a type of working memory. Conceptual differences between these terms and the way they are used are often incredibly important for researchers, but for the sake of this discussion, I’m going to use them interchangeably.

  Christian Tamnes and his fellow researchers at the University of Oslo in Norway6 examined the maturation of working memory in people between the ages of 8 and 22. In a paper they published in 2013 they found that changes in specific parts of the brain were related to improvements in working memory. In particular, they showed that maturation of the so-called fronto-parietal network in the brain was responsible for short-term memory development. The research showed that short-term memory is closely related to our ability to use our higher level thinking (frontal lobe) in harmony with our senses and language (parietal lobe), and that this ability improves with age. The more the relationship between these parts of the brain develops, the better we become at keeping items in short-term memory.

  The four major sections of the human brain

  That sounds very neuroscience-heavy, so let me break it down. Our brain is divided into four major sections. The parietal lobe, which sits right at the top of the brain, is responsible for integrating sensory information and language, which is necessary for short-term memory. The frontal lobe is the section that sits at the front of the brain, behind the forehead. This part of the brain is responsible for higher cognitive functions such as thinking, planning and reasoning. The prefrontal cortex, the very front part of the frontal lobe, is assigned particular credit for complex thinking, and is associated with abilities such as planning complex behaviour and decision-making.

  The prefrontal cortex is a part of the brain that used to be severed in some individuals who presented with severe mental illness, in a procedure known as a prefrontal lobotomy. These crude interventions, which were essentially completed by shoving an ice pick through the patient’s eye socket and into the brain, were known to severely affect the patient’s personality and intellect. This was considered justified at the time because it was thought to diminish the symptoms of their illnesses. Perhaps this was the case, but only in the sense that the operation typically made those who underwent it into zombies with virtually no personality whatsoever. Prefrontal lobotomies were conducted on many thousands of patients in the US, the UK, the Nordic countries, Japan, the Soviet Union and Germany, among others. The technique was first reported by Egas Moniz in 1936 – he surprisingly received a Nobel Prize for its discovery7 – but was generally abandoned in 1967, when psychiatrist Walter Freeman killed one of his patients.8

  Who would have guessed we need such a big network to store such a seemingly small amount of information? Of course, as discussed in Chapter 2, in order to perform even small memory tasks we need to be able to do a tremendous number of things at once – we need to be able to perceive many things simultaneously and sort through them, and we need to be able to integrate that information into our existing memory schemas so that we can understand what it is we are seeing or remembering.

  Bringing the discussion back to our early childhood memories, infants and children have been shown to have some short-term memory capability, albeit less than adults, and their memory strategy generally seems to be different – not so much in terms of the basic capacity of short-term memory (although there has been some debate about this over the years) but more in terms of how they approach their environment.

  We’ve already mentioned that short-term memory can hold a certain number of items at any one time. And an item means different things at different times. Let’s take a phone number again. While you could try to remember each number individually, seven-five-three-eight-nine-six-zero, it’s easier for you to chunk the numbers together: seventy-five, thirty-eight, ninety-six, zero. By doing that you have just diminished the number of items from seven to four, making it considerably easier to keep the number in your short-term memory.

  The use of the technical term ‘chunking’ for grouping things together when performing a task was coined by George Miller,9 the same man who brought us the paper on the magical number seven. The word is really referring to our ability to apply higher level cognitive processes (hence the importance of the prefrontal cortex) to what we consider a unit in our environment. By using our amazing ability to connect things, our brains can actively or passively organise information into pieces.

  For example, if I say ‘Starbucks’ to you, you know that I mean a multibillion-dollar behemoth of a corporation that started in Seattle. Or, you know, coffee and free wi-fi. What this means is that you already have a representation of ‘Starbucks’ and what this concept entails in your brain. Thus, in memory processing terms, this counts as one unit of information, rather than the countless different items that you would have to hold in your short-term memory if I just gave you the isolated concepts associated with Starbucks; green, mermaid, coffee, wi-fi, comfy chairs, baristas, venti, grande, tall, latte, muffins, frappuccinos, America, misspelled names on cups … you get the idea.

  The same goes for the rest of our world. The more we can group ideas or concepts together into chunks, the more impressive our working memory becomes. This is one of the abilities that improves as we get older; as we come to have more experience interacting with and interpreting the world around us, we get significantly better at chunking.

  This means that we are better at holding things in working memory in adulthood than in childhood, and we are better in childhood than in infancy, since in our early years we are less able to process stimuli simultaneously, never mind to consolidate them into more permanent memories that can later be accessed in adulthood.

  But what about long-term memory? First of all, while short-term memory is indeed very short-term, I should clarify that long-term memory is not necessarily very long-term. What memory researchers mean by ‘long-term’ is often anything that is kept in the memory for longer than 30 seconds (although, once again, researchers argue about this). However, the term also encompasses memories that we have until we die – including our episodic memories of events and our semantic memories of factual information. And the research on the kinds of long-term episodic memories that last days, years, or even a lifetime has come up with some fascinating results.

  Childhood amnesia

  Early childhood recollection is one of the most researched areas in the world of memory science. Researchers generally agree that the magic age at which we can begin to form memories that last into adulthood is 3.5 years of age, although some, such as Qi Wang of Cornell University,10 argue this figure is likely to depend on the individual and can be anywhere between 2 and 5 years of age.

  Why? Because in addition to necessary brain structures being underdeveloped, before the age of three everything is new, exciting and unfamiliar. We don’t know what is important, and we don’t have the structure – and the language – to make sense of the world, never mind the cognitive resources necessary to process it. Because young children and infants don’t properly understand or
discriminate they don’t have any framework for understanding what they should be trying to remember and what they should be forgetting.

  This results in a lack of the ability to form early childhood memories that last into adulthood, a phenomenon called childhood amnesia (or infantile amnesia). It is a phenomenon we have known about since 1893 when psychologist Caroline Miles first coined the term.11 In her research she found that most people’s earliest memories were between the ages of two and four. Our understanding of what this means and why it is the case has become significantly more refined since then, but her age estimate was pretty spot on. This is particularly amazing since the notion of false memories, inaccurate pseudo-memories of entire events that never happened, was not to be properly researched or understood for another 70-odd years – when researchers like Elizabeth Loftus came around and revolutionised how we think about memory malleability.

  I am not saying that young children do not have memories – they do. Just not memories that generally last into adulthood. From the time we are newborns we can remember simple shapes and colour combinations for up to a day. They are even influenced by the kind of emotion these shapes are paired with; in a 2014 study, Ross Flom and his colleagues in Utah showed five-month-old babies geometric shapes – squares, triangles, circles – at the same time as exposing them to human faces that were either smiling, neutral or angry. This meant that they associated, say, circle with happy, or square with neutral. When tested shortly after exposure, infants were best at remembering the ‘happy’ shapes. The next day, however, they were best able to remember the shapes that were shown alongside a neutral face. How do we test babies’ memories? We measure how long infants look at things. Infants have a preference for new objects, which means that if they remember an object they are going to spend less time looking at it. The results of this study mean that not only can infants remember things for at least a day, which of course counts as long-term memory, but their brains also process and store information about the emotion that was attached to an experience.