We argue that memory is imperfect, but perfectly imperfect. The ‘flaws’ are the best and most interesting parts, giving us insight into how—and why—our memory works the way it does. (Location 83)
If remembering the events of your life is like taking a walk down memory lane, then each memory is not a listed building, with a preservation order maintaining it exactly as it was when it was first built. Instead, you might think of Memory Lane as a neighbourhood that is constantly under construction, with individual buildings being built, remodelled, and even razed to the ground. (Location 87)
Rather than wasting precious mental resources on recording the faces of people we have never seen before (and will likely never see again), our memory systems prioritise the faces of those who form part of our social networks and whose actions we need to remember. (Location 153)
Me pasa muchísimo.
decades of research have shown that our memories for events like these are much more fallible than we realise. (Location 161)
We contend that the best way to understand memory performance in daily life is to use methods that mimic real-world circumstances as closely as possible. (Location 171)
Extensive research has clearly demonstrated that memory does not provide a perfect record of our lives. At first blush, this might seem like a bad thing; surely if memory is good for anything it should be to accurately record what we see and do. However, if we stop and think not just about what memory is, but what memory is for, we can begin to see things a little differently. Remember that, just like our bodies, our brains and minds have evolved over hundreds of thousands of years. The principles of evolutionary theory tell us that traits that have survived natural selection over millennia are likely adaptive in some way—that is, they provide some benefit to survival or reproduction. In this context, it is not obvious that a perfect memory is something we would necessarily have evolved. The ability to recall every last piece of information in perfect detail may sound wonderful, but this would be an enormous drain on our limited cognitive resources. Instead, our memories have evolved to allow us to remember the things that are likely to be of value to us in the future, and to forget those that are not. Our memories do not work like computers, perfectly preserving the past. Instead, we reconstruct our memories every time we recall them. The key theme of this book is that this is no accident or failure of evolution, but rather our memories doing exactly what we need them to do. (Location 181)
Throughout the history of psychology, researchers and theorists have looked around at new advances in technology and used them to provide insight into the workings of the mind. (Location 231)
In the nineteenth century, advances in physics and engineering focused on hydraulic systems, like the steam engine and hydroelectric dam, which harnessed energy from steam or water. Sigmund Freud drew inspiration from these innovations to develop his theory of the mind. (Location 232)
In the early twentieth century, the dominant model of psychology was behaviourism, which studied how particular responses could be conditioned to occur in response to a given stimulus—the most famous example of this is Ivan Pavlov’s experiments in which dogs were conditioned to salivate when they heard a bell ring. Here, a particularly influential metaphor was the telephone switchboard. In the telephone system of the 1910s and 1920s, a phone call would come into a central station and be relayed to another location by an operator who physically switched wires from one socket to another. (Location 237)
By the 1960s, technology had moved on, and developments in computing gave rise to a new metaphor for the mind: the brain is like a computer that accepts inputs via our senses, performs some operations on that information, and produces outputs in the form of behaviour. As computer technology has developed, so too have the metaphors, and cognitive scientists often conceive of the mind as software running on the hardware of the brain. (Location 243)
In considering what memory is, however, we should also take some time to think about what memory is for. What functions do our memory systems serve? Why has this particular form of memory survived the pressures of natural selection? We keep these questions in mind throughout this book. (Location 259)
Esta reflexión es fundamenfal extenderla también al psicoanálisis. Framework útil para entender la naturaleza de la memoria y sus deformaciones, similar a las críticas de buzsaky.
The perceptual and attentional capacity of the brain is limited; we only have a certain amount of mental bandwidth available to process the vast quantities of information we encounter in the world. As a result, the majority of the information that we absorb from the world and process in our sensory stores will quickly be lost to us. (Location 284)
Without working memory, everyday life would be impossible. We would not be able to follow a conversation, read a book, or remember why we walked into a room. (Location 297)
Procedural memories are often not easily accessible by our conscious minds, and it can be hard to verbalise the information. (Location 304)
Take a look at the blank keyboard in figure 2.2. What letters do the highlighted keys represent? Where are the keys for the letters ‘I’ and ‘B’? You might find this task surprisingly difficult. Now close your eyes and mime typing your own name in the air or on a tabletop. It might feel a bit like your fingers have a mind of their own—they know exactly where to go to find the correct letters in the correct order, even if you have trouble explicitly saying where those keys are to be found. This will only work if you are a reasonably practised typist, but you can try it with any other skill in which you are proficient. (Location 305)
Buenísimo experimento.
Each neuron is connected with an average of 10,000 other neurons, each of which is connected with thousands more in a vast associative network. (Location 344)
When we take in a new piece of information, that information is encoded in the form of synaptic connections in the hippocampus, a structure deep in the centre of the brain. As the connected hippocampal neurons fire, they produce mental experiences—emotions, visual images, representations of sound and touch—what psychologists call the phenomenology of memory. (Location 350)
Not only can we learn new information, but we can alter and update our response to existing information when circumstances change. Imagine that you have always loved banana milkshakes, but you recently drank one made with sour milk and became violently ill. The smell of bananas, which used to trigger one response (yum!) now produces memories of nausea and a total aversion to anything banana-flavoured (yuck!). The yum-to-yuck transition might seem trivial, but the ability to form new memories and update old ones is critical to everyday life. Losing this ability can therefore have devastating effects on our ability to interact with the world. (Location 367)
Despite its importance, the role of the hippocampus in memory was only really understood in the 1950s, following the now famous case of Henry Molaison—better known in the medical literature by his initials, H.M. (Location 375)
During his life, he worked with a number of psychologists, in particular Brenda Milner and Suzanne Corkin, who used his case to make some important discoveries about memory (Location 390)
Milner observed that, while H.M.’s declarative memory was seriously impaired, his procedural memory was intact. He was unable to form any new episodic memories (like remembering where he went yesterday) and had very limited ability to acquire new semantic information (such as learning who the president was), but he could still perform all the motor skills he had learned before the surgery, such as speaking, writing, and riding a bicycle. He could even learn new procedural tasks, although this took him longer than normal as he could not remember from day to day what he was supposed to be learning, or reflect on his progress thus far. (Location 401)
The second crucial insight from H.M.’s case relates to the specific role of the hippocampus. The fact that H.M. lost the ability to form new memories but did not lose his memories of events from earlier in his life demonstrated that while memories may be formed in the hippocampus, they are not stored there. If they were, they would have been destroyed by the surgery. This means that, at some point, memories must be transferred out of the hippocampus. (Location 410)
The question arises then: How can new and sometimes contradictory memories be stored without destroying old ones? The answer lies in a process called consolidation, whereby memories are ‘locked down’ and transferred from short-term memory stores to long-term memory. (Location 425)
Consolidation happens in two stages. The first stage, synaptic consolidation, occurs within the first few hours after learning, and consists of strengthening the synaptic connections that have just been formed within the hippocampus. The next stage, systems consolidation, happens over a much longer period of days, weeks, or years. During this phase, connections are made between neurons in the hippocampus and neurons in other parts of the brain. Over time, the hippocampal neurons become less and less important in these new associative networks, until the memories eventually become independent of the hippocampus and are distributed throughout the neocortex—the outer layer of ‘grey matter’ that makes up much of the brain. (Location 427)
We prefer to think of memory as a Lego tower. When a memory is first formed, the tower consists of lots of bricks put together in a very specific way. Those pieces are then broken down and stored throughout the brain, only to be put back together again when we try to recall the memory. Thus, each time we remember something, we are not retrieving that memory from storage but are actually reconstructing it. (Location 439)
Memoria como reconstrucción o reimplementación.
Every element of this memory is a brick in the Lego tower. When you retrieve this memory, you are rebuilding the tower, brick by brick. A lot of the time, this process works just fine: you rebuild your tower, and it looks just like it did when you first created it. Sometimes though, there are bricks missing from your tower, or you add in some bricks that were not there the first time around. (Location 457)
Every time we reactivate a memory, the synaptic networks underlying it become plastic again. This means that the associations between neurons in the network are now susceptible to change, and their strength or connectivity may be modified before being reconsolidated and locked down once more. (Location 461)
on a neural level, the pathways between these concepts have been altered, and you may now be more likely to remember Uncle John handing you the plate, as that route has become a bit more established, and overtaken the original memory of Sarah. (Location 469)
Schemas are a sort of mental framework that provide an efficient method for storing and organising information. They play an important role in how we encode memories in the first place, and in how we remember them later. Within the hippocampus, a schema is a network of neurons that are repeatedly activated at the same time, and are thus tightly associated with each other3. Building a new schema from scratch takes a lot of time (much like designing a completely new building). Thus, schemas are usually developed over the course of several years as we gain experience and learn which elements frequently co-occur (e.g., barbecue + sunshine + burgers + Uncle John). Once this schema has been developed, we can rely on it to structure our understanding of new events, much as an architect might use existing blueprints to create a new building that looks like the original. Thus, when we encounter some new information or have a new experience, we don’t need to reinvent the wheel (or design a brand-new tower) by creating a new associative network from scratch. Instead, the new information can be integrated into the existing schema, a much less demanding process. One consequence of this is that schemas influence how we attend to the incoming information, and how the different elements are interpreted and stored. (Location 481)
This passage probably seems fairly incomprehensible to you, and as a result you may have found it hard to remember every detail. Now imagine that the text had the title ‘Washing Clothes’, and read it again. Suddenly, the whole passage makes sense! The references to ‘piles’ and ‘facilities’ are perfectly clear in the context of laundry. This example was first employed by Bransford and Johnson in 1972, who found that people were able to remember twice as many details if they read a version of the story that began with the title ‘Washing Clothes’ (Location 496)
Schemas can also affect the retrieval and reconstruction of a memory. In general, we are much more likely to remember details and events that are consistent with our schemas, and we may sometimes distort our memories to fit. (Location 507)
Take a minute to imagine your life if your brain truly worked like a video camera or a computer, and you remembered everything you’ve ever experienced. (Location 541)
In Price’s case though, her amazing library of memories are not neatly stored away, waiting to be called upon. They are involuntarily triggered by people, places, and objects she encounters in her day-to-day life. This means that her mind is often overrun with memories, tumbling into her consciousness at every opportunity. (Location 561)
Most have called it a gift but I call it a burden. I run my entire life through my head every day and it drives me crazy!!!’ (Location 567)
neuroimaging studies have demonstrated that typical brain activity associated with recalling past episodes is not evident in these individuals. Their memories are functionally different from most of the population in a way that likely overlaps with the condition aphantasia—a lack of visual imagery. (Location 595)
Perhaps the most important function of forgetting is to make us more efficient at remembering important things. (Location 626)
Forgetting allows us to shed memories of mundane experiences that we are unlikely to ever need again. We can conceive of this kind of forgetting as a sort of mental decluttering process. It helps us maintain mental clarity and ensures that the really important things that we do need to remember are not needles in a haystack of humdrum memories. Our brains are expensive organs to run, requiring a constant supply of energy, so our bodies and brains have evolved to be efficient. What would be the purpose in devoting a huge amount of resources to processing and storing unimportant information in great detail? (Location 630)
Forgetting also provides a sort of ‘mental digestion process’, where specific details are lost, but we retain the gist and can therefore more easily identify patterns or commonalities across similar experiences. (Location 636)
Many decades of research have demonstrated that most of us tend to forget the negative aspects of our past more readily than the positive. This ‘positivity bias’ means that positive events are remembered more easily and in greater detail than negative events, thereby improving our overall happiness and satisfaction with our lives. (Location 644)
Imagine how you would feel if, every single morning, you recalled in living colour every humiliating experience you ever had. A healthy forgetting mechanism allows you to go about your day without bowing under the weight of shame and embarrassment—supported by the knowledge that those around you are also likely to have forgotten your mishaps. (Location 660)
Forgetting can help us maintain a stable self-concept by allowing us to quietly discard things we don’t want to think about. (Location 668)
Desalojo.
this study showed that when we feel we have behaved selfishly, we are likely to misremember the extent of our selfishness. (Location 681)
Many studies have shown that participants are less likely to remember negative details, but only when they are presented as relating to themselves8. They have no such trouble recalling negative details about Chris. This tendency is thought to be self-protective, ultimately allowing us to maintain a more positive self-concept. (Location 687)
we forget the majority of our experiences and do not retain a perfect library of the past in our minds. (Location 729)
Our memories did not evolve to act as a perfect record of our lives; they evolved to serve a purpose—to help us live, thrive, and reproduce. Forgetting is an important part of that. (Location 731)
By definition, successful forgetting often goes unnoticed. We are constantly forgetting things—indeed some would argue that remembering is the exception rather than the rule. We cannot retain everything, so we selectively retain most of what matters; and this plays an important role in making us who we are. (Location 735)
it is simply impossible to recall information you did not encode to begin with, and we often overestimate how much of the world around us we actually take in. (Location 782)
This is an example of what psychologists call ‘inattentional blindness’, a failure to detect something that should be clear and obvious because your attention is directed elsewhere. (Location 789)
When the participant reached the next room, however, the ink blot test was swiftly discarded, and instead they were asked if they had noticed anything unusual in the previous room. Earlier, when the researcher stepped behind the divider, she actually swapped places with another researcher (see figure 4.1). Of the 103 participants, 63% detected the change (and were relieved to hear an explanation for the odd person-swapping). This means that more than one-third of participants completely failed to notice the obvious change in the person they were interacting with. This is called change blindness and is a similar phenomenon to inattentional blindness but is focused on an item changing rather than appearing. (Location 811)
We ran our study in two rooms, one that was completely bare and one that was filled with clutter—posters hung all over the divider and objects were piled up on the desk. We found that participants were more likely to suffer change blindness in the more cluttered room than the empty room; that is, only 52% of participants in the cluttered room detected the researcher-swap, while 71% of participants in the bare room detected the swap. Because there was so much visual stimulation in the cluttered room, the participants likely processed the face of the researcher to a lesser extent. (Location 820)
our ability to count the passes made by those in white (the primary task) is dependent on our ability to ignore those dressed in black, as well as any other unrelated objects. That we do not notice the gorilla is not really a problem or a cognitive failure at all. The problem arises from a mismatch of our expectations with the reality of our cognitive skills—we often presume that we attend to more details in the world than we really do. (Location 853)
a schema is a kind of mental framework or scaffolding that we use to make sense of experiences, people, and ideas. Schemas can serve as a shortcut or template for long-term memory, helping us organise information about the world. Schemas can also help us fill in the blanks of our memories. (Location 866)
We tend to impose structure and order on our experiences, according to our preconceived notions of the world. (Location 916)
Schemas are also related to stereotypes we might hold. When we have stereotyped views of individuals based on their sex, race, social class, or any other characteristic, it affects how we remember the individual and their actions. This tendency is apparent in even very young children. In one study, five- and six-year-olds were shown line drawings of male and female actors performing activities that were either consistent with gender stereotypes (e.g., a boy playing with a train) or inconsistent with gender stereotypes (e.g., a girl sawing wood)9. When their memory for these images was tested one week later, they tended to display memory distortion, whereby they would change the sex of the actor in the images depicting gender-inconsistent activities (e.g., stating that a boy was sawing wood). This did not occur with the gender-consistent images. The students were also much more confident in their memory for the pictures that were gender-consistent. (Location 926)
What all these studies show is that our memories are not encoded and recalled in a manner that is isolated from our prior experiences, knowledge, and expectations. We often have an incomplete memory, and we fill in the gaps based on schemas, stereotypes, and information we learn after the fact. (Location 949)
Drawing on what we know about the world to help us interpret and expand our memories is not a mishap; it’s a strategy that is typically very effective. It improves our efficiency and helps us maintain a consistent understanding of the world. If all our memories existed in some kind of mental quarantine, separate from the rest of our knowledge and experiences, it would be like using a slow, inefficient computer program that could only show you one file at a time, never drawing connections or updating incorrect impressions. (Location 953)
Many experimental studies have demonstrated that we are better able to remember a face (the who) than to recognize the circumstances under which we encountered that face (the when). (Location 1031)
These findings clearly have applied consequences. Many experiments have shown that a witness to a crime is much more likely to wrongly identify a person (as the culprit) in a line-up if the witness has previously seen that person in a different line-up. This might happen in the real world if a police officer shows a witness a series of photographs of potential suspects, then follows that up with an in-person line-up where the witness is asked to select the perpetrator. Research has conclusively shown that simply having seen a person in the photo line-up increases the likelihood that they will be chosen from the second line-up, as the sense of familiarity can lead eyewitnesses to erroneously believe they recognise the person from the crime15 (Location 1041)
We usually remember the gist much better than we remember the specifics. Mostly this serves us well, but we must be aware of this limitation when making claims about the accuracy and detail of our memories. (Location 1051)
Most of us are much better at distinguishing between members of our own race than of other races, often reporting that we have trouble distinguishing individual characteristics of those who are not of our own race. This is called the cross-race effect (or own-race bias), and it can play a substantial role in eyewitness identifications. The cross-race effect is a reliable phenomenon that has been observed around the world, across racial groups, in adults and in children as young as three months old. Research has shown that this is not genetic but a product of experience. Studies of children adopted from one culture into another help us understand what is driving this effect. (Location 1083)
Our memories support us as we move through the world and complete necessary tasks. Our memory has not evolved to be a recording device, as this is typically utterly unnecessary and inefficient. We use shortcuts, such as schemas and stereotypes, to fill in the gaps in our incomplete memory. In day-to-day life these efficient mechanisms serve us perfectly well—you may not remember the face of the customer you served this morning, but you most likely don’t need to. On the other hand, we are usually very good at remembering faces that we see repeatedly in our social groups. This is typically of great benefit and, from an evolutionary perspective, very useful in maintaining social bonds and living in a community. Many of the catastrophic consequences of memory distortion arise not because our individual memories are terrible, but because we have unrealistic expectations about how memory works, treating it as a video camera rather than a reconstruction. (Location 1117)
Sobre cómo considerar la función evolutiva de la memoria y el tradeoff con el uso de recursos nos permite entender sus “fallas”.
Memory is a costly process for your brain, requiring much energy and attention to maintain and update. It therefore makes sense that we are set up to optimise on-the-go decision-making, even if that occasionally means blending two sources of information instead of separately quarantining them in our memory stores. (Location 1177)
‘Memory works a little bit more like a Wikipedia page: You can go in there and change it, but so can other people’2. (Location 1190)
Using our metaphor of memory as a Lego tower, Loftus’s leading question inserted a different Lego block into participants’ memories of the event, entirely without their awareness. In similar studies, Loftus found that even a slight modification of the wording of questions, such as changing ‘the’ to ‘a’, could distort witnesses’ memories. For example, asking, ‘Did you see the broken headlight?’ resulted in twice as many participants falsely recalling seeing a broken headlight than those who were asked, ‘Did you see a broken headlight?’4 The use of the definite article (‘the’) provided a hint of sorts to the eyewitnesses, implying that there was indeed a broken headlight, and altering their memory for what they had seen. (Location 1205)