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FORGETTING

Why You Won’t Remember the Contents of This Book—Thereby Retaining the Most Important Information

DON’T BE SCARED. I am going to give you a pop quiz right at the beginning of this book. I want to be certain that you, dear reader, are paying attention. Here goes: What were the first three words on the previous page? Okay, that’s not a very easy question, no worries. But perhaps you can answer this: What were the first three words of the introduction? And if that’s still too hard: What is the title of this book? I’ll bet you can answer that. If you responded by saying, “Scatterbrain,” well, at least you’ve shown the strength of ingrained language patterns.

In any case, isn’t it astounding? You sharpened all of your senses and focused in order to start reading (at least, I hope so). And yet you cannot remember something you read only two or three pages ago, or else are only able to do so after an intensive round of thinking. Sometimes your thoughts wander or sometimes you are concentrating so much on what you are reading that you forget what you had read only moments before. This will happen throughout the book, regardless of how hard I try to make the text as captivating as possible. As an author, I’m naturally happy if the reader can retain every tidbit that I’ve laboriously tapped out on the keyboard. But as a neuroscientist, I am also aware that humans rarely remember what they’ve read. Hardly anyone is going to be able to recall, word for word, the contents of this book by the end. (Although, if that does happen to you, please contact me. Help and the Guinness Book Committee will be on their way.) You should, however, be able to recall the primary message of each chapter. Hopefully. If not, please buy the book again in order to read it from the very beginning, newly cracked open and smelling of fresh ink. That would make me happy, too.

Apparently, the brain is in a permanent state of forgetting. Anyone who has driven a longer stretch in a car knows what I am talking about. You’re driving nonchalantly along the road and then you pause after an hour and ask yourself, “Where am I, actually?”—as though you had somehow switched on a mental autopilot that blocked your memory. Who needs a self-driving Google car when our brains have already mastered the art of autonomous driving? The fact that we don’t recall much about a journey through the landscape may have one of two causes: Firstly, the surrounding terrain may have been exceptionally boring (anyone who has driven through Kansas on the I-70 knows what I mean). Or secondly, the brain decided it should simply delete most of the information from the previous sixty minutes. The latter case is the default setting of our thought organ.

This isn’t such a bad thing when we are driving a car. But there are other situations in which our brains don’t notice a lot. What was last night’s newscast headline? What were you thinking about last night before you went to sleep? Did you really lock the door? Question after question that the brain does not want to answer. What an incredibly slipshod organ! Always forgetting, deleting, and blundering. But why is that? Why doesn’t the brain remember more than it does and why does it seem to wipe out so much information?

Whether it is dealing with banal everyday topics or really important information, the brain discards everything with the same mechanism. In this age of media overkill, we get used to short-term thinking and are constantly bombarded by new information and messages. Articles that we skim but don’t retain. News items that we come across in our smartphone apps but soon forget about. Emails that drown in a flood of messages. Never before in history has it been possible to attain so much new knowledge, and never before has it been so complicated to keep hold of what is truly important. What is going on in our brain when we forget something that we just experienced? And what can we do to not to let the most important bits slip from our memory once again?

A dressing room for memories

FIRSTLY, LET ME reassure you: you shouldn’t worry too much if you were unable to remember what was written two pages ago. It is not your brain’s job to save as much information as possible. Of much more importance is that the brain forgets the right things at the right time, deleting them from consciousness. Memories are not static; they aren’t data bits that can be accessed once the brain has uploaded them. Rather, memories are dynamic and constantly changing. Only in this way is it possible for the brain to generate new knowledge.

In order for this system to continue, your brain has become an expert at throwing things away to keep them from distracting you. The discarded information might be sensory perceptions, as well as memories, new information, or impressions. In order to maintain as flexible and adaptable a recollection as possible, the brain must eliminate as much information as possible. Only that which is very important is allowed to enter our consciousness, ensuring that we may recall it later on.

Although the brain is a very powerful and dynamic organ, possessing in principle the ability to retain much more information than it actually does, it is also quite lazy. This is why it divides up its energies. For this reason, incoming information is not immediately saved in the brain for the long term but is, instead, placed on a trial period.

We know this from our everyday lives, in which we require things to prove their worth before they are allowed to become permanent fixtures in our routines. Imagine, for example, you are in the market for a new pair of jeans. You would never simply grab the first pair you see in the store display window. You would first test them out. So, what do you do? You take the jeans into the dressing room and try them on, paying attention to two factors: Do they fit well? And do they match your style?

The brain essentially does the same thing. Well, okay, not exactly the same thing, since our heads are more complicated than garments. But the principle is similar: before we decide to commit something to long-term memory (that is, available after several hours or days), it has to pass through a trial period. Our intellectual dressing room is the hippocampus, a banana-shaped structure located in the center of the brain between our two cerebral hemispheres. Because the first neuroanatomist to describe this structure believed it resembled a sea horse, he named it the hippocampus (the Latin term for sea horse). I wonder sometimes what drugs my colleague must have been taking because I myself have never seen anything in the shape that resembles a sea horse; it doesn’t even look like a snake or an eel or any other kind of marine animal to me. To me, the supposed sea horse looks much more like a banana-shaped C smack dab in the middle of the brain.

Each half of the brain possesses a hippocampus that helps us save short-term memories. Everything that should be saved in long-term memory is first “tried on” in the hippocampus. Quite like checking whether the jeans fit you well, the brain also decides whether a possible memory goes well with your previous wealth of experience. The corresponding information is therefore stored in the hippocampus, a process lasting for a few seconds (though if you are hit on the head during this critical phase, your short-term memory will also be gone) or a few hours. The hippocampus will retrieve and analyze the information later—at the very latest while you sleep—in order to decide whether the information should be saved long-term. The decisive criterion is how novel the information is. It is only when something truly new happens to us, which promises to benefit us in some way and that clearly stands out as divergent from our previous experiences, that we will “purchase,” or rather, save the information. This transaction costs something too—namely, energy which our neurons must produce in order to adjust their synapses to create a long-term memory. Energy expenditure is the reason why the brain is cautious about remembering. Only the most valuable information is retained; almost everything else is forgotten—even if it’s something we see all the time.

A bite in the apple—right or left?

WHAT SHAPE IS the Apple logo? You probably know right off the bat: a bitten apple, black against a white background. But, is the bite mark on the right or the left side of the apple? Does the apple have any other bulges or concavities?

The Apple logo seems very familiar to us because we see it all the time, but in a study conducted through the University of California in Los Angeles, only one of eighty-five participants was able to correctly draw the logo on the first attempt (these test subjects even lived in the country of Apple’s origins), and less than half of them were able to select the correct logo from a selection of slightly varying logos.¹ It’s no wonder then that it’s so easy for copycats to rip products off. On that topic, a little tip for all you vacationers looking for a good deal at the beach: “Guchi” is not written with a “ch.”

The more often we are confronted with a piece of information, the duller our memory of it becomes. It is not only the Apple logo that we filter out over time. Study participants have also found it nearly impossible to recall the critical locations of fire extinguishers,² the order of characters on a computer keyboard,³ or the exact details of transportation signs.⁴ Do you perhaps know how many people are depicted on a standard pedestrian crosswalk sign? Our brain does not function as a memory machine designed to save details. Instead, it is equipped to forget every last little detail or, to put it another way, to sacrifice to the greater good for the bigger picture.

Active forgetting

SO FAR, SO good. Our intellect filters out reoccurring sensory impressions and sends them into our subconscious. The tiny (and mostly insignificant) details of our memory are sacrificed for the purpose of seeing and recalling the big picture later on. But sometimes one actually does wish to take note of something or other but finds that it has vanished almost immediately from memory—for example, a newspaper article that you just finished reading. You peruse the article only to realize at the end that you have hardly retained any of the information. Or you have just finished watching a daily news program on TV and try to jog your memory about the whole lineup of news stories (which is no easy task, by the way). In these cases, the brain seems to be applying its filter to information that is clearly useful.

Don’t worry. This is not detrimental, rather it points to the brain’s original strength. Because how relevant is it for us, ultimately, to be able to recall all of the little details of our lives? It is much more important for us to be able to recognize larger patterns from the news and the daily bombardment of information to which we often subject ourselves. In order for us to be able to retain valuable pieces of information, our brain has to forget in a manner that is both targeted and controlled.

Can you recall, for example, your very first day of school? You most likely have one or two noteworthy images in your head, such as putting your crayons and pencils into your pencil case or the first time you went into the classroom. But that’s probably the extent of the specifics. Those additional details that are apparently unimportant are actively deleted from your brain the more you go about remembering the situation. The reason for this is that the brain does not consider it valuable to remember all of the details as long as it is able to convey the main message (i.e., your first day of school was great). In fact, studies have shown that the brain actively suppresses regions responsible for insignificant or minor memory content that tend to disturb the main memory.⁵ Over time, the minor details vanish more and more, though this in turn serves to sharpen the most important messages of the past.

Rather than allowing intricate details to dim our memories, the brain also deletes these patterns of activity, sacrificing them to the greater good for a somewhat abbreviated but also sharper memory of the main event. Thus, if you wish to retain a detail-rich memory of the past, your best bet is to recall your memory as infrequently as possible. Of course, you won’t get much out of the memory because you won’t actively be remembering it. But at least you could comfort yourself in knowing that your detail-rich memories have not yet been actively deleted and are still floating around somewhere inside your head.

An intellectual bookmark

AS IMPORTANT AS it is for the brain to forget actively in order to accentuate valuable information, it is equally important that significant information is set aside for later use. Even if you can no longer remember what was in yesterday’s news stories, the informational content has not yet been forgotten. You simply cannot recall it—that is the difference.

What does that mean exactly? When we see or hear something new, we don’t know right away whether it is going to be important later on. Therefore, the brain has to tag the kind of information that may be used later on so that it might more readily recall it in the future. Think of it as an intellectual bookmark of sorts. We do this in our houses or apartments too. Various objects are scattered around, some of them maybe not so valuable or useful at first glance. We could throw them away, but then we consider they might end up being useful at some point . . . so we decide to hang on to them. We collect these objects in boxes and baskets and store them away in the attic. And we don’t even really remember what we have up there (we’ve most likely forgotten). But if a golden opportunity opens up in the future, we can dig out the objects and put them to use.

This is what the memory is like. Of course, our brain doesn’t store everything in intellectual boxes or baskets, but it does use a similar technique to bookmark potentially valuable information for the future. For the short run, however, the information can be deleted from our conscious memory. In order to demonstrate this, a study tested the bookmarking behaviors of participants.⁶ First, they were shown pictures of tools and animals. A few minutes later, the participants were again shown images of either tools or animals, but this time they also received a small electrical shock whenever they looked at the animals. It’s no surprise that it was much easier for these participants to later recall the images of the animals, which had been accompanied by an electrical shock! On the following day, the participants were able to list off several of the animal images which they had seen even before the electric shock had been administered. It was as if the subsequent electrical shocks had helped the test subjects to dig out their earlier memories even more efficiently. How practical! Finally, a scientifically proven method to kick-start the memory: electroshocks at the right moment can work wonders.

But before you run off to the nearest self-defense store to purchase a memory-jogging device—wait! A radical method such as this is only the second-best solution. A much more important piece of advice is this: even when you seem to have forgotten things from your past, your brain is able to dig them out—when they become important. Very little information is actually deleted permanently. Most of it exists in a waiting state. The brain’s supposed weakness (namely, that it quickly blocks out and seems to forget so many things) turns out to be its strength, enabling it to kill two birds with one stone. Firstly, the brain avoids getting bogged down with too much information. And secondly, this enables it at a later time to more flexibly select which information should be remembered. If the brain had to decide immediately which new information, and in which context, should be stored long-term, it would be too sluggish. We are only capable of building up new knowledge when our memories are unstable.

The intellectual tax return

IT SOUNDS LIKE a paradox to claim that the brain is able to produce new knowledge precisely because the brain is so bad at retaining information accurately. The way our memory is organized seems to go against our everyday experience. If we want to organize something in real life, we do it in a particular location. We save our tax documents and receipts in a certain folder, which we place into a cabinet where we can easily find them later on. We put a receipt for a business meal into a folder labeled “Additional Expenses” (if the deal was a good one), and that is how we create order, avoid chaos, and work productively.

The brain is theoretically equipped to do the same thing, to store information in a way that is spick-and-span, orderly and efficient. But it doesn’t. If it did, it might be able to master its forgetfulness, but the brain would thereby lose one of its greatest strengths in the process—namely, its ability to dynamically combine information. If you sort your information too early on, it’s much harder to put things into a different kind of order later down the road. This pinpoints the difference between a brain and a computer. Whereas a computer mindlessly saves information, the brain creatively combines it to make something new.

Thus, if you were to ask your brain to file an intellectual tax return, it would never sort the business meal receipts into detailed folders but would first put them all into a single stack and mark them each in different ways. You could use the business meal receipts to find out a variety of things. You could review whether a certain restaurant was too expensive, what exactly you ate, or what your client enjoyed eating. This manner of flexible organization only works, however, if you do not determine too early on how the information should later be used, allowing you in retrospect to decide what to do with any given piece of information.

The benefit of shaky memories

THE ABOVE MIGHT sound strange but scientific studies have confirmed it.⁷ Test participants were first asked to memorize a list containing words from four different categories (furniture, modes of transportation, vegetables, and animals). Shortly thereafter, they had to learn a typed keyboard combination by heart. Unbeknownst to them, the order of the combination followed the pattern of the word categories (a piece of furniture corresponded to the typed number 1, a mode of transportation with number 2, a vegetable with number 3, and an animal with number 4). The list of words and the keyboard combination both followed the same basic structure, so it was no surprise that the test subjects were able to learn the keyboard combination with remarkable speed, since it matched the word list form they had memorized earlier. What was interesting, however, was that in a follow-up test twelve hours later, the subjects’ ability to type in the correct key combination improved the more they had forgotten the list of words—as though the word scheme had been directly “copied and pasted” onto the scheme of keyboard keys.

You are doubtless already familiar with this scientific hypothesis: the more insecurely we save and store a piece of data, the easier it is to combine it with other things. Every piece of information that has not yet been fixed into our memories finds itself in a strange state. It may interact with other impressions and input and influence the learning process. Of course, because the memory must be unstable and shaky, information may also be more easily lost in this state.

In order to gather new knowledge, we are therefore compelled to forget concrete details. But forgetting details isn’t such a bad thing since, first of all, the enormous mass of corresponding details would eventually overwhelm even the best brain. And second of all, details really aren’t that important. We pick up on patterns, abstract correlations, and the stories behind them—not the little things that often only serve to trip up the brain. In other words: forgetting is a means to an end.

Mental digestion

RECENT RESEARCH HAS shown there is one thing that the brain especially requires to fulfill all of its functions: taking breaks. This is particularly a problem in our modern era, where we are inundated with news headlines, articles, phone calls, and emails. As soon as our brains receive a new piece of information, another piece of information comes along to compete with it. Under such conditions, it’s hard for us to evaluate (and forget) individual memories in order to build up new knowledge.

This is why, at this point, I am going to say: don’t overstrain your brain’s filter—and forgetting—system. Instead, make sure to give it breaks and rest at regular intervals. Because we don’t learn when we think that we are learning. We learn in the pauses between the thinking. Just as athletes don’t improve during their training, but rather in the rest periods between training sessions when they allow their bodies to adapt and heal.

When I read the newspaper over breakfast in the morning, I don’t look up the most recent news stories on my smartphone afterward while I’m on the subway. Instead, I wait. I allow myself to get a little bored. This requires a fair amount of courage, as anyone knows who commutes on the subway and who is not absorbed on their smartphone. You start to feel a bit like a communication relic from the 1990s, locked out of the modern Apple and Android universe. But I know it’s worth receiving pitying glances from fifteen-year-olds who just earned their latest Candy Crush levels on their phones.

I know I won’t be able to remember all of the details I read in my morning newspaper over breakfast. But just as my gastrointestinal tract is digesting my muesli and breaking it down into individual components from which my body will later generate new cells (hopefully a lot of muscles and as few fatty tissues as possible!), my brain is also, in this moment, breaking down the pieces of information from my morning. I can no longer taste the muesli in my stomach any more than the newspaper articles are still present in my mind. But they are having an effect on my brain. And depending on how my day goes, my brain will dig out some or other piece of news from earlier in the day, combine it with the present moment and allow me to brag about my knowledge (which I really enjoy doing). This is only possible if I have taken sufficient informational breaks to allow for mental digestion.

Forgetting in order to retain

NOW YOU KNOW why we (seem to) forget so many things in life. Either they are so homogenous that our brain’s information filters cannot distinguish them, or else they are so important that they first have to float around in an unsorted limbo in our subconsciousness so that they can later resurface to combine more flexibly with other bits of information. Strictly speaking, you don’t actually forget about these things. You simply aren’t able to recall them for the time being. Don’t underestimate the extent to which your brain, without your conscious effort, is able to recognize patterns and relationships in your life. You may not be able to remember a particular conversation with your boss, but your brain retains the really important content for when you might need it later.

All of this is only possible, however, if you don't subject your brain to information overkill and the constant bombardment of new data. If your brain remains in an overloaded state, it wouldn’t be able to pay attention to the contents of new information, but only to how it changes (rings, vibrates, buzzes, or pops up on the screen). Your brain would eventually set its filter threshold so high that very few new pieces of information could be consciously experienced. You can avoid this by taking deliberate breaks and giving your brain some downtime to reflect.

And now: a break!

CAN YOU REMEMBER the first three words from two pages ago? You don’t have to. It’s not important because forgetting details is one of the brain’s methods. Detail forgetting allows the brain to work its magic of recognizing patterns. It’s the same with this chapter. If you are able to remember that it’s not a weakness of the brain to forget something, but rather a clever trick of choosing the most relevant bits out of a jungle of information and later combining them in new ways, you’ve successfully grasped the most important message. The brain is neither a memory machine nor an organizational fanatic that goes around pedantically making sure nothing is forgotten and everything is neatly in its place. No, it’s much more scatterbrained than that, bouncing around from one thought to another. But these leaps of thought are precisely what make us creative and independent.

Even though you are probably going to forget most of the details from the past few pages, please try to hold onto this correlation, which is the most significant one: breaks make it possible for your brain to organize information and to bookmark it for later use. Give yourself the freedom to put down this book for a few minutes. Relax a little and let the information soak in before you continue to read. Because now you know that, even if you can’t remember the chapter, your brain is diligently taking note of its most valuable information for later on.