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
