Thank you to brilliant dot org for supporting
PBS Digital Studios. Sherlock Holmes, the legendary detective,
had a theory that the brain is like an attic where a person can only store a limited amount
of memories. Dr. Watson once told him that the Earth travels
around the sun, duh, to which Holmes replied, âNow that I do know it I shall do my best
to forget it.â Holmes figured, clutter your attic with random
facts and trivia, and you wonât have room for the things that matter, like identifying
the tiny differences between lethal poisons. Was Holmes right? Is our memory limited, like the storage capacity
of a computer? Or is our memory unlimited? And if we did have perfect memory, what would
life be like if you never forgot anything? [OPEN] The animated film Inside Out depicted memories
as glowing spheres stacked in the brain, like books in a library. But the reality is a little more complicated. There is no one place in the brain that serves
as our memory bank. Instead, individual memories are scattered
all over the brain. Many brain cells, in several different regions,
work together to make one memory. For example, a memory of eating grandmaâs
apple pie might involve some brain cells to help you remember what the pie looked like,
others to remember the smell of the cinnamon, and even cells to remember the delicious taste
â just to name a few. In reality, though, a memory isnât a physical
thing that we can find in any given brain cell. Itâs an action, not an object. Think of baseball fans doing âthe waveâ:
no single fan IS the wave, the magic only happens when all the fans are together, doing
their thing in a specific order. In the same way, a memory only happens when
many connected neurons fire in a specific pattern. And because the same cells can fire in many
unique patterns, one group of neurons can encode multiple memories. This increases the memory storage capacity
of the brain. Buried deep in the middle of the brain we
find a group of cells shaped like a seahorse, which is why 18th century scientists named
this bit the âhippocampus.â Without your seahorse, you might never remember. We owe a lot of our understanding of memories
to one famous patient, known for years only by his initials, H.M. In 1953, H.M. underwent a surgery for epilepsy
which demolished most of his hippocampus, and for the rest of his life, he exhibited
a severe type of amnesia where he was unable to form new memories of facts or events, but,
he was still able to remember things he had learned before the surgery. This showed us that the hippocampus is a key
to making memories, but that it isnât where memories are stored. So how do experiences become memories? If we look inside the brain of a mouse in
a maze, we could draw a kind of map, showing which brain cells
are active as the mouse experiences something [mouse in maze]. Later, we would see
the mouse's brain cells firing in the same patterns, replaying the experience in fast
forward, over and over, backwards and forwards, to make the connections
between cells stronger. This is called consolidation, and itâs how
animals - including humans - commit new memories to long-term storage. Days or weeks later, a smell might trigger
this same pattern of cells nerve firing in the mouse brain, a recall of the maze memories
- just like smelling cinnamon might trigger memories of grandma for you. But the brainâs way of creating memories
isnât foolproof. Sometimes, our mental replay of something
we only imagined can feel as vivid as a real experience. If you picture all the sights, smells, and
sounds of a crime scene from someoneâs description, you activate similar brain networks as if
you had really been there. The more you replay the scene in your mind,
the more it feels like a real memory. Thatâs why a detective who asks leading
questions can inadvertently plant a false memory in a witness. Weâre able to remember a lot, but we forget
even more. Some forgetting just happens, but our brains
also forget on purpose. We have at least three different ways of forgetting. The first is what happens when a memory fades
over time, so-called âpassive oblivescenceâ (a term you will probably forget). This may happen because the connections between
brain cells gradually weaken over time; or perhaps the memory is still there, but you
might lose the triggersâsights, sounds, smellsâyou need to retrieve it. Another idea says memories could theoretically
last forever, but when the same neurons get used in other memories, this âinterferenceâ
disrupts the original memory. This slow fade type of forgetting happens
to all of us, eventually. A second type of forgettingâtargeted forgettingâhappens
at night while we sleep. This is when we clear out random, useless
tidbits of information weâve learned during the day and erase outdated memories. For example, if yesterday, you thought Earth
was, say, a flat disk supported by three elephants, and today you learned that the Earth is round,
your brain needs to purge one of these contradictory ideas - hopefully, the one about the elephants. In certain stages of sleep, we trim and prune
connections between cells and erase unneeded memory circuits. The third type of forgetting is motivated
forgetting, something we all wish we could do for one thing or another. This is when a person intentionally suppresses
unpleasant memories. Forgetting on purpose is a way to regulate
our emotions and to focus on what needs to be done in the present, instead of getting
lost in negative memories of the past. We may need motivated forgetting to maintain
our self-image, to maintain confidence, to stay optimistic about the future, or to be
able to maintain relationships with people who have hurt us. We donât know exactly how motivated forgetting
happens, but part of our brain seems to step in and block the troubling memory from being
retrieved. So that even though itâs still somewhere
in our brain, eventually we canât find it. Our brains have so many ways to forget because
forgetting is one of the most important things we do. Forgetting allows us to move past traumatic
life events. In fact, PTSD may be a problem where someone
simply remembers too much. Forgetting also allows us to clear out junk. Imagine every sight, sound, smell, and piece
of information your brain processes every day! If our brains didnât sweep out the garbage
every night, we would soon overflow our neural networks with random useless trivia, just
like Sherlock Holmes predicted. We also wouldnât be able to replace things
that are no longer true with better information and update our mental models of the world. Deep in the scientific literature we find
stories of a handful of people who NEVER forget anything. They are so rare that their unforgetfulness
has a medical name: hyperthymesia. The most famous case is Jill Price, an American
woman now in her fifties. Starting from age 14, Jillâs memory of her
life is nearly perfect. For any date in the past, she remembers what
she wore and had for lunch that day, key historical events that she paid attention to, and detailed
incidents from her life. She describes memories playing in her mind
in vivid detail like a video reel that has been enhanced with smells and emotions, whether
the events occurred yesterday or decades ago. This might sound like a blessing, especially
if youâre in school, but Jill has described being haunted by upsetting memories and by
regrets, because unlike the rest of us, she can clearly remember every choice she made
and how it turned out. Thereâs probably something you truly *want*
to forget, like that extremely embarrassing moment in high school that always seems to
pop up at the worst times. Can we erase those unwanted memories somehow? In an episode of House, MD, Dr. House treated
a patient suffering from painful memories by performing something called electroconvulsive
therapy: controlled electric shocks to the brain. People who undergo ECT do lose some memories
â only not necessarily the ones they hope. When it comes to erasing memories in humans,
our best tool still works like a hammer, not a scalpel. Itâs no accident that our ability to forget,
like our ability to remember, is a complex and finely-tuned mechanism. If humans couldnât remember and learn from
important events, our species probably wouldnât have survived. But it seems that being able to forget is
just as critical, an elementary part of solving this great mystery we call life. Stay curious! So you probably canât teach yourself to
have perfect memory, and never forget anything. Not without a massive brain injury or something. But is memorization really the best way to
learn something? Memorizing can definitely help you get started
with a new concept. However, truly understanding it requires much
more - seeing how concepts are related to each other, looking for different interpretations,
dealing with new information. These are the skills that will help you learn
anything, and if youâd like to sharpen your brain and develop these tools, then Brilliant
could be the place to go for that. Check out this Brilliant course on logic and
deduction [screen recording] Itâs got fun and challenging riddles and
mind-benders, broken up into bite size pieces, and theyâll guide you through the problems
until youâre a Sherlock Holmes-level logical thinker⌠To support Itâs Okay To Be Smart and learn
more about Brilliant, go to brilliant dot org slash BESMART and sign up for free. And also, the first 200 people that go to
that link will get 20% off the annual Premium subscription.
I did not expect a Hellraiser reference.
AAAA fuck off with that style of presentation and mannerisms you wannabe