Memory: Crash Course Study Skills #3

Memory: Crash Course Study Skills #3

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This episode is supported by
The Great Courses Plus. Hi, I’m Thomas Frank, this is
Crash Course Study Skills, and if you happen to be watching this at whatever
point in the future that we all get neural implants to
let us store our memories on servers in space, what I’m about to tell you is
woefully inaccurate. Also, do we have flying cars yet? For those of you who still rely on that
mushy gray stuff in your cranium to remember
things, though, listen up. Today we’re digging into how your memory
works and how you can make it work better. At least, I think we are. Nick, we’re not filming those makeup tutorials
today, are we? [Theme Music] The science of how memory works is
complicated, to say the least. After all, how do we explain how a bunch of
nerve cells, chemicals, and electrical jolts somehow let you remember algebra, where you
left your car keys, and all the lines to The Dark Knight? Well, it’s simple. We, uh…. rely on Hank
from 3 years ago to do it for us. Seriously, there are two whole episodes of Crash Course Psychology that go through the entire process of how memories are formed and retrieved. But just like Xzibit left to his own devices
in a car dealership, I can’t resist putting
crash courses in your Crash Course. Plus, understanding how your memory works
will help you to optimize the way you study. So let’s do a quick review. Your brain turns information into memories
by putting it through a few different stages. The first is sensory memory, which
processes pretty much everything your senses
detect or experience in the real world. That sensory memory has the attention span
of a five-year-old at the DMV, though, so most of
what it takes in is lost almost immediately. But what does stick moves into your short-term
or working memory. This type of memory is sort of like the
RAM in your computer – the memories don’t
stick around permanently. In fact, unless you continuously rehearse
what’s floating around in working memory, it’ll pull
a disappearing act after about 15-30 seconds. This can also happen if you try to cram too much in at once, because your working memory can really only handle 4-7 bits or items of information at a time. Now you can somewhat increase this limit
by grouping bits into chunks – like splitting “FBIKGBCIA” into
FBI, KGB, CIA, but there’s still a limit. Now, all this happens primarily in your
brain’s prefrontal cortex, but eventually the information has to
make its way to other areas of the brain if it’s
going to be encoded in long-term memory. To greatly simplify things, it’ll first
head to the hippocampus, which augments it
with chemicals called neurotransmitters. Along with many other functions, these transmit
details about the information – metadata, if you will. Eventually, this leads to the formation of new synapses, which are essentially connections between neurons – though the neurons don’t actually touch. Instead, they prefer to keep a small gap between
each other and let more of those neurotransmitters
move information between them. The whole process of memory formation
causes physical changes within your brain: neurotransmitters shuttle all over the place,
neural pathways are forged, and neurons themselves undergo structural improvements using proteins such as brain-derived neurotrophic factor, or BDNF. And, just like the process of strengthening your
muscles through exercise, this all takes time – which is why cramming for a test doesn’t
work, and why you can’t instantly just
download jujitsu into your brain like Neo. As Pierce J. Howard noted in his book The
Owner’s Manual for the Brain: “Work involving higher mental functions, such
as analysis and synthesis, needs to be spaced out
to allow new neural connections to solidify. New learning drives out old learning when
insufficient time intervenes.” Now that you have a bit of an understanding
of how your memory works, one crucial tip
should be clear: you have to space your
learning out over time. But we’re not going to just leave it at that, because – as cognitive scientists have known for a long time – the way you do that spacing matters quite a bit. To explain this, let’s start with why we
forget things in the first place. Part of the reason is that your brain doesn’t
encode all memories equally. During the long-term encoding process, the hippocampus will use different levels of neurotransmitters based on, among other things, how important the information is. And this plays a big role in how strongly it’s embedded in long-term memory. This filtering mechanism is great for survival, as it
allows your brain to safely disregard unimportant things, like what you had for breakfast two weeks ago,
while paying special attention to what’s important,
like that fact that there are ninjas behind you right now. Unfortunately, you can’t always consciously
decide what’s important and what’s not, which is why it can be hard to remember all
the details from that history chapter you just read. At a primal level, your brain just doesn’t think the
details of Genghis Khan’s war with the Quarismian Shah
in 1219 are as important as a bear attacking you. However, there are a few tricks you can pull
to make it care a bit more. First, understand that your brain latches more readily onto things that are tangible, visual, and uncommon than it does with the abstract or the mundane. Because of this, it can be helpful to develop mnemonics, which are mental devices that help you associate pieces of information in ways that are easier to remember. And mnemonics can take many forms. You can create sayings to remember sequences of
letters – such as “Ernie Ate Dynamite, GoodBye Ernie”
to remember the names of the strings on a guitar. Or you can make up weird stories in your
head that includes cues to the information
you’re trying to associate. Like, the way I remember that Helsinki is the capital of Finland is by imagining a giant flaming sinkhole in the ground opening up with a bunch of sharks jumping out of it. Since it’s weird, it’s easy to remember, and
it helps me associate the words Hell, Fin, and Sink,
which in turn connect Finland and Helsinki. Additionally, the more connections that lead
to a memory, the stronger it’ll be – especially
if they’re learned in different contexts. When I first learned about caravels, which were
those small ships that Portuguese explorers used
to travel down the African coast in the 15th century, I had a hard time remembering
that name – caravels. But once I started using them in Civilization
V to build my empire – and to make sure Ghandi never got far enough
to nuke me, the memory became a lot more solid,
since I was interacting with it in a new context. Of course, you still have to repeatedly
access your new memories once they’re
encoded if you want them to stick around. This is pretty much the iron law of memorization: Except in cases where they’re attached to a
particularly intense emotional experience, memories
fade away unless you repeatedly recall them. Well, sort of.
Let’s go to the Thought Bubble. In the 1880’s, a German psychologist named
Herman Ebbinghaus wanted to understand how
memories decayed over time, and he especially wanted to know how
long the process took. He began by running countless tests on his own memory, forcing himself to recall long lists of meaningless letters until eventually, he came up with the Forgetting Curve. While largely hypothetical and simplistic in its details, this model demonstrated how memories decay quickly unless accessed again and again. Since Ebbinghaus’s days, our understanding
of how memory decays has come a long way. According to the Forget-to-Learn theory, which is presented in Benedict Carey’s book How We Learn, memories actually have two different strengths: storage strength and retrieval strength. Picture your brain as a library where none
of the books ever get stolen or damaged. When a new book is put on a shelf, it’s
there for good. This represents storage strength, which, according
to the theory, doesn’t weaken. Once a memory is encoded, the neural pattern
can only get stronger. Now, unfortunately this library has a particularly lazy librarian who doesn’t do a very good job of keeping
the library’s catalog organized. This represents retrieval strength, which
does fade with time. Unless you go in and organize the catalog
– or recall the memory – you’ll eventually
lose track of it. Thanks, Thought Bubble.
Now here’s where it gets good. The more a memory’s retrieval strength has
faded, and the greater the difficulty of recalling it,
the greater the increase in learning will be. This is called the Spacing Effect. It’s essentially the “No pain, no gain,”
of the mental realm; the harder you have to work to recall something,
the greater the reward for doing so. There’s an obvious catch, though – if you wait too
long, the retrieval strength diminishes so much that
you won’t be able to recall the memory at all. This where the Principle of Desirable Difficulty
comes in. To maximize the efficiency of your studying,
you want to the find the point right before
you’re about to forget something. And you can do this by using spaced repetition
techniques. The general idea behind spaced repetition is to
steadily increase the amount of time in between
each study session for any piece of information. So instead of reviewing a fact or concept
once every few days, you’d use a schedule like this where you’d wait a day between the first and second sessions, three days between the second and third, and so on. To do this precisely, you need a system that tracks your progress in memorizing each piece of information you need to study – since it never happens evenly. If you’ve got 100 Japanese kanji to learn,
it’s inevitable that you’ll remember some
easier than others. If you use the exact same time delays for
every kanji, you’ll spend too much time studying
some, and others won’t ever be learned at all. To solve this problem, you can use the Leitner
System. In it, you’ve got five boxes, each of which
represents a specific study interval. Box 1 gets studied every day, Box 2 every
three days, Box 3 once a week, and so on. Every fact or term gets its own flash card,
and all cards start off in Box 1. Once you get a card right, move it to the
next box. And if you get a card wrong – no matter
what box it’s in – send it back to Box 1. If you play by these rules, you’ll ensure that you
maximize your efficiency by spending more time
studying the cards you have the weakest grasp on. The increasing time intervals of the boxes
also help you leverage the spacing effect and
get to close to that point of desirable difficulty. There are also a ton of spaced repetition
apps for both computers and smartphones that
will let you make this whole process digital. The best known one is probably Anki, which
is free on most platforms, but there’s also
TinyCards, Quizlet, and many, many others. Now when it comes to subjects that aren’t easily
studied through flash cards – like math or even a sport like skateboarding – it’s harder to use a rigid spaced repetition algorithm. However, the spacing effect applies here as well,
so be sure to space out your practice over time. During any given day’s practice, you’ll eventually
hit a wall where you stop making progress whether it’s learning derivatives in calculus
or kickflips in skateboarding – but if you come back to it a few days later,
everything will be more likely to click into place. In each of these study sessions, make sure
you’re putting the focus on recalling information
from your own memory. As we talked about in our video on reading
assignments, there are two main kinds of
memory – recognition and recall. Recognition is what happens when you’re
exposed to information you’ve already seen
before and remember it. But recall involves dredging the information up from
the depths of your memory banks without seeing it, which is exactly what you’ll have to do in both
your exams and in many real-world situations. So when you study, make sure you’re focusing
on active recall. Don’t just passively read over your notes or
slides – use them to create quizzes for yourself, or challenge yourself to sit down and write out
a summary of what you’ve learned from memory. If you’re studying a subject like math or physics, put a huge emphasis on practicing with real problems and actually use the concepts and formulas you’ve learned. In short, studying should feel like work,
and it should challenge your brain. When it does, you’ll remember more while
spending fewer hours at your desk. Thanks for watching, and I’ll see you next
week. This episode is brought to you by The Great
Courses Plus, an on-demand subscription service where you can get unlimited access to over
7,000 different video lectures about any topic
that interests you, including science, literature, history, math,
even cooking or photography. The classes are taught by award winning
professors – from the Ivy League and other
top schools around the world. If you’re looking to improve your study skills
further, you might like this lecture from Professor Steve Joordens, called Encoding—Our
Gateway into Long-Term Memory where you’ll
learn more about how to improve your own recall. Right now, The Great Courses Plus is offering
Crash Course viewers a free one-month trial. Go to,
or click on the link in the video description
below, to start your free trial today. Crash Course Study Skills is filmed in the
Dr. Cheryl C. Kinney Crash Course Studio in
Missoula, MT, and it’s made with the help
of all of these nice people. If you’d like to keep Crash Course free for
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14 thoughts on “Memory: Crash Course Study Skills #3”

  1. Really thanks for sharing.If only I have watched this in my early life,not too late though.Initially I just want to practice my listening in English ,then I just get trapped!! Luckily I have chosen the series first ,then I can apply the learning skills to other specific subjects!😇

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