math, physics

How to Memorize Faster and Easier for Exams


We’re coming upon that time of the year: final exams. Everyone wants to know the shortcut for how to memorize faster and easier for exams.

As they say, there are no shortcuts in life. But there is a lot of scientific research on what’s most effective. I’ll leave links at the end, but I’m not going to try to convince you of the science.

This is a how to. Take it or leave it.

There’s this idea that everyone learns differently. Sure, there might be some outliers, but for the most part, everyone learns the same way.

Human brains are remarkably similar. We’re super good at learning things, but we’re also super good at forgetting things.

What I’m going to describe below is how to gain the longest term memory with the least amount of effort and time.

Unfortunately, this doesn’t mean a short time span. It means the least amount of time actually spent studying.

This brings us to the first principle.

Forgetting is the First Step to Remembering

The way you build things into memory is to struggle to recall something you’ve forgotten or are just about to forget.

I can’t stress this enough. One of the best things you can do when studying is to struggle and make a guess, even if it’s wrong.

There’s strong evidence that when you look up the right answer/formula/translation, you’ll remember it better.

This should make intuitive sense. I used to do this all the time. When something would come up on a test, I’d remember my wrong guess, know it was wrong, then work my way toward the right thing.

The wrong guess helps build a neural pathway to the right answer. Don’t just give up and look up the answer without guessing first!

This is why cramming is so bad. Cramming means you learn everything all at once then try to recall it on the exam.

If you do this, you won’t have forgotten it once and then recalled it.

It’s also why doing flashcards 20 times in a row is an ineffective waste of time.

So, what should you be doing?

Spaced Repetition System (SRS)

There’s a method called SRS or spaced repetition. Your brain is always forgetting things. In theory, you’d forget your own name if you never heard anyone use it in the next 100 years.

Spaced repetition has been scientifically studied since the 30’s, but it didn’t really gain a lot of popularity until the 70’s. The most effective language learning programs like Pimsleur use it.

Here’s the overview:

If you do your flashcards 20 times in a row, the last 18 times do pretty much nothing and waste time.

It’s far better to go through them once then wait a day. Now you’ve had time to forget. Do them once again. It should be easier, and the recall puts them into longer term memory.

Now do them again in a few more day’s time.

Notice, you’ve only done the flashcards 3 times, but because you’ve spaced the repetitions out with enough time to start to forget, they are insanely more effective.

You’ve spent 1/10 the time and haven gotten 100 times more benefit.

Anki

I know what you’re thinking: do I just make up these spaces? Like, how often am I supposed to review?

Like everything in this article, this has all been studied in depth. Different “systems” use different algorithms, but they are about the same.

The most famous right now that you can use for free is Anki.

It’s not the most UI friendly thing, but once you get over the initial 10-20 minute hump, you’ll be saving so much time and getting such good grades, you’ll thank me in the comments.

Anki’s algorithm works great if you just check for “reviews” once a day. It’s not as scary as it sounds. Sometimes you’ll have several days in a row with no reviews (if you’re not constantly adding new cards).

Remember, it will only make you review a card if you’re right at the scientifically-studied point of forgetting.

So, it wants you to take days or even weeks away from them, even if you’re checking in every single day.

Anki is popular, so you can find a bunch of pre-made material. Do NOT use these. Making your own cards is a relevant and useful part of the process.

Download it here. It’s cross platform and syncs. Trust me, you’ll get used to it’s ugliness.

A video for help:

Um…Doing Flashcards Everyday Doesn’t Sound Faster OR Easier

Okay. Go back to whatever you were doing. You’re going to spend 10 times longer doing it that way and only remember 1/10 of it.

It’s up to you.

It sucks that you have to start studying in advance, but you will have so much more free time this way.

And really, if you start 2 weeks before finals, that’s plenty of time. You’ll only be reviewing a few of those days anyway.

The system forces you to take days off! That’s part of why it works.

That’s Great for Memorizing Vocab but What About Math/Science?

I’m glad you asked. This method still works, it just takes a bit more planning. You could make cards with formulas and theorems on them, but actually, this is kind of bad.

Human brains are great at abstract reasoning but terrible at recalling abstract things. If you’re trying to brute force memorize the formula for Maxwell’s equations, you’ll have a hard time.

What you want to do on your flashcards is make a keyword trigger. Let’s do an example.

One of Maxwell’s equations is Gauss’s Law for magnetism. Don’t try to memorize the symbols.

Instead, memorize what the symbols mean in the real world. Start from as simple a form as possible, and then expand from there.

Magnetism becomes “every magnet has two poles.” Well, this is simple, and you don’t need a theorem to tell you that.

Now, expand it again. If it has two poles, what does this say about the magnetic field? Well, some parts are going out and some are going in.

Image result for magnetic field

We’re basically at Gauss’s Law, which is just precise formulation of this.

If you take any blob surrounding the magnet, the amount of the field pushing out is exactly equal to the amount pulling in.

How does one compute such a number?

Well, the component of the electric field perpendicular to the blob at a point on the surface is given by the dot product of B with the (unit) normal vector of the surface at the point.

To compute how much is going through the blob, we add each of these values up. Adding values across a surface is doing the surface integral.

Guass’s Law is saying that if we do this, each place that goes out will be canceled by a place coming in. Therefore, the integral should be zero.

Voila. You’ve now remembered Gauss’s Law:

(You get the differential form by applying Stoke’s Theorem).

Anki even lets you store an image such as the one above as a supplemental note to help you visualize while creating the memory!

Make Abstract Things into Concrete Stories

This is our final principle from the above example.

You made an abstract formula into something concrete and intuitive. You started with “every magnet has a north and south pole” and ended up with the integral form of Gauss’s Law.

If you use Anki, you can make a card with “Gauss’s Law” on the front with a keyword trigger like “magnetic monopole” for the back.

From the trigger, you run the story until you arrive at the formula.

This is what memory experts have been doing for decades. Check out people who memorize the order of a deck of cards in a minute.

They use this exact technique. They just visualize a story or room of concrete things that represent the abstract cards.

Anyway, I think you get the point.

You might want to check out my post on Surviving Upper Division Math for more techniques specifically for abstract math courses.

Sleep

The last thing I’ll point out is that you need sleep. Sleep is when your brain consolidates memory.

You can negate all the work you’ve done by not sleeping enough, and you can accelerate your memory with good sleep.

This is why pulling an all-nighter is bad before a test. How on Earth are you going to remember all the stuff you crammed if you haven’t given your brain a chance to turn the studied material into memory?

References

Optimising learning using flashcards: Spacing is more effective than cramming

Spaced Repetition Promotes Efficient and Effective Learning: Policy Implications for Instruction

Or, for a less technical overview, this book:

Grammarly Writing Support

1 thought on “How to Memorize Faster and Easier for Exams”

  1. Hmmm… This explains how I managed to get through high school with flying colors studying very little.

    OK, I have a good memory. But also, basically, I found most teachers boring and I spent long chunks of their classes not paying attention to them but browsing through the textbook. Obviously, I wouldn’t pay attention to the bits I knew well and understood already, I would read or re-read the things that I didn’t understand or remember. Effectively, i was doing all my studying during classes. And since textbooks are carefully written, and often explain better than teachers, me not paying all that much attention to teachers didn’t do that much harm.

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