Maybe you're trying to make sure your BFF doesn't fail algebra, or helping your kid with their social studies homework.

Or maybe you're a teacher-teacher who wrestles with classes of students every day, and if you are, let me just say thank you for doing that, because teachers rock, and society would crumble without you.

Regardless of who or why you're teaching, though, the goal is ultimately for your student or students to retain the information you're trying to pass on.

And you might think you know how to make that happen.

But it turns out that a lot of classic teaching wisdom isn't backed by science.

Like, you might have heard you should be super enthusiastic.

But while enthusiastic teaching seems to improve course evaluations — including ratings of the textbook, weirdly enough — it doesn't seem to do much for students' grades.

Or, maybe you've been told you have to tailor you lessons to fit your pupil's quote "learning style".

Well, turns out there isn't really any evidence that that's important, either.

But psychologists have been studying teaching for decades, and all that research has stumbled on a few tried-and-true methods to improve teaching.

Some of them might surprise you. Like, that cramming is bad.

And quizzes are good. So today, we're going to be talking about three ways you can use psychology to be a better teacher — or even a better student.

One of the most well-supported tricks to up information retention is to use a technique called the spacing effect, or spaced practice.

The idea is that if you have an hour to study, you'll do better if you can split up that hour up — like 30 minutes on two different days.

And you might even want to space those days weeks apart!

There have been hundreds of studies on the spacing effect — we've known about it since the 1880s.

But, one early example published in 1925 showed it by having students try to memorize the ephebic oath — something every ancient Greek citizen knew, but no one in the study had heard before.

Half the participants were read the oath 6 times in a row — the other half heard it 3 times each on two separate days which were three days apart.

When they were tested immediately after the readings, it seemed like having the study sessions all massed together improved people's memory a little bit.

But on a test 4 weeks later, the group who studied with a 3 day gap in between did much better.

This seems to be a general trend, too — if you want to remember information for longer, space your studying out with bigger gaps.

One study published in the Journal of Experimental Psychology: General in 2011 recruited 335 students and assigned them to practice learning material according to one of 5 schedules.

The shortest was to try to get everything done in about 10 days — the longest took about 38 days to study, with practicing scheduled about a week apart.

And though everyone who spaced out their practice did better than a control group, those who spread out their study the most did the best on a test given 4 months after their final study session.

This effect seems to work across all kinds of things you can learn from memorizing facts, to motor skills, to classroom material.

It even seems like rats, bees, and fruit flies learn this way!

But it's not entirely clear why it works.

One idea is that whenever you learn something new, you tend to think about it a few times later on for no particular reason.

Memory researchers call this "autonomous reactivation."

When you space out your practice, you get more of this autonomous reactivation — which for your brain, is just more practice.

There's also the possibility that if you space out practice, you might be studying the material in multiple contexts — like, you're hearing about it at home instead of a classroom, or even just learning different things around it.

That means you'll have more associations with the memory you have of the content, and that gives you a better chance of retrieving it at the right time.

Another explanation is that when you learn something, you stimulate dendritic spines on neurons in a part of your brain called the hippocampus.

These spines reach out to connect to other neurons, and when you stimulate them, you get more connections that last longer, which improves your memory.

The thing is, these neurons need a bit of time to recover before they can fire again the same way.

That bit of time is called a refractory period.

And basically, when you study the same material right away, your brain keeps stimulating the neurons during that period — and that isn't as good for maintaining the connections with other neurons as stimulating them after they've had a chance to reset entirely.

But research on neurons in a hippocampus is hard to do on humans — so those ideas are mostly drawn from research on rats and flies.

Even if we don't know exactly why spacing works, your students — who probably aren't rats or flies — can benefit from it.

Like, you can try spending more time in class reviewing older material.

Devote a bit of time each day to covering material that was first introduced yesterday — or a week ago.

There's some evidence this really works in classrooms, too.

One teaching method called "direct instruction" focuses 90% of every class day on practicing older material.

And it was found to improve kids' achievement test scores — particularly, in a poor school district with historically low reading scores.

If you're a student, this can help you too.

The lesson is basically: don't cram.

I know!

Cramming for exams is just how it's done.

I did it a lot, and it helped me when I needed it too, but it did not help me retain that information in a long term.

So, if you've got a test coming up in 3 weeks, you'll probably do better to spread your study time out and do a little each week than to try to fit it all into the night before.

And when you're doing that spread-out studying, you might try spending a good chunk of it quizzing yourself.

That's because of what's called the "testing effect" — or retrieval-based learning.

Imagine you've got 2 hours to devote to studying something, and you're trying to decide how to split that up.

You can either spend the whole time reading through your notes and textbook — or, take half of the time and use it to quiz yourself on what you studied the first half.

Research shows you're probably better off if you actually spend less time studying — and more time testing yourself.

Which isn't fun, because that's the part that's more stressful.

But that's right!

Tests and quizzes are a good thing.

And they don't just determine what you know — they actually help you learn.

Though this is another effect we've known about for a while, a clear example of it was published in Psychological Science in 2006.

Researchers recruited 120 students and had them all try to memorize two short passages.

One passage they memorized by studying in two 7 minute chunks.

The other passage, they were told to study for the first 7 minutes — and then they were tested on what they could recall from it for 7 more minutes.

Then they got a final test on both passages.

If they were asked to recall the passages 5 minutes later, just rereading the material for that extra 7 minutes did give them a slight edge

— they remembered about 81% of the passage, as compared to 75% of the passage they were read for 7 minutes and were quizzed on for 7 minutes.

But 2 days or a week after the study sessions, having a pre-test improved their scores compared to the one they just studied — by about 14% at both of those time points.

What's also cool is that the effect isn't limited to what's on the tests.