Working Memory: Make it Bigger, or Use it Better?

Cognitive science has LOTS of good news for teachers.

Can we help students remember ideas and skills better?

Yes, we can! (Check out retrieval practice and other desirable difficulties).

Can we promote students’ attention?

Yes, we can! (Posner and Rothbart’s “tripartite” theory gives us lots of guidance.)

Can we foster motivation?

Yes, we can! (As long as we’re modest about expectations and honest about the research, growth mindset can help.)

At the same time, we’ve occasionally got bad news as well.

Do cell phones distract students from their work?

Yes, they do! (Even when they’re turned off.)

Do students have “learning styles”?

Not in any meaningful way, no. (As Daniel Willingham says: when it comes to learning, people are more alike than different.)

The WORST News

I regularly talk with teachers and school leaders about working memory.

After a definition and some fun exercises, I emphasize three key points:

First: working memory is ESSENTIAL for learning. No academic information gets into long-term memory except through working memory. (Really.)

Second: it’s sadly LIMITED. (You probably can alphabetize 5 random words. You probably can’t alphabetize 10. You’ve run out of WM.)

Third: we know of no artificial way of making it bigger … except for letting children grow up. (WM capacity increases as we age, until our early twenties. No, you don’t want to know what happens next.)

This third point consistently creates genuine consternation.

Because: we REALLY want to make working memory bigger. After all: it’s essential, and it’s limited.

And because: almost every other cognitive function CAN get bigger.

If you want to learn more Spanish, practice Spanish. You’ll learn more.

If you want to get better at meditation, practice meditation; you’ll get better.

If you want to increase your working memory – and, trust me, you do – common sense suggests that practice should help.

That is: if you keep doing working memory exercises, your working memory should improve.

And yet, weirdly, it just doesn’t. People have tried and tried. Some companies make big claims.

Alas, we just don’t have consistent, robust research suggesting that any of these strategies work.

So, as I say, that’s really bad news.

Don’t Panic: There’s REALLY Good News

After all that bad news, it’s time for some good news. Let me start with an analogy.

I’m 5’10”.

I’m never the first pick for anyone’s basketball team. And: no matter how much I try, I’ll never get any taller.

However – and this is the key point – I can use the height I have more effectively. If I learn how to play basketball well (at my height), I can be a better player.

I’m not taller; my “height capacity” hasn’t changed. But my use of that height can improve.

So too, teachers can help students use the working memory they have more effectively.

In fact, we have LOTS of strategies for helping teachers do so. We have so many strategies that someone should write a book about them. (It’s possible I already did.)

For instance: “dual coding” doesn’t increase students’ WM capacity. It does, however, allow them to use more of the WM that they already have.

For that reason, dual coding – used correctly – can help students learn.

Don’t Stop Now

The good news keeps going.

Like dual coding, relevant knowledge in long-term memory reduces WM demands. The precise reasons get complicated, but the message is clear: students who know more can – on average – think more effectively.*

For that reason, a well-structured curriculum can help students learn. The knowledge they acquire along the way transforms WM-threatening tasks into WM-friendly tasks.

In many cases, simple common sense can manage WM load.

Once teachers understand why instructions take up WM space, we know how to dole out instructions more effectively.

Once we see why choices both motivate students’ interest and stress students’ WM, we can seek out the right number of choices.

So too, once we focus on “the curse of knowledge,” we start to recognize all the ways our own expertise can result in WM overload. This perspective powerfully reshapes lesson plans.

In other words: when teachers understand WM, we begin – naturally and intuitively – to adjust classroom demands to fit within cognitive limits.

That process takes time, with stumbles and muddles along the way. But the more we practice, the more skillful and successful we become.

And, notice this key point: none of these strategies make WM bigger. Instead, they help students use it better.


Although working memory is VITAL for learning, students (and adults) don’t have very much.

We therefore WANT to make it bigger.

The good news is: although we really can’t make it bigger, we really can help students use it more effectively.

When we shift our focus from making it bigger to using it better, we adopt teaching strategies that help students learn.

* For this reason, cognitive scientists get very antsy when they hear the claim that “students don’t need to know facts because they can look them up on the interwebs.” Because of working memory limits, students must have knowledge in long-term memory to use large amounts of it effectively.

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