In the practical use of our intellect, forgetting is as important a function as recollecting. – William James

As teachers, we tend to do all in our power to prevent students from forgetting what we have taught them. This seems entirely correct and not open to debate: forgetting is clearly the enemy of learning. Well, according to Robert and Elizabeth Bjork, the way our memories work is a good deal more complex than that. For all practical purposes our capacity to store new information appears limitless – our brains have sufficient space to comfortably store every experience we’re likely to have over our lives. But what’s incontrovertible is that sometimes we cannot access or retrieve these memories. Bjork theorises that every item in memory has a storage strength (how well we know something; the quantity of schema to which an individual item is linked) and a retrieval strength (how easily we can recall that thing right now.) There’s stuff rattling around in my brain that I know I know, I just can’t always remember what it is. Our response to this well-known dilemma is to keep students’ retrieval strength as high as possible by providing cues and prompts and restudying material.

In one of the most counter-intuitive ideas I’ve come across in the field of cognitive psychology, preventing students from forgetting – boosting their current performance – actually prevents them from being able to retain information over the longer term and transfer it to new contexts. This is one of those curious areas of our intelligence – forgetting can increase our capacity to better store items in memory. The better you currently know a thing, the smaller the gains from additional practice. But when we have forgotten something, the act of successfully dredging it up from memory actually helps us remember it better in the future. The other interesting finding is that it’s much easier to relearn stuff we’ve forgotten.

Here’s a video of Robert Bjork explain all this with much more clarity and cogency than I’m capable:

Anyway, all of this is an overlong preamble to following. This guest post by Gerald Haigh (@geraldhaigh1) is a marvellous musical riff in response to some of my pontificating on the importance of forgetting.

Some years ago, after I’d played some ragtime at a piano workshop, the concert pianist running the course encouraged me to learn Scott Joplin’s ‘Maple Leaf Rag,’ which I had always thought out of my reach. Thus encouraged, I learned it as I always do, a bar, or even less, at a time, never going on until the studied section is secure. As a result, at the end, I really did know it. I played it a few times for friends and at a music festival.

Then I left it and moved on to other pieces. Earlier this year, though, I decided to revive Maple Leaf Rag. I got it out and tried it and, perhaps unsurprisingly, it was a struggle. I played it, but with hesitations and wrong notes. Immediately, I stopped. I knew it was no use trying just to correct the details, which would have been a bit like painting and patching the rust on an old car – cover one bit up and you soon discover another so you end up with an unsatisfying ramshackle old banger.

So I simply set to and learned the piece over again from the beginning. And do you know, four things happened. None, when you think about it, are particularly surprising;

  • The learning was much quicker the second time.
  • I uncovered errors I had consistently missed the first time.
  • I discovered musical subtleties, touches of Joplin genius, which I had also missed the first time.
  • The end result was better than before – more mature, more confident, more musical.

I’m far from the only one to have found this. The piano forum has a thread on it:

Experiences related there vary, but there’s a consistent feeling that a piece comes out better the second time. For example;

‘Things not only come back much faster, but to a much higher level. Technical problems you once faced often just melt away, and you can often gain a much better understanding of the “big picture” of the piece the second time.’

I leave others to work out how, and whether, anecdotes like this have any bearing on children’s learning. I’m sure, though, that there’s something here worth looking at, perhaps particularly when it comes to helping students with ways of revising.

For further detail on how to induce the power of forgetting, read this post on Bjork’s concept of desirable difficulties.