Teachers often assume that because they are teaching and their students are sitting there in front of them - looking attentive - that they are actually learning. They could be right. On the other hand, it could be that their students are just performing the role of student - but not learning. 

Even if they are learning, how long will they retain that information and knowledge in their heads and will they be able to recall and transfer it, say in a year's time?

How much do we know about memory, and recall? Are there techniques that classroom teachers can use to help improve memorisation, retention and transfer?

In short, how do teachers ensure that what they teach, sticks?

Cognitive science is now telling us that some techniques are much more effective than others. And many teachers might not be aware of this.

Robert Bjork of UCLA says it's important to distinguish between actual learning and performance.

What we can observe and measure during instruction is performance. But learning, is about the long-term retention and transfer of skills and knowledge and this must be inferred. Indeed, current performance can be a highly unreliable guide to whether learning has happened.

A German psychologist Herman Ebbinghaus found, unsurprisingly, that over time the retention of words went down – until the words were reviewed. Then retention increased. With regular review, what he terms the 'forgetting time' gets longer. So going back over the words made it easier to remember them.

So if we want students to be able to remember things, we need to keep returning to them and reviewing them.

"If you study and then you wait, tests show that the longer you wait, the more you will have forgotten," says Bjork. "Its obvious - over time, you forget. But if you study, wait, and then study again - the longer the wait, the more you'll have learned after this second study session."

So there are some techniques that really do seem to work.

Take a look at some of the following sources ...