Active recall is a principle of efficient learning, which says that we need to actively stimulate memory in the learning process. It is an opposite to passive review in which the learning material is processed passively (e.g. by reading, watching, etc.).

For example, when you read a text about George Washington, this is passive review.

If you answer a question "Who was the first US President?", this is active recall.

Active recall is many times more efficient in consolidating long-term memory. This is why just reading your study notes before exam is not likely to leave a long-lasting memory trace. On the other hand, if you ask your colleague to test you on the same material, the results will be better in the long run.

Because our recall of a memory may be influenced by its position within a sequence of self-test questions it can be advantageous to randomise the order of those questions. This could be done for instance by putting questions and answers in a spreadsheet and sorting them by values produced by a randomisation function. Flashcards are also often used to stimulate active recall in education.

It is at the start of a learning task that active recall tasks need to be at their most frequent for retention. As long term memories form, rates of testing can be reduced. Recognition of this fact may aid efficient learning.

For more information on improving memory see Mnemonics.