Towards the end of the 17th Century, John Locke made a similar observation regarding the importance of repeated retrieval for retention in his 1689 book "An Essay Concerning Human Understanding".
"But concerning the ideas themselves, it is easy to remark, that those that are oftenest refreshed (amongst which are those that are conveyed into the mind by more ways than one) by a frequent return of the objects or actions that produce them, fix themselves best in the memory, and remain clearest and longest there.
"[9] Towards the end of the 19th century, Harvard psychologist William James described the testing effect in the following section of his 1890 book "The Principles of Psychology" "A curious peculiarity of our memory is that things are impressed better by active than by passive repetition.
[10]The first documented empirical studies on the testing effect were published in 1909 by Edwina E. Abbott [11][12] which was followed up by research into the transfer and retrieval of prior learning.
[16] In more recent research with contributions from Hal Pashler, Henry Roediger and many others, testing knowledge can produce better learning,[17][18][19] transfer,[20] and retrieval [21] results when compared to other forms of study [18] that often use recognition [22] like re-reading [23] or highlighting.
[31] Functional magnetic resonance imaging suggests that retrieval practice strengthens subsequent retention of learning through a "dual action" affecting the anterior and posterior hippocampus regions of the brain.
[34] Despite some doubting knowledge transfer across a topic when testing[35] with some studies showing contradictory evidence[36] suggesting recognition was better than recall,[37] inferential thinking has been supported[38] and the transfer of learning is at its strongest with application of theory to practice, inference questions, medical education,[39] and problems involving medical diagnosis.
[42] Using retrieval practices also produces less forgetting than studying and restudying[43] while helping to identify misconceptions and errors[44][45][46] with effects lasting years.
[53] Even unsuccessful retrieval can enhance learning,[69] as creating the thought helps with retention[70] due to the generation effect.
[86] Quicker learning can reduce the rate of forgetting for a short period of time, but the effect doesn't last as long as more effortful retrieval.
[87] Cueing can be seen when encoding new information overlaps with prior knowledge making retrieval easier[88][89] or from a visual or auditory aid.
[91] Pre-testing can be used to get greater results,[92][93] and the post-testing can be used to facilitate learning and memory of newly studied information, known as the forward testing effect.
Multimedia testing can be used[109] alongside flashcards as a method of retrieval practice but removing cards too early can result in lower long term retention.
[60] It is advised that students,[113] people in care units[114] and teaching professionals[115][116][117][118] use distributed[119] retrieval practice[120] with feedback to aid their studies.
[129] Further research has demonstrated that higher-order retrieval does not need to be based on a lower-level factual recall, and that from the beginning of the learning period, both should be combined for best effect.