The Retention Toolkit #1 : Retrieval Practice

klsgfx-Swiss-Army-Knife-2The Retention Toolkit is a series of posts describing research based tools which help improve long-term knowledge retention.

Imagine the following scenario: You are presented with a Swahili-English word pair list to study for a fixed amount of time. An hour later, you have a choice: You can either re-study the list, or use a blank sheet of paper to attempt to recall all the word pairs you can. You will be tested on this material in one week. What should you choose?

Many such studies have been done, and they demonstrate repeatedly that self-testing (also called retrieval practice) is significantly more effective in long-term retention than re-studying the material for the same amount of time. This is known as the testing effect. Using the testing effect to improve retention is known as test-enhanced learning.

“Learning is usually thought to occur during episodes of studying, whereas retrieval of information on testing simply serves to assess what was learned. [… However,] retrieval practice is actually a powerful mnemonic enhancer, often producing large gains in long-term retention relative to repeated studying.” (1)

Test enhanced learning doesn’t just help a little bit. In a representative study, test subjects who repeatedly self-tested during their study session doubled their retention over those who only self-tested once. However, in both groups, repeated study sessions with the same material had virtually no effect on retention!

Sans titre
Students were given Swahili-English word pair lists to memorize, then tested one week later. The two bars on the left show retention in students who practiced retrieving information (recalling from memory) multiple times throughout a study session. The two bars on the right measure retention in students who only attempted to recall from memory once during the study session. The dark blue bars are from students who were given several additional study times (to reread, review) with the material. Additional study time shows virtually no effect on retention, whereas repeated attempts to retrieve infromation from meory (retrieval practice) doubled retention one week later. (1)

What is retrieval practice / self-testing?

You are probably already familiar with many techniques of retrieval practice. Retrieval practice is the act of calling information to mind rather than rereading it or hearing it. (1) The effort necessary to recall the information is what makes testing beneficial to retention. Techniques can include:

  • Short response questions (written)
  • Recitation (oral rote memory drills)
  • Oral or written narration (Charlotte Mason style narration)
  • Flashcards used correctly (recalling the answer before turning the card)

A word of warning: do not use multiple choice or true/false tests as part of test enhanced learning. I will explain why in my next blog post.

What about feedback?

Amazingly, retrieval practice maintains its effectiveness even without feedback (correction of wrong answers) as compared to repeated studying. A student could simply complete a short answer quiz after reading material, and then throw it away, and still have used his time more efficiently than had he chosen to re-read the material a second time instead.

However, feedback does enhance long term retention over no feedback test enhanced learning. Conventional wisdom (and Charlotte Mason) tells us to correct mistakes in our student’s work immediately. However, repeated studies show that delayed feedback (correction of errors) is actually a more effective technique! The good news for homeschooling parents: We do not need to hover over our students as they use retrieval practice. Going over all corrections following a test, or even the next day is a more effective retention tool, and may be due to the spacing effect, which I will discuss later in this series.

How often?

Repeated retrieval practice is better than non-repeated, but there is a trick to it.  Asking for a word definition every minute for ten minutes (ten retrievals) will have the same impact as asking for it only once, after one minute.  This is because the subsequent retrievals are not challenging enough.  I will go into the details of when to use retrieval practice in my next Retention Toolkit Series post.

The Rote Memory Fallacy

There is a strong bias in modern education against “rote memorization.”  There is a fear that students taught to parrot information have no ability to use that information in any meaningful sense.  The most sought-after skill in students is transfer:

“the ability to generalize learning from one context to another or to use learned information in a new way (e.g. to solve a problem)” (1)

So the key question is, does test enhanced learning improve transfer?  The answer is, once again, a resounding yes.  Test enhanced learning far outperforms repeated studying (rereading, reviewing notes, listening to a lecture again) in improving a student’s ability to transfer and apply knowledge.

A Meeting of the Minds

It is my policy to listen closely when cognitive science confirms something which classical educators and ancient sages have reasoned to be true. The testing effect is not a new discovery.

Psychologist and philosopher William James wrote in 1890,

“A curious peculiarity of our memory is that things are impressed better by active than by passive repetition. I mean that in learning by heart (for example), when we almost know the piece, it pays better to wait and recollect by an effort from within, then to look at the book again. If we recover the words in the former way, we shall probably know them the next time; if in the latter way, we shall very likely need the book once more.” (2)

And if that isn’t far enough back to satisfy you, Aristotle wrote in 350BC that,

“Exercise in repeatedly recalling a thing strengthens the memory.” (3)

Application in the Homeschool

Move testing from an evaluation tool to a method of study.    Self-testing is a study skill that can replace review (rereading listening to a lecture again, reviewing notes).   Teach students to self test independently, and use a parent-directed testing such as oral narration or short free response quizzes to improve students’ retention of material.  Give feedback after testing but don’t worry about doing it immediately. It’s okay to put material into your inbox and address is later in the day or the following day. Students can also provide their own feedback during self-study by recalling as much as possible without aid, then reviewing material, putting it aside, and practicing retrieval again. Emphasize to your student the importance of allowing retrieval to be a struggle- do not give up too early and peek at notes!

Do not use multiple choice or true/false tests.

Timing is everything. See the next post in this series: The Spacing Effect.


This post was a summary of the information available in the article by Roediger, cited below. Direct paraphrases in my post are indicated by the “(1)”.

(1) Roediger, Henry L. et al. The critical role of retrieval practice in long-term retention. Trends in Cognitive Sciences, Volume 15, Issue 1, 20-27. 2010

(2) James, William. The Principles of Psychology.

(3) Aristotle. On Memory and Reminiscence. 350 BC

5 thoughts on “The Retention Toolkit #1 : Retrieval Practice”

  1. This may be part of why I like Sporcle so much for memorization. I’ve always said it’s because it makes otherwise boring work into a game, and I’m sure that’s a good part of it, but the biggest reason is that it works for me. It’s a very convenient way (if you have a computer) to do repeated retrieval practice. Most of the games require you to come up with the answer, but I find their version of multiple choice (“Clickables”) very helpful, too, especially in the beginning stages (and most especially if you’re using a phone instead of a real keyboard).

  2. Hmm. Janet can comment but I can’t. I’ll try again. But I hope my previous comment didn’t get lost, because I’m not sure I can create it again. I’m too busy trying to recreate a much longer post of my own that disappeared overnight….

  3. Hi everyone! I wanted to let you know that I recently launched, a “hub” of information for educators (K-12 and higher ed) about retrieval practice. It’s pretty new and I’ll be adding more content in the coming months – research summaries, information for students, additional resources, etc.

    In particular, I’ve linked to this article on the “Press & Testimonials” page of the website! Don’t forget to check out the 11-page free PDF guide about retrieval practice on the download page.


    Pooja K. Agarwal, Ph.D.
    Cognitive Scientist, Memory Expert, & Education Consultant

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