How Human Memory Works: Encoding, Storage and Retrieval
By the end of this guide you will be able to describe memory as three steps (encoding, storage and retrieval) and name one study action that serves each step. That gives you a short checklist for working out why a fact did not stick: it never went in properly, it faded between sessions, or you never practiced pulling it back out.
Treat the three steps as a teaching tool, not a map of the brain. Researchers have disagreed about how best to divide memory into parts, and we do not claim that remembering happens in neat stages one after another. We keep the model because it is useful for planning a study session, and we point out below where it stops being accurate.
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The three steps in plain words
Encoding is getting information into a form your memory can work with. When you read a definition and connect it to something you already know, you are encoding it. Storage is keeping that information over time, including the hours and days between study sessions. Retrieval is pulling it back when you need it, such as on a quiz.
This split is a simplification we use for planning. Craik and Lockhart (1972) reviewed the evidence for theories that treat memory as a set of separate stores and pointed out difficulties with that approach. They outlined an alternative built around how deeply information is processed. The steps also overlap in practice: as the retrieval section below shows, answering questions can change what you remember later.
| Step | Plain meaning | A common way it goes wrong | One study action |
|---|---|---|---|
| Encoding | Getting the material into a usable form | You read it once without working with its meaning | Put one idea on one card and add an example from your own life |
| Storage | Keeping it between sessions | Long gaps with no review at all | Come back to the material on several different days |
| Retrieval | Pulling it back out | You only reread, so you never practice pulling it out | Answer from a blank page before you check your notes |
Encoding: what happens while you study
Working memory is the small mental workspace you use to hold information and think about it right now. Baddeley and Hitch (1974) examined its role in reasoning, language comprehension and free recall. They suggested that its core is a limited-capacity work space that can be divided between storage and control processing. In plain terms, the same small space does the holding and the thinking, so a task that asks for too much at once crowds it.
Keeping each card to one idea is a sensible response to that limit. It is practical advice built on the working-memory idea; the studies we cite did not test flashcard design. The guide on working memory vs. short-term memory goes deeper, and deep vs. shallow processing explains why meaning matters at this step.
Storage: what happens between sessions
Storage covers everything after you close the book. Two points from the sources matter for students.
First, loss over time shows up in classic memory experiments. Murre and Dros (2015) repeated Ebbinghaus's classic experiment with one participant, who relearned lists of nonsense syllables after intervals from 20 minutes to 31 days. The results were similar to Ebbinghaus's original forgetting curve. One person and made-up syllables make a narrow test, so read it as an example of loss over time, not as a prediction for your notes. The forgetting curve explained goes through the details.
Second, sleep appears to play a role. Diekelmann and Born (2010) reviewed research describing sleep as a state that can optimize the consolidation of newly learned information, depending on the conditions of learning and the timing of sleep. Consolidation means the processes that help new information settle into longer-lasting memory. The abstract we read gives no advice on how much to sleep, and neither do we. See sleep and memory for students for what it does and does not say.
Retrieval: pulling information back is an active step
Retrieval is not always like playing a recording. Loftus and Palmer (1974) showed people films of car accidents and then asked questions. A question using the verb "smashed" produced higher speed estimates than questions using "hit" or "bumped". A week later, people asked with "smashed" were more likely to say they had seen broken glass, which was not in the film. The authors read this as consistent with later questions causing a reconstruction of memory. It was a small lab study, so it does not mean all memories are unreliable. It does suggest that remembering can involve rebuilding.
Retrieval can also strengthen memory. In two experiments by Roediger and Karpicke (2006), students studied prose passages and then either took recall tests or restudied. When the final test came 2 days or 1 week later, repeated testing led to better recall than repeated restudying. After 5 minutes, repeated studying did better. Repeated studying also made students more confident that they would remember, even though they remembered less on the delayed tests.
To use this today, close your notes after a study session and write what you remember before you look. Then check and fix the gaps. The Practice tool follows the same pattern: you read the front of a card, try to answer, flip it and judge yourself.
- Encoding: did I put each idea in my own words, one idea per card?
- Storage: is my next review already planned for a different day?
- Retrieval: did I try to answer before I looked?
Common mistakes
- Blaming a failed quiz on a bad memory without asking which step failed. Ask three questions: did I work with the meaning (encoding), did I look again after a gap (storage), did I practice answering without notes (retrieval)? Change the step that looks weakest.
- Picturing memory as a video that replays exactly what happened. Remember that recall can involve rebuilding. After you recall something, check it against your notes or book.
- Taking the three-step model as exact science. Use it as a planning checklist. The steps overlap, and the model is a teaching simplification.
- Rereading the chapter again and again instead of testing yourself. Close the notes, answer from memory, then check. Reread only the parts you missed.
Frequently asked questions
What are the three stages of memory?
Encoding is getting information in, storage is keeping it over time, and retrieval is pulling it back out. This is a simplified teaching model. Real memory does not move through the stages in a fixed order, but the model helps you decide what to change in a study routine.
Is memory like a computer hard drive?
Only loosely. A drive returns the same file every time. In the Loftus and Palmer study, the wording of a question changed what people reported about a film, which suggests that remembering can involve rebuilding.
Which step matters most for studying?
The sources we cite do not rank the steps. A practical rule: if you mostly reread, add retrieval practice. If you study everything once, add reviews on later days.
Does this model come from one experiment?
No. It is a simple way of organizing the topic, not the result of one experiment. Craik and Lockhart pointed out difficulties with separate-store theories in 1972. Use it as a planning guide, not as a law.
Sources
We opened each source below before citing it. See Methodology and Sources for how we check them.
- Craik, F. I. M., & Lockhart, R. S. (1972). Levels of processing: A framework for memory research. Journal of Verbal Learning and Verbal Behavior, 11(6), 671-684. Open the source
- Baddeley, A. D., & Hitch, G. (1974). Working memory. In G. H. Bower (Ed.), The Psychology of Learning and Motivation, Vol. 8 (pp. 47-89). Academic Press. Open the source
- Murre, J. M. J., & Dros, J. (2015). Replication and Analysis of Ebbinghaus' Forgetting Curve. PLOS ONE, 10(7), e0120644. Open the source
- Diekelmann, S., & Born, J. (2010). The memory function of sleep. Nature Reviews Neuroscience, 11(2), 114-126. Open the source
- Loftus, E. F., & Palmer, J. C. (1974). Reconstruction of automobile destruction: An example of the interaction between language and memory. Journal of Verbal Learning and Verbal Behavior, 13(5), 585-589. Open the source
- Roediger, H. L., & Karpicke, J. D. (2006). Test-Enhanced Learning: Taking Memory Tests Improves Long-Term Retention. Psychological Science, 17(3), 249-255. Open the source
This guide is general study help, not medical or professional advice. It was last reviewed on November 12, 2026. Spot a mistake? Tell us here.