What Is Relearning in Psychology? Why You Keep Forgetting
In psychology, relearning means learning something again after you have forgotten it. It is also a way of measuring memory: if the second round takes less time than the first, some of the original learning survived, even when you could not recall any of it. That's why you keep relearning things: the memory never fully went away, but you couldn't get at it any more. The fix is to bring it back on a schedule, before it fades completely.
This guide explains the research behind relearning (it goes back to 1885), what it means for anything you study, from exam material to Spanish vocabulary, and a simple routine so that the next time you study something, it's for the last time.
Relearning in psychology: a short definition
The concept comes from Hermann Ebbinghaus, the German psychologist who ran the first systematic experiments on memory. In Memory: A Contribution to Experimental Psychology (1885), he memorised lists of nonsense syllables until he could recite them perfectly, waited, and then relearned them to the same standard. He then compared how long each round took.
The time saved in the second round is called savings, and the approach is known as the savings method (or "method of savings"). The modern replication by Murre and Dros explains it with a simple example: if it takes 25 repetitions to learn a list and only 20 to relearn it a day later, you have saved 5 out of 25, which is 20% savings (Murre & Dros, 2015, PLOS ONE).
Savings matter because they reveal memory you can't access directly. You might look at a word list and feel that you remember none of it. But if relearning goes faster than learning did, the first round left a trace.
| Term | What it means | Everyday example |
|---|---|---|
| Learning | Encoding information for the first time | Learning la cuenta = "the bill" before a trip to Spain |
| Forgetting | Losing the ability to retrieve it, not necessarily losing it entirely | Six months later, you blank when you need to ask for the bill |
| Relearning | Learning it again to the same standard | Seeing la cuenta once and thinking "oh, of course" |
| Savings | How much faster relearning is than original learning | It took 5 tries the first time and 1 the second |
| Retrieval practice | Deliberately pulling the information out of memory | Covering the English and saying la cuenta from memory |
What Ebbinghaus actually found
Ebbinghaus tested himself after delays ranging from about 20 minutes to 31 days. His own summary, in the 1913 English translation, is worth quoting directly (Ebbinghaus, 1885/1913, Chapter VII):
"One hour after the end of the learning, the forgetting had already progressed so far that one half the amount of the original work had to be expended before the series could be reproduced again… After 24 hours about one third was always remembered; after 6 days about one fourth, and after a whole month fully one fifth of the first work persisted in effect."
Two things stand out:
- Forgetting is fastest at the start. Most of the loss happened within the first hours and days. After that, the curve flattens.
- Something survives, even a month later. After 31 days, he still saved about a fifth of the original effort. In his words, the complete disappearance of that effect would take "an indefinitely long period of time."
More than a century later, Jaap Murre and Joeri Dros repeated the experiment, with one person spending 70 hours learning and relearning lists at delays from 20 minutes to 31 days. Their curve closely matched Ebbinghaus's. Savings dropped from about 42% at 20 minutes to about 9% at 31 days (Murre & Dros, 2015).
A caveat: these are nonsense syllables learned by single, highly motivated individuals. Meaningful material, like a language you're actually using or concepts you understand, is usually retained better. The shape of the curve is the useful part: steep at first, then gradual. If you want the full story, we cover it in The Forgetting Curve: How Fast You Forget and How to Remember More.
Why you keep relearning: storage strength vs retrieval strength
If the memory is still in there, why can't you get to it? The most useful explanation comes from psychologists Robert and Elizabeth Bjork, whose "new theory of disuse" describes each memory as having two separate strengths (Bjork & Bjork, 1992):
- Storage strength is how well something is learned. In their theory, it builds up with every study or recall and, "to at least a first approximation," is never lost.
- Retrieval strength is how easily you can access the memory right now. It fades with disuse and as new memories compete for the same cues.
Their own example: a home phone number you had for five years, twenty years ago, has high storage strength but low retrieval strength. Your hotel room number on day three of a holiday is the opposite.
This explains relearning neatly. When you "forget" something you studied properly, it's usually the retrieval strength that has dropped, not the storage. Relearning is fast because the storage is still there to build on.
The theory makes one more prediction that matters for how you study. Retrieving a memory boosts it more than re-studying does, and the boost is bigger when retrieval is harder, that is, when the memory has started to fade but isn't gone. So a well-timed, slightly effortful review is worth more than a review the day after you learned something.
The relearning loop (and what it costs you)
Most people know this pattern:
- You learn something properly: a chapter, a framework, 300 Spanish words.
- You feel confident because it's fresh.
- Weeks pass and you don't use it.
- You need it again and it's "gone."
- You start over from your notes, often with the same method that didn't stick the first time.
The loop isn't a sign that you're bad at learning. It happens because most study is organised around acquisition (getting to the point where you know it) and not maintenance (keeping it retrievable). Courses end, exams pass, the trip is over, and nothing brings the material back before retrieval strength drops too far.
The cost is time. Every round of starting from scratch is time you could have spent building on what you knew, and it compounds for anyone learning large amounts: medical students, language learners, people preparing for professional exams.
The good news: relearning gets cheaper each time, especially when it's spaced
Relearning isn't wasted effort. Each round adds storage strength, and spacing those rounds out has a dramatic effect.
The clearest evidence comes from foreign-language vocabulary. In a nine-year study, Harry Bahrick and three family members learned and relearned 300 English–foreign language word pairs, with relearning sessions 14, 28 or 56 days apart, then tested themselves up to five years after training ended (Bahrick, Bahrick, Bahrick & Bahrick, 1993, Psychological Science). The wider gaps slowed down learning a little during training, but that was "offset by substantially higher retention." Thirteen sessions spaced 56 days apart produced retention comparable to 26 sessions spaced 14 days apart. Half the sessions, same result.
Larger reviews agree. A meta-analysis of 317 experiments by Cepeda and colleagues found that spacing out learning sessions generally beats massing them together, and that the best gap grows with how long you need to remember the material (Cepeda et al., 2006, Psychological Bulletin). A follow-up study of more than 1,350 people put rough numbers on it: the optimal gap between study sessions was about 20–40% of the retention period when the test was a week away, falling to about 5–10% when the test was a year away (Cepeda et al., 2008, Psychological Science).
And it can last a very long time. Bahrick's earlier study tested 587 people who had studied Spanish in school or university between 1 and 50 years earlier. Retention dropped for the first 3–6 years, then stayed essentially unchanged for up to 30 years. How much survived in this "permastore" depended on how well people learned it originally (Bahrick, 1984, Journal of Experimental Psychology: General).
The practical lesson: you don't need to study more. You need to come back to it at better times.
Worked example: relearning Spanish vocabulary you "lost"
Here's what this looks like for a real learner. Say you studied Spanish at school or took a course before a trip to Valencia two years ago, and now you're planning another trip.
Step 1: test before you re-study. Take a list of 50 everyday words you once knew (food, directions, numbers, travel phrases) and test yourself English → Spanish without looking. You might get 15 instantly, half-remember another 15 ("la… cuen… la cuenta!"), and blank on 20.
Step 2: notice the savings. Now go through the 35 you missed or struggled with, once, checking each answer. Many of the "blanks" will come back as soon as you see them: "aparcamiento, yes, of course." That feeling of instant recognition is savings in action. You aren't learning these from zero; storage strength did the work.
Step 3: sort, don't re-study everything. Split the words into three piles:
| Pile | What it means | What to do |
|---|---|---|
| Instant (recalled with no hesitation) | High retrieval strength | Review again in about a week |
| Effortful (recalled after a struggle, or recognised immediately when shown) | Stored, but retrieval has faded. This is the sweet spot | Review tomorrow, then after a few days |
| Truly new (no recognition at all) | Probably never well learned | Treat as new words: add an example sentence, test yourself again within the session |
Step 4: space the follow-ups. Test yourself again the next day, then after 3 days, then a week, then a few weeks. Each time, words you recall easily get pushed further out and words you miss come back sooner. If your trip is two months away, the Cepeda findings suggest gaps of up to about a week or two will serve you well by the end. If you want Spanish to stick for good, as in Bahrick's 56-day schedule, keep stretching the gaps after the trip.
Step 5: use the words in context. Bahrick's long-term Spanish study found that retention depended on how well the language was originally learned. Recalling words inside short phrases ("¿Nos trae la cuenta, por favor?") builds a stronger, more connected memory than recalling isolated words.
The result: instead of re-reading a whole vocabulary book, you spend most of your time on the ~20 words that actually need it, and you stop relearning the ones you already have.
A simple routine to stop relearning things
You can use this for any subject, from a psychology module to a work certification.
- Assume forgetting is the default. It's not a personal failing; it's how memory works. Plan for it at the moment you learn something.
- Turn what you learn into questions. At the end of a study session, write 5–10 questions or flashcards covering the key ideas, such as "What is the savings method?" and not "Ebbinghaus – savings."
- Test first, read second. When you come back to material, try to answer from memory before opening your notes. That's active recall, and the attempt helps even when you get it wrong.
- Review on an expanding schedule. A good starting rhythm: 1 day → 3 days → 1 week → 2–3 weeks → 1–2 months. Shorten the gap for anything you miss; lengthen it for anything that felt easy.
- Aim for "effortful but successful." If every review is effortless, you're reviewing too soon. If you're failing most items, you waited too long, or the material wasn't understood in the first place.
- Keep the system small enough to keep. Ten minutes a day you actually do beats a two-hour weekend session you skip.
Once you're managing more than a few hundred items, doing step 4 by hand gets messy. That's where software helps.
Where Brainbank fits
Brainbank is built around this routine. You can ask the AI Tutor "why" and "how" questions until a concept makes sense, have it generate a deck of flashcards (including cloze cards) from a topic or your own notes, and then let the spaced repetition scheduler decide when each card comes back. The scheduler estimates when you're likely to forget each card and brings it back around then, aiming at a target retention probability, so you spend your time on the cards at risk and not the ones you already know.
If you'd like to try the Spanish example above, you can start on the Free plan: build your own deck or begin with one of the ready-made Spanish decks, and study with the AI Tutor and the Quiz and Practice modes. Premium ($9.99/month) adds a "Cards at Risk" mode that pulls together the cards you're closest to forgetting. You can find out more about Brainbank here.
Sources
- Ebbinghaus, H. (1885/1913). Memory: A Contribution to Experimental Psychology, Chapter VII. Translated by H. A. Ruger & C. E. Bussenius. Classics in the History of Psychology
- Murre, J. M. J., & Dros, J. (2015). Replication and analysis of Ebbinghaus' forgetting curve. PLOS ONE, 10(7), e0120644. doi:10.1371/journal.pone.0120644
- Bjork, R. A., & Bjork, E. L. (1992). A new theory of disuse and an old theory of stimulus fluctuation. In From Learning Processes to Cognitive Processes: Essays in Honor of William K. Estes (Vol. 2, pp. 35–67). Hillsdale, NJ: Erlbaum. PDF
- Bahrick, H. P., Bahrick, L. E., Bahrick, A. S., & Bahrick, P. E. (1993). Maintenance of foreign language vocabulary and the spacing effect. Psychological Science, 4(5), 316–321. doi:10.1111/j.1467-9280.1993.tb00571.x
- Bahrick, H. P. (1984). Semantic memory content in permastore: Fifty years of memory for Spanish learned in school. Journal of Experimental Psychology: General, 113(1), 1–29. doi:10.1037/0096-3445.113.1.1
- Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354–380. doi:10.1037/0033-2909.132.3.354
- Cepeda, N. J., Vul, E., Rohrer, D., Wixted, J. T., & Pashler, H. (2008). Spacing effects in learning: A temporal ridgeline of optimal retention. Psychological Science, 19(11), 1095–1102. doi:10.1111/j.1467-9280.2008.02209.x
Frequently Asked Questions
What is relearning in psychology?+
Relearning is learning information again after it has been forgotten. In memory research it's also a measurement method: Ebbinghaus's savings method compares how long it takes to relearn something with how long it took originally. Any time saved shows that some of the original memory survived, even if you couldn't consciously recall it.
What is an example of relearning?+
Relearning Spanish vocabulary years after school is a classic example. Words you couldn't produce on demand often come back after a single look, and relearning a list takes far less time than learning it did originally. Bahrick's 1993 study, in which four people learned and relearned 300 foreign-language word pairs over nine years, is a well-known research example.
Why is relearning faster than learning the first time?+
Because forgetting usually affects access more than storage. In Bjork and Bjork's theory, a memory's storage strength builds up with practice and is largely kept, while its retrieval strength fades with disuse. Relearning restores access to a memory that is still stored, which takes less work than building it from scratch.
What is the difference between relearning, recall and recognition?+
Recall is producing information with no cues ("What's Spanish for 'the bill'?"). Recognition is identifying it when you see it ("Does la cuenta mean 'the bill'?"). Relearning is learning it again after forgetting. Relearning can reveal memories that neither recall nor recognition picks up, which is why Ebbinghaus used it.
How do I stop forgetting what I learn?+
Use retrieval practice (testing yourself) at spaced intervals, reviewing each item just as it's starting to fade. In Bahrick's vocabulary study, wider gaps between relearning sessions produced substantially better long-term retention, and 13 sessions 56 days apart matched 26 sessions 14 days apart.
How often should I review to avoid relearning?+
Start with short gaps (a day, then a few days) and expand them as recall gets easier. Research by Cepeda and colleagues suggests the ideal gap depends on how long you need to remember the material: roughly 20–40% of the time until a test a week away, and about 5–10% for a test a year away.