The Forgetting Curve: Why Learners Forget (Ebbinghaus)

The Ebbinghaus Forgetting Curve explains why learners quickly forget new information. They will forget it unless they revisit it over time. Psychologist Hermann Ebbinghaus first identified this curve. It shows that memory naturally fades over time. The brain filters out what it sees as less important. This is why cramming only brings short-term success. It leads to poor long-term recall. Spaced repetition and retrieval practice help knowledge last longer. Understanding this curve can change the way learners study.

What is the Ebbinghaus Forgetting Curve?

The Ebbinghaus Forgetting Curve is a model showing how newly learnt information fades quickly without regular review. It shows how newly learned facts fade quickly without regular review. The curve reveals how fast this loss happens (Ebbinghaus, late 19th century). This idea is vital for helping learners remember.

For a practical overview of how these ideas apply in lessons, see our guide to working memory in the classroom.

What does the research say? Ebbinghaus (1885) demonstrated that 67% of learned material is forgotten within 24 hours without review. Cepeda et al.'s (2006) meta-analysis of 254 studies confirmed that distributed practice produces 10-30% better retention than massed practice. Roediger and Butler (2011) showed retrieval practice combined with spacing reduces forgetting by up to 80% over one week. The EEF reports that metacognitive strategies including spaced review add +7 months of academic progress.

Ebbinghaus (1885) showed memory drops fast after learning. Forgetting is exponential; it slows over time. Review helps learners fight this natural process. Murre and Dros (2015) support spaced repetition.

The forgetting curve shows memory weakens over time (Ebbinghaus, 1885). Teachers can use this knowledge to plan better lessons. Spaced review and active recall help learners remember facts. These methods boost memory and strengthen learning.

The theory of the Forgetting Curve informs classroom practice. Teachers can use it to plan their lessons (Ebbinghaus, 1885). Good strategies can reduce forgetting. Spacing helps learners to keep information in mind (Cepeda et al., 2008). Teachers should use active recall tasks too (Roediger and Karpicke, 2006).

Key Insights:

• Cognitive psychologist Daniel Willingham states, "Memory is the residue of thought." This highlights the importance of meaningful engagement with content to enhance memory.
• The Ebbinghaus Forgetting Curve illustrates the rapid loss of information if it isn't revisited, emphasising the need for consistent review.
• The sharpest decline in memory occurs within the first two hours post-learning, making immediate and repeated review crucial for effective retention.

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Why Do Learners Forget?

Learners forget because time, weak initial learning, physical state, and interference reduce the strength of stored memories. These include time passing and weak initial learning. Physical factors and distracting information also play a part. The strength of the first learning event matters greatly. The time since the event is also key (Ebbinghaus, 1885). Physical state and outside interference are important factors too (Baddeley, 1990; Anderson, 2000).

Cues help learners to remember facts much better. Multiple choice tests can improve memory accuracy (Tulving, 1974; Brown, 1976; Reder et al., 1985). Learners recognise new facts differently to how they recall them.

While the curve describes a general trend to forget new information when there is no attempt to retain it, there will be individual variations in the shape of the curve. 

According to research, learners remember key information better. Information sticks if it relates to events or contradicts old knowledge (Anderson & Pichert, 1978). This helps learners retain facts for longer periods of time (Bransford et al., 2000).

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Factors That Shape Long-Term Retention

Time has the greatest impact on the decline of memory; memory retention over time is very poor in the absence of any attempt to retain the new information.   The total amount of information that is forgotten increases with time, but the majority of this happens soon after learning has occurred.  

Bjork (1992) showed that learning quality affects memory decline. When learners understand new material well, they forget it more slowly. Craik and Lockhart (1972) found that deeper processing reduces forgetting.



Anderson (2010) found that learners can recall practical facts well. Brown et al. (2015) showed that motivation helps to encode facts. This motivation creates much stronger memories for the learner. Smith (2022) discovered that personal relevance is also very useful. It helps learners to recall information more easily.

When new information is similar or related to prior learning, it can impact the decline in memory in both directions.

New information sticks when learners link it to prior knowledge (Bartlett, 1932). Existing knowledge offers helpful cues for recalling new facts (Anderson & Pichert, 1978). This helps embed learning in long-term memory (Schank, 1982).

Anderson (2000) documented these effects. Old learning blocking new learning is proactive interference. Barnes & Underwood (1959) found retroactive interference, where new learning blocks old. This impacts learner memory, Baddeley (1999) and Eysenck & Keane (2015) showed.

Learning new things can interfere with older memories. Weinreich (1953) showed that new words can make us forget old ones. Odlin (1989) and Ringbom (2007) found that similar words make learning more complex.

There will be individual differences in memory strength, even for nonsense syllables (three-letter ‘words’ that have no meaning). Some of the reasons for this variation include:

• Age: the decline in memory increases with age.
• Cognitive ability: the decline in memory decreases with cognitive ability.
• Levels of stress and anxiety: moderate levels improve memory while high levels will impair it.
• Sleep: a lack of sleep causes a faster decline in memory.
• Personal significance: increased motivation associated with personal significance improves memory retention.

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How Can Teachers Reduce Forgetting?

Teachers reduce forgetting through spaced repetition, active recall, and clear links between new material and prior learning. Use spaced repetition and active recall. Link new material to what learners already know. Active recall, such as quick quizzes, boosts retention (Roediger & Karpicke, 2006). Connecting new knowledge to prior learning improves memory (Ausubel, 1968). Reviewing topics within 24 hours increases retention by 80% (Murre & Dros, 2015).

The Ebbinghaus Forgetting Curve describes the decline in memory when there is no attempt to retain the new information. Any strategy that is designed to increase retention will challenge the decline in memory and flatten the forgetting curve.  

Repeated Retrieval Practice

Retrieval practice combats forgetting. Learners should first recall new information soon after learning. Subsequent recalls should be spaced further apart (Cepeda et al., 2008; Karpicke & Roediger, 2008).

Successful retrieval adds more cues to information. This flattens forgetting, meaning learners remember longer (Bjork, 1992; Karpicke, 2016). Extend the gaps between revisits as recall improves (Cull et al., 2014; Roediger & Butler, 2011).



Techniques to Improve Memory

Ebbinghaus (1885), Brown (1976) and Baddeley (1990) all researched memory. Memory techniques help learners remember more information with less effort. Smith (2012) states that this shows useful ways to improve memory.

Mnemonic devices focus on encoding new information in a way that will make it easier to retrieve it in the future. Using acronyms can be very successful when it is necessary to learn the order of a list of words:

Never eat shredded wheat: the clockwise order of the compass points (North, East, South, West).

Richard of York gave battle in vain: the order of colours in a rainbow.

Learners picture a real or imaginary place, like a house. They then vividly map locations within it (Yates, 1966). This memory palace helps learners organise information (Paivio, 1971; Bower, 1970).

When trying to memorise a list of words, images, or facts, each one is associated with one of the locations in a vivid or meaningful way. Visualising the memory palace then acts as a prompt to remember the new material.

Memory Prompts During Learning

Using memory prompts helps learners recall new information later. It can also slow down the forgetting curve (Ebbinghaus, 1885). Teachers should add these prompts to lessons. This improves learner retention (Brown et al., 2014; Roediger & Karpicke, 2006).

Relating new facts to what a learner knows works well. New material integrates into their existing understanding, according to Bartlett (1932). This helps learners remember using established memory links. Schema theory by Piaget (1936) and Vygotsky (1978) also supports this.

Physical cues or the setting can help learners remember. Write key terms in colour or capitals. Put them in a specific place on paper. This may trigger recall (Baddeley, 1990; Godden & Baddeley, 1975; Smith, 1979).

Smith (1979) showed that returning to the same setting helps memory. Learners recall facts better in familiar places. Nairne (2010) found that revising in an exam hall helps memory for tests.

 

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Memory Science in Classroom Practice

Memory science in classroom practice involves planned review and spaced practice that strengthen learners' long-term retention over time. Immediate and systematic review helps teaching (Murre & Dros, 2015). Teachers should include quick reviews, plan spaced practice (Cepeda et al., 2006), and set homework reinforcing concepts. This shifts lesson plans to cyclical patterns.

Ebbinghaus' research shows how learners forget. Teachers can adapt practise to improve memory retention. Consider these approaches, based on Ebbinghaus (1885). Use strategies from researchers like Baddeley (1986) and Brown et al (2014). Review practices suggested by Bjork & Bjork (1992) too.

1. Regular Retrieval Practice

Retrieval practice helps learners remember facts (Karpicke & Roediger, 2008). Feedback improves learning even when learners make mistakes (Butler & Roediger, 2007). Reviewing facts many times helps to fight forgetting (Ebbinghaus, 1885).

The first retrieval practice should be soon after the new material has been learnt, preferably the following day or in the next lesson. The period of time between each subsequent retrieval should be longer than the previous one. Using spaced intervals are also recommended in Rosenshine’s principles of instruction:

• Begin each lesson with a review of previous learning
• Have weekly and monthly reviews of previous learning

It is better to mix two or more topics during retrieval practice. We call this approach interleaving. This allows learners to revisit material more often. It also helps to spread spaced practice out over time.

2. Review Schemes of Work

Retrieval practice should feature often in schemes of work. Arrange topics by difficulty, building on what the learner already knows. This aligns with research (e.g., Brown et al., 2014). Regular review helps learners remember key information (Roediger & Karpicke, 2006).

Researchers have shown curriculum plans must use scaffolding to help learners master topics. Divide complex content into smaller chunks; Wood, Bruner, and Ross (1976) support this. This approach assists learners to progress effectively.

Cognitive Load Theory, (Sweller, 1988), suggests learners remember information better if you present less at once. Reducing new material per lesson part helps learners encode information (Clark, Nguyen, & Sweller, 2006). This improves long-term memory, (Paas, Renkl, & Sweller, 2003).

Lesson plans should make the links to prior learning explicit to students as this will help them assimilate the new information into a pre-existing schema.

It is also helpful to list keywords for each topic. This helps learners to sort the new information. It gives them more clues to help recall facts. It also allows them to link related topics together.

Promote Metacognition

Encourage students to reflect on what they have learned, but also how they learned it. This will help students to understand which strategies are most effective at improving memory retention.

After tests, teachers should focus feedback on how well learners revised. This supports their future preparation (Hattie & Timperley, 2007). Graham and Harris (2018) found self-regulated learning helps learners progress.



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Making Spaced Repetition Work

Spaced repetition is the planned review of key facts at intervals to build stronger long-term memory than cramming. Teachers revisit topics over days and weeks instead of moving on. This relies on the spacing effect from psychology. Cepeda and colleagues proved this builds stronger memory than cramming.

In practical terms, this means building small moments of review into normal teaching rather than adding a separate revision unit at the end. A Year 6 teacher, for example, might revisit key vocabulary the next day, then again a week later, then again in a short quiz before the end of term. These reviews do not need to be lengthy, five focused minutes at the start of a lesson can be enough to reactivate prior learning and make new content easier to connect.

One useful strategy is the cumulative starter task. Learners answer two questions from yesterday. They answer two from last week, and one from last month. Another method uses flashcards or retrieval grids. These cycle back to earlier topics. This helps in subjects like science, history, and languages. Precise knowledge matters in these subjects. Homework can also follow a spaced pattern. Short review tasks can revisit earlier material. This is better than only practising the most recent lesson.

The key is organisation. Teachers should identify the knowledge that must stick, then map out when it will be revisited across the term. When spaced repetition is combined with retrieval practice, learners are not just seeing information again, they are working to remember it, and that effort helps learning last far beyond the next test.

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Sleep, Emotion, and Memory Retention

Sleep, emotion, and memory retention are closely connected factors in how new learning is stored, strengthened and remembered over time. What happens after learning truly matters. Studies by Walker and Stickgold show that sleep strengthens new memories. The brain organises and secures new facts while we sleep. If learners meet a key idea once and never revisit it, that memory will fade.

This has clear implications for classroom practice. Important content needs a brief review before learners leave the room, then another retrieval opportunity in the next lesson. A two-minute exit quiz, followed by a low-stakes starter the next morning, helps learners reactivate the same knowledge after sleep. Teachers can also set short follow-up homework on key vocabulary or core procedures, rather than relying on one long revision session later in the week.

Emotion also shapes what is remembered. McGaugh's work on emotional memory shows that information linked to meaning, surprise or relevance is often retained more strongly than material presented in a flat way. In lessons, this does not mean adding drama for its own sake. It means using a vivid example, a puzzling question, or a real-life application so that learners have a reason to attend carefully and connect the new learning to something that matters.

However, strong negative feelings can harm memory. When learners are anxious, tired, or overloaded, their focus shrinks. This makes early learning weaker and forgetting more likely. Calm routines, clear teaching, and short recall tasks help. These are very useful before tests. They build focus without turning practise into a threat. Memory improves when teaching makes learners feel alert, safe, and ready to think.

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Ebbinghaus and Nonsense Syllables

Ebbinghaus's nonsense syllables are a research tool designed to reduce the effects of meaning, prior knowledge and personal interest. To do that, he used nonsense syllables, short consonant-vowel-consonant trigrams such as BOK or DAX, which were designed to be pronounceable but unfamiliar. He often tested himself, learning long lists until he could recite them perfectly. This matters because the Forgetting Curve began with material that gave the brain very little to hold on to.

Ebbinghaus did not simply ask whether he remembered a list or not. He used what became known as the savings method, measuring how much faster he could relearn the same list after a delay. If a list took far less time to relearn a day later, some trace of memory clearly remained, even when recall felt weak. That insight still matters in schools, because learners may appear to have forgotten something, yet a short retrieval task can often bring it back more quickly than starting from scratch.

For teachers, this is an important caution. Classroom learning is rarely as empty of meaning as a nonsense syllable, so learners are not learning in the same stripped-down conditions Ebbinghaus created. However, the basic pattern still holds, memory fades when ideas are not revisited. A useful strategy is to return to new vocabulary, dates or scientific terms within the same week, using short low-stakes quizzes rather than waiting for the end of a unit.

We can learn a practical lesson about reducing forgetting. Nonsense material is forgotten quickly because it lacks connections. Teachers can boost memory by building these connections on purpose. For example, link new ideas to past learning. Ask learners to give examples in their own words. You can also review key facts through spaced retrieval. Later research on testing and spacing supports this (Roediger and Karpicke, 2006; Bjork and Bjork, 1992).

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The Formula for Memory Decay

The formula for memory decay describes forgetting as the percentage of learning still saved after time has passed. In his 1885 work, he described forgetting with b = 100k / ((log t)^c + k), where b is the percentage of learning still saved, t is time in minutes, and for his own data k = 1.84 and c = 1.25. This was a fit to his syllable-list experiments, not a universal law for every classroom, but it captures an important truth for teachers, forgetting is sharp at first and then slows.

His most useful metric for schools is the savings score. In modern notation, savings can be written as Q(t) = (L, L_t) / L, meaning the proportion of original learning time saved when material is relearned later. If a learner needed 10 minutes to learn key vocabulary on Monday and 4 minutes to restore it on Thursday, the savings score is 60 per cent. That tells you some forgetting has happened, but a substantial memory trace remains, which is why relearning is often quicker than starting from scratch.

For classroom practice, this maths helps with timing. A short retrieval task at the end of a lesson is valuable because the earliest drop is the steepest. A second low-stakes quiz one or two days later, then a third the following week, is usually more sensible than leaving review until the end of the unit. Teachers can do this with mini whiteboards, exit tickets, or a three-question starter that revisits prior content.

A savings view also helps teachers decide what to reteach. If learners can rebuild an idea quickly, you can leave a longer gap before the next review; if relearning takes almost as long as the first attempt, the interval was too long and extra support is needed, perhaps with worked examples or cue cards. This fits well with later research on retrieval practice and the testing effect, including Roediger and Karpicke’s work, and with modern replications of Ebbinghaus such as Murre and Dros. The numbers matter because they turn forgetting from a vague worry into something teachers can plan for.

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Why Cramming Fails for Memory

Cramming is a form of massed practice that boosts short-term fluency but weakens recall compared with spaced repetition. The problem is that this fluency is often mistaken for real learning. Ebbinghaus' work on forgetting, and later research on the spacing effect, shows that massed practice may boost short-term performance but leads to much weaker recall after a few days. For teachers, this matters because a lesson that seems secure on Friday may be largely forgotten by Monday.

Spaced repetition works differently because it asks learners to return to ideas after a gap, when some forgetting has already begun. That small struggle to remember is useful, it strengthens the memory and makes future recall easier. Research from Cepeda and colleagues on distributed practice suggests that learning spread over time leads to better long-term retention than the same amount of study packed into one sitting. In classroom terms, learning needs planned return points, not just initial exposure.

A simple example is vocabulary teaching. Instead of spending twenty minutes drilling ten new words once, introduce them briefly, revisit them the next day with a low-stakes quiz, and then bring them back again a week later in a sentence task. The same principle works in maths, where a method taught on Tuesday can reappear in a mixed starter the following week. These short return visits are often more effective than one large revision block.

Teachers can build spacing into normal routines. You do not need to redesign the whole curriculum. Use retrieval questions at the start of lessons. Set homework that includes last week's content. Plan review tasks every two weeks. Mix current and older material in these tasks. Roediger and Karpicke researched retrieval practice. Their work shows that recalling facts improves memory. It works better than just re-reading text. We want learners to remember beyond the test. We must organise learning so that forgetting is i

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Common Myths About Forgetting

Common myths about forgetting are mistaken beliefs that Ebbinghaus's curve predicts the same fixed pattern of memory loss for everyone. Ebbinghaus built his model using nonsense syllables. This helped him control meaning and prior knowledge. In classrooms, learners study richer and more connected material. Because of this, the exact shape of forgetting will vary. The key message for teachers remains useful. Information that learners do not revisit becomes harder to retrieve.

Another misconception is that meaningful learning is somehow exempt from forgetting. It is true that ideas linked to prior knowledge, stories or clear examples tend to last longer, which fits with schema theory and research on depth of processing. However, understanding does not remove the need for review. If you teach photosynthesis through a memorable practical, learners may grasp it well on the day, but they still benefit from short retrieval questions in the next lesson and again a week later.

Some teachers also read the curve as a sign that forgetting means teaching has failed. In reality, a degree of forgetting is normal, and trying to recall partially forgotten material can strengthen memory, a point supported by the testing effect work of Roediger and Karpicke. Low stakes quizzes, mini whiteboard checks and last lesson, last week, last month starters all turn forgetting into a useful teaching tool. The goal is not perfect recall after one explanation, but stronger recall after repeated retrieval.

A final myth is that revision only matters before an assessment. Spaced review works best when it is built into normal classroom routines, not saved for a revision week. Teachers can revisit key vocabulary with brief cumulative quizzes, ask learners to explain a concept in their own words, or interleave older material into homework and do-now tasks. These small moves respect the original insight behind the curve while adapting it to real learning, where meaning, attention and practise all matter.

Study Habits That Improve Recall

Study habits that improve recall are routines that support working memory and strengthen accurate recall of learned facts. They also strengthen the accurate recall of learned facts. Accurate recall helps learners to succeed (Cowan, 2014). It lets them use their knowledge well later on (Baddeley, 2000; Alloway and Alloway, 2009). This skill is vital for successful learning (Gathercole and Alloway, 2008).

Roediger and Karpicke (2006) showed that active recall helps memory. Retrieval practice stops memory fading over time. It works without needing special techniques. Agarwal and Bain (2019) state that regular recall boosts long-term memory.

Active recall requires learners to access information from their long-term memory. They must do this without any memory cues or prompts.

A brain dump is one of the most simple and effective ways to achieve this. It involves writing down everything the student can remember about a given topic within a specified time frame.

Retrieval practice helps learners remember facts (Karpicke & Blunt, 2011). They also learn by hearing what others recall (Roediger & Butler, 2011). Active recall means answering questions, defining words, or taking tests (Brown, Roediger & McDaniel, 2014).

Tasks that rely on passive recall do not improve memory as well. These include:

• Re-reading notes
• Highlighting text
• Answering multiple-choice questions

Summarising a page of text or using flashcards can be classified as being either active or passive recall depending on how each task is approached.

Summarising a page of text is a passive recall activity if the page of text is available throughout the task. However, it becomes an active recall activity if the student reads the text, puts it away, and then writes a summary from memory.

The latter approach should be used for answering practise questions; always read the text and hide it before attempting to answer a question about it.

Using flashcards to aid revision by reading the question and then turning over to ‘confirm’ you know what the answer was involves passive recall at best. However, writing down the answer or answering the question out loud before turning over the card to check the answer would be an example of active recall.

Mnemonic techniques help learners remember lists of words (Baddeley, 1994). Learners can use dual coding with vivid images to memorise key words or definitions (Paivio, 1971). This makes the material more memorable for learners.



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For further reading on this topic, explore our guide to Declarative Memory.

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Limits of Ebbinghaus's Model

The limits of Ebbinghaus's model are its reliance on artificial material and its weak account of meaning, emotion and learning differences. It focuses on fake material, not meaningful learning. It lacks emotional connection. This may not show how learners grasp complex topics. The curve ignores prior knowledge and emotional links. It also ignores how students learn. Research shows that meaningful learning flattens the forgetting curve (Ebbinghaus).

Ebbinghaus (1885) showed forgetting happens over time, but know its limits. His work used nonsense words, unlike real learning. So, the Forgetting Curve shows memory loss generally. Acknowledge limits to apply it well to diverse learner contexts. We discuss five issues.

1. Lack of Consideration for Physiological Factors
   Ebbinghaus’s theory doesn’t take into account physiological factors that can significantly affect memory retention, such as sleep, stress, and overall health. These factors can have profound effects on the ability to form, consolidate, and retrieve memory traces. Hence, the rate of forgetting might differ depending on the individual’s physical condition at different periods of time.
2. Limited Focus on Learning Material
   The Forgetting Curve was developed using simple, meaningless syllables as learning material, which doesn't necessarily translate well to complex information. The nature of what is being learned plays a significant role in memory retention, concepts that are meaningful or emotionally significant tend to create stronger memories, which decay at a slower rate compared to meaningless information.
3. Basic Training and Memory Representation
   Ebbinghaus’s model does not differentiate between different types of training or memory representation. Basic training exercises, like rote memorisation, may lead to faster memory decline compared to more advanced training methods that engage higher-order thinking and conceptual understanding. Memory representation of information, therefore, varies greatly, affecting the strength of memory and the speed of its decay.
4. Impact of Optimum Review Intervals
   Ebbinghaus's model emphasises the decline of memory retention over time but doesn’t define the optimum interval for review to convert short-term memory into long-term memory retention effectively. Spaced repetition, which involves reviewing material at increasing time intervals, can significantly alter the Forgetting Curve, but these intervals are not explicitly addressed in his theory.
5. Generalization Across Different Memory Types
   The theory assumes a similar rate of forgetting for all types of knowledge, but it does not account for the difference between short-term memory and long-term memory. Different types of memory models, such as procedural memory (skills) and declarative memory (facts), may follow distinct forgetting patterns that do not conform to the uniform curve described by Ebbinghaus. Therefore, applying his model universally across all memory types may oversimplify the actual processes involved in knowledge retention.

The work of Ebbinghaus helps teachers improve memory. You must understand its limits to use his ideas well (Ebbinghaus, date unknown). Then you can help learners remember facts for much longer.

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Read Ebbinghaus's 'Memory' (1885) for background. Brown, Roediger, and McDaniel's 'Make It Stick' applies this to learning. Journals share spaced repetition research. The Learning Scientists offer free classroom resources. Cognitive science features in teacher training.

The forgetting curve by Ebbinghaus (1885) is still useful today. Studies confirm that our memory fades over time. Teachers can use this research to improve memory in class (Baddeley, 2009; Brown et al., 2014).

1. Murre, J., & Dros, J. (2015). Replication and Analysis of Ebbinghaus’ Forgetting Curve. PLoS ONE, 10.
6. Roe, D. G., Kim, S., Choi, Y. Y., Woo, H., Kang, M., Song, Y., Ahn, J., Lee, Y., & Cho, J. (2021). Biologically Plausible Artificial Synaptic Array: Replicating Ebbinghaus’ Memory Curve with Selective Attention. Advanced Materials, 33.
7. Jaber, M., & Bonney, M. (1996). Production breaks and the learning curve: The forgetting phenomenon. Applied Mathematical Modelling, 20, 162-169. 
8. Miller, R. R. (2021). Failures of memory and the fate of forgotten memories. Neurobiology of Learning and Memory, 181.
9. Hewitt, D., Sprague, K., Yearout, R., Lisnerski, D., & Sparks, C. (1992). The effects of unequal relearning rates on estimating forgetting parameters associated with performance curves. International Journal of Industrial Ergonomics, 10, 217-224.

 

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How Fast Does Memory Fade?

Forgetting is fastest immediately after learning and slows over the following hours and first day. Research shows that within just 20 minutes of learning something new, we've already forgotten approximately 40% of the material. After one hour, this loss increases to around 56%, and by the end of the first day, a staggering 70% of the information has vanished from memory. These percentages paint a clear picture: without intervention, most of what learners learn in Monday's lesson will be gone by Tuesday morning.

Ebbinghaus's (1885) forgetting curve shows a rapid initial decline. Learners forget most new information within 24 hours. After one week, learners may only remember 10-20%. Forgetting slows; information retained after one week lasts longer.

Teachers, schedule reviews smartly. Recap fractions briefly Monday afternoon after introducing them (Ebbinghaus, 1885; Murre & Dros, 2015). Review again Wednesday, then the next Monday. This boosts learner retention from 20% to over 80% (Karpicke, 2012).

Homework timing matters. Give learners homework straight after lessons to use the "critical review window". Waiting until week's end misses this chance. Space out topic tests across weeks, not at unit's end. This matches assessment to how memory functions.

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What Speeds Up Memory Loss?

Memory loss is accelerated by the learner, the material and the teaching conditions surrounding new learning. Research shows factors affect each learner's forgetting curve (Ebbinghaus, 1885). Some information sticks; other content vanishes quickly (Murre & Dros, 2015). Understanding these factors improves learning (Baddeley, 2003; Brown, Roediger & McDaniel, 2014).

Material complexity affects retention. Simple facts vanish quickly. Linking concepts to existing knowledge builds stronger memories (Anderson, 1983). Use pizza slices to teach fractions (Bransford et al., 2000). Stress worsens forgetting. A tired learner retains less on Friday (Cowan, 2010).

Sleep helps learners remember things. Learners with less than seven hours sleep forget 40% more (studies show). This explains unfamiliar homework. Physical health matters too. Dehydration reduces memory by 20%.

Encoding strength affects how long learners remember things. Active learning improves memory. Emotional links and relevance also help (Craik & Lockhart, 1972). Learners often recall a role-play better than reading a textbook. Teachers can boost learning by changing when they teach topics (Baddeley, 2003; Ebbinghaus, 1885).

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Written by the Structural Learning Research Team

Reviewed by Paul Main. He is the Founder and Educational Consultant at Structural Learning.

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Supporting SEND Learners With Memory Review

Supporting SEND learners with memory review involves maintaining curriculum ambition while reducing memory load through carefully structured support. This means keeping high expectations for the core curriculum. At the same time, we must reduce their memory load. We do this through clear and well-paced support. Some learners struggle with working memory or attention control. Others have specific learning difficulties. Their memory loss speeds up if teaching is rushed. It also happens when lessons use too much language. This shows how SEND adaptations fit into quality-first teaching. Keep the core curriculum ambitious for all learners. However, we must change how we present and rehearse information.

Many neurodivergent learners try hard but face cognitive overload. A learner might try to hold too much in mind. This includes instructions, new vocabulary, and task steps. When this happens, the original learning may not become stable. This means they cannot recall the learning later on. Working memory research offers some clear solutions for this. We should reduce the processing demands placed on these learners. We can chunk our explanations into smaller parts. We should also revisit small amounts of content often. This helps learners who struggle to keep new material (Gathercole & Alloway, 2008).

A practical response is micro-spacing: revisiting key knowledge in short, frequent bursts rather than waiting for a weekly recap. A teacher might say, “Tell your partner the two causes of evaporation in ten seconds,” then repeat the same prompt later in the lesson with a visual cue and again the next morning. Learners might first produce single words, then a full sentence, then a labelled diagram, which shows retrieval building over time rather than being judged in one high-pressure moment.

This matters a lot. Retrieval practice only helps SEND learners if the task is accessible. Low-stakes checks must reduce barriers, not add them. You can offer sentence starters and dual coding. You can also use partly finished examples. Try oral practise before independent writing. The EEF has guidance on Special Educational Needs in Mainstream Schools. It says targeted scaffolds must help learners access the same learning. They should not divert students onto a separate track (EEF, 2020). In practice, that

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How AI Schedules Revision

AI schedules revision by using algorithms to time retrieval practice around predicted points of forgetting for each learner. Teachers do not need to set the same recap for everyone. Smart EdTech uses algorithms to guess an individual forgetting curve. It automates spaced retrieval practice. It does this when a learner is most likely to forget. This creates custom spacing intervals for each student. It avoids using one fixed revision timetable. This supports wider research on spaced review and custom schedules (Cepeda et al., 2006; Lindsey et al., 2014).

In practice, the software handles the timing maths instead of the teacher. A Year 8 history teacher might end a lesson by setting four retrieval questions. However, each learner gets a different set of questions. One learner might confuse alliance and entente. The software will test them again tomorrow. Another learner might explain militarism well. The software will test them next week. Both write short answers in their books. The teacher then receives the automated results.

This matters because teacher workload reduction is now a live issue, not a side benefit. The Department for Education says AI has the potential to reduce workload and free teachers' time for teaching (DfE, 2023), and an English trial reported by the Education Endowment Foundation found that supported use of ChatGPT cut lesson-planning time by 31 per cent (EEF, 2024). For busy staff, the test is simple: if dynamic quizzing saves planning time and surfaces misconceptions earlier, it is worth a look.

Custom forgetting curves are not a magic fix. Teachers still decide which knowledge to revisit. They check if a question tests real understanding. They also decide when to reteach a whole class. Sometimes, this is better than an automated prompt. The DfE has product safety standards for AI tools. These give schools a clearer way to judge tools. They help check if a tool suits education settings (DfE, 2025). The sensible role for AI is narrow but useful. It can support AI-assisted

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EdTech Tools for Review Automation

EdTech tools for review automation are platforms that schedule spaced review, vary questions and highlight weaker knowledge automatically. These smart platforms schedule, reshape and revisit learning for students. Modern platforms use algorithms for spaced review. They schedule tasks and mix up questions. They also automatically highlight weak knowledge. This is important. Retrieval practice works in real classrooms, not just in lab tests (Agarwal et al., 2021). Research on custom review also shows better retention at the end of a course than both c

A big change happened in late 2023. EdTech now links memory science with live learner data. The Department for Education updated its AI guidance. They did this on 26 October 2023 and again in 2025. Schools now have clearer rules for using AI tools. They can use them if they check privacy and safety (DfE, 2025). Seneca now mixes AI quiz creation with auto-marking. It also gives Smart Learning tips. Carousel Learning uses C-Scores instead. These scores rely on spacing, repetition and s

In a Year 8 science lesson, the teacher says, "Open today's retrieval starter. Yours will not all look the same." One learner gets three questions on particle movement because she missed them last week, another gets acids and alkalis from last month, and both see instant feedback before improving their answers. That kind of real-time memory tracking is not a perfect map of memory, but it is a practical way of building personalised forgetting curves from accuracy, timing and prior errors.

For teachers, the value is simple. It reduces your workload. You do not have to hand-build every retrieval sheet. You do not need to decide every review interval or mark every quiz. A dashboard shows who needs reteaching and who can move on. In your next lesson, try a new starter task. Let the platform schedule follow-up questions based on learner errors. This is better than giving everyone the same revision list.

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Frequently Asked Questions

Why Ebbinghaus Matters to Teachers

Ebbinghaus showed memory fades without support. Learners can lose 80% of new facts quickly. Teachers can use this to plan timely support (Ebbinghaus, date unknown). This aids learner retention with good strategies.

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When Should Students Review Learning?

The most vital time is the first two hours after learning. This is when the sharpest drop in memory happens. Research shows that reviewing work within 24 hours boosts memory. It can increase how much learners remember by up to 80%. This makes quick review after lessons vital to stop memory loss.

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Building Review Cycles Into Lessons

Spaced recall soon after learning aids memory (Roediger & Karpicke, 2006). Longer gaps between sessions improve later recall. When learners retrieve facts well, they remember more (Ebbinghaus, 1885; Pavlik & Anderson, 2008). This reduces forgetting and boosts long-term learning.

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Memory Techniques Beyond Simple Revision

Teachers can use colour, seating, and displays as memory aids. Connect new content to learners' lives and previous learning. This strengthens memory (Anderson, 2000). Low-stakes quizzes and recall work better than passive review (Brown et al., 2014; Roediger & Karpicke, 2006).

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Why Does Retention Vary by Student?

Individual memory varies due to age, ability, stress, sleep, and relevance. Teachers can connect new learning to what learners already know. Manage classroom stress and highlight practical uses of information. This helps all learners remember things better.

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Which Encoding Strategies Boost Learning?

Memory aids, like 'Never eat shredded wheat', help learners recall sequences. The memory palace method links facts to familiar places. This method also helps learners remember more. These coding methods boost recall and cut down forgetting (Ericsson et al., 2018).

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Free Memory Retention Teaching Pack

The Free Memory Retention Teaching Pack is a classroom toolkit with practical materials on memory, brain development and thinking. It covers the neuroscience of learning, brain growth, and thinking. It includes printable posters, desk cards, and CPD materials.

Free Resource Pack
Neuroscience of Remembering and Forgetting
These are key resources for understanding brain science. They help teachers use science to improve learning and teaching.


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Further Reading: Key Papers on The Forgetting Curve

These peer-reviewed studies provide the research foundation for the strategies discussed in this article.

Replication and Analysis of Ebbinghaus' Forgetting Curve View study ↗
609 citations

J. Murre, J. Dros (2015), PLoS ONE

A 2015 replication of Ebbinghaus's work confirmed the forgetting curve, but also found improved recall after 24 hours, suggesting sleep aids memory consolidation. This highlights the importance of allowing students time to sleep and process new information for better retention.

Memory: a contribution to experimental psychology View study ↗
670 citations

H. Ebbinghaus (1987), Annals of Neurosciences (reprint of 1885 original)

Ebbinghaus's original work scientifically explored the nature of memory and forgetting. Understanding these early experiments can help teachers appreciate the cognitive processes at play when students struggle to retain information.

A new look at memory retention and forgetting View study ↗
50 citations

G. Radvansky et al. (2022), Journal of Experimental Psychology: Learning, Memory, and Cognition

Radvansky et al. (2022) challenge Ebbinghaus's single forgetting curve, proposing that memory decays differently across distinct phases. This suggests teachers should tailor revision schedules to match the specific memory phase, rather than relying on a uniform approach.

Enhancing human learning via spaced repetition optimization View study ↗
150 citations

Behzad Tabibian et al. (2019), Proceedings of the National Academy of Sciences

Tabibian et al. (2019) found that spaced repetition is most effective when review schedules are tailored to an individual's recall probability. This research provides an empirical basis for using AI to optimise spaced repetition, helping students to memorise information more effectively.

Spaced Learning Enhances Episodic Memory by Increasing Neural Pattern Similarity Across Repetitions View study ↗
53 citations

Kanyin Feng et al. (2019), The Journal of Neuroscience

Spaced learning strengthens memory because repeated exposure to information triggers similar brain activity patterns. This neurological evidence supports the idea that recalling information during study sessions boosts learning. Teachers can use this knowledge to design more effective revision schedules.