The Ebbinghaus Forgetting Curve: Why Students Forget and
Ebbinghaus showed that 70% of new information is lost within 24 hours without review. Apply spacing, retrieval practice and interleaving to flatten the...
What is the Ebbinghaus Forgetting Curve?
The Ebbinghaus Forgetting Curve is a fundamental concept in the psychology of memory, developed by Hermann Ebbinghaus in the late 19th century. It provides a visual representation of how quickly information fades from our memory over time if it is not actively reinforced.
Key Takeaways
- Immediate review is critical to prevent rapid memory decay. The Ebbinghaus Forgetting Curve demonstrates that pupils forget a significant portion of newly learned material within hours if not reinforced. Implementing retrieval practice shortly after initial learning significantly reduces this initial, rapid memory decline, as evidenced by research on the testing effect (Roediger & Karpicke, 2006).
- Spaced repetition fundamentally outperforms massed practice for long-term retention. The spacing effect, a robust finding in cognitive psychology, proves that distributing learning over time dramatically improves pupils' long-term memory, rather than cramming (Bjork & Bjork, 1992). Teachers should integrate spaced retrieval practice into curriculum planning, ensuring pupils revisit content at increasing intervals to strengthen memory traces and enhance recall efficiency (Dunlosky et al., 2013).
- Active retrieval practice is one of the most potent strategies to combat the forgetting curve. Research consistently shows that the act of retrieving information from memory, known as the testing effect, is far more effective for consolidating learning than passive re-reading (Roediger & Karpicke, 2006). Regular low-stakes quizzes, self-testing, and explaining concepts without notes force pupils to actively recall information, strengthening memory pathways and making recall more robust.
- Varying learning contexts and utilising environmental cues significantly aids memory retrieval. The encoding specificity principle posits that memory recall is enhanced when retrieval cues match those present during encoding (Tulving & Thomson, 1973). Teachers can leverage this by varying the context of learning and retrieval, or by intentionally creating specific classroom cues, to provide pupils with multiple pathways to access stored information, making recall more robust and less susceptible to forgetting (Godden & Baddeley, 1975).
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.
The curve illustrates that memory retention drops sharply within the first few hours after learning, often dramatically so due to working memory decay. This decline is not linear; instead, it follows an exponential pattern, with rapid initial forgetting that eventually slows down over subsequent days. This phenomenon underscores the critical role of timely review and reinforcement to counteract the natural forgetting process.
For educators, understanding the dynamics of this curve is key to designing effective teaching strategies that help students retain information more effectively. By recognising when memory loss is most pronounced, teachers can implement timely interventions, such as spaced repetition and active recall, that maximise retention and deepen learning.
The theoretical foundations of the Ebbinghaus Forgetting Curve, discuss how it can be practically applied in educational contexts, and offer strategies to help combat forgetting in the classroom.
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.
- 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.
- Begin each lesson with a review of previous learning
- Have weekly and monthly reviews of previous learning
- Re-reading notes
- Highlighting text
- Answering multiple-choice questions
- 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. - 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. - Basic Training and Memory Representation
Ebbinghaus’s model does not differentiate between different types of training or memory representation. Basic training exercises, like rote memorization, 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. - 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. - 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. - Murre, J., & Dros, J. (2015). Replication and Analysis of Ebbinghaus’ Forgetting Curve. PLoS ONE, 10.
- 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.
- Jaber, M., & Bonney, M. (1996). Production breaks and the learning curve: The forgetting phenomenon. Applied Mathematical Modelling, 20, 162-169.
- Miller, R. R. (2021). Failures of memory and the fate of forgotten memories. Neurobiology of Learning and Memory, 181.
- 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.
What does the Curve Teach us About Forgetting?
The forgetting curve shows that we forget the majority of new information soon after it is initially learnt. Ebbinghaus defined forgetting as an ability to recall information in the absence of any cues.
Our ability to recognise new information does not follow the same pattern; being presented with cues or multiple-choice options increases the accuracy of our memory.
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.
New information that is of significant value, is related to a major event, or offers a surprising contradiction to previously learnt material, is less likely to be forgotten at such a rapid rate.
What Factors Influence the Decline of Memory?
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.
The quality of learning also has a significant impact on whether the new material will be resistant to the steep decline in memory observed by Ebbinghaus. Information that is fully understood or deeply processed is likely to be forgotten less quickly.
Similarly, if the new information is of personal significance or has a practical application, it is more likely to be remembered well, partly because the person is more motivated to encode it effectively into their long-term memory.
When new information is similar or related to prior learning, it can impact the decline in memory in both directions.
Retention increases if new knowledge is assimilated into a pre-existing schema of related information in the long-term memory because the prior learning offers an abundance of cues for the new information.
However, when information is similar but unrelated to something that has been previously learnt it can increase the decline in memory for the new information (proactive interference) or the previously learnt information (retroactive interference).
Both types of interference can be seen when learning a new foreign language; words from a previously learnt foreign language may be forgotten when the new language is learnt (retroactive) or it can be more difficult to learn new vocabulary if it is too similar to the previously learnt vocabulary.
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:
How Can Teachers Combat the Forgetting Curve in the Classroom?
Teachers can combat the forgetting curve through three evidence-based strategies: implementing spaced repetition by reviewing material at increasing intervals, using active recall techniques like frequent low-stakes quizzing, and creating meaningful connections between new information and students' prior knowledge. Research shows that reviewing material within 24 hours can increase retention by up to 80%, while combining these techniques can help students retain information for months or even years.
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 Practise
The most effective way to challenge the forgetting curve is through repeated retrieval practise. The first attempt to retrieve the new information should be soon after it was originally learnt, with subsequent retrievals becoming increasingly spread out over longer time periods (spaced repetition).
Each successful retrieval increases the number of cues associated with the information, which flattens the forgetting curve and makes it possible to extend the length of time between future retrievals.
Techniques to Improve Memory
Developing techniques to improve memory will reduce the rate of forgetting, even in the absence of any further attempts to retain the new information.
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.
Another popular technique is creating a memory palace. This involves developing a mental image of a real or imaginary location, often a house or palace, that has vivid and distinct locations throughout it.
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
Having an awareness of memory prompts and incorporating them into the learning process will make it easier to recall the newly learnt information at a later date and slow down the steep decline in memory.
Linking new information to prior learning is one of the most effective ways to achieve this; incorporating the new material into a pre-existing schema will allow it to benefit from all of the existing memory prompts and cues that are already in place.
Alternatively, consider using physical cues or the environment as a memory prompt. For example, writing key terms in a different colour pen, in capital letters, or in a certain position on a piece of paper can act as a memory prompt during subsequent recall attempts.
It can also help to learn new material in the same, or similar, environment to where it will need to be recalled; revising in an exam hall in silence would be more effective than revising in a bedroom with music.
Teaching Applications of Forgetting Curve
The forgetting curve reveals that without review, students lose up to 70% of new information within 24 hours, making immediate and systematic review essential for effective teaching. Teachers should structure lessons to include brief reviews at the start of each class, schedule spaced practise sessions throughout units, and design homework that reinforces rather than introduces concepts. This understanding transforms lesson planning from linear progression to cyclical reinforcement patterns.
Understanding how students forget can allow teachers to make changes to their practise to challenge the Ebbinghaus Forgetting Curve and increase their students’ memory retention. The following approaches are recommended to teachers in response to Ebbinghaus’ research:
1. Regular Retrieval Practise
Repeated exposure to information strengthens memory retention and flattens the forgetting curve. Asking students to retrieve information forces them to revisit the information, even if they recall it incorrectly, due to the corrective feedback that they receive.
The first retrieval practise 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:
It is better to interleave two or more topics together during retrieval practise; this allows the material to be revisited more often and spaced practise to be spread out over time.
2. Review Schemes of Work
Schemes of work should be reviewed to ensure they include regular opportunities for spaced retrieval practise and that topics are arranged by increasing level of difficulty to build on prior learning.
Curriculumplans should be designed to promote mastery by using scaffolding and dividing complex information into smaller and more manageable chunks.
By reducing the volume of new material that students need to learn in each part of the lesson, they are more likely to encode it effectively into their long-term memories.
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 the keywords and related keywords for each topic as this will help students to reorganise the new information, provide more cues to aid recall, and allow them to make links between related topics.
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.
This is particularly important after a test or assessment, and part of the teacher’s feedback should be focussed on the effectiveness of the revision strategies and processes that the student used.
Student Memory Retention Strategies
Being able to accurately recall information gives students a distinct advantage in our current educational system and is a precursor to being able to effectively manipulate and evaluate that information.
Practising active recall strategies and using memory-enhancing techniques as often as possible will challenge the decline in memory that occurs in the absence of retrieval attempts and memory retention strategies.
Active recall requires students to access information from their long-term memory in the absence of 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.
There are no restrictions or demands about what information can be recalled, which means that students will often also benefit from hearing what their peers have been able to recall. Answering practise questions, defining or generating a list of keywords, or completing an assessment are other useful examples of active recall.
Activities that involve passive recall are much less effective at improving memory. These include:
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 are an effective way to boost memory, especially when it is necessary to remember a list of words in order. Students may also benefit from using dual codingto memorise key words or definitions; this involves pairing the new material with a particularly vivid image to make it more memorable.
For further reading on this topic, explore our guide to Declarative Memory.
Forgetting Curve Limitations in Education
While groundbreaking, Ebbinghaus's original research used nonsense syllables rather than meaningful content, which may not accurately reflect how students learn complex subject matter with personal relevance. The curve also doesn't account for individual differences in learning styles, prior knowledge, or emotional connections to material, all of which can significantly impact retention rates. Modern research suggests that meaningful, contextualized learning can create much flatter forgetting curves than Ebbinghaus originally documented.
While the Ebbinghaus Forgetting Curve has been a foundational concept in understanding how memory retention declines over time, recognise its limitations. The original research conducted by Hermann Ebbinghaus focused on memorizing nonsensical syllables in a controlled environment, which is far removed from the complexity of real-world learning. Therefore, while the Forgetting Curve provides useful insights into the general pattern of memory loss, several limitations should be acknowledged to apply this theory effectively to different learning contexts. Below, we discuss five potential limitations of Ebbinghaus's theory.
By understanding these limitations, educators can more effectively apply and adapt Ebbinghaus's insights to various learning scenarios, allowing for improved methods to enhance long-term memory retention.
Additional Forgetting Curve Resources
Teachers can deepen their understanding through Hermann Ebbinghaus's original work 'Memory: A Contribution to Experimental Psychology' (1885) and modern applications in books like 'Make It Stick' by Brown, Roediger, and McDaniel. Educational psychology journals regularly publish studies on spaced repetition and memory retention, while organisations like the Learning Scientists provide free, research-based resources for classroom implementation. Many teacher training programmes now include modules on cognitive science and memory research.
Subsequent research has supported the concept of an exponential forgetting curve and the conclusions that can be drawn from Ebbinghaus’ research to challenge the decline in memory have been shown to effectively improve memory in real-life settings. To learn more about these studies and the Ebbinghaus forgetting curve, please use the links below.
How Fast Do We Forget?
The speed at which we forget new information is startling. 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 pupils learn in Monday's lesson will be gone by Tuesday morning.
The forgetting curve follows a predictable pattern that teachers can use to their advantage. The steepest decline occurs within the first 24 hours, particularly in the first few hours after learning. After one week, retention typically drops to just 10-20% of the original material. However, the rate of forgetting slows considerably after this initial plunge, meaning that information surviving the first week has a better chance of remaining in long-term memory.
Understanding these timeframes allows teachers to schedule reviews strategically. For instance, a maths teacher introducing fractions on Monday morning should plan a brief recap that same afternoon, perhaps through a quick starter activity. A more substantial review on Wednesday, followed by another the following Monday, can dramatically improve retention rates from 20% to over 80%.
The implications for homework timing are equally significant. Setting homework immediately after a lesson capitalises on the critical review window, whilst waiting until the end of the week wastes this opportunity. Similarly, spacing topic tests across several weeks, rather than cramming them at the end of a unit, aligns assessment practices with how memory actually works.
Factors That Influence the Forgetting Curve
Not all forgetting happens at the same rate, and understanding what accelerates or slows memory loss can transform your teaching practise. Research shows that several key factors determine how steeply the forgetting curve drops for each pupil, making some information stick whilst other content vanishes within hours.
The complexity of material plays a crucial role in retention rates. Simple facts and isolated information tend to disappear rapidly, whilst concepts linked to existing knowledge create stronger memory networks. For instance, teaching fractions becomes more memorable when connected to pizza slices or chocolate bars rather than abstract numbers. Similarly, stress and fatigue significantly steepen the forgetting curve; a Year 11 student revising for multiple GCSEs will struggle to retain information learnt during period 6 on a Friday afternoon compared to fresh material covered on Monday morning.
Sleep quality directly impacts memory consolidation, with studies showing that pupils who get less than seven hours nightly forget 40% more content than well-rested peers. This explains why homework reviewed the next morning often seems unfamiliar to tired students. Physical health and nutrition also matter; dehydration alone can reduce memory performance by up to 20%, making those water bottles on desks more than just a comfort measure.
Perhaps most importantly for teachers, the initial strength of encoding determines retention duration. Information learnt through active participation, emotional engagement, or personal relevance creates deeper memory traces. A history lesson where pupils role-play Victorian children in a workhouse will outlast any textbook reading. By recognising these factors, teachers can adjust their practise accordingly, scheduling complex topics for optimal times and ensuring proper conditions for learning.
Frequently Asked Questions
What is the Ebbinghaus Forgetting Curve and why is it important for educators?
The Ebbinghaus Forgetting Curve is a visual representation showing how quickly information fades from memory over time without active reinforcement. It demonstrates that memory retention drops sharply within the first few hours after learning, with students potentially losing up to 80% of information. Understanding this curve helps teachers implement timely interventions to maximise student retention and design more effective teaching strategies.
When is the most critical time to review material with students according to the forgetting curve?
The most critical period is within the first two hours after learning, when the sharpest decline in memory occurs. Research shows that reviewing material within 24 hours can increase retention by up to 80%. This makes immediate review after lessons essential rather than optional for preventing massive information loss.
How can teachers implement spaced repetition effectively in their classroom practise?
Teachers should schedule the first retrieval practise soon after initial learning, then gradually increase the intervals between subsequent reviews. Each successful retrieval strengthens memory and allows for longer gaps between future practise sessions. This approach flattens the forgetting curve and helps students retain information for months or even years.
Beyond Traditional Revision: Advanced Memory Techniques
Teachers can transform classroom environments into memory aids by using coloured pens, strategic seating arrangements, and wall displays as retrieval cues. They should also connect new content to students' personal experiences and prior knowledge, as information with personal significance creates stronger memory resistance. Low-stakes quizzing and active recall techniques are more effective than passive review methods.
Why do some students remember information better than others, and how can teachers account for these differences?
Individual memory strength varies due to factors including age, cognitive ability, stress levels, sleep quality, and personal significance of the material. Teachers can address these variations by helping students make meaningful connections to prior learning, managing classroom stress levels, and emphasising the practical applications of new information. Creating personally relevant contexts for learning significantly improves retention rates across all students.
What memory techniques can teachers introduce to help students encode information more effectively?
Teachers can introduce mnemonic devices like acronyms for remembering sequences, such as 'Never eat shredded wheat' for compass directions or 'Richard of York gave battle in vain' for rainbow colours. The memory palace technique, where students associate information with vivid locations in a familiar setting, can also be highly effective. These encoding strategies make information easier to retrieve and naturally flatten the forgetting curve.
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Further Reading: Key Research Papers
These peer-reviewed studies provide deeper insights into ebbinghaus forgetting curve and its application in educational settings.
This paper compares traditional lecture-based teaching methods with modern e-learning approaches, examining how different instructional strategies affect student engagement and learning outcomes. For teachers interested in the Ebbinghaus Forgetting Curve, this research is relevant because it explores how interactive digital learning methods might help combat memory decay by providing more engaging and memorable learning experiences than passive traditional instruction.
Barriers and Facilitators to Teachers’ Use of behavioural Classroom Interventions 26 citations Lawson et al. (2022) This study investigates what prevents or encourages teachers from implementing behavioural classroom interventions, particularly for students with ADHD or behavioural challenges. The research connects to the Ebbinghaus Forgetting Curve by highlighting how consistent implementation of behavioural strategies is crucial for long-term retention, as inconsistent or infrequent use of interventions leads to faster forgetting of desired behaviours and academic content. The impact of an interactive digital learning module on students’ academic performance and memory retention 15 citations Tarigan et al. (2023) This research examines how interactive digital learning modules affect student academic performance and memory retention compared to traditional electronic learning methods. The study directly relates to the Ebbinghaus Forgetting Curve by providing empirical evidence on how interactive digital toolscan slow memory decay and improve information retention over time.Undergraduate Biology Instructors Still Use Mostly Teacher-Centred Discourse Even When Teaching with Active Learning Strategies 22 citations Kranzfelder et al. (2020)
This study reveals that biology instructors continue to use teacher-centred communication patterns even when implementing active learning strategies in their classrooms. For educators concerned with memory retention and the forgetting curve, this research suggests that simply adopting active learning techniques may not be enough if the underlying discourse remains passive, potentiall y limiting the memory-enhancing benefits of student engagement.
Happy Together? On the Relationship Between Research on Retrieval Practise and Generative Learning Using the Case of Follow-Up Learning Tasks View study ↗30 citations
Roelle et al. (2023)
This paper explores the relationship between retrieval practise and generative learning activities, examining how they work together to support both memory consolidation and the construction of coherent mental representations. The research is highly relevant to understanding the Ebbinghaus Forgetting Curve because it demonstrates how retrieval practise specifically helps consolidate information in memory, directly addressing the memory decay that Ebbinghaus documented in his forgetting curve research.
