Forgetting curve

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A representation of the forgetting curve showing retained information halving after each day Forgetting curve decline.svg
A representation of the forgetting curve showing retained information halving after each day

The forgetting curve hypothesizes the decline of memory retention in time. This curve shows how information is lost over time when there is no attempt to retain it. [1] A related concept is the strength of memory that refers to the durability that memory traces in the brain. The stronger the memory, the longer period of time that a person is able to recall it. A typical graph of the forgetting curve purports to show that humans tend to halve their memory of newly learned knowledge in a matter of days or weeks unless they consciously review the learned material.

Contents

The forgetting curve supports one of the seven kinds of memory failures: transience, which is the process of forgetting that occurs with the passage of time. [2]

History

The forgetting curve, with original data from Ebbinghaus Ebbinghaus curve.png
The forgetting curve, with original data from Ebbinghaus

From 1880 to 1885, Hermann Ebbinghaus ran a limited, incomplete study on himself and published his hypothesis in 1885 as Über das Gedächtnis (later translated into English as Memory: A Contribution to Experimental Psychology). [3] Ebbinghaus studied the memorisation of nonsense syllables, such as "WID" and "ZOF" (CVCs or Consonant–Vowel–Consonant) by repeatedly testing himself after various time periods and recording the results. He plotted these results on a graph creating what is now known as the "forgetting curve". [3] Ebbinghaus investigated the rate of forgetting, but not the effect of spaced repetition on the increase in retrievability of memories. [4]

Ebbinghaus's publication also included an equation to approximate his forgetting curve: [5]

Here, represents 'Savings' expressed as a percentage, and represents time in minutes, counting from one minute before end of learning. The constants c and k are 1.25 and 1.84 respectively. Savings is defined as the relative amount of time saved on the second learning trial as a result of having had the first. A savings of 100% would indicate that all items were still known from the first trial. A 75% savings would mean that relearning missed items required 25% as long as the original learning session (to learn all items). 'Savings' is thus, analogous to retention rate.

In 2015, an attempt to replicate the forgetting curve with one study subject has shown the experimental results similar to Ebbinghaus' original data. [6]

Ebbinghaus' experiment has significantly contributed to experimental psychology. He was the first to carry out a series of well-designed experiments on the subject of forgetting, and he was one of the first to choose artificial stimuli in the research of experimental psychology. Since his introduction of nonsense syllables, a large number of experiments in experimental psychology has been based on highly controlled artificial stimuli. [6]

Increasing rate of learning

Hermann Ebbinghaus hypothesized that the speed of forgetting depends on a number of factors such as the difficulty of the learned material (e.g. how meaningful it is), its representation and other physiological factors such as stress and sleep. He further hypothesized that the basal forgetting rate differs little between individuals. He concluded that the difference in performance can be explained by mnemonic representation skills.

He went on to hypothesize that basic training in mnemonic techniques can help overcome those differences in part. He asserted that the best methods for increasing the strength of memory are:

  1. better memory representation (e.g. with mnemonic techniques)
  2. repetition based on active recall (especially spaced repetition).
Forgetting Curve with Spaced Repetition ForgettingCurve.svg
Forgetting Curve with Spaced Repetition

His premise was that each repetition in learning increases the optimum interval before the next repetition is needed (for near-perfect retention, initial repetitions may need to be made within days, but later they can be made after years). He discovered that information is easier to recall when it's built upon things you already know, and the forgetting curve was flattened by every repetition. It appeared that by applying frequent training in learning, the information was solidified by repeated recalling.

Later research also suggested that, other than the two factors Ebbinghaus proposed, higher original learning would also produce slower forgetting. The more information was originally learned, the slower the forgetting rate would be. [7]

Spending time each day to remember information will greatly decrease the effects of the forgetting curve. Some learning consultants claim reviewing material in the first 24 hours after learning information is the optimum time to actively recall the content and reset the forgetting curve. [8] Evidence suggests waiting 10–20% of the time towards when the information will be needed is the optimum time for a single review. [9]

Some memories remain free from the detrimental effects of interference and do not necessarily follow the typical forgetting curve as various noise and outside factors influence what information would be remembered. [10] There is debate among supporters of the hypothesis about the shape of the curve for events and facts that are more significant to the subject. [11] Some supporters, for example, suggest that memories of shocking events such as the Kennedy Assassination or 9/11 are vividly imprinted in memory (flashbulb memory). [12] Others have compared contemporaneous written recollections with recollections recorded years later, and found considerable variations as the subject's memory incorporates after-acquired information. [13] There is considerable research in this area as it relates to eyewitness identification testimony, and eyewitness accounts are found demonstrably unreliable. [13]

Equations

Many equations have since been proposed to approximate forgetting, perhaps the simplest being an exponential curve described by the equation [14]

where is retrievability (a measure of how easy it is to retrieve a piece of information from memory), is stability of memory (determines how fast falls over time in the absence of training, testing or other recall), and is time.

Simple equations such as this one were not found to provide a good fit to the available data. [15]

See also

Notes

  1. Curve of Forgetting | Counselling Services
  2. Schacter, D. L. (2009). Psychology . New York: Worth Publishers. p.  243. ISBN   978-1-4292-3719-2.
  3. 1 2 Ebbinghaus, Hermann (1913). Memory: A Contribution to Experimental Psychology. Translated by Ruger, Henry; Bussenius, Clara. New York city, Teachers college, Columbia university.
  4. Wozniak, Piotr (22 November 2017). "Did Ebbinghaus invent spaced repetition?". www.supermemo.com. Retrieved 2020-07-11.
  5. Ebbinghaus (1913), p. 77
  6. 1 2 Murre, Jaap M. J.; Dros, Joeri (2015). "Replication and Analysis of Ebbinghaus' Forgetting Curve". PLOS ONE . 10 (7): e0120644. Bibcode:2015PLoSO..1020644M. doi: 10.1371/journal.pone.0120644 . PMC   4492928 . PMID   26148023.
  7. Loftus, Geoffrey R. (1985). "Evaluating forgetting curves" (PDF). Journal of Experimental Psychology: Learning, Memory, and Cognition. 11 (2): 397–406. CiteSeerX   10.1.1.603.9808 . doi:10.1037/0278-7393.11.2.397. Archived (PDF) from the original on 2006-09-10.
  8. Curve of Forgetting | Counselling Services
  9. Pashler, Harold; Rohrer, Doug; Cepeda, Nicholas J.; Carpenter, Shana K. (2007-04-01). "Enhancing learning and retarding forgetting: Choices and consequences". Psychonomic Bulletin & Review. 14 (2): 187–193. doi: 10.3758/BF03194050 . ISSN   1069-9384. PMID   17694899.
  10. Averell, Lee; Heathcote, Andrew (2011). "The form of the forgetting curve and the fate of memories". Journal of Mathematical Psychology. 55: 25–35. doi:10.1016/j.jmp.2010.08.009. hdl: 1959.13/931260 .
  11. Forgetting Curve | Training Industry
  12. Paradis, C. M.; Florer, F.; Solomon, L. Z.; Thompson, T. (August 1, 2004). "Flashbulb Memories of Personal Events of 9/11 and the Day after for a Sample of New York City Residents". Psychological Reports. 95 (1): 309. doi:10.2466/pr0.95.1.304-310. PMID   15460385. S2CID   46013520.
  13. 1 2 "Why Science Tells Us Not to Rely on Eyewitness Accounts". Scientific American. doi:10.1038/scientificamericanmind0110-68.
  14. Woźniak, Piotr A.; Gorzelańczyk, Edward J.; Murakowski, Janusz A. (1995). "Two components of long-term memory" (PDF). Acta Neurobiologiae Experimentalis. 55 (4): 301–305. PMID   8713361. Archived (PDF) from the original on 2010-09-20.
  15. Rubin, David C.; Hinton, Sean; Wenzel, Amy (1999). "The precise time course of retention". Journal of Experimental Psychology: Learning, Memory, and Cognition. 25 (5): 1161–1176. doi:10.1037/0278-7393.25.5.1161. hdl: 10161/10146 .

Related Research Articles

<span class="mw-page-title-main">Forgetting</span> Loss or modification of information encoded in an individuals memory

Forgetting or disremembering is the apparent loss or modification of information already encoded and stored in an individual's short or long-term memory. It is a spontaneous or gradual process in which old memories are unable to be recalled from memory storage. Problems with remembering, learning and retaining new information are a few of the most common complaints of older adults. Studies show that retention improves with increased rehearsal. This improvement occurs because rehearsal helps to transfer information into long-term memory.

<span class="mw-page-title-main">Hermann Ebbinghaus</span> German psychologist (1850–1908)

Hermann Ebbinghaus was a German psychologist who pioneered the experimental study of memory, and is known for his discovery of the forgetting curve and the spacing effect. He was also the first person to describe the learning curve. He was the father of the neo-Kantian philosopher Julius Ebbinghaus.

Long-term memory (LTM) is the stage of the Atkinson–Shiffrin memory model in which informative knowledge is held indefinitely. It is defined in contrast to sensory memory, the initial stage, and short-term or working memory, the second stage, which persists for about 18 to 30 seconds. LTM is grouped into two categories known as explicit memory and implicit memory. Explicit memory is broken down into episodic and semantic memory, while implicit memory includes procedural memory and emotional conditioning.

<span class="mw-page-title-main">Spaced repetition</span> Learning technique performed with flashcards

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<span class="mw-page-title-main">Rote learning</span> A memorization technique based on repetition

Rote learning is a memorization technique based on repetition. The method rests on the premise that the recall of repeated material becomes faster the more one repeats it. Some of the alternatives to rote learning include meaningful learning, associative learning, spaced repetition and active learning.

Recall in memory refers to the mental process of retrieval of information from the past. Along with encoding and storage, it is one of the three core processes of memory. There are three main types of recall: free recall, cued recall and serial recall. Psychologists test these forms of recall as a way to study the memory processes of humans and animals. Two main theories of the process of recall are the two-stage theory and the theory of encoding specificity.

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The Decay theory is a theory that proposes that memory fades due to the mere passage of time. Information is therefore less available for later retrieval as time passes and memory, as well as memory strength, wears away. When an individual learns something new, a neurochemical "memory trace" is created. However, over time this trace slowly disintegrates. Actively rehearsing information is believed to be a major factor counteracting this temporal decline. It is widely believed that neurons die off gradually as we age, yet some older memories can be stronger than most recent memories. Thus, decay theory mostly affects the short-term memory system, meaning that older memories are often more resistant to shocks or physical attacks on the brain. It is also thought that the passage of time alone cannot cause forgetting, and that decay theory must also take into account some processes that occur as more time passes.

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<span class="mw-page-title-main">Testing effect</span> Memory effect in educational psychology

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Memory has the ability to encode, store and recall information. Memories give an organism the capability to learn and adapt from previous experiences as well as build relationships. Encoding allows a perceived item of use or interest to be converted into a construct that can be stored within the brain and recalled later from long-term memory. Working memory stores information for immediate use or manipulation, which is aided through hooking onto previously archived items already present in the long-term memory of an individual.

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The forward testing effect, also known as test potentiated new learning, is a psychological learning theory which suggests that testing old information can improve learning of new information. Unlike traditional learning theories in educational psychology which have established the positive effect testing has when later attempting to retrieve the same information, the forward testing effect instead suggests that the testing experience itself possesses unique benefits which enhance the learning of new information. This memory effect is also distinct from the 'practice effect' which typically refers to an observed improvement which results from repetition and restudy, as the testing itself is considered as the catalyst for improved recall. Instead, this theory suggests that testing serves not only as a tool for assessment but as a learning tool which can aid in memory recall. The forward testing effect indicates that educators should encourage students to study using testing techniques rather than restudying information repeatedly.

References