Forgetting

1. Um I forget….. Forgetting

2. Forgetting • Forgetting – refers to the inability to retrieve previously stored information. • The information may still be stored in your memory but you are unable to retrieve it when you want to for some reason. • If you didn’t forget, your mind would be too cluttered with so much info. you would have difficulty retrieving and selecting the information you need. Remembering might take hours rather than seconds! • Forgetting has an adaptive purpose and contributes to our survival and our sanity.

3. The Forgetting Curve • German psychologist, Hermann Ebbinghaus was the first person to scientifically study forgetting in the late 1800s. • Ebbinghaus sought to measure the amount of information retained and the rate at which information is forgotten.

4. Ebbinghaus’ research • Ebbinghaus learned a series of lists of 13 three-letter nonsense syllables (e.g. qel, nuz) until he could recite them all without error on 2 successive occasions. • Used nonsense syllables as they are all equally difficult to learn and don’t have a specific meaning or personal associations like words where his past experience of the information being learned may influence forgetting.

5. Ebbinghaus’ research • Ebbinghaus tested his recall of each list after a specific period of time had elapsed from the initial learning. The delay period ranged from 20 minutes to 31 days. • Ebbinghaus was then able to measure the amount (quantity) and rate (speed) of forgetting.

6. Ebbinghaus’ research results • 20 minutes 58% recalled • 1 hour 44% recalled • 1 day 34% recalled • 1 week 21% recalled • The graph that demonstrates Ebbinghaus’ findings is known as the forgetting curve.

7. The forgetting curve

8. The Forgetting Curve • The forgetting curve shows the pattern (rate and amount) of forgetting that occurs over time. • Forgetting is rapid soon after original learning and then rate of memory loss gradually declines followed by stability in the memories that remain. • More than half memory loss occurs in the first hour after learning. • Almost all material that will be forgotten is lost in the first eight hours (about 65%).

9. Other “forgetting” research • Since Ebbinghaus, other research using different kinds of learned information has found results that consistently indicate a characteristic pattern of forgetting demonstrated by the forgetting curve. Learning: New skill similar to flying plane (Fleishman & Parker, 1962) New language (Bahrick, 1984) Cardio-pulmonary resuscitation (McKenna & Glendon, 1985) Psychology subject (Conway, Cohen & Stanhope, 1991)

10. Lengthier learning period • When initial learning takes place over more extended periods of time, (e.g. weeks or months) more information is retained, but the rate at which information is lost remains the same. • See graph on following slide.

11. The forgetting curve

12. Influences on forgetting • The pattern of forgetting outlined by the forgetting curve is applicable to a wide variety of materials under many conditions. • However, the more meaningful the material, the slower the rate of forgetting. • How well the information is initially encoded influences the amount and rate of forgetting. The better the initial learning, the longer it is likely to be retained. • When material is well learned, the rate of retention is about the same whether the material is difficult or not and whatever the learning ability of the individual. • Slow learners and fast learners both forget at about the same rate. • Easily learned material does not appear to be retained longer than more difficult material.

13. Measures of retention – measuring memory • Research findings suggest that the amount of information that will be retrieved from memory depends, at least partly, on the type of retrieval question asked. • Three kinds of measures are used to determine how much information has been retained: recall, recognition and relearning.

14. Measures of Retention – Measuring MemoryRecall • Recall - Being asked to reproduce information with the fewest possible cues to assist retrieval. e.g. Required to learn a list of randomly selected words. • Free Recall – when participants are simply asked to remember as much information as possible in no particular order –e.g. List of grocery items • Serial Recall – asked to recall information in a particular orderNames of Cities (itinerary) • During recall a general cue is used to retrieve information associated with the cue, by searching through LTM storage system to find something that matches the cue (Best, 1999). However, often the general cue doesn’t provide enough of a hint to enable location of the relevant information because the list of possible matches is quite large. • Therefore, the more specific the cue, the more likely location and retrieval of the relevant information from LTM.

15. Recall • Cued Recall - makes use of more specific cues to aid retrieval. Given a cue then asked to recall e.g. Seven Dwarfs: first letter of • B, G, S, D, D, H, S

16. Measures of Retention – Measuring MemoryRecognition • Identifying correct information from among alternatives. Can retrieve more this way as recognition provides more cues for retrieving from LTM. Example – multiple choice Q’s • Recognition is more sensitive measure of memory than recall for testing information stored in LTM. • Uni students asked to recall seven dwarfs – mean of 69% of the names. When given a list of alternatives from which to select the seven names, the accuracy rate increased to a mean of 86% (Meyer & Hilterbrand, 1984).

17. Recognition • Generally, irrespective of the kind of information, people can typically recognise more than they can recall. • In recall we ask: “What is the item?” • In recognition we ask “Is this the item?” • Incorrect alternative answers (“distractors”) on multiple choice questions are extremely similar to the correct answers.

18. Measures of Retention – Measuring MemoryRelearning • Even if can’t recall or recognize doesn’t mean there is no memory. • Relearning or the “method of savings” involves learning information again that has been previously learned and stored in LTM. • If information is learned more quickly the second time, it is assumed that there must be some information retained (or “saved”) from the first learning experience, whether the person realises it or not. • Relearning is considered the most sensitive measure of retention.

19. Relearning • By “re-studying” a weak association regains its original strength in memory. It’s as if the previous experience has prepared us for remembering the material better when we encounter it again. • Ebbinghaus (1885) was the first researcher to scientifically study relearning. He found that even if he couldn’t remember a single word from the original list, he could relearn the list of nonsense syllables much more quickly a second time than the time he took to initially learn the list. He assumed therefore, that some information had been retained from the initial learning.

20. Savings Score • If initial learning took 10 trials to remember list and then six months later it only took 5 trials to relearn the list the savings would be 50%. Savings = (no. of trials for original learning) – (no. of trials for relearning 100 ____________________________________________________________________________________________________ X __ (no. of trials for original learning) 1

21. Savings score • Savings scores can also be calculated on the basis of the time taken to relearn information.

22. Measures of retention - sensitivity • The sensitivity of a measure of retention refers to its ability to assess the amount of information that has been stored in memory. • Recall worst • Recognition better • Relearning best (i.e. More likely to detect information that has been learned and stored in memory at some point in the past).

23. Research on sensitivity of 3 measures of retention • Nelson (1978) used 24 uni students. • 3 stages of experiment • 1. Initial learning stage • 2. Stage in which recall and recognition were tested. • 3. A relearning stage Students were not told of the second and third stages of the experiment at the beginning.

24. Research on sensitivity • 1st. Stage – given a series of 20 number-word pairs to learn (e.g. 48-party, 95-horse) – these are called “paired associates”. • 2nd. Stage – 4 weeks later – participants required to participate in testing and relearning stages. Testing – complete 2 different types of tests of memory – a test of recall (given 48 and then asked for the word) and then a test of recognition (given 48 then 20 possible words to pick the correct word of the pair). Then participants given a distraction task for 10 minutes. 3rd. Stage – relearning ten of previously learned paired associates that were incorrectly recalled earlier as well as ten new paired associates. Then given a test of recall and debriefed before leaving.

25. Research results on sensitivity • Mean of 48% of target words correctly recalled • Mean of 69% of target words correctly recognised (2nd. Stage) • Target words correctly recalled after relearning was 88% for old items and much higher than for the new items. • These results were found to be statistically significant at p<0.001 (an acceptable difference) – due to the types of measure of retention used rather than due to chance factors. • See Table 7.1 on p. 369

26. Theories of Forgetting • Psychologists have developed a number of theories to explain why we forget. 1. The right retrieval cue or prompt is not used 2. There is interference from competing material 3. There is some underlying motivation not to remember 4. Memory fades through disuse over time. No single theory alone is able to explain all instances of forgetting. • The inability to retrieve previously stored information. If you forget that doesn’t mean that the information is gone forever, it simply means that for whatever reason you have failed to retrieve that information.

27. Theories of forgetting • Retrieval Failure Theory: Forget because fail to use the right retrieval cue. • A retrieval cue is any stimulus that assists the process of locating and recovering information stored in memory. • A retrieval cue acts as a prompt or a hint that guides the search and recovery process within memory. • Being asked a question is an example of a cue. It focuses your search for information in LTM in specific areas. • Other cues are less direct and might not be recognised as memory prompts. E.g. smell of a particular perfume, a photograph, the look of someone’s face. • The theory is often referred to as “cue-dependent forgetting”.

28. Theories of forgetting • Tip of the tongue (TOT) phenomenon: is a state or “feeling” that occurs when you are aware of knowing something, and confident you will eventually remember it, but you are not able to retrieve it from memory at that point in time. • When information is eventually recalled it usually occurs suddenly like it “pops” out of memory, often when not consciously thinking about it. • We seem to have some information about the word being searched for (e.g. beginning letter or how many syllables or what it rhymes with). • We can often confidently eliminate words that are incorrect based on improper sound or length.

29. Tip of the Tongue phenomenon • Possibly due to partial retrieval process where bits of information can act as retrieval cues for the required information. • Lack of correct cue.

30. Tip of the Tongue phenomenon • Provides evidence that information in LTM is stored in an organised way and in a variety of forms. • Illustrates that retrieving is not an “all or nothing process” as we can remember parts of what we want to retrieve. • Information is stored in LTM but is not accessible without the right retrieval cue. • As information is stored in LTM in a variety of forms, a certain type of cue is required for a certain type of information. • TOT experiences indicate that information stored in LTM is organised and connected in relatively logical ways. In the struggle for retrieval, logically connected bits of information are frequently triggered which can act as additional cues, helping us to find the memory.

31. Interference theory • Interference theory proposes that forgetting in LTM occurs because other memories interfere with the retrieval of what we are trying to recall, particularly if the other memories are similar. • The more similar the information, the more likely it is that interference will occur. • If learning the similar information occurs close in time, interference is more likely. Two main kinds of interference: • Retroactive interference– New information interferes with the remembering of old information • Proactive interference- Old information interferes with ability to remember new information

32. Motivated forgetting • Motivated forgetting describes forgetting that arises from a strong motive or desire to forget, usually because the experience is too disturbing or upsetting to remember. • Defense mechanism that protects us from distressing memories. Two types of motivated forgetting: Repression Suppression

33. Repression • Repression - unconsciously blocking a memory of an event or experiences from entering conscious awareness. Based on Freud’s theories that a memory is too psychologically painful or unpleasant to remember the specific information. According to Freud, repression is a form of self-protection or self-defence (called a defence mechanism) from the anxiety or distress associated with the experience. Information is not lost from memory but is not easily accessible during normal waking consciousness. Repressed information can signal it’s existence in dreams, or when a person pauses, fumbles for words, or blushes when certain topics are raised. Freud believed a repressed memory can be retrieved when some of the unpleasant emotion associated with the related experience is “diffused” (lessened).

34. Suppression • Suppression – involves being motivated to forget an event or experience by making a deliberate conscious effort to keep it out of conscious awareness. The person is aware of the event/experience but consciously chooses not to think about it. • Research using brain imaging techniques now suggests suppression may be possible. • Using fMRI images of people actively trying to forget a list of words learned showed a higher level of activation in the left and right frontal cortical lobes (brain areas apparently involved in suppression of memories) which resulted in reduced activation of the hippocampus (brain area involved in recalling information). • Motivation can change the tone and content of memories that we do retrieve. Research found that motivation can also lead us to recode distressing memories as more pleasant by selectively reworking memories as neutral or even pleasant. Remembering not what actually was, but rather the way we would have liked them to have been.

35. Repression and Suppression • Many psychologists accept that memory can be affected by an individual’s conscious or unconscious needs fears, anxieties and desires. • Read case study on motivated forgetting in Box 7.3 on page 382.

36. Infantile amnesia • Usually our earliest memories are for events occurring between 3 and 5 years old. Sometimes as early as age 2 for significant events such as sibling birth or a hospitalisation. • Recollections by adults of memories from age 1 are usually memory reconstructions. (Loftus, 1993) • Infantile amnesia is the loss of memory for our experiences during infancy.

37. Explanations of infantile amnesia • Freud’s explanation for infantile amnesia is because the infant’s sexual impulses and fantasies are too psychologically threatening to be consciously remembered. Problem with this is that ALL memories are amnesic not just the threatening or disturbing ones. • Another explanation is lack of language development which prevents a child from encoding the experiences into LTM. • Another explanation involves brain development. The hippocampus does not mature until 2 years of age. Thus it is unable to encode and store events and other experiences in LTM prior to this time. Other late maturing brain structures such as the cerebral cortex may also play a role in formation and/or storage of memories.

38. Decay theory • Decay Theory is based on the assumption that when something new is learned, a physical or chemical memory trace, (sometimes called an engram) containing stored information is formed in the brain as the information is consolidated in LTM. • Decay Theory proposes that forgetting occurs because a memory (or the memory trace fades through disuse as time passes, unless it is reactivated by being used occasionally. e.g. like gradual fading of a photograph Earliest theory of forgetting. Explains forgetting in physiological terms. Probably the most commonly believed in the wider community.

39. Decay theory • One research study, a pattern of rapid then more gradual deactivation of neural pathways in the hippocampus (part of the brain involved in consolidation of memory) was observed. • It also appears that the mere passage of time (but not time alone) may also contribute to forgetting both in sensory memory and STM, but not in LTM. • Many people have vivid memories of things they have not thought about for years. • Most people can, in time, also recall material that was apparently “lost”. E.g. Name of an old friend you bump into in the street.

40. Decay theory • If memory trace simply decayed over time, then the presentation of retrieval cues would have no effect on the retrieval of information or events that have been held in LTM for a considerable period of time, but it does. • Thus other factors such as interference or inappropriate retrieval cues make memories difficult to retrieve, not simply because of fading memory traces over time. • Read Box 7.5 comparing theories of forgetting (page 385) • Read Box 7.6 on Pseudoforgetting: encoding failure (page 385)