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Overview of Memory Research

Overview of Memory Research. Modal Memory Model. Basic Distinctions. STM short term memory limited capacity limited duration holding available recent and relevant information in a temporary store LTM long term memory unlimited storage relatively permanent

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Overview of Memory Research

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  1. Overview of Memory Research

  2. Modal Memory Model

  3. Basic Distinctions • STM • short term memory • limited capacity • limited duration • holding available recent and relevant information in a temporary store • LTM • long term memory • unlimited storage • relatively permanent • store for episodic and semantic memory

  4. Modal Model of Memory(Atkinson & Shiffrin, 1968) Short-term memory is a limited capacity store for information -- place to rehearse new information from sensory buffers Items need to be rehearsed in short-term memory before entering long-term memory Probability of encoding in LTM directly related to time in STM

  5. a memory test... TABLE CANDLE MAPLE SUBWAY PENCIL COFFEE TOWEL SOFTBALL CURTAIN PLAYER KITTEN DOORKNOB FOLDER CONCRETE RAILROAD DOCTOR SUNSHINE LETTER TURKEY HAMMER

  6. In free recall, more items are recalled from start of list (primacy effect) and end of the list (recency effect) Distractor task (e.g. counting) after last item removes recency effect Serial Position Effects nodistractor task distractor task

  7. Explanation from Modal Memory Model: Early items can be rehearsed more often  more likely to be transferred to long-term memory Last items of list are still in short-term memory (with no distractor task)  they can be read out easily from short-term memory Serial Position Effects

  8. Encoding & Retrieval Effects

  9. Levels of Processing(Craik & Lockhart, 1972) Modal Memory Model  time in rehearsal buffer determines memory strength Levels of processing effect: The way information is processed affects recall. Deeper levels of processing (e.g., emphasizing meaning) leads to better recall  encoding effect

  10. Encoding Specificity Principle • Recollection performance depends upon the interaction between the properties of the encoded event and the properties of the retrieval information • Example: • context dependent effects: information learned in a particular context is better recalled if recall takes place in the same context

  11. Godden & Baddeley (1975) Memory experiment with deep-sea divers • Deep-sea divers learned words either on land or underwater • They then recalled the words either on land or underwater

  12. Mood Congruence • Easier to remember happy memories in a happy state and sad memories in a sad state. • Teasdale & Russell (1983): subjects study positive or negative words in normal state. Test in positive or negative induced states.  mood primes certain memory contents

  13. State-dependent recall • Does physical state matter? • Eich et al. (1975): study while smoking normal or marijuana cigarette. Test words under same or different physical condition

  14. Spacing effects • Memory is better for repeated information if repetitions occur spaced over time than if they occur massed, one after another. • Experiment: study 48 words, 24 of which are repeated. Spacing interval varied from 1,2,4,8,20 to 40 presentations. • Results: better memory for items with greater spacing. • Explanation based on encoding specificity principle: spaced items can be encoded in multiple ways  more likely to be retrieved Melton & Schulman, 1970

  15. Working Memory

  16. Views on Short-Term memory • Miller’s memory span (7 ± 2 discrete slots) • Short-term memory = activated long-term memory • Baddeley’s theory of working memory • Set of slave systems rehearsing and “working” on information • Working memory capacity • Measures focus of attention with distracting tasks

  17. Baddeley’s working memory theory • Concept of working memory: brief, immediate memory of material we are currently processing • Working memory is not a passive store-house such as short-term memory – it is more like a work bench where material is constantly handled, combined and transformed Visuo-spatial sketchpad Phonological Loop Central Executive Long-term memory

  18. Phonological Loop(a.k.a. articulatory loop) • Stores a limited number of sounds – number of words is limited by pronunciation time, not number of items • Experiment: • List 1: “Burma, Greece, Tibet, Iceland, Malta, Laos” • List 2: “Switzerland, Nicaragua, Afghanistan, Venezuela, Philippines, Madagascar” • Typical results: list 1  4.2 words list 2  2.8 words

  19. Note: most working memory tasks involve serial recall Short-term memory worse for phonologically similar items  interference in phonological loop Phonological Similarity man mad cap can map pen rig day bar cup big huge broad long tall old late thin wet hot (Baddeley, 1966)

  20. Reading rate determines serial recall • Baddeley (1986) tested recall for five words varying from 1 to 5 syllables. • 1 syllable:wit, sum, harm, bay, top • 5 syllables:university, opportunity, aluminum, constitutional, auditorium • Reading rate seems to determine recall performance • Phonological loop stores 1.5 - 2 seconds worth of words

  21. Different languages have different #syllables per digit Therefore, recall for numbers should be different across languages E.g. memory for English number sequences is better than than Spanish or Arabic sequences Working memory and Language Differences (Naveh-Benjamin & Ayres, 1986)

  22. Pronunciation time does not always predict recall very well Problems with Baddeley’s theory

  23. Problems with Baddeley’s theory • Even with long delays, memory span does not decrease much • Underspecified processes and representation • Serial recall requires memory for the order of items  how is order information stored? • How does central executive work? • How does interference in phonological loop work?

  24. Long-Term Memory Systems

  25. Are there multiple LTM memory systems? • How do you learn a new skill? • How do you learn a new fact? • How about learning about an event? • Is there one long-term memory (LTM) system for these types of knowledge or are there multiple LTM systems?

  26. Squire’s Taxonomy of memory MEMORY EXPLICIT IMPLICIT SEMANTIC (facts) EPISODIC (events) PRIMING (perceptual, semantic) PROCEDURAL (skills)

  27. Implicitand explicit memory • Implicit memory: past experiences influence perceptions, thoughts & actions without awareness that any info from past is accessed • Explicit memory: conscious access to info from the past (“I remember that..” ) -> involves conscious recollection -> term often used synonymously with episodic memory

  28. Explicit & Implicit MEMORY TESTS Look at the following words. I will test your memory for these words in various ways.

  29. SPONGE CANDY DOLPHIN PACKAGE POSTER LICORICE ZEBRA SECTION CAMOFLAGE MISTAKE PORTAL KNAPSACK COFFEE QUAIL ALPINE HANDLE PANTRY CARPET EAGER CELLO PRESSURE LLAMA ORIOLE ACRID

  30. EXPLICIT TEST OF MEMORY: RECALL WRITE DOWN THE WORDS YOU REMEMBER FROM THE LIST IN THE EARLIER SLIDE IMPLICIT TEST OF MEMORY: WORD FRAGMENTS ON THE NEXT SLIDE, YOU WILL SEE SOME WORDS MISSING LETTERS, SOME “WORD FRAGMENTS” AND SOME ANAGRAMS. GUESS WHAT EACH WORD MIGHT BE.

  31. EGNOPS *AN*Y *OL*H** PACKAGE P*S*E* LICORICE *E*RA SE*T*O* C**O*LA*E *I*TA*E PORTAL KNAPSACK COFFEE *U*IL AEILNP *AN*LE *A*T*Y ACEPRT *A*E* C*L** *RE*S**E AALLM EILOOR *C*ID

  32. Implicit Memory Tasks • Word-fragment completion is an implicit memory task.Fragments are (often) completed with words previously studied in the absence of an explicit instruction to remember the word • Amnesiacs often showed spaired implicit memory  dissociation suggest different systems for implicit and explicit memory systems

  33. HM: Amnesic • Severe epilepsy, treated with surgery to bilaterally remove medial temporal lobes, including hippocampus • Operation 9/1953, 27 years old HIPPOCAMPUSMEDIAL TEMPORAL LOBES

  34. HM: Amnesic Operation 9/1953, 27 years old • Tested 4/1955, age 29 • Reported date as 3/1953, age of 27 • No memories since operation • IQ better than pre-op (112) • Fewer seizures

  35. HM: Amnesic • Profound failure to create new memories • Can’t find new home (after 10 mos.) • Can’t remember new people, names, tasks • Events/People since operation • Language essentially frozen in 50’s • Exceptions: Ayatollah, rock ‘n roll

  36. HM: Amnesic • Mirror tracing task, Milner, 1965

  37. HM: Amnesic Mirror tracing task, Milner, 1965 • improvement in H.M. • no conscious recollection of previous training episodes

  38. HM: Stem-completion Graf et al. (1984): Study: word list (table, garden,umbrella) Test: - free recall - cued recall: complete word stem with word from study list umb____ ?? - word stem completion: complete word stem with first word that comes to mind gar___??

  39. HM: Stem-Completion • Free Cued Completion • Recall Recall • HM: No memory for studying of list

  40. Learning to Miror-Reverse Read

  41. Amnesics can learn to mirror-reverse read and are sensitive to repetitions

  42. Spared implicit memory in anterograde amnesia • Claparede study (1911). • Patient never remembered having met Claparede (doctor) before • Claparade offers handshake with pin hidden in his hand • Next time, patient has no explicit memory of painful event (or doctor) • Still, patient refuses to shake hands and offers explanation: “sometimes pins are hidden in people’s hands”

  43. Implicit/ Explicit Memory with Normals • Jacoby (1983) • Study conditions: • generate: give antonym to hot - ... • context: study word in context hot - COLD • no context: ... - COLD • At test: • Explicit memory test: recognition memory • Implicit Memory test: Speed up on perceptual identification test: how much faster can you identify a word flashed 40ms on screen when you have studied word before?

  44. Results

  45. Knowledge & Memory

  46. How well do people recall events? • Memory is not just reproductive • We do not recall the original event exactly • Memory for events is often reconstructive • We construct a memory by combining elements from the event with our existing knowledge.

  47. What does a penny look like?

  48. Memory for Details vs. Gist • Memory is better for meaningful, significant features than for details of language or perception, suggesting that we have knowledge representations based on our interpretations of meaning. • Representation for meaning • Propositional representations • Semantic Networks • Schemas • Scripts • Latent Semantic Analysis (LSA)

  49. Evidence for Schema’s A simple demonstration experiment I am going to show you a picture of a graduate student’s office. Just take a look at it for a while

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