Presentation on theme: "Long-term memory (LTM): Is it unitary or are there different types? Consider the following questions and see their diversity: Did you have water at dinner."— Presentation transcript:
Long-term memory (LTM): Is it unitary or are there different types? Consider the following questions and see their diversity: Did you have water at dinner last night or some other drink? How did you feel during your last break-up with a boyfriend / girlfriend? How many siblings do you have? Do all birds fly? Who sang the song “Time after time”? Is “welderly” an English word?
Long-term memory (LTM): Conceptual distinction of two different types Tulving 1972/1983: distinction between episodic memory and semantic memory episodic memory: remembering the past - memory for episodes / events distinct in time and space - associated with ‘mental time travel’ - conscious recollection of personal past experience (‘me’-ness) semantic memory: knowing about things learnt in the past - memory for world knowledge - timeless; does not rely on ‘mental time travel’ - does not involve conscious recollection - shared with others
Episodic memory as one type of LTM typical research method: study-test paradigm Study: try to memorize the following words for a memory test Test:what were the words you saw 20min ago? free recall cued recall recognition most tasks typically used in ‘old’ research on LTM (Atkinson & Shiffrin) involve episodic memory
3 stages of processing for manipulation of mental representations: Encoding (acquisition of info) Storage (retention of info) Retrieval (recovery of info) Information-processing approach to memory: basic framework time Encoding Retrieval Storage
Episodic memory: Encoding processes Examples: Try to memorize following sentences BMW just introduced a new 7 series model. The German social-democratic party has shifted to the right under Bundeskanzler Schroeder The BOLD response is susceptible to movement artefacts.
Episodic memory: Encoding processes How do we acquire information about episodes? Role of attention Role of practice Role of intention Role of depth of processing / elaboration Role of organization
Episodic memory: Encoding processes Role of attention Does encoding of an episode require attending to it in the first place? study by Murdock with dual-task paradigm: - free recall task with list of unrelated words - secondary card-sorting task during learning - secondary task varies in attentional demands (different # of sorting categories) Results: # of items recalled decreases as # of sorting alternatives increases -> encoding of information into episodic memory is attention demanding; not all or none phenomenon
Episodic memory: Encoding processes Role of attention dramatic evidence from studies in surgical patients undergoing anesthesia (e.g. Millar & Watkinson, 1983) subsequent to surgery, patients can’t recall words presented auditorily during anesthesia -> attending is critical for episodic memory at encoding role of attention: putting info into conscious awareness -> we can only remember those aspects of an episode that we were consciously aware of in the first place e.g. remembering conversations from dinner party
Episodic memory: Encoding processes Role of practice Role of practice / repetition (rote learning): in a strict sense, does not apply to memory for episodes because each episode is unique in time and can’t be repeated BUT on more abstract level, repetitions together can be defined as study episode e.g. what was the list you read 5 times yesterday?
Early research by Ebbinghaus on practice effects: Number of repetitions of list on first day has dramatic effects on time needed to learn it to perfect performance level on second day
Episodic memory: Encoding processes Role of practice much research undertaken to look at effects of distributed versus massed practice (starting with Ebbinghaus) -> general result: memory performance better when repetitions are separated (distributed practice) But: amount of benefit from distributed practice depends on many factors, including + interval between repetitions within study session -> related to attentional capture of info + rest-interval between successive study sessions -> related to consolidation (biological processes that let info ‘sink in’)
Episodic memory: Encoding processes Role of practice despite general benefits of practice / repetition in episodic memory: many studies with study-test paradigm have shown that repetition only of limited value for successful encoding e.g., Baddeley’s studies on BBC change in radio frequency -> what other factors are relevant then??
Episodic memory: Encoding processes Role of intention Do we need to make an active effort to memorize an episode in order to remember it later? e.g. what was the last movie you saw at a theatre? relates to distinction between incidental and intentional encoding
Episodic memory: Encoding processes Role of intention experiment by Mandler (1967) encoding conditions: incid. 1 sorting of cards with words by category intent. 2 sorting of cards with words by category plus memorization incid. 3 arrange cards with words in straight columns intent. 4 memorization only Results: no difference in free recall for 1, 2, 4 BUT subjects show poor recall in 3 -> intention to remember not a critical factor -> instead: type of processing of words is relevant
Episodic memory: Encoding processes Levels of Processing Framework Craik & Lockhart (1972) + challenged Atkinson & Shiffrin’s multi-store model + memory performance is not simply determined by what store info is in (e.g. STM vs LTM) + critical how info is processed at time of encoding -> level / depth of processing different levels for processing of words: perceptual feature analysis processing of sounds (phonology) processing of meaning (semantics) Increasing depth
Episodic memory: Encoding processes Levels of Processing Framework Craik & Lockhart (1972) empirical test of framework with incidental orienting tasks (level of processing induced by experimenter) shallow (perceptual / surface): Is this word in upper-or lower case letters? dog phonological (sound): Does this word rhyme with mat? hat deep (semantic): Does this word fit into the sentence ‘the man ate his …’meal
Episodic memory: Encoding processes Levels of Processing Framework typical advantage of deep over phonological over shallow encodingon recognition memory test
Episodic memory: Encoding processes Levels of Processing Framework important implication: encoding processes are essentially those involved in the perception and comprehension of episodes (no intention required) BUT: encoding processes are attention-demanding nonetheless -> attention and intention are not the same!
Episodic memory: Encoding processes Levels of Processing Framework further important component of framework: elaborative rehearsal (versus maintenance rehearsal) degree of semantic elaboration during encoding determines subsequent success in memory performance e.g. what color, shape, size does tiger have? Why? semantic elaboration allows for creation of more distinct memory representations -> representation includes more features -> makes memory representations of different episodes more discriminable
Episodic memory: Encoding processes Levels of Processing Framework Experiment by Klein & Saltz (1976) on elaborative rehearsal two incidental encoding conditions 1 categorize words on one semantic dimension eggis this word pleasant or unpleasant? 2 categorize words on two semantic dimensions beeris this word pleasant or unpleasant? does this word refer to something animate or inanimate? finding: more elaborate encoding in condition 2 produces better memory performance
Episodic memory: Encoding processes Levels of Processing Framework Why is semantic processing at encoding so powerful for episodic memory?? -> allows for integration with existing (semantic) knowledge e.g. try to learn name of person at party either when you know or don’t know his friends e.g. What were the three sentences you saw earlier? -> learning difficult when info cannot be integrated
Episodic memory: Encoding processes Levels of Processing Framework research on importance of integration with existing knowledge: experiments by Ericsson on episodic memory for chess- positions on boards presented to experts vs novices in lab chess masters remember positions much better than beginners, but only if pieces positioned in real, i.e. permitted, configurations + experts studied chess for approx. 25,000 h ( = 12 years full-time job with 40 h/week) + beginners 100 h total! e.g., other examples for effects of expertise?
Episodic memory: Encoding processes Levels of Processing Framework studies on chess also point to uniqueness of elaboration in different individuals -> unique personal background (autobiography) relevant e.g. chess configuration previously encountered in real world game -> what individual remembers about episode is determined by how episode is experienced by that particular person at encoding -> subjective nature of encoding (‘me’-ness)
Episodic memory: Encoding processes Levels of Processing Framework important consequences of unique elaborations during encoding on subsequent remembering -> Schacter’s example of different individuals’ memory for Magritte’s painting ‘The Menaced Assassin’ in Museum of Modern Art Schacter: “ memory recollections are largely at the mercy of our elaborations;…. we remember only what we have encoded, and what we encode depends on who we are”
Episodic memory: Encoding processes Levels of Processing Framework Why is LoP framework so attractive?? + based on simple principle + memory as by-product of ongoing cognitive activity (respecting true incidental nature of most episodic learning) + offers new way of asking questions: e.g., do elderly people have difficulties with elaborative rehearsal?
Levels of Processing Framework Criticisms heuristic value of framework undeniable theoretical problems: + definition of levels e.g. when applied to stimuli other than words -> danger of circularity +optimal type of encoding may differ depending on type of memory test (situation) e.g., hand writing of person -> encoding that is beneficial for one purpose may be less beneficial for another
Episodic memory: Encoding processes How do we acquire info about episodes? Role of attention Role of practice Role of intention Role of depth of processing / elaboration Role of organization
Episodic memory: Encoding processes Role of organization Bousfield experiment (1953) + list with 60 unrelated words + other list with 60 words from 4 semantic categories (animals, boys’ names, professions, vegetables); presented in scrambled order two major findings: + better recall of words from organized lists + subjects show tendency to recall words in related clusters Bartlett: people’s effort after meaning ->attempt to impose organization on info to help understand and remember it e.g., names at family reunion
Benefits of more complex organization at learning (Bower, 1969) + demonstration of hierarchy at learning: 73/112 words recall + hierarchy obscured at learning (random order): 21/112 words recall
Episodic memory: Encoding processes Role of organization People show spontaneous tendency to organize material even if no objective principle is present in material -> subjective organization – term coined by E. Tulving Experiment by Tulving, 1962 Word list: apple bell table coffee school lamp car roof potato shoe disk paint + several learning trials; words in different orders + after each learning trial: free recall major finding: + people recall words in same clusters on different trials e.g. subject 1 always school – coffee …… subject 2 always school – apple ……
Episodic memory: Encoding processes Role of organization Benefits of organization are not limited to verbal information (Mandler et al. 1976/1977) -> people remember location of objects better if organized in a room (3D organization with floor and ceiling)
Episodic memory: Encoding processes Role of organization and Levels of Processing General point 1: research on Levels of Processing and on organization shows that successful encoding of new information relies on linking incoming new information to existing knowledge e.g. think of Bower’s minerals experiment -> organization won’t have benefits if no existing knowledge about hierarchical organization (e.g. metals vs stones)
General point 2: even though much of what we encode happens without intention to memorize (Levels of Processing), memory performance can still be improved by specific attempts to commit new information to memory -> strategic aspects of memory (people can actively take control over their ‘battle with memory’) e.g. waitress’ effort in restaurant to keep orders from different customers apart Episodic memory: Encoding processes Role of organization and Levels of Processing
General point 3: research on organization and Levels of Processing suggests that the way in which info is encoded also plays important role as to how it can best be accessed later (i.e. what cues will help most). e.g. experiment with minerals what were the rare metals I saw earlier? -> encoding benefits closely linked to retrieval benefits Episodic memory: Encoding processes Role of organization and Levels of Processing