Memory Flashcards
Coding
Format in which information is stored in the various memory stores
Research on coding
“Baddeley (1966) Word lists: acoustically/semantically similar or dissimilar, Asked to recall in correct order
Immediate recall: worse with acoustically similar words, After 20 minutes: worse with semantically similar words. STM acoustic, LTM semantic”
Acoustically similar
Sound similar
Semantically similar
Similar meaning
Research on coding - artificial stimuli (Evaluation)
- Words had no personal meaning. 2. Cautious about generalising. 3. Meaningful tasks: may use semantic even for STM. 4. Limited application
Capacity
Amount of information that can be held in a memory store
Research on capacity - digit span
“Jacobs (1887) Researched reads 4 digits and increases until ppt cannot recall order correctly
Mean span: 9.3 numbers, 7.3 letters”
Research on capacity - digit span (Jacob’s, lacks validity)
- Conducted a long time ago 2. Early research lacked adequate control of extraneous variables. 3. Ppts may have been distracted. 4. Results may not be valid - confounding variables not controlled
Results confirmed in other research, supporting validity (miller) Research on capacity - span of memory and chunking.
- Things often come in 7s (weekdays, deadly sins, musical notes). 2. Suggests capacity of STM is 7+/-2 items
People can recall 5 words as well as they can 5 letters
Chunking: grouping sets of digits/letters into meaningful chunks
Research on capacity - span of memory and chunking (overestimated capacity)
Cowan (2001) reviewed other research. 1. Capacity of STM only around 4 chunks. 2.Lower end of Miller’s estimate (5 items) more appropriate than 7
Duration
Length of time information can be held in memory
Research on duration - STM
Peterson & Peterson (1959). 24 students given consonant syllable (e.g. YCG) to remember and 3 digit number to count backwards from. Counting backwards prevented rehearsal. Retention interval: 3, 6, 9, 12, 15, 18 seconds. 3s: recalled 80% syllables correctly. 18s: only 3%. STM without rehearsal: 18-30s
Research on duration - STM (Evaluation, artificial stimuli)
Does not resemble real-life memory activities (meaningful) Lacked external validity. Do sometimes try to remember meaningless things e.g. phone numbers, not totally irrelevant
Research on duration - LTM
Bahrick et al (1975) 392 Americans 17-74 yrs. Recognition test: 50 photos from high school yearbook. Free recall: names of graduating class. Free recall: 15 yrs: 60% 48 yrs: 30%. Photo recognition: 15 yrs after graduation: 90% accurate 48 yrs: 80% accurate. LTM lasts a very long time
Research on duration - LTM (Research support + Evaluations)
Real-life meaningful memories. Lab studies with meaningless pictures: recall much lower (Shepard 1967). Confounding variables not controlled (looked at yearbooks and rehearsed memories over the years)
Multi-store model of memory (MSM)
Atkinson & Shiffrin (1968)- How info flows through memory system. 3 stores linked by processing
MSM - 1: sensory register
Stimulus from environment passes into SR along with lots of other sights/sounds e.t.c. 5 stores (each sense), main iconic (visual) and echoic (auditory). Duration: less than half a second. Capacity: high (over 100 million cells in each eye storing data). Coding: depends on sense. Needs attention to transfer to STM
MSM - 2: STM store
Limited capacity/duration Coding: acoustic. Capacity: 7+/-2 items (5-9). Duration: 18-30 seconds without rehearsal. Maintenance rehearsal: repeat to ourselves. Keep in STM with rehearsal. Rehearse long enough: passes into LTM
MSM - 3: LTM store
Permanent memory store. Coding: semantic. Capacity: unlimited. Duration: up to a lifetime. Recall: must be transferred back to STM by retrieval
MSM - supporting evidence
Baddeley: mix up acoustically similar words in STM and semantically similar in LTM Coding: STM acoustic, LTM semantic. Supports MSM view that stores are separate/independent
MSM - more than one type of STM
Shallice & Warrington: study of KF (amnesia patient). Poor STM recall for digits when read out loud. Recall much better when read digits himself. MSM states only one STM store. KF: one STM to process visual info and another for auditory. Working memory model better explains (includes separate stores)
MSM - more than one type of rehearsal
Craik & Watkins: two types of rehearsal - maintenance and elaborate. Maintenance described in MSM. Elaborate needed for long term storage. Occurs when you link info to existing knowledge/process it. Type of rehearsal matters, not amount. Research findings cannot be explained by model
Who Came up with Types of LTM
Tulving (1985) MSM view of LTM too simplistic. 3 LTM stores, different kinds of info: Episodic, semantic, procedural memory
Types of LTM - episodic
Stores events from our lives. Complex memories: time-stamped (when they happened) and contain several elements (people, places, objects, behaviours). Conscious effort to recall
Types of LTM - semantic
Knowledge of the world. Includes facts/what words & concepts mean. Not time-stamped. Less personal - knowledge that we all share. Also usually need to be deliberately recalled
Types of LTM - procedural
Stores memories for how we do things (actions/skills). Hard to explain to others - recall without conscious awareness/effort
Types of LTM - episodic supported by case study evidence
Clinical studies of amnesia (HM, Clive Wearing): both had difficulty recalling events from past. Semantic memories unaffected (HM did not remember stroking a dog but did not need concept explained). Procedural memories also intact. Support for multiple LTM stores. One store can be damaged but others left unaffected
Types of LTM - brain scan studies
Tulving et al: ppts perform memory tasks during PET scan. Prefrontal cortex: semantic (L) episodic (R). Physical reality of different types. Supports validity
Types of LTM - problems with clinical evidence
Based on what happens when memory is damaged. Lack of control of variables (precise location of damage/personality). Difficult to generalise to determine exact nature of LTM
Working memory model (WMM)
Baddeley & Hitch (1974) How one aspect of STM is organised/functions. Concerned with part of mind active when temporarily storing/manipulating information e.g. playing chess
WMM - 1: central executive
Attentional process. Monitors incoming data/makes decisions/allocates slave systems to tasks. Co-ordinates activities/allocates processing resources to 3 subsystems. Coding: flexible. Capacity: very limited
WMM - 2: phonological loop
Deals with auditory information. Preserves order in which info arrives. Subdivided into phonological store and articulatory process
WMM - phonological loop (phonological store)
Stores words you hear
WMM - phonological loop (articulatory process)
Allows maintenance rehearsal (repeating to keep in WMM while needed). Capacity: 2s worth of what you can say