Memory Flashcards
Who did research on coding?
Baddeley 1966
Research on coding - Baddeley 1966
- Group 1 = acoustically similar
- Group 2 = acoustically dissimilar
- Group 3 = semantically similar
- Group 4 = semantically dissimilar
- Results = STM recall worse acoustically similar - LTM recall worse semantically similar
- Suggests info = encoded semantically in LTM
Limitations of research on coding
Limitation; artificial stimuli
- Artificial rather than meaningful - no personal meaning - take caution when generalising findings to diff mem tasks
Who did research on capacity?
- Jacobs 1887; digit span
- Miller 1956; chunking
Research on capacity - Jacobs 1887 & Miller 1956
- J; researcher reads out 4 digits & p’s recall out loud in correct order - if correct, adds 1 more dodger to list - indiciares individual’s digit span - mean span for digits = 9.3 items - means span for letters = 7.3
- M; observations of everyday practice - come in 7’s - capacity of STM = 7+/-2 items - chunking allows better recall
Strength of research on capacity
- Jacobs’ study = replicated - may have been distracted during testing (confounding variable) - Bopp & Verbarghen 2005 confirmed findings - validity
Limitation in research on capacity
- Cowan 2001 concluded capacity of STM only about 4+-1 chunks - suggests estimate of 5 = more appropriate
Research on duration - Peterson & Peterson 1959 & Bahrick et al 1975
- STM - 24 students - 8 trials - student given consonant syllable & 3 digit number - counted back until told to stop to prevent mental rehearsal
- Each trial retention interval - 3s, 6s, 12s, 15s / 18s - findings = after 3s avr recall = 80%, after 18s = 3%
- Suggest STM duration = 18s unless rehearsed
Research on duration - Bahrick et al 1975
- LTM - 392 Americans - 17-74yrs - high school yearbooks - recall1 = photo recognition = 50 photos from yearbooks - recall2 = free recall test = p’s recalled names of graduating class
- 15yrs of graduation = 90% accurate in photo recognition - after 48yrs recall declined to 70%
- 15yrs of graduation = 60% accurate in free recall - after 48 yes recall dropped to 30%
- LTM may lay to lifetime - free recall = less accurate than recognition
Strength of research on coding
- Clear difference between 2 memory stores - later research shows STM = acoustic coding & LTM = semantic coding
Strength of research on duration
- High external validity Bahrick’s study - researchers investigated meaningful memories - recall = lower with meaningless pictures (Shepard 1967)
- Suggests findings reflect more ‘real’ estimate of duration of LTM
Limitation of research on duration
- Stimulus material = artificial - however we do sometimes recall meaningless info (phone numbers) - lacks external validity
What does the multi-store model describe?
- Describes how info flows through memory system & suggests that memory = made up of 3 stores linked by processing
What are the key features of the sensory register?
- Coding = depends on sense passing through - store coding for visual = iconic memory, acoustic = echoic memory + other senses
- Capacity = very high
- Duration = <0.5s
- Info passes further through system if you pay attention
What are the key feature of short-term memory?
- Coding = acoustic
- Capacity = limited to 7+/-2
- Duration = 18s
- Maintenance rehearsal occurs when we repeat material over & over - can keep info in STMs if rehearsed & if long enough, into LTM
What are the key feature of long-term memory?
- Coding = semantic
- Capacity = unlimited
- Duration = unlimited
- To recall into from LTM, it has to be transferred back into STM with process of retrieval
What case study concerns the multi-store model?
- HM - brain surgery to relieve epilepsy - procedure wasn’t fully understood - hippocampus = removed from both sides of brain (central to memory function)
- Memory = assessed in 1955, thought it was 1953 - little recall of operation - couldn’t form new long-term memories e.g. read same magazines without remembering but performed well on test that measured STM
Strengths of the multi-store model?
- Supporting evidence that STM & LTM = diff - Baddeley 1966; tend to mix up acoustic words when using STMs & semantic words when using LTM - clearly show they’re separate & independent memory stores
- Case study of HM proves existence of diff memory stores
Limitations of the multi-store model
- Real life application - digits & letters (Jacobs) words (Baddeley) & consonant syllables (P&P) use meaningless materials but support MSM - not valid model for memory in everyday life
- Shallice & Warrington 1970; more than one STM store - KF = amnesia - STM for digits = poor when read to him - recall = better when read himself - MSM wrong claiming 1 STM store
- Craik & Watkins 1973; type of rehearsal = imp than amount - elaborative needed for LT storage - occurs when linking info with existing - info can be transferred to LTM without prolonged rehearsal
Who suggested 3 LTM stores containing different types of information?
Tulving 1985 - realised MSM’s view of LTM = too simplistic & inflexible
What is episodic memory?
- Refers to ability to recall events in our lives e.g. record of personal experiences
- Memories = complex
- Time-stamped - remember when & what happened
- Conscious effort to recall memories
What is semantic memory?
- Shared knowledge of world e.g. facts - less personal
- Aren’t time-stamped - don’t remember when
- Contains immense collections of material that’s constantly being added to depending on experiences
What is procedural memory?
- Refers to memory for actions / skills
- Can recall without conscious effort e.g. riding bike, driving - automatic through practice
- Hard to explain to others
Strengths of the types of LTM
- Case studies of HM & Clive Wearing - e mem = impaired due to brain damage - s & p mem = unaffected - understood meaning of words & could walk & speak - W; musician could read read & sing music & play piano - diff mem stores in LTM
- Real world application - harder to recall e mem with age - Belleville et al 2006; improve e mem in older people - trained p’s = better on e mem test than control group - specific treatment
Limitations of the types of LTM’s
- Lack of control of variables - brain injuries = unexpected - no way of controlling before & after injury - no knowledge of mem before damage - limits what clinical studies can tell us
- Buckner & Petersen 1996; reviewed evidence of location of s & e mem - concluded s mem = left prefrontal cortex & e = right - Tulving et al 1994; links left prefrontal cortex with encoding of e mem & right prefrontal cortex with e retrieval