memory Flashcards
capacity def.
a measure of how much can be stored in our memory in digits
encoding def.
the way information is changed so that it’s stored in our STM/LTM
duration def.
a measure of how long info is stored
what was Miller’s theory on capacity of stm?
- include date
Miller (1956) concluded that people can remember 5-9 items so came up with 7+/-2 rule.
miller’s theory on chunking?
that the STM capacity may be enlarged by grouping items together by associations/links they have with each other eg odd and even numbers in a sequence
what is the span of our immediate memory?
7 items
describe peterson’s and peterson’s study on STM duration
- ppts given a nonsense triagram and a three digit number.
- ppts had to count down in threes from their three digit number and had a retention period of 3,6,9,12,15,18 seconds, after they had to recall the nonsense triagram
- only 2% correct after 18 seconds suggested STM has a short duration less than 18 secs
what counteracts petersons and petersons study (1959) on STM duration?
Reitman (1974) suggested the use of numbers ppts were counting may have displaced the syllables they had to remember instead of the limited duration
- instead he used auditory tones so that displacement wouldn’t occur and interfere with verbal rehearsal
- found duration of STM was longer
describe baddeleys study on coding in ltm and stm
baddeley (1966) gave ppts words list to learn
- semantically similar
- acoustically different
- semantically different
- acoustically similar
ppts struggled with AD in terms of their stm memory and struggled with SS with their ltm
- so came to the conclusion that STM is coded acoustically and LTM is coded semantically
evaluate Baddeley’s research: LTM
- ltm was tested after waiting 20 mins, but some question if it was really ltm
- ltm may not be exclusively semantic: (frost 1972) showed long term recall was related to visual as well as semantic categories, and Nelson and Rothbart (1972) found evidence of acoustic coding in the ltm
evaluate Baddeley’s research: STM
- stm may not be exclusively acoustic eg Brandimote et al (1992) found ppts used visual coding in STM if they were given a visual task and were prevented from doing any verbal rehearsal in the retention period (by repeating la la la) before a visual recall task
- other research shows that stm sometimes uses semantic code (Wickens et al. 1976)
evaluate capacity of stm
- capacity of the stm is not the same for everyone, eg Jacobs found that digit span increase with age eg 8 year olds could remember an avg of 6.6 digits whereas the mean for 19 year olds was 8.6 digits.
age increase may be due to changes in the brain capacity or development
evaluate testing of the stm
- research investigating stm is artificial eg trying to memorise consonant syllables does not truly reflect most everyday memory activities - so lacks ecological validity
describe harry bahrick’s study on duration of the LTM
- harry bahrick 1975 tested 400 people of various (17-74) on their memory of classmates
- he conducted a photo recognition test of 50 photos, some from the ppts high school yearbook
- free recall ppts were asked to list names they could remember of those in their graduating class - free recall was 60% accurate after 15 years and 30% after 48 years
- other ppts who were tested within 15 years of graduation were 90% accurate in identifying faces
- after 48 years this declined to 70%
- shows duration of ltm can last years
who was the WMM conducted by and why?
Baddeley and Hitch (1974) as felt that STM was more than one store
who was the MSM conducted by?
Richard Atkinson and Richard Shiffrin (1968)
evaluation of msm - weaknesses
- ltm involves more than maintenance rehearsal e.g flashbulb memories or craik and lockhart (1972) suggested enduring memories are created by processing what you do eg deep processing - shown when craik and tulving 1975 conducted experiment asking ppts to memories nouns then asked deep/shallow processing questions and ppts remembered more words when asked deep processing
- stm may rely on ltm as well (logie 1999) eg in order to chunk you need to recall meaningful groups of letters that are stored in the ltm
- msm is too simple eg doesn’t talk about different kids of memory stored in each store eg maintenance rehearsal can explain long-term storage but doesnt explain episodic (experience) memory
evaluation of msm - strengths
- supporting evidence eg beardsley (1997) found prefrontal cortex is active during stm but not ltm tasks which shows separation
- case studies eg hm (scoville and milner 1957) after brain damage, personality and intellect remained intact but could not form new ltms but only remembering things before surgery, again supporting msms notion of separate stores
describe working memory model
- central executive - monitors and coordinates all other mental functions in working memory
- episodic buffer - receives input from many sources, temporarily stores this info and then integrates it and records episodes of what is being experienced then sends info to ltm
- phonological loop - deals with auditory info and preserves order of information - phonological store (baddeley 1986) holds words you hear - inner ear - articulatory loop words heard or seen - inner voice
- visuo-spatial sketchpad codes visual information and the relationship between things - logie (1995) subdivided it into a visual cache in terms of visual items eg form and colourand an inner scribe of arrangement of objects
ao3 - wmm - weaknesses
- central executive is too vague eg could be same as ‘attention’ is msm as it only allocates resources and could be more components eg eslinger et al (1985) studied evr who had a cerebral tumour removed - performed well on tests that required reasoning but had poor decision skills suggesting CE was not wholly intact
- using case studies may not prove completely accurate as brain injury is traumatic so may alter behaviour of persons performance and individuals may have difficulties paying attention - also case studies unique to person so cannot be generalised - pop.validity
ao3 - wmm - strengths
- evidence eg shallice and warrington (1970) studied kf whos stm of auditory info was greater than visual stimuli and auditory info limited to verbal material and not meaningful sounds so brain damage restricted to phonological loop -
- farah et al (1988) studied lh who performed better on spatial tasks than visual imagery due to car accident
- so supports separate visual and spatial systems
- PL holds amount of info said in two seconds (baddeley et al 1975) so harder to remember list of long words than list of shorter words as long words don’t fit so rehearsal isn’t possible - word length effect disappears if given an articulatory suppression task eg saying ‘the, the, ‘the’ while recalling short words
- evidence for articulatory process, supporting WMM