Phonological Loop model (Working Memory)

developmental & cross-linguistic differences
1. developmental differences
  1. faster rehearsal means better recall (more rehearsal per per 2sc)
  2. developmental growth of memory span, Dempsey (1981)
  3. as children's rate of speech increases so does their recall span, Nicholas (1981)
2. cross-linguistic differences
  1. differences with mean digit span correlates with differences in how long it takes to say them
    1. NOTE: these are correlations not causal relations
3. younger children have poorer recall performance on longer spoken words compared to same stimuli presented as images
  1. older children (7yo) show word-length effect in both modalities, Hitch et al. (1988)
Irrelevant speech effect
1. Salamé and Baddeley (1982) ignoring irrelevant speech was more interfering than other irrelevant noise
  1. demonstrates unattended speech enters phonological store (Blocking subvocalised word stimuli) BUT other noises don't
  2. Suppression eliminates the irrelevant speech effect (possibly by blocking word encoding)
2. Macken & Jones (1995) contradictory evidence that unattended non-speech (tones) can cause the same disruptive effect
  1. possibly due to broader memory mechanisms rather than phonological loop
3. possible both theories correct in different situations
neurological study
1. Vallar & Baddeley (1984) - studied P.V. who showed selective verbal memory deficit
  1. Left parietal lesion from stroke- only left with 2 digit auditory span yet fluent and normal rate of speech
    1. Poor recall with phonemically similar words- possible phonological store damage? Had no word length effect- also support phonological store damage theory
      1. subvocal rehearsal wouldn't help recall shorter words rather than long words
    2. better memory span with visual words than spoken
      1. showed no phonemic similarity or word length effect
        possibly compensating for phonological loop damage by using her visio-spatial scratchpad more
  2. this is an example of dissociation suggesting storage and rehearsal are separate
2. Paulesu et al. (1993)- used PET scans for 3 tasks
  1. task assumptions- phonological loop associated with Broca's area and supramarginal gyrus. rehearsal associated with Broca's area. phonological store associated with supramarginal gyrus. if these assumptions are correct!
theoretical issues
1. it doesn't explain irrelevant speech effect
2. Lovatt et al. (2000)- challenged word length effect. claimed word complexity was responsible. word length effect could be eliminated if complexity was the same.
3. Hulme et al. (1984)- challenged rehearsal is affected by word length. example: 4yo not developed rehearsal ability showed word length effect.
4. Cowan et al. (1992)- demonstrated word length effect caused by output delays (doesn't affect rehearsal)
5. Baddeley (2000) - suggested a 4th component- the episodic buffer.
  1. explains that articulatory suppression which 'should' eliminate recall by occupying all resources (rehearsal/subvocalisation), thereby preventing visual stimuli registering in the phonological loop, has only a weak effect.
  2. evidence shows visual similarity of word stimuli affect span. suggesting visual and phonological info are bound. therefore, a separate system involved.
  3. very amnesic patients (damaged episodic LTM) can keep current info in mind (not learned). eg. Tulving recorded a patient could remember the objective in a game of bridge, the cards played and the score across a series of games. suggesting if STM & LTM not linked there must be another store.
6. addressing the issues:
  1. create a new model from scratch
  2. revise the model addressing its deficiencies
  3. use computational modelling to create alternative models.
phonological store
1. stores small amount of what's seen/heard
subvocalisatino process
1. speech automatic access to loop. visual stimuli needs recoding
Phonological working memory, Baddeley (1975)
1. articulatory suppression, Baddeley (1984)
  1. secondary task involving repetition of irrelevant words
    1. word-length effect
  2. memory span reduced
  3. word length effect reduced in both modalities
  4. phonemic similarity effect reduced in visual stimuli
  5. eliminates word-length effect for both modality
  6. only eliminates phonemic similarity effect in visual stimuli
2. phonemic similarity effect
  1. more difficult to remember similar sounding words

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Phonological Loop model (Working Memory)

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	Created by phoenixisis over 10 years ago