Empirical support & evidence for the MSM + case studies

• input to sensory memory:

  • based on the 5 senses; sight, taste, touch, hearing and smell.
• the sensory register:

  • a stimulus from the environment passes into sensory register along w/ many other stimuli, e.g. smell, sight etc.
  • there is a store for EACH sense.
  • the 2 main stores are:

  1. iconic memory
  2. echoic memory

  these are passive stores. we can't control what enters our sensory memory. they are constantly bombarded w/ info- far too much to deal w/ in our memory processing system.
• what is iconic memory?

  for visual info- coded visually.
• to what extent is the info recieved by sensory registers encoded?

  very limited encoding.
• what is the capacity of the sensory register?

  • very high, like cells (in the millions).
• what is the duration of the sensory register?

  • very short, less than 1/2 a second for iconic register, perhaps 3 seconds for echoic.
  • thus very little of what goes into the sensory register passes further into the memory system.
  • if you pay attention to it, it will be further processed.
• peterson & peterson (1959)- duration of short term memory:

  • aim: to investigate how long info is retained in STM w/out rehearsal.
  • procedure:

  1. p's given trigrams (e.g. XPD) and asked to recall them after varying delays (3,6,9,12,15,18 seconds).
  2. to prevent rehearsal, p's performed a counting task (e.g. counting backwards in 3's from a given no.)

  • findings:

  1. after 3 secs, recall was about 80%.
  2. after 18 secs, recall dropped to less than 10%.
  3. suggests STM has very limited duration (about 18-30 secs) if rehearsal is prevented.

  • conclusion:

  1. STM has short duration, unless info rehearsed.
  2. supports the MSM, suggests STM is temporary & requires rehearsal for transfer to LTM.
• baddeley (1996)- coding in STM and LTM:

  • aim: to investigate how info is coded in STM (phonological) & LTM (semantic).
  • procedure:

  1. p's presented w/ 4 types of word lists- acoustically similar/dissimilar, semantically similar/dissimilar.
  2. STM recall (immediate recall task) p's were asked to recall the words immediately.
  3. LTM recall (delayed recall after 20 mins) p's recalled words after a delay.
• baddeley (1996) continued. - coding in STM and LTM:

  • findings:

  1. STM- p's struggled more w/ acoustically similar words, suggesting STM relies on acoustic coding.
  2. LTM- p's struggled more w/ semantically similar words, suggesting LTM relies on semantic coding.

  • conclusion:

  1. STM is primarily encoded acoustically.
  2. LTM is primarily encoded semantically.
  3. supports MSM, which suggests that STM & LTM are separate systems w/ diff coding methods.
• glanzer and cuntiz (1966):

  • serial position exp.
  • procedure:

  1. p's hear a list of words, asked to recall them in any order (free recall).

  condition 1- immediate free recall.

  condition 2- free recall after interference task.

  to obtain results, plotted position of each word in the list against how many of the p's recalled it.

  • findings:

  
• glanzer and cunitz (1966) continued:

  • results:

  1. p's recalled more words at beginning (primacy) and end (recency) of the list.
  2. the interference task removed the recency but not the primacy effect.
  3. implies that primacy words were stored somewhere diff to recency words.

  • conclusion:

  therefore, we have 2 separate memory stores.
• evaluation of the MSM:

  • glanzer and cunitz- is rehearsal rlly necessary for transferring info? in real life, we rarely rehearse info, yet we can store lots of things. craik & lockhart's levels of processing might be a better explanation of how memory works.
  • case studies- oversimplified, STM & LTM don't operate in a singular way. there might be a no. of diff stores within them.
  • baddeley, peterson & peterson and glanzer & cuntiz- lab exps used to test memory (lack of ecological validity). p's may have shown demand characteristics.
  • evidence against the case studies- case study of KF. brain damage following motorcycle accident. underwent brain surgery. normal LTM, but STM capacity of only 2 items. if STM is necessary for storage in LTM, LTM would have also been affected.
• strengths of the MSM theory?

  • exps to support had high control over variables- carefully manipulate IV, controlling extraneous variables, increasing internal validity.
  • replicable- standardised procedures, allow for repetition to check for reliability.
• evaluation of glanzer & cuntiz:

  • STM capacity varies depending on chunking strategies and individual differences.
  • LTM capacity is difficult to measure, as it is theoretically unlimited.
  • lack of mundane realism (ecological validity).
  • amount of extraneous variables, e.g. time of day.
• evaluation of clive wearing and HM as support:

  • provides rich, detailed data about memory processes.
  • supports the MSM by showing distinct impariments in STM & LTM.
  • however, findings from brain damaged individuals may not generalise to the wider pop. , low reliability.
  • ethical issues in studying individuals w/ memory loss (informed consent, privacy).
• clive wearing (case study that provides evidence for the MSM):

  • clive suffered from amnesia due to brain damage. he had retrograde amnesia (could remember/recall some long-term, past memories from before the damage, but can't form new ones).
  • this shows that as his STM became damaged, his ability to pass info from STM to LTM was impacted. this suggests separate stores for STM and LTM.
• HM (case study that provides evidence for the MSM):

  • in youth, cracked his head in an accident, causing seizures & epilespy.
  • doctors decided to remove hippocampus through lobotomy practices, had vital pieces of the brain taken out, e.g. hippocampus.
  • lost memories/struggled to form new ones.
  • capacity to transfer info decreased.
  • could remember through repetition.
  • shows STM and LTM are separate as his STM was intact, despite the fact he could not form new-long term memories/lost old ones.
• evaluation of baddeley:

  • supports the MSM distinction between STM & LTM.
  • high reliability (lab exp).
  • other factors (e.g. visual coding) may play a role in STM & LTM.
  • individual differences in memory strategies weren't accounted for.
• evaluation of peterson & peterson:

  • supports MSM claim that STM has a limited duration.
  • lacks ecological validity- trigrams aren't a natural task.
  • interference from counting might have affected results rather than just decay.
  • suggests rehearsal is needed to transfer info to LTM (support).