The multi store model of memory - topic 1

outline of the study

• atkinson and shriffin created it in 1968

• attempted to explain how our memory is split across 3 different stores in the human brain - each one with different coding’s , durations and capacities

order of the msm

• environmental stimuli

• sensory memory

• attention

• short term

• maintenance rehearsal;

• elaborative rehearsal so it moves into long term memory

sensory memory

• mass amount of sensory data that you receive from your 5 senses

• constantly receiving information but none of this gets attention

• data remains for about 1-2 seconds

• if a persons attention is focused on data in sensory store t gets transferred to the short term memory store

• encoding - sense specific

• duration - 0.25-0.5 milliseconds

• capacity - very large / unlimited

• Sperlings research for sensory memory capacity:

• demonstrated the very brief duration of the sensory memory using a grid of digits and letters exposed for 50 milliseconds

• when asked to report the whole thing recall was poorer than when asked to give on row only

• shows information decays rapidly in the sensory memory

• sperlings research for sensory memory duration: Walsh and Thompson

• Walsh and Thompson - found that the iconic sensory store has an average duration of 500 milliseconds , which decreases as individuals get older - this suggests the duration of sensory memories is limited and dependant on age.

short term memory

• holds a limited amount of information for a brief period of time before it is either forgotten or transferred to long term memory

• this information will disappear if new information enters STM pushing out and displacing the original information - happens because the STM has limited capacity

• maintenance rehearsal will ensure - lasts in stm not forgotten and goes to LTM

• encoding - acoustic

• duration - 18-30 seconds

• capacity - 7+ or -2 items

• research for short term memory - capacity

• Jacobs (1887) - tested STM capacity with the serial digit span method where participants are presented with increasingly long lists of numbers or letters and have to recall them in the right order - Jacobs found the capacity for numbers was 9.3 and for letters 7.3 for immediate recall.

• Miller - capacity - the STM can hold the magic number 7 plus or minus 2

• the capacity of stm can be considerably increased by combining / organising separate bits of information (eg letters or digits into larger chunks)

• chunking involves making the information more meaningful through organising it in line with existing knowledge from your long term memory

• Peterson and Peterson duration:

• to investigate the duration of STM

• 24 psychology students

• students had to remember a nonsense 3 letter trigram (WRH) at different intervals (3,6,9,12,15 seconds)

• participants asked to count backwards in 3s from a large random 3 digit number for varying periods of time

• after 3 seconds delay - there was 80% recall compared to just 10% after 18 second

• concluded that stm had a general duration of between 18-30 seconds for the majority of individuals

• Baddeley - coding research:

• gave participants 4 sets of words ( set 1 all has similar words - cat , map etc

• second set different sounding words - dog , bin , cup , pen

• set 3 - similar meanings - big , large , huge

• set 4 - different meanings - huge , good , light , blue

• when asked to recall immediately (testing STM) , participants made more mistakes on words that sounded alike (set 1 )

• this supports that coding is acoustic because similar sounding words interfered with each other

long term memory

• holds information over extended periods of time - potentially for a lifetime

• duration - unlimited

• encoding - systematic

• capacity - unlimited

• research for long term memory - duration

• duration - bahrick et al

• asked 392 of various ages to put names to faces from their high school year book

• ages ranged from 17-74

• those who graduated less than 15 years before were about 90% accurate in identifying names and faces

• this declined to 60% after 47 years

• concluded that peoples long term memories can last for their whole life even though they may weaken over time

• Wagener - capacity

• created a diary of 2400 events over 6 years and tested himself on recall of events rather than dates , finding he too had excellent recall again suggesting the capacity of LTM is extremely large

• Baddeley - encoding in LTM is semantic

• they gave participants 4 sets of words

• set 1 - similar words (acoustically similar) - cat , map , mat

• set 2 different sounds - dog , bin , cup ,pen

• set 3 similar meanings - big , large , huge , vast

• set 4 different meanings - huge , good , light ,blue

• after delayed recall - 20 mins ( recall supposed to be from LTM ) , participants had more difficulty remembering the semantically similar words - replacing huge with vast or night and dark

further evidence supporting the multi store model of memory

• brain scanning research - mri scans show which part of the brain is being used when it is carrying out certain tasks

• pre frontal lobes active when using your short term memory

• hippocampus active with activities involving the long term memory

• case study evidence: CLIVE WEARING

• background - musician who suffered brain damage from a vital infection

• left him with severe amnesia - memory

• lost ability to form new long term memories - memory span of few seconds

• his stm is intact and can hold small amount of information briefly

• procedural LTM is also intact - can still play piano

• episodic LTM (personal events) - severely damaged - cannot remember his past experiences

• supports the multi store model idea that stm and LTM are separate stores - the STM is functioning while the LTM is impaired

• demonstrates that information may fail to transfer from STM to LTM

• PATIENT HM

• background - H.M had surgery in the 1950s to treat severe epilepsy

• surgeons removed parts of his hippocampus and surrounding brain areas

• STM was normal - could hold information for about 20-30 seconds if he rehearsed it

• unable to transfer new information into LTM (anterograde amnesia)

• his older long term memories from before the surgery were mostly intact

• procedural memory working fine - could learn new skills

• shows that STM and LTM are separate stores - STM was intact whereas the LTM are separated stores

• challenges the MSM because it suggests LTM is more complex than one store (episodic vs procedural)

evaluations for multi store model of memory

• ✅ PEEL Strength — Clive Wearing (supports MSM and LTM distinction)

  P (Point): A strength of the multi-store model of memory is that it is supported by case study evidence, such as Clive Wearing.
  E (Evidence): Clive Wearing, a musician, suffered severe brain damage from a viral infection, resulting in the destruction of parts of his hippocampus. Despite being unable to transfer new information into long-term memory (anterograde amnesia), he retained some long-term memories, such as how to play the piano and his love for his wife.
  E (Explain): This suggests a clear distinction between different stores of memory: his short-term memory was severely impaired, but some types of long-term memory (e.g., procedural memory) remained intact. This supports the multi-store model’s idea of separate memory stores, and also lends support to later distinctions within LTM (e.g., episodic vs. procedural memory).
  L (Link): Therefore, Clive Wearing’s case supports the existence of multiple memory stores, giving credibility to cognitive models such as the MSM and the idea that LTM is not a single, unitary store.

✅ PEEL Strength — HM (supports LTM and role of hippocampus)

P (Point): Another strength of memory models comes from clinical case studies such as HM (Henry Mollison).
E (Evidence): HM had parts of his hippocampus removed to treat severe epilepsy, which led to profound anterograde amnesia — he could not form new long-term memories, although his short-term memory and procedural memory remained intact.
E (Explain): This supports the idea that the hippocampus plays a critical role in transferring information from STM to LTM. It also provides evidence for different types of long-term memory, as HM was able to learn new motor skills (e.g., mirror drawing) but had no conscious recollection of learning them, showing a dissociation between declarative and procedural memory.
L (Link): Therefore, HM’s case provides strong biological evidence for the separation of memory systems and supports models that view LTM as composed of multiple components.

❌ PEEL Weakness — MSM lacks detail about long-term memory

P (Point): A major weakness of the multi-store model of memory is that it does not account for the complexity of long-term memory.
E (Evidence): Research by Tulving (1985) suggests that long-term memory is not a single, unitary store as the MSM implies. Instead, it consists of multiple types: episodic (personal events), semantic (facts and knowledge), and procedural (skills).
E (Explain): The MSM treats LTM as one homogeneous store, failing to explain why someone like Clive Wearing can lose his episodic memory but retain his procedural memory (e.g., playing piano). This shows that the model is overly simplistic and lacks explanatory power when it comes to real-life memory functioning.
L (Link): Therefore, the MSM is limited because it does not reflect the true complexity of long-term memory, reducing its overall validity as a model of human memory.

❌ PEEL Weakness — MSM is overly simplistic

P (Point): A key weakness of the multi-store model is that it is overly simplistic and reductionist.
E (Evidence): The model suggests that memory operates in a linear way with three distinct, unitary stores (sensory register, STM, and LTM), and that information simply flows from one to the next. However, research shows that both STM and LTM are more complex than the model suggests. For example, the Working Memory Model (Baddeley & Hitch) proposes that STM consists of multiple components, such as the phonological loop and visuospatial sketchpad.
E (Explain): This shows that memory processes are more dynamic and interactive than the MSM accounts for. By reducing memory to a basic input-store-output process, the model ignores the role of factors such as rehearsal type, emotional significance, and meaning.
L (Link): Therefore, the MSM is too simplistic to fully explain how memory works in real life, limiting its overall usefulness as a psychological model.

❌ PEEL Weakness — Limited real-life application

P (Point): Another weakness of the multi-store model is that it lacks real-life application because much of the supporting research is based on artificial tasks.
E (Evidence): Studies that support the MSM, such as those by Peterson & Peterson or Baddeley, often use highly controlled lab experiments involving tasks like memorising random word lists or trigrams. These tasks lack mundane realism and don’t reflect how memory is used in everyday situations, such as remembering meaningful information or emotional events.
E (Explain): This reduces the ecological validity of the model, as it may not accurately represent how memory functions in the real world. In everyday life, memory is often influenced by factors like motivation, emotional context, and prior knowledge, which the MSM fails to consider.
L (Link): Therefore, while the MSM may help us understand basic memory processes, its practical usefulness is limited because it does not fully apply to memory in real-world settings.

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