Multi-store Model of Memory (MSM) (AQA A Level Psychology)

Sensory register: coding, capacity & duration

• The multi-store model of memory (MSM) was proposed by Richard Atkinson and Richard Shiffrin (1968-1971)

• MSM describes a system for how memories are made and stored

  • There are three stores:

    • Sensory register

    • Short-term memory

    • Long-term memory

  • The stores are linked by processes that enable information to flow from each store

Sensory register

• The sensory register (SR) (also referred to as sensory memory) is where all sensory information from the environment passes into or is held

• There are five senses that our body detects

  • Eyes for sight

  • Ears for sounds

  • Nose for smell

  • Tongue for taste

  • Skin for touch/pressure

• There are several registers (stores) within the brain for each of the senses

Coding

• Coding is how the memory is stored e.g. acoustic codes, visual codes or semantic codes

• Coding in the SR depends on the sense involved, it is therefore modality-specific, e.g.

  • Iconic memory is the register/store coding for visual information

  • Echoic memory is the register/store coding for acoustic (sound) information

Coding in the SR depends on the sense involved

Capacity

• Capacity refers to how much data can be held in the memory store

• The SR has a very high capacity, e.g. the cells in the eye contain over 100 million cells, each storing visual data

Duration

• Duration is how long a memory is held within a store

• Most sensory information is only held within the SR for milliseconds

• This is because the brain receives millions of pieces of information from the SR every second

• The brain would find it impossible to retain or give attention to this amount of data, nor does it need to

Attention

• Attention is a key process connecting the SR to the short-term memory store (STM)

• If attention is paid to the information passing into the SR then it can be passed onto STM

Short-term memory: coding, capacity & duration

• Information that enters the short-term memory (STM) is used for present and immediate tasks e.g. for following directions or recalling someone's name immediately after learning it

Coding

• Information entering the STM is typically acoustic (Baddeley 1966)

Capacity

• The capacity of short-term memory is limited, only a certain number of items can be remembered through the STM

  • Research (Miller 1956) suggests the capacity of STM is between five to nine items

    • Miller's 'magic number 7' refers to this capacity (STM can hold 7 items at once + or - 2)

Duration

• STM has a limited duration, around 18 seconds (unless the information is rehearsed)

• This means that STM is a temporary memory store

Rehearsal

• For information to be passed from STM into long-term memory (LTM) it must be rehearsed

  • Maintenance rehearsal is a surface-level repetition of the information (e.g. repeating a phone number in your head)

  • Elaborative rehearsal involves deeper processing (e.g. learning lines for a play)

Long-term memory: coding, capacity & duration

• Long-term memory is a permanent memory store of past events or items, e.g.

  • your first day at primary school

  • a birthday party or celebration

  • the name of your favourite teacher

• To recall information that has passed into LTM it must be accessed and transferred to STM, this is known as retrieval

Coding

• Information in LTM is coded semantically (based on meaning)

Capacity

• The capacity of LTM is potentially unlimited

Duration

• Duration is thought to be for the lifetime of each individual

• Items in LTM may be prone to forgetting

  • Some research suggests that the memory was never actually stored in LTM in the first place i.e. it was displaced from STM

  • Some LTMs may be unavailable i.e. resistant to retrieval

    • This means that some memories in LTM decay

  • Research using brain scanning techniques indicates that STM and LTM may be stored in different brain regions which may explain their differing durations

Evaluation of multi-store model of memory

Strengths

• Controlled lab studies on coding, capacity and duration support the theory of having separate memory stores

  • Baddeley (1966) tested the recall of four groups of participants with different lists of words

  • Baddeley found that similar-sounding (acoustic) words can get mixed up when using STM, but similar-meaning (semantic) words get mixed up when using LTM

  • This suggests that there is a clear distinction between STM and LTM

• The case study of HM who suffered from epilepsy and underwent brain surgery to correct this, removing his hippocampus

  • Following this surgery, HM could remember events and some information and details from before the surgery (LTM) but he could not form new memories (STM could not be transferred to LTM)

    • This adds weight to the argument that the brain uses separate regions or structures for STM and LTM

Limitations

• The MSM may be too simple:

  • Research suggests that STM and LTM are made up of more than one store

  • The working memory model supports the above idea, as it includes five components of STM

• Much of the research into the MSM uses artificial tasks such as recalling a string of digits/letters

  • Baddeley (1966)used artificial stimuli instead of meaningful material

    • This suggests there is a limited application to real world memory use

    • The use of artificial tasks and application means that the study lacks ecological validity