multi-store model of memory (MSM)

creators of MSM

• Atkinson and Shiffrin (1968-71)

three stores of MSM

• sensory register

• short-term memory

• long-term memory

how information is transferred in MSM

sensory register (SR) definition

• SR is where all sensory information from the environment passes into or is held

• SR is a passive filter

• SR receives information from all 5 senses (touch, smell, sight, hearing, taste)

coding definition

• coding is how memory is stored

• coding in the SR is modality specific (depends on the sense involved)

5 types of coding in SR

• haptic

• echoic

• iconic

• olfactory

• gustatory

capacity definition

• how much data can be held in a memory store

capacity, duration, coding of three stores of memory

duration definition

• how long a memory is held within a store

duration of SR

• most memory information is only held within the SR for milliseconds

• as 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

attention in the MSM

• paying attention to information allows it to pass from the SR to the STM

coding of the STM

information enters the STM acoustically (Baddeley 1966)

capacity of the STM

• capacity of STM is limited; only a certain number of items can be remembered through the STM

  • Miller (1956) suggests the capacity of STM is between 5-9 items

  • Miller’s ‘magic number 7’ refers to this capacity - capacity is 7±2

• Jacobs (1887)

  • Sample of 445 female students (aged 8-19)

  • Jacobs asked his participants to repeat back a string of numbers or letters in the same order as they were presented

  • The number of digits/letters was gradually increased until the participants could no longer recall the complete sequence

  • Jacobs’ results showed that the students had an average memory span of 7.3 letters and 9.3 words

duration of STM

• limited duration around 18 seconds (unless information is rehearsed)

• thus STM is a temporary memory store

duration of STM - Peterson and Peterson (1959)

• Procedure

  • Used the Brown-Peterson Technique to investigate the duration of the STM

  • The participants were shown a trigram (three consonants such as BVM or CTG)

  • Then the participants were asked to recall the trigram they had seen 3, 6, 9, 12, 15 or 18 seconds late

  • During the time in between being presented with the trigram and being asked to recall it, they were given an interference task

  • In this case, the participants had to count backwards in three from a three digit number

• Findings

  • Participants were able to recall the trigram very well after only 3 seconds, less well after 6 seconds and so on

  • By the time 18 seconds had elapsed, the participants found it very hard to recall the trigram

  • They concluded that the memory trace in STM completely disappeared within 18 seconds (refer in exams as <30s)

rehearsal

• for information to be passed from STM to LTM, information must be rehearsed

maintenance rehearsal definition

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

elaborative rehearsal definition

• deeper processing than maintenance rehearsal (e.g. learning lines for a play)

long term memory definition

• permanent memory store of past events/items

• to recall information from LTM, it must be accessed and transferred to STM (retrieval)

coding in LTM

semantically coded

capacity of LTM

unlimited (potentially)

duration of LTM

• thought to be lifetime for each individual

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

duration of LTM - Bahrick, Bahrick and Wittenger (1975)

• Investigation into the duration of the LTM used 400 ex-high school students of varied ages as participants

• These participants were asked to free recall the names of their year peers

• They were also shown photographs from their year book and asked them to recall names attached to their faces

strengths of MSM explanation

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

  • Baddeley (1966) tested the recall of 4 groups of participants with different lists of words

  • Baddeley found that similar acoustic words can get mixed up when using STM, but similar semantic words get mixed up when using the LTM

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

• The case study of HM who suffered 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 could not form new memories (STM could not be transferred to LTM)

    • HM suffered retrograde amnesia (inability to recall memories and events before specific point in time) and anterograde amnesia (inability to create new memories after an event that caused amnesia)

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

weaknesses of MSM explanation

• The MSM may be too simple

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

  • The working memory model supports this idea as it includes five components of STM

  • The study of KF promotes the idea that the MSM is too simplistic

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

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

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

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