Multi-Store Model

• Who proposed the multi-store model?

  Atkinson and Shiffrin (1968)
• what are the different components of the MSM?

  FOLLOWING:

  
• capacity of SR

  unknown but very large
• duration of SR

  • very limited (approx 250ms)
• coding for SR

  raw/unprocessed information
• capacity of STM

  limited (7±2 items)
• duration of STM

  approx 18 seconds
• coding of STM

  acoustic
• capacity of LTM

  unlimited
• duration of LTM

  lifetime
• coding for LTM

  semantic
• results of Miller (1956) - capcity of STM

  • existing research suggested that organising stimulus input into a series of chunks enabled STM to cope with about seven chunks
• conclusion of Miller (1956) - capacity of STM

  organisation can extend the capacity of STM and enable more information to be stored there
• strength of Miller (1956)

  • supported by psychological research. For example, Jacobs (1887) conducted an experiment using a digit span test, to examine the capacity of STM for numbers and letters. Jacobs used a sample of 443 female students. Participants had to repeat back a string of numbers or letters in the same order and the number of digits/letters was gradually increased, until the participants could no longer recall the sequence. Jacobs found that the students had an average span of 7.3 letters and 9.3 words, which supports Miller’s notion of 7+/‐2.
• limitations of Miller (1956)

  • he did not specify how large each ‘chunk’ of information could be and therefore we are unable to conclude the exact capacity of STM. Consequently, further research is required to determine the size of information ‘chunks’ to understand the exact capacity of STM.
  • Finally, Miller’s (1956) research into STM did not take into account other factors that affect capacity. For example, age could also affect STM and Jacobs’ (1887) research acknowledged that STM gradually improved with age
• method of Peterson and Peterson (1959) - duration of STM

  • 24 male and female university students
  • 48 three letter trigrams
  • participants were showed trigram then had to count down backwards from a three digit numbers to prevent rehearsal
  • participants then had to recall the trigram
• results of Peterson and Peterson (1959) - duration of STM

  • longer the interval the less accurate the recall
  • 3 seconds - 80% trigrams correctly recalled
  • 18 seconds - only 10%
• conclusion of Peterson and Peterson (1959) - duration of STM

  • limited duration of approximately 18 seconds
  • if we are unable to rehearse information it will not be passed to LTM
• strength of Peterson and Peterson (1959)

  • highly controlled and took place in a laboratory of Indiana University. As a result Peterson & Peterson had a high degree of control for extraneous variables, which makes their procedure easy to replicate to test reliability.
• limitations of Peterson and Peterson (1959)

  • used 24 psychology students:
  • may of encountered the MSM of memory previously and therefore might of demonstrated demand characteristics
  • small sample size
  • low levels of ecological validity. In this study participants were asked to recall three‐letter trigrams, which is unlike anything people would want to memorise in their everyday lives. As a result we are unable to apply these results to everyday examples of memory and are unable to conclude if the duration of STM may be longer for more important information, such as a vital phone number.
• method of Bahrick (1975) - duration of LTM

  • 392 American university graduates were shown photographs from their high school yearbook and for each photograph participants were given a group of names and asked to select the name that matched the photographs.
• results of Bahrick (1975) - duration of LTM

  • 90% of participants correctly match the names and faces 14 years after graduating
  • 60% of participants were able to correctly match the names and faces 47 years after graduation
• conclusion of Bahrick (1975) - duration of LTM

  • Bahrick concluded that people could remember certain types of information, such as names and faces, for almost a lifetime.
  • These results support the MSM and the idea that our LTM has a lifetime duration (at least 47 years), and is semantically encoded.
• strength of Bahrick (1975)

  • high levels of ecological validity as the study used real‐life memories. In this study participants recalled real‐life information by matching pictures of classmates with their names. Therefore, these results reflect our memory for real‐life events and can be applied to everyday human memory.
• limitations of Bahrick (1975)

  • sample of 392 American university graduates and therefore lacks population validity. Psychologists are unable to generalise the results of Bahrick’s research to other populations. As a result, we are unable to conclude whether other populations would demonstrate the same ability to recall names and faces after 47 years.
  • His research is unable to explain whether LTM becomes less accurate over time because of a limited duration, or whether LTM simply gets worse with age. This is important because psychologists are unable to determine between the two
• strengths of MSM !(1)

  • Clive Wearing: contracted a virus that caused severe amnesia. Could only remember information for 20-30 seconds however he was able to recall information from his past. Wearing was unable to transfer information from STM to LTM. Support‘s idea of seperate stores and memories are formed by passing information from one store to the next
• strengths of MSM (2)

  • The MSM takes a nomothetic approach, trying to create a universal model to explain the process of human memory. An idiographic, individual approach that used examples of real‐life remembering may result in a more complex (and arguably more accurate) picture of memory.
  • research by Miller, Peterson and Peterson, Bahrick etc support the different elements of the MSM and therefore suggest MSM is an accurate representation of memory
• strengths of MSM (3)

  • evidence from brain scans has shown that different areas of the brain are active when performing STM tasks (hippocampus and subiculum) and LTM tasks (motor cortex). The hippocampus is also involved in transferring short‐term memories into long‐term memories. This suggests that different brain regions are responsible for the different components of the MSM, supporting the idea that our memory is made up of discrete stores.
• limitations of MSM

  • Baddeley and Hitch (1974) developed the working memory model (WMM) as an explanation of the complexity of STM and a way of explaining some of the research findings that could not be accounted for by the MSM
  • Research examining the MSM is a clear example of experimental reductionism, as it attempts to explain a complex behaviour by relying on isolated variables operationalised in laboratory experiments. However, as memory is a complex phenomenon, many psychologists argue that reducing memory to isolated variables undermines the complexity of human memory.