What is the Multi-Store Model of Memory (SL IB Psychology)

The MSM

• The multi-store model of memory (MSM) was devised by Atkinson & Shiffrin (1968) as a way of conceptualising the processes by which memories are encoded and stored
• The model encapsulates the flow i.e. from one storage facility to the next, whereby information reaches the senses and is then translated into memories
• The model is a linear representation of the ways in which information is either retained and stored in the memory or lost, e.g. due to lack of rehearsal
• The model consists of three separate storage units:
  • the sensory memory/register;
  • short-term memory (STM) and
  • long-term memory (LTM)

What is the Sensory Register?

• The sensory register (SR) is the point at which environmental stimuli are picked up by the five senses (sight, sound, smell, touch, taste)
• Sounds are encoded in the SR as echoic memory and images are encoded as iconic memory
• This environmental information is held onto for a fraction of a second i.e. its duration is tiny – half a second at most
• Any information in the SR that is noticed or paid attention to is then passed onto STM i.e. if we ignore or don’t pick up specific items of sensory information then they will not be transferred to STM

What is Short-Term Memory?

• The STM store is a temporary storage facility which has a limited duration and capacity for holding onto information that may – or may not – then be transferred to the LTM
• The capacity of STM is 7 items, plus or minus two, according to Miller’s ‘magic number 7’ theory
• The duration of STM is up to around 30 seconds
• New information entering the STM from the SR pushes existing information out (the ‘FIFO’ or ‘first in, first out’ idea) due to the limited duration and capacity of the STM
  • For example,  if you go into a room to find a book then you notice that your cat is on your bed, then by the time you have moved the cat from your bed you may well have forgotten what it is you came into your bedroom for
• In order to hold on to information it is necessary to rehearse it so that it is able to be passed on to LTM
• Maintenance rehearsal is a shallow form of rehearsal as it is simply requires you to repeat information verbally for long enough to be able to use it, e.g. on the way to the shop you keep telling yourself ‘Don’t forget to buy milk’ but once the milk has been bought you don’t need the information any more so you can stop rehearsing it
• Elaborate rehearsal is a deep form of rehearsal as it requires you to learn information in several ways e.g. repetition, re-framing the information, writing the information down, re-interpreting the information
• Elaborate rehearsal would be used to revise for an exam or to learn lines for a play as you need the information to be embedded in your memory and for it to endure over time
• Information which is not rehearsed will be lost from STM via displacement
• Encoding in STM happens acoustically i.e. via sound
• STM can be improved by the process of ‘chunking’ information e.g. a phone number can be chunked into groups of three digits (e.g. 485 362 971 886) so that it is easier to ‘digest’ and thus to recall

Chunking turns a huge ‘lump’ of information into handy bite-size pieces!

What is Long-Term Memory?

• LTM is, metaphorically a huge Amazon-type warehouse holding a vast number of memories, some of which you may not even know are there
• Both the capacity and the duration of LTM is not really known but researchers agree that both may be limitless
• LTM is difficult to research (unlike STM which can be studied using lab experiments) due to its ‘slippery’ nature
• Information may decay in LTM if it is not visited frequently or if the cues to retrieve it are missing, however there is no definitive evidence that any items from LTM are lost forever (just think of times when you suddenly recall something that you didn’t even know you knew!)
• Encoding in LTM happens semantically i.e. via meaning

Which research studies support the MSM?

• Glanzer & Cunitz (1966) – prevention of rehearsal erodes the recency effect in STM
• The case of HM (Milner 1958; Corkin 1997) – the case study of a brain-damaged patient provided evidence of two separate memory stores for STM and LTM

Glanzer & Cunitz (1966) is available as a separate ‘Key Study’ – just navigate the ‘Cognitive Processing’ section of this topic to find it along with the Key Study for the ‘Working Memory Model’ (Two Key Studies of Models of Memory)

Evaluation of the Multi-Store Model of Memory

Strengths

• This was the first model to attempt to conceptualise memory and it paved the way for further research in this field
• The existence of separate memory stores has been supported by lab experiments and by more than one case study (see also the case of KF for further information)

Weaknesses

• As the MSM is a linear model it lacks flexibility and dynamism i.e. it presents STM and LTM as static stores without explaining how they operate
• Subsequent research has identified that there is more than one type of LTM:
  • episodic memory contains information from your own personal history e.g. birthday parties;
  • procedural memory contains information that helps you to perform actions such as riding a bike or playing the piano;
  • semantic memory contains information as to meaning e.g. knowledge about the world (e.g. Paris is the capital of France)