The Multi-store Model of Memory (DP IB Psychology): Revision Note

The multi-store model of memory

• 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, stored and lost

• Information flows linearly: from the sensory register (SR) → short-term memory (STM) → long-term memory (LTM)

• Without rehearsal, information is quickly lost

• The model consists of three separate storage units:

  • the sensory memory/register;

  • short-term memory (STM) and

  • long-term memory (LTM)

The sensory register (SR)

• This 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 half a second at most

• Any information in the SR that is noticed or paid attention to is then passed onto STM

Short-term memory (STM)

• This is a temporary storage facility which has a limited duration and capacity

• The capacity of STM is 7 items, + or - 2, 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 due to the limited duration and capacity of the STM

  • E.g., you go into a room to find a book then you notice that your cat is on your bed; by the time you have moved the cat from your bed you have forgotten what it is you came into the room for

• In order to transfer information to LTM it is necessary to rehearse it

  • 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’

  • Elaborate rehearsal is a deep form of rehearsal, as it requires you to learn information in several ways

    • E.g., repetition, reframing the information, writing the information down, and reinterpreting the information

• 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

Long-term memory (LTM)

• This is a permanent storage facility, 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)

• Information may decay in LTM if it is not visited frequently or if the cues to retrieve it are missing

• Encoding in LTM happens semantically i.e., via meaning

Serial position effect & the MSM

• Serial position describes the placement of an item in a list

  • E.g., whether it's 1st, 2nd, 3rd, last, etc.

• Research suggests that the position of an item on a list affects how well it is remembered

• When people are presented with a list of items (e.g., words), they tend to remember the first few items on the list and the last few items on the list

  • items in the middle of the list are more likely to be forgetten

• This is known as the serial position effect (SPE)

  • The primacy effect is when items from the beginning of a list are recalled best compared to items in the middle

  • The recency effect is when items from the end of a list are recalled best compared to items in the middle

• SPE has relevance to the MSM because:

  • it provides evidence for STM (linked to the recency effect: items most recently seen/heard and are still in STM)

  • it provides evidence for LTM (linked to the primacy effect: items seen/heard first have transferred to LTM)

  • items in the middle have not been rehearsed and have been displaced by the more recent items

Research which supports the MSM

Glanzer & Cunitz (1966)

Aim:

• To investigate SPE as evidence for there being two separate stores of memory (STM and LTM), which supports the MSM

Participants:

• 46 males who were all enlisted in the US army

Procedure:

• Each participant was individually shown 15 lists, each containing 15 words. There were three conditions of the independent variable:

  • Immediate recall after being shown the list

  • Recall after a 10-second interference task (the Brown-Peterson technique of counting backwards aloud from a given number in 3s)

  • Recall after a 30-second interference task (the Brown-Peterson technique of counting backwards aloud from a given number in 3s)

Results: 

• Participants in the immediate recall condition showed the expected SPE – more items recalled from the beginning and the end of the list, showing both primacy and recency effect

• Participants in the 10-second delay condition showed a similar primacy effect to the immediate recall group but much less of a recency effect

• In the 30-second delay condition the primacy effect was high but the recency effect had disappeared, with fewest items recalled from the end of the list compared to the other two conditions

Conclusion:

• Prevention of rehearsal (eliminating the recency effect), means that items from the end of a list cannot be rehearsed in STM so they cannot be transferred to LTM

• There appear to be two separate storage facilities for STM and LTM

Evaluation of the MSM

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 HM (opens in a new tab) for further details)

Limitations

• As the MSM is a linear model it lacks flexibility and dynamism

  • 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)

Link to concepts

Causality

• Research into the MSM has been largely lab-based with the implementation of a clear, operationalised independent variable and a dependent variable which is measured quantitatively and so can withstand statistical analysis

  • This means that the research tends to be objective and appropriate for hypothesis-testing, adhering to the features of science

  • Humans, though, are not easily quantified, so lab-based research can lose a lot in translation

  • It cannot fully convey real experience (in the case of memory, it cannot explain how some memories do not need to be rehearsed but instead go directly into LTM)

Causality

• The MSM is a conceptual cognitive model, an example of machine reductionism

• It could be argued that the MSM is an overly contrived attempt to make direct comparisons between a computer/machine and human memory

  • The comparison is artificial and forced

  • Human memory is often unpredictable, multi-faceted and affected by emotion (e.g., flashbulb memories)

    • A computer is not designed to respond in the same way as a person might, which means that the MSM only has limited application to human memory