The multi-store model of memory: sensory register, short-term memory and long-term
memory
Always draw out diagrams of memory models if you have time as this gains you credit
● The Multi-Store Model of Memory was devised by
Atkinson and Shiffrin in 1968.
● This theoretical model seeks to explain how
information is transmitted from the outside world through
different stores memory, and how it is processed at each
point.
Features of each store: coding, capacity and
duration.
★ Coding is which format the information is stored in.
★ Capacity is how much (the quantity) of information that can be held in the memory store
at any one time.
★ Duration is how long information stays in the memory store.
★ Function is what each store does.
● The mind is flooded with environmental stimuli coming from the eyes, ears, taste
receptors, touch receptors ..etc.
● This information arrives at a part of the mind called the Sensory Register. The
information enters and is coded in the sensory register in whatever form it was perceived
in (so it is modality specific) and each kind is stored in a different store within the sensory
register depending on which sense organ the information came from. Visual memory is
stored in the Iconic store, sound in the Echoic store, smell in the Olfactory store, touch in
the Haptic store, and taste in the Gustatory store. As there is a lot of stimulus coming in
all the time the capacity of the sensory register is unlimited. As most of the sensory
information that comes in doesn’t need to be consciously considered, and there is a lot
of it, the duration of for sensory memory in the sensory register is only about 250
milliseconds.
● Only sensory information that we pay attention to will move to the next store, and so the
vast majority will be lost.`
★ The Short Term Memory store is the next store. It has a duration of about 18-30
seconds. Only information that is rehearsed (consciously repeated inside the mind) here
will pass into the next store, and the rest will be lost, as by rehearsing information we
can keep it in the store for longer than 18-30 seconds. Short term memory is coded
acoustically as the information is rehearsed using our internal voice.
★ There are two kinds of rehearsal. Maintenance rehearsal keeps the information in the
short term memory for longer, and it may pass into the long term memory eventually.
Elaborative rehearsal is where we semantically encode the information (give it meaning),
moving it directly from the short term memory to the long term memory.
, ★ Chunking is a way to improve short term memory by grouping items so that each group
is treated as one item by the short term memory, thus improving recall as the overall
number of ‘items’ is reduced.
● The next store is the Long Term Memory. Information in the long term memory has an
unlimited duration and it has an unlimited capacity. Information in our long term memory
may be lost (we lose access to it), but this may be regained at a later date. Information in
the long term memory is coded semantically (based on its meaning).To use the
information in the long term memory we need to bring it out of the long term memory and
back into the short term memory. This process is called retrieval.
● Unlike the short and long term memory the sensory register is not under conscious
control; it is recorded automatically. Any information found in the short or long term
memory is initially gathered by the sensory register.
Research on the sensory register
➔ Capacity- Sperling (1960) flashed a grid of 20 letters onto a screen for a 20th of a
second. When participants were asked to recall random rows of letters the recall was
strong. This suggests that all the rows of letters were stored in the sensory register as
participants didn’t know which row would be asked for, meaning that the iconic store in
the sensory register has a large capacity.
Research on the short term memory
➔ Coding- Baddeley (1966) gave four 10 word lists to four participant groups. The first list
consisted of acoustically similar words (words that sound similar). The second list
consisted of acoustically dissimilar words (words that sound different). The third list
consisted of semantically similar words (words with similar meanings), and the fourth list
consisted of semantically dissimilar words (words with unrelated meanings). Baddeley
found that immediate recall was worst for list 1, and recall after 20 minutes was worst for
list 3. This suggests that information in the short term memory is coded acoustically,
meaning that immediate recall for list 1 was hardest because the words all sounded
similar, so they were all effectively stored as one item, making recall difficult.
➔ Capacity- Jacobs (1887) presented participants with a list of letters or numbers.
Participants then had to recall the list in order. Jacobs found that the capacity for letters
was around 7 items and 9 for numbers, suggesting that the capacity of the short term
memory is very limited.
➔ Duration- Peterson and Peterson (1959) showed participants 3-letter trigrams (i.e:
HFR, TKD). Trigrams with any meaning were avoided so that participants could not
rehearse the information semantically. Then participants had to count backwards for a
few seconds. This interference task was designed to stop maintenance rehearsal.
Peterson and Peterson found that after 18 seconds recall was less than 10%. This
suggests that information remains in the short term memory for only a few seconds
before it disappears.
Research on long-term memory
➔ Coding- Baddeley (1966) (see above)
, ➔ Capacity- Wagnaar (1986) kept a diary over the course of six years which recorded
over 2,400 events. He tested himself on the events and found a 75% recall after 1 year
and a 45% recall after 5 years, suggesting that the capacity of the long term memory is
very large, potentially limitless.
➔ Duration- Bahrick (1975) showed old photographs and names (including those of old
school friends) to participants aged 17-74, recall was 90% after 15 years, and still 80%
for names after 48 years. This suggests that the duration of the LTM is very large,
potentially limitless.
Evaluation of the Multi-store Model
★ The short duration of the SR is supported by evolutionary theory, as in the wild quick
reactions are vital for survival, so only important information would be retained and
processed. Too much information would lead to slower reactions.
★ There is a large base of research that supports the idea of distinct STM and LTM
systems. An example of this is the Shallice and Warrington (1974) study of KF, a
brain-damaged case study patient whose STM was impaired following a motorcycle
accident, but his LTM remained intact.
★ It makes sense that memories in the LTM are encoded semantically – i.e. you might
recall the general message put across in a political speech, rather than all of the words
as they were heard.
★ The MSM was a pioneering model of memory that inspired further research and
consequently other influential models, such as the Working Memory Model.
★ Some research into STM duration has low mundane realism, as the stimuli participants
were asked to remember bear little resemblance to items learned in real life, e.g.
Peterson and Peterson (1959) used nonsense trigrams such as ‘XQF’ to investigate
STM duration. Similarly the ecological validity of many of the experiments is low as they
were carried out in lab environments, so participant behaviour may not be the same as
would be expected in a more natural environment. This can lead to low external validity
for the findings.
★ The model is arguably over-simplified, as it sees each store as a single unit, but
evidence suggests that there are multiple short and long-term memory stores, e.g. ‘LTM’
can be split into Episodic, Procedural and Semantic memory.
★ It does not make much sense to think of procedural memory (a type of LTM) as being
encoded semantically, i.e. knowing how to ride a bike through its meaning.
★ The capacity of the STM can be significantly altered by factors such as age (reduces)
and practice (increases). This means that the view of a fixed STM capacity is incorrect.
★ It is only assumed that LTM has an unlimited capacity, as research has been unable to
measure this accurately.
Types of long-term memory: episodic, semantic, procedural
● Long term memory is the storage of memories over a long period of time. It is
suggested that there are different kinds of LTM. The two main types are
memory
Always draw out diagrams of memory models if you have time as this gains you credit
● The Multi-Store Model of Memory was devised by
Atkinson and Shiffrin in 1968.
● This theoretical model seeks to explain how
information is transmitted from the outside world through
different stores memory, and how it is processed at each
point.
Features of each store: coding, capacity and
duration.
★ Coding is which format the information is stored in.
★ Capacity is how much (the quantity) of information that can be held in the memory store
at any one time.
★ Duration is how long information stays in the memory store.
★ Function is what each store does.
● The mind is flooded with environmental stimuli coming from the eyes, ears, taste
receptors, touch receptors ..etc.
● This information arrives at a part of the mind called the Sensory Register. The
information enters and is coded in the sensory register in whatever form it was perceived
in (so it is modality specific) and each kind is stored in a different store within the sensory
register depending on which sense organ the information came from. Visual memory is
stored in the Iconic store, sound in the Echoic store, smell in the Olfactory store, touch in
the Haptic store, and taste in the Gustatory store. As there is a lot of stimulus coming in
all the time the capacity of the sensory register is unlimited. As most of the sensory
information that comes in doesn’t need to be consciously considered, and there is a lot
of it, the duration of for sensory memory in the sensory register is only about 250
milliseconds.
● Only sensory information that we pay attention to will move to the next store, and so the
vast majority will be lost.`
★ The Short Term Memory store is the next store. It has a duration of about 18-30
seconds. Only information that is rehearsed (consciously repeated inside the mind) here
will pass into the next store, and the rest will be lost, as by rehearsing information we
can keep it in the store for longer than 18-30 seconds. Short term memory is coded
acoustically as the information is rehearsed using our internal voice.
★ There are two kinds of rehearsal. Maintenance rehearsal keeps the information in the
short term memory for longer, and it may pass into the long term memory eventually.
Elaborative rehearsal is where we semantically encode the information (give it meaning),
moving it directly from the short term memory to the long term memory.
, ★ Chunking is a way to improve short term memory by grouping items so that each group
is treated as one item by the short term memory, thus improving recall as the overall
number of ‘items’ is reduced.
● The next store is the Long Term Memory. Information in the long term memory has an
unlimited duration and it has an unlimited capacity. Information in our long term memory
may be lost (we lose access to it), but this may be regained at a later date. Information in
the long term memory is coded semantically (based on its meaning).To use the
information in the long term memory we need to bring it out of the long term memory and
back into the short term memory. This process is called retrieval.
● Unlike the short and long term memory the sensory register is not under conscious
control; it is recorded automatically. Any information found in the short or long term
memory is initially gathered by the sensory register.
Research on the sensory register
➔ Capacity- Sperling (1960) flashed a grid of 20 letters onto a screen for a 20th of a
second. When participants were asked to recall random rows of letters the recall was
strong. This suggests that all the rows of letters were stored in the sensory register as
participants didn’t know which row would be asked for, meaning that the iconic store in
the sensory register has a large capacity.
Research on the short term memory
➔ Coding- Baddeley (1966) gave four 10 word lists to four participant groups. The first list
consisted of acoustically similar words (words that sound similar). The second list
consisted of acoustically dissimilar words (words that sound different). The third list
consisted of semantically similar words (words with similar meanings), and the fourth list
consisted of semantically dissimilar words (words with unrelated meanings). Baddeley
found that immediate recall was worst for list 1, and recall after 20 minutes was worst for
list 3. This suggests that information in the short term memory is coded acoustically,
meaning that immediate recall for list 1 was hardest because the words all sounded
similar, so they were all effectively stored as one item, making recall difficult.
➔ Capacity- Jacobs (1887) presented participants with a list of letters or numbers.
Participants then had to recall the list in order. Jacobs found that the capacity for letters
was around 7 items and 9 for numbers, suggesting that the capacity of the short term
memory is very limited.
➔ Duration- Peterson and Peterson (1959) showed participants 3-letter trigrams (i.e:
HFR, TKD). Trigrams with any meaning were avoided so that participants could not
rehearse the information semantically. Then participants had to count backwards for a
few seconds. This interference task was designed to stop maintenance rehearsal.
Peterson and Peterson found that after 18 seconds recall was less than 10%. This
suggests that information remains in the short term memory for only a few seconds
before it disappears.
Research on long-term memory
➔ Coding- Baddeley (1966) (see above)
, ➔ Capacity- Wagnaar (1986) kept a diary over the course of six years which recorded
over 2,400 events. He tested himself on the events and found a 75% recall after 1 year
and a 45% recall after 5 years, suggesting that the capacity of the long term memory is
very large, potentially limitless.
➔ Duration- Bahrick (1975) showed old photographs and names (including those of old
school friends) to participants aged 17-74, recall was 90% after 15 years, and still 80%
for names after 48 years. This suggests that the duration of the LTM is very large,
potentially limitless.
Evaluation of the Multi-store Model
★ The short duration of the SR is supported by evolutionary theory, as in the wild quick
reactions are vital for survival, so only important information would be retained and
processed. Too much information would lead to slower reactions.
★ There is a large base of research that supports the idea of distinct STM and LTM
systems. An example of this is the Shallice and Warrington (1974) study of KF, a
brain-damaged case study patient whose STM was impaired following a motorcycle
accident, but his LTM remained intact.
★ It makes sense that memories in the LTM are encoded semantically – i.e. you might
recall the general message put across in a political speech, rather than all of the words
as they were heard.
★ The MSM was a pioneering model of memory that inspired further research and
consequently other influential models, such as the Working Memory Model.
★ Some research into STM duration has low mundane realism, as the stimuli participants
were asked to remember bear little resemblance to items learned in real life, e.g.
Peterson and Peterson (1959) used nonsense trigrams such as ‘XQF’ to investigate
STM duration. Similarly the ecological validity of many of the experiments is low as they
were carried out in lab environments, so participant behaviour may not be the same as
would be expected in a more natural environment. This can lead to low external validity
for the findings.
★ The model is arguably over-simplified, as it sees each store as a single unit, but
evidence suggests that there are multiple short and long-term memory stores, e.g. ‘LTM’
can be split into Episodic, Procedural and Semantic memory.
★ It does not make much sense to think of procedural memory (a type of LTM) as being
encoded semantically, i.e. knowing how to ride a bike through its meaning.
★ The capacity of the STM can be significantly altered by factors such as age (reduces)
and practice (increases). This means that the view of a fixed STM capacity is incorrect.
★ It is only assumed that LTM has an unlimited capacity, as research has been unable to
measure this accurately.
Types of long-term memory: episodic, semantic, procedural
● Long term memory is the storage of memories over a long period of time. It is
suggested that there are different kinds of LTM. The two main types are
