Atkinson and Shiffrin (1968) developed the multi store model, which is a representation of how
memory processes work. The multi store model is a structural model composing of 3 separate stores
the sensory memory (SM), short term memory (STM) and long term memory (LTM). Information is
passed between these stores in a linear way and each of these stores are distinct and separate, if
one were to get damaged the other stores would still work. Each of these stores also differ in terms
of 3 characteristics coding (the form in which information can be stored, whether it is coded visually,
acoustically or semantically), capacity (how much information can be stored) and duration (how long
the information can be stored for).
The sensory memory is the first storage system for incoming information. Information received is
raw and unprocessed and is from environmental stimuli (5 senses). The sensory memory has several
stores called sensory register with each processing information from a particular sense. The Iconic
store is where visual images are kept for a short period of time (processes vision), the Echoic store is
where auditory senses are kept for a short period (processes sound-hearing) and finally the Haptic
stores which retains physical sense of touch and internal muscle tension (processes touch). If
information in the sensory memory is paid attention to it is transferred to the short-term memory.
The capacity of the sensory memory is quite large, but the duration is small.
The next storage system is the short-term memory, which receives information that has been paid
attention to from the sensory memory. Information in the short-term memory has limited duration
of up to 18 seconds and is in a ‘fragile’ start and will decay (memory fades away if nothing is done
with it) very easily if not rehearsed. The capacity of the STM is 7+/-2 items according to Jacob and
millers study, so the capacity is limited. Due to the limited capacity information from the STM will
disappear if new information comes in also referred to as displacement. However, if information is
rehearsed and processed deep enough (e.g. through elaborative or maintenance rehearsal)
information is passed to the long-term memory. The short-term memory codes information
acoustically (e.g. keep repeating the word doughnut to remember it).
The last storage system is the long-term memory, which is potentially a permanent memory store
for information that has been rehearsed for a prolonged time. LTM is believed to have unlimited in
duration and capacity. When we want to recall information, it must be transferred back into the STM
by retrieval. According to the multi store model none of our memories are rehearsed directly from
LTM. The long-term memory codes information semantically and is based on meaning.
A strength of the multi store model is that the supporting evidence from controlled lab experiments
on capacity, duration and coding support the existence of separate STM and LTM, which is the basis
of the MSM. For example, Beardsley (1997) found that the prefrontal cortex is active during short
term memory and not long term memory. As a results this confirms the existence of the Short-term
memory and shows that there is a difference between the STM and LTM, supporting the multi store
model of memory. Therefore, this increases the validity of the MSM.
A strength of the MSM is that from evidence from case studies, psychologist have shown different
areas of the brain being involved in STM and LTM. For example, the study of HM who had a bike
crash suffered from brain damage due to the removal of hippocampus. His personality and intellect
remained intact, but he was unable to form new LTMs. Therefore, this support the idea of the STM
and LTM being separate types of memory as despite HM LTM was destroyed his STM remained.
However, evidence from case studies can’t be generalised to other people and situation as case
studies are unique and one off event.