The Multi-Store Model of Memory

Who created the multi store model of memory?

Atkinson and Shiffrin (1968)

The MSM is a linear model, what does this mean?

Information is shown to flow through the system in one direction

The MSM has passive stores, what does this mean?

The stores hold on to information before being passed on or lost

What are the 3 MSM stores?

• Sensory register

• Short term memory

• Long term memory

What are the 3 important features of each store?

Coding = how different information types/formats the brain uses to store

Capacity = how much information can be held by a store

Duration = how long information can be held in that store for before loss

What is the sensory register?

• Store is not under cognitive control like STM or LTM

• Sensory information coming from the senses is detected and recorded automatically

• All information found in STM and LTM were initially gathered by the sensory register

• Information is passed on to STM by paying attention

How is information in the sensory register coded?

Store depends on the sense organ that the information comes from..

Iconic = vision

Echoic = sound

Haptic = touch

Gustatory = taste

Olfactory = smell

*or can be called modality specific

What is the capacity of the sensory register?

Very large, has to contain all the sense impressions for all the senses in the moment. However only what is paid attention to is paid to the STM

What is the duration of the sensory register?

Very short, as low as 250 milliseconds. As so much information is held, it cannot be retained for very long

What is the short term memory store?

• STM receives information from the sensory register by paying attention

• STM passes information to LTM through rehearsal

• Through either maintenance rehearsal (repeating the information) or elaborative rehearsal (linking to information already in LTM)

• Information is passed back from LTM with retrieval

• Information can be lost via displacement (new info) or decay (lost over time)

How is information in the short term memory coded?

Information in the STM is stored acoustically (in the form of sound/spoken words)

What is the capacity of the short term memory store?

Miller suggests it is small, approximately 7 items plus or minus 2 items (5-9) and this can be improved by chunking (making small sets/groups of items. This reduces the number of items overall

What is the duration of the short term memory store?

Short, 18-30 seconds. However duration of information can be extended by verbal rehearsal (rehearsal loop)

What is the long term memory store?

• Information comes into LTM from STM via rehearsal and in order to use information in LTM it needs to be passed back to STM via retrieval

How is information in the long term memory store coded?

Information in LTM is stored semantically, this is in the form of ‘meaning’

What is the capacity of the long term memory store?

No limit has been found to the amount of information that can be stored in LTM. Information can be lost, but this doesn’t seem to be because it is ‘out of room’, the information may still be in LTM but not accessible

What is the duration of the long term memory store?

Duration is potentially unlimited as recall of childhood events is normal even for the oldest people

AO3 Glanzer and Cunitz (1966) - Evidence that the STM and LTM stores are separate processes

Asked participants to free recall word lists (any order). It was found recall was much stronger for words at the start and at the end of the list. These results suggest there are separate short and long term memory stores, with the words first heard entering LTM being recalled (primacy effect) and the most recent words being held by STM being recalled (recency effect), the middle words were in STM but were displaced by later words

AO3 Sperling (1960) - Sensory register capacity

Trained participants were presented with a three by four grid of letters (12 total). When presented quickly (1/20th of a second), then had to recall one row. It was found that recall for a row was over 75%. This suggests that all rows were contained within the capacity of the iconic store, so sensory memory is large

AO3 CODING OF STM- Baddeley (1966)

Gave four 10 word lists to four participant groups. 1) Acoustically similar - word sound the same 2) Acoustically dissimilar - words sound different 3) Semantically similar - have related meaning 4) Semantically dissimilar - words are unrelated. It was found that immediate recall was worst for list 1 and recall after 20 minutes was worst with list 4. This suggests that the coding in STM is acoustic, as recalling list 1 was most difficult as similar sounds caused confusion

AO3 CAPACITY OF STM - Jacobs (1887)

Participants were presented with lists of letters or numbers. Participants then had to recall the list. It was found that the capacity for letters was on average around 7 items for letters and 9 for numbers (usually stated 7+ / -2). This suggests that the capacity of STM is very limited. Miller suggested this can be improved by chunking, making small sets/groups of items, this reduces the total number of items overall

AO3 DURATION OF STM - Peterson and Peterson (1959)

Showed participants three letter trigrams (eg HFD, TKU). Then participants had to count backwards for a few seconds to stop maintenance rehearsal (interference task). It was found after 18 seconds recall was less than 10%. This suggests that unless maintained information is held in STM for only a few seconds (18 to 30 seconds max) before it disappears

AO3 CODING OF LTM - Baddeley (1966)

Gave four 10 word lists to four participant groups. 1) Acoustically similar - word sound the same 2) Acoustically dissimilar - words sound different 3) Semantically similar - have related meaning 4) Semantically dissimilar - words are unrelated. It was found immediate recall was worst for list 1 and recall after 20 mins was worst with list 4. This suggests that coding in LTM is semantic, as recalling was most difficult as recalling similar meanings caused confusion

AO3 CAPACITY OF LTM - Wagenaar (1986)

Created a diary of over 2400 events during the course of six years including recording who, when, what and where. It was found when tested using these cues he had 75% recall of one particular critical detail after 1 year and 45% after 5 years. And his sense of remembering the event (retention judgement) was high, 80% after 5 years. This suggests the capacity of LTM is very large, potentially limitless

AO3 DURATION OF LTM - Bahrick (1975)

392 participants aged 17 to 74 were tested for memory of old photographs and names of their school friends. It was found recall in matching names to faces was 90% after 15 years, and still 80% for names after 48 years. This suggests that the duration of LTM is very large, potentially limitless

General AO3 - Artificial studies

Cognitive experiments testing aspects of the MSM are often lacking in external validity. There is low ecological validity, results collect in lab environment may not be generalisable to other more naturalistic situations like school and work. Also there is a lack of mundane realism, the experimental tasks testing the MSM are unlike how people use their memory in real life scenarios

General AO3 - Hard to research memory

The artificial nature of the design of experimental studies may be the only way of clearly measuring memory, and testing the limits of memory. This approach may ultimately uncover the underlying internal mental structure of memory

General AO3 - Research based on inferences

Models of memory cannot be directly observed so researchers have to make inferences on the structure of memory based on the behaviour observed during experimentation. These inferences are effectively educated guesses and could be incorrect

General AO3 - Links to assumptions from evolutionary theory

The large capacity and short duration of the sensory register matches what would be expected from evolutionary theory, that as much information as possible is gathered from the environment, but only the important information is processed

General AO3 - MSM is not a full explanation

Later research has demonstrated that neither STM or LTM are unitary stores. There are multiple types of LTM and STM is better explained by the WMM. Also the MSM lacks face validity, we all have LTM’s of tastes and smells, and many people experience the capacity of STM, not as fixed, but changing over a lifetime