The Multi Store Model for memory

What is the MSM?

• Atkinson and Shiffrin (1968)

• Is an information processing model of memory

• Information is linear (shown to flow through systems in one direction)

• Has passive stores (The stores hold on to information before being passed on or lost)

What are the MSM stores?

• Sensory register

• STM

• Ltm

What is coding?

The different information types the brain uses to store memory

What is capacity?

The amount of information a memory store is able to hold

What is duration?

The time period that a memory store can hold information for

What is the sensory register?

• A store that codes information coming from the senses

• This store is not under cognitive control

• All information found in the STM and LTM were initially from the SR

• Information is passed onto the STM via attention

• Codes modality specific

• Has a large capacity due to the millions of receptors in the body

• Has a very brief duration- less than half a second

STM

• The store that receives information via paying attention to the SR

• Codes accoustically

• Has a capacity of 7+_ units (Miller 1956) but can be increased by chunking

• Has a duration of 18-30 seconds however information can be extended by maintenance rehearsal

• Passes data to the LTM via maintenance rehearsal or retrieves from the LTM via retrieval

• Info can be lost by displacement or decay over time

LTM

• Codes semantically

• Has a relatively limitless capacity

• Has a lifetime’s worth of duration

Research on MSM- primacy and recency effects

• Glanzer and Cunitz 1966

• Asked ppts to free recall word lists in any order

• Recall was stronger for words at the start and end of the word list

• Suggests that LTM and STM are separate stores

• The words first heard entering LTM(primacy effect) and words last heard enter STM (recency effect)

• The middle words were in STM but were displaced

Baddeley research on coding

• 1966

• Baddeley gave word lists to ppts

• Acoustically similar or dissimilar

• Semantically similar or dissimilar

• He had to two conditions

• STM: recalled immediately after

• LTM: recalled after 20 minutes

• Baddeley found that the groups with the worst recall in his STM condition were the acoustically similar

• In the LTM condition, Baddeley found that the group with the worst recall was the semantically similar group

• However, lacks mundane realism- is an artificial example of real life LTM scenarios- 20 minutes is not long enough

Jacobs research on capacity

• Jacobs 1887

• Presented ppts with liists of numbers of letters

• Ppts had to recall the list

• The amount of letters/numbers in the list would increase by one with each correct recall

• The average digit recall was 9+_2

• The average letter recall was 7+_2

• Miller suggested the capacity can be improved by chunking- reduces the total numbers ovr

Peterson and Peterson’s research on the duration of the STM

• Peterson and Peterson 1959

• Showed ppts trigrams then had them count back from a 3 digit number in intervals of 3 or 4 to prevent maintenance rehearsal

• The original time they would count for would be 3 seconds- intervals would increase by 3 up to 18 seconds

• At 18 seconds, recall was 10%

• Suggests that information is only held briefly in the STM (18-30 seconds) before it is forgotten

Bahrick’’s research on the duration of the LTM

• Bahrick 1975

• 392 ppts aged 17-74

• Tested for memory of old photographs and names of their school friends

• It was found that recall in matching names to faces was 90% over 15 years and 80% after 48 years

• Suggests that the duration of the LTM is potentially limitless

Limitations of research on MSM

• Models cannot be directly observed- based on inferences

• Some research suggests that LTM or STM are unitary stores- patient KF- supports the WMM

• Mundane realism

• Artificial tasks

• Lack of generalisability to naturalistic situations

• Low ecological validity

• Lack of external validity

Strengths of research on MSM

• Artificial nature is the only clear way of measuring memory and testing the limits of memeory

• The large capacity and short duration of the SR matches what would be expected from the evolutionary theory- as much information from an environment is gathered however only important information is processed