The Multi-Store Model

Question 1

What is Memory?

Answer 1

The process by which we retain and recall information from past events or experiences

Question 2

Atkinson & Shiffrin (1968)

The Multi-Store Model of Memory

Answer 2

• Structural Model
• Memory consists of Sensory Register (SR), Short Term Memory (STM), and Long Term Memory (LTM)
• Information passes from store to store in a linear way
• STM & LTM are unitary stores

Question 3

How does information move across stores?

Answer 3

• SR –> STM - Attention
• STM –> LTM - Rehearshal
• LTM –> STM - Retrieval
• Maintenance rehearsal keeps information in STM
• Information can decay out of all stores, but can also be displaced from STM

Question 4

Encoding, Capacity, Duration

Answer 4

• Encoding: How information is perceived so it can be stored in memory (visual, acoustic, semantic)
• Capacity: How much information can be stored
• Duration: How long information can last in a store

Question 5

Roles of SR, STM, LTM

Answer 5

• SR - Receives information from each of the 5 senses and contains one sub-store for each sense
• STM - Active (changing) memory system that contains information currently being thought about
• LTM - Involves storing information over lengthy periods of time

Question 6

Coding, Capacity, Duration of SR

Answer 6

• Coding - Sense specific (different stores for each sense)
• Capacity - All sensory experience, Very large capacity
• Duration - 1/4-1/2 second

Question 7

Coding, Capacity, Duration of STM

Answer 7

• Coding - Mainly acoustic
• Capacity - 7+/- 2 items
• Duration - 18-30 seconds

Question 8

Coding, Capacity, Duration of LTM

Answer 8

• Encoding - Mainly semantic
• Capacity - Potentially Unlimited
• Duration - 48 years<

Question 9

Research into SR, STM, LTM: Sperling (1960)

Answer 9

• Method: Flashed 3x4 grid of letters on a screen for 1/20 second and asked participants to recall one row
• Findings: As information would fade very quickly, it sounded different tones (high, medium, low) to indicate which row to recall. Recall of all letters in the indicated row was high.

Question 10

Baddeley (1966): Encoding in STM

Answer 10

• Found participants had difficulty remembering acoustically similar words in STM, but not in LTM
• Semantically similar words posed little problem for STM but led to muddled LTM

Question 11

Posner & Keele (1967): Encoding in STM

Answer 11

• Participants faster in assessing A & A as the same letter than A & a
• Suggests visual coding occurs in STM, contradicting Baddeley’s study

Question 12

Jacobs (1887): Capacity of STM

Answer 12

• Average span for digits was 9.3 items v 7.3 items for letters
• Suggested that it was easier to recall digits as there are only 9 digits v 26 letters

Question 13

Miller (1965): Capacity in STM

Answer 13

• Wrote memorable article, ‘The magic number 7+/- 2’, where he carried out research
• Concluded that the span of STM to be ~7 items - sometimes a bit more/less
• You can also recall five words as well as five letter words, you can chunk things together to remember more

Question 14

Peterson & Peterson (1959): Duration of STM

Answer 14

• Used 24 students, each given a consonant sllable and a 3 digit number (eg. THX 512)
• Asked to recall consonant syllable after retention intervals of 3 seconds up to 18 - had to count backwards during intervals from the 3 digit number
• Findings: Participants able to recall 90% of their syllables correctly after 3 seconds, 2% could correctly recall after 18 seconds

Question 15

Frost (1972): Encoding in LTM

Answer 15

Long Term recall related to visual as well as semantic categories

Question 16

Anokhin (1973): Capacity in LTM

Answer 16

• Estimated the number of possible neuronal connections in the human brain is 1 followed by 10.5km of noughts
• ‘No human yet exists who can use all the potential of their brain’, suggesting limitless capacity

Question 17

Bahrick et al (1975): Duration of LTM

Answer 17

• Tested 400 people of various ages on memory of classmates using a photo recognition test (some from yearbooks) and a free recall test of as many names as they could from their graduating class
• Findings: Tested wihtin 15 yrs of graduation had 90% accuracy in identifying faces and 60% at free recall, after 48 years this declined to 70% for photo recognition and 30% in free recall

Question 18

Supporting evidence for MSM: Brain Scans

Answer 18

• Studies using brain scanning techniques have shown difference between STM and LTM
• Beardsley (1997): found that PFC is active during STM, but not LTM
• Squire et al (1992): found that the hippocampus is active when LTM is engaged

Question 19

Supporting evidence for MSM: Case Studies

Answer 19

• Provides evidence for the difference between STM & LTM
• Scoville & Milner (1957): HM had an operation to reduce epileptic seizures, but had brain damage. HM couldn’t form new LTM but could remember things from before the surgery
• Supports the idea of separate stores as HM cannot pass info from STM to LTM but was able to retrieve info from before

Question 20

Opposing evidence for MSM: Processing

Answer 20

• Craik & Lockhart (1972): Suggest LTM created through processing, not maintenance rehearsal. Things that are processed more deeply are more memorable
• Craik & Tulving (1975): Gave participants a list of nouns and asked questions that needed deep or shallow processing. Better recall when the tast involved deep processing than shallow

Question 21

Opposing evidence for MSM: Too Simple

Answer 21

• Shallice & Warrington: Amnesiac patient KF had poor STM recall for auditory stimuli, but better recall for visual stimuli (suggests multiple types of STM)
• Same is true for LTM, research shows different types of LTM with different functions. Maintenance rehearsal explains LTM storage in semantic, but not episodic memory