MemoryThe Multi-Store Model

The Three Processes of Memory

EncodingTaking information / stimulus from

environment and programming it into our brains. Stimulus is usually visual

(iconic) , but it can be sound (acoustic) and smells etc. It can then be

programmed or ‘encoded’ into our brains as iconic or acoustic encoding

Storage

Retrieval

Once information is encoded it has to be stored until it is required at a later time.The length of

time the information is stored is the store’s DURATION and how much information can be

stored is its CAPACITY

Recalling by using ‘cues’ to remember items you have stored. People may do this differently.

(what has to happen in order for a memory to be formed and remembered)

Activity2

Who has the best attention?Watch the video clip carefully and count the number of

times the white team bounces or catches the ball.

Multi-Store Memory Model

Environment

Sensory Stimuli

Sensory Memory

Long Term

Memory

Attention Short Term

Memory

If not attended to information is lost

Retrieval

Rehearsal

Loss via displacement or decay if not

rehearsed

Coding

Coding

Coding

By Atkinson & Shiffrin

DETAIL: Sensory Memory Store:• Temporary storage of information stimulus taken

in….• Visual encoding (iconic) • Auditory encoding (acoustic) • Probably others as well (smell – chemical)

– Capacity: Very large– Duration: Very short

• about 250 ms. for iconic (visual)• 1-2 sec. for acoustic (sound)

• Forgetting: Information can be lost (storage failure) because of lack or diversion of attention remember the gorilla experiment!

Detail: Short Term Memory (STM)• Capacity: Small: 7 plus or minus 2 units or

‘chunks’ (Miller, 1956)Chunk: a meaningful unit

Examples: • A group of letters (FBI)• A group of words (Four score and seven years

ago) • Let us recreate Miller’s experiments now.

• Duration: Short:20-30 seconds without rehearsal (Peterson & Peterson, 1959)

• Encoding: mainly acoustic (by sound)

• Forgetting due to displacement and trace decay. (storage failure)

Bread

Displacement in STM

Bread

STM7 slots

( For 7 units or ‘chunks of information)

Lost from STM

MilkBreadFlourMilkBread

ApplesFlourMilkBread

SyrupApplesFlourMilkBread

PeasSyrupApplesFlourMilkBread

EggsPeasSyrupApplesFlourMilkBread

CheeseEggsPeasSyrupApplesFlourMilk

Detail: Long Term Memory (LTM)

• Capacity: Potentially Infinite • Duration: A lifetime (decades)• Encoding: Organized by meaning (semantic)• Forgetting: cue dependant retrieval failure and interference

unlikely to be much decay

• Procedural Memory: habits and motor skills, conditioned or practiced

• Declarative Memory: Memory for semantic knowledge (facts) and personal experiences (episodic)

Evidence for the MSM

Remember the following words:

TIMEPEAKSLOWPENSLONGAGESTHANVASTHEATRAINMORESOMETUNERAREWITHBEARTHISTIESHEARLIFE

Count how many you recalled:

TIMEPEAKSLOWPENSLONGAGESTHANVASTHEATRAINMORESOMETUNERAREWITHBEARTHISTIESHEARLIFE

7371457167624534464834454148426753344578

Primacy-Recency orSerial-position effect

Primacy Effect

• First items in a list are remembered better than items in the middle

Recency Effect

• The last items in a list are remembered better than items in the middle, if tested immediately

• This primary-recency or serial position effect is evidence for the MSM model.

Brain Damage Patient Studies H.M. & C.WFurther supporting evidence for MSM model

• H.M. became unable to form new memories after surgical removal of the hippocampus (so no STM)

• Still able to acquire procedural information (he learned a mirror writing skill. Can you explain this?)

• He was still able to access his original long term memories but not able to form new ones.

• This is evidence for the multi-store model in that it shows LTM and STM storage areas are in different locations.

Summary of Multi Store Memory Model Components

EVALUATION: Evidence In support of MSM

• Primacy and recency effects. First items arerecalled from LTM, having been rehearsed, and

last items are still being held in STM.• Baddeley’s research into acoustic and semantic

coding shows that STM & LTM are separate.• Case studies, e.g. HM (p79) shows that STM & LTM are separate

Problems and limitations

• Rehearsal does not always lead to storage.Storage occurs without rehearsal!

• If coding in the STM is predominantly acoustic,how do we understand language?

• Initial oversimplification of LTM store• Some types of information are not amenable to

rehearsal, e.g. smells.

Multi-Store Memory Model Activity (In Pairs or threes) Read through & Discuss the handouts:

Then in your groups complete a poster detailing the Multi Store Model:

The title should be “Memory ~ The Multi Store Model (Evidence and Evaluation)”

• Outline the model and evidence in support of the model. • Then evaluate the model fully listing all the positive and

negative criticisms you can find. • At the end of the lesson the class will vote on the poster

with the fullest explanation and evaluation of the model, and the best presented poster.

• Students will have to explain and present their posters to the class, and justify why their poster deserves to be displayed.