Memory Short term memory (a.k.a. Working Memory)

Memory

Short term memory

(a.k.a. Working Memory)

Course Overview

Knowledge

- Different types of knowledge (visual K, language, categories)

ch. 3: Vision. How are objects recognized? -It looks easy but it’s not

Ch. 6-11: Memory- to know is to remember

The Brain

Acquisition(perception)

ch.4: Attention. -Filters perceptual input

ch. 5: Working Memory - Buffer for mental representations

Use

- Deficits & Errors

Ch. 12-14: Reasoning

- inductive - deductive

Problem Solving

Emotion

Ch 4:Executive Functions

Free Recall Task

Subjects: - hear items (usually 10-40 words), then - they say or write all the items they can

remember, in any order.

Serial Position Function

Position in Original List

Probability of reporting

the item

1 2 ……… 30

?

1. Monster2. Camera3. Tricycle4. Melon5. Window6. Guest7. Quiet8. Cherish9. Waiting10. Rabbitt11. Computer12. Child13. Chicken14. Ghost15. Slave

(Glanzer & Kunitz, 1966)

RecencyPrimacy

STM contributionPrivileged rehearsalbetter LTM encoding

Villanova

distinctiveness

Position in Original List

Prob.Of Rept.

1 10 20 30 40

List Length

20 30 40

Serial position effects are consistent over different list sizes...

LTM

“Modal Model” (Atkinson & Shiffrin, 60’s)

•Unlimited capacity•Hard to get stuff into it.•Organized semantically

• Consciously available• Flexible material •Fixed # of slots (7+2 chunks)•Decays if not rehearsed

STM

•Very rapid decay (1-2 secs)•Modality specific (iconic, echoic)•Vulnerable

early sensoryprocessing

Memory Processes

• Attention

SensoryMemory

Short-termWorkingMemory

Long-termMemory

Memory Processes

• Storage

SensoryMemory


Long-termMemory

Memory Processes

• Retrieval

SensoryMemory


Long-termMemory

Memory Processes

• Information loss/ Forgetting

SensoryMemory


Long-termMemory

Memory Processes

• Rehearsal, Elaboration, etc.

SensoryMemory


Long-termMemory

LTM

Modal Model: Primacy and Recency Effects

•Unlimited capacity•Hard to get stuff into it.•Organized semantically

• Consciously available• Flexible material •Fixed # of slots (7+2 chunks)•Decays if not rehearsed

STM

•Very rapid decay (1-2 secs)•Modality specific (iconic, echoic)•Vulnerable

early sensoryprocessing

STM

LTM

Recency

Primacy

(Murray Glanzer)

STM

(Murray Glanzer)

LTM

Independence of LTM and STM: Neurological evidence

Patient H.M. - surgery in 1953 to relieve epilepsy.- Normal working memory: normal digit span - Impaired Long-term memory (anterograde amnesia): unable to learn most new information. he can recall facts from before surgery (events from school days, preserved language skills, recognized people).

Patient K.F. - closed head injury. - Impaired working memory: Digit span of 1 item- Normal Long-term memory (recall a short story, learn word lists when lists presented repeatedly, and do fine on long-term recognition).

Position

Prob.Of Rept.

STM Patients

Normals

(Alan Baddeley)

LTM

Sensory

Anterograde Amnesia might be explained as a blockage of the flow of information from STM to LTM

STM

LTM

STM

Entry into STM is not necessary for entry into LTM

Sensory

BUT…short term memory deficits in the absence of LTM deficits spell trouble for this gateway model of LTM acquisition...

Impairment

• Double dissociations guard against resource artifacts (differences in task performance that stem from differences in task difficulty)

• For example,– I can juggle 3 balls, but

– I cannot juggle 5 balls,

• Should we conclude that juggling 3 balls is a process independent from juggling 5? Or that juggling 5 balls is a more difficult task?– We’ll argue for independence only if we find someone who is unable to

juggle 3 balls but can juggle 5 (double dissociation). Quite unlikely :-)

Double dissociations guard against resource artifacts (differences in task performance that stem from differences in task difficulty)

For example, Patient H. M. has:- impaired LTM but,- normal STM

Should we conclude that LTM is a process independent from STM? Or that LTM is a more difficult task?

We’ll argue for independence only if we find someone who is unable to hold things in STM but can retain them in LTM (patient K.H.).

Working Memory

• A cognitive system that allows the maintenance of information on line or available for immediate processing.

Model of Memory

SensoryMemory


Long-termMemory

FILTER

Model of Memory

SensoryMemory

CentralExec.

Visual

Auditory

FILTER

Long-termMemory

Working Memory (Alan Baddeley)

VisuospatialVisuospatialBufferBuffer

CentralCentralExecutiveExecutive

PhonologicalPhonologicalBufferBuffer

Short-Term Memory for Visual andVerbal Materials: One or two stores?

Approach 1: Store maximum capacityof one type -- then see if person can remember any of the other type.

3 9 8 2 1 7 4 +Example:

Usual Finding:

ZERO interference between verbal and visual STM loads

(Sanders & Scarborough)





The phonological buffer

PhonologicalPhonologicalshort-term storeshort-term store

Verbal informationVerbal informationsubvocalrehearsalprocess

Phonological Buffer: Evidence

• Task: Memory Span– Listen a list of items, and repeat them

• Effect of:– Phonological Similarity (phono store)– Articulatory suppression (subvocal rehearsal)– Word length (subvocal rehearsal)

• Neurological overlap with language areas

Phonological Similarity

Confusions occur if words sound alike:Confusions occur if words sound alike:mad, cat, man, map, catmad, cat, man, map, cat

But not for similar meaning:But not for similar meaning:huge, long, tall, big, widehuge, long, tall, big, wide

or for similar-looking:or for similar-looking:bough, cough, dough, throughbough, cough, dough, through

Articulatory Suppression

repeatedly say “the” while hearing a list

B C P T VB K X Y R“the the the the the the the the”

Word length effectPeople can generally remember about as many words

as they can say in 2 seconds.

memory span for “sum, wit, harm”

better than for “opportunity, individual, university”

Same number of chunks…but one of the sets takes longer to articulate.

This result provides support for the notion of articulatory rehearsal of phonological information.

Speech production areas and language receptive areas are active when people try to remember phonological information

Neural overlap between verbal WM and language

Phonological Buffer

• The contents of storage is limited by:– the time it takes to rehearse the items – the number of “chunks” encoded

The standard estimate of the capacity of the phonological buffer is 7 plus or minus 2 “chunks” of information.

A chunk is a meaningful unit of information.

In a typical digit span task, subjects can hear and report back about 5-9 randomly selected digits.

F B I C I A F D R J F K

chunking allows storage of greater amounts of information…because information is

“packaged” more efficiently

F B I C I A F D R J F K

Chunking and the capacity of the phonological buffer





rehearsal

storage?

Object

Spatial

Brain Activations during Spatial and Object Working Memory

It appears that different brain regions are active during the storage of spatial and object information in working memory.

Task A System ABrain region ABrain region B

Task B System BBrain region ABrain region B

Double Dissociation based onBrain Localization

Working Memory




rehearsal

storage

spatial

object

The Central Executive

• Supervise attention

• Planning/Coordination

• Monitoring

the least well understood aspect of working memory.

Frontal lobe syndrome

• Distractibility, difficulty concentrating

• Problems with organization, planning

• Perseveration: fail to stop inappropriate behavior

Documents

Memory Short term memory (a.k.a. Working Memory)