Upload
blanche-flowers
View
256
Download
2
Tags:
Embed Size (px)
Citation preview
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
Short-termWorkingMemory
Long-termMemory
Memory Processes
• Retrieval
SensoryMemory
Short-termWorkingMemory
Long-termMemory
Memory Processes
• Information loss/ Forgetting
SensoryMemory
Short-termWorkingMemory
Long-termMemory
Memory Processes
• Rehearsal, Elaboration, etc.
SensoryMemory
Short-termWorkingMemory
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
Short-termWorkingMemory
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)
Working Memory (Alan Baddeley)
VisuospatialVisuospatialBufferBuffer
CentralCentralExecutiveExecutive
PhonologicalPhonologicalBufferBuffer
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
Working Memory (Alan Baddeley)
VisuospatialVisuospatialBufferBuffer
CentralCentralExecutiveExecutive
PhonologicalPhonologicalBufferBuffer
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
VisuospatialVisuospatialBufferBuffer
CentralCentralExecutiveExecutive
PhonologicalPhonologicalBufferBuffer
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