working memory components evidence different codes dual-task paradigm dissociations
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Working Memory
Components
EvidenceDifferent codesDual-task paradigmDissociations
Primary Memory Secondary Memory
Short-term Store Long-term Store
Short-term Memory Long-term Memory
Immediate Memory(Miller, 1956)
*Working Memory
Info InfoShort-termMemory
Long-term
Memory
Info InfoWorkingMemory
Long-term
Memory
Baddeley & Hitch (1974)
WorkingMemory
Long-termMemory
Baddeley & Hitch (1974)
Baddeley & Hitch (1974) -- Working memory
Baddeley & Hitch (1974) -- Working memory
Long-termMemory
Baddeley & Hitch (1974) -- Working memory
Long-termMemory
CentralExecutive
Baddeley & Hitch (1974) -- Working memory
Long-termMemory
CentralExecutive
PhonologicalLoop
Visuo-spatialSketchpad
Baddeley & Hitch (1974) -- Working memory
Long-termMemory
CentralExecutive
*PhonologicalLoop
Visuo-spatialSketchpad
*also called Articulatory-
Rehearsal Loop
Baddeley & Hitch (1974) -- Working memory
Long-termMemory
CentralExecutive
*PhonologicalLoop
Visuo-spatialSketchpad
*also called Articulatory-
Rehearsal Loop
Slavesystem
Slavesystem
Baddeley & Hitch (1974) -- Working memory
Long-termMemory
CentralExecutive
*PhonologicalLoop
Visuo-spatialSketchpad
Slavesystem
Slavesystem
Info Response
Working Memory
Why divide STM into different components?
Evidence Different codes
Phonological effects with visual stimuliRelease from PIMental rotation of visual stimuli
Different codesPhonological effects with visual stimuli
Conrad (1964)immediate recall of visual stimuli (letters)noticed phonological errors in recall protocols
(ē confusions, ĕ confusions)
Different codesPhonological effects with visual stimuli
Conrad (1964)immediate recall of visual stimuli (letters)noticed phonological errors in recall protocols
(ē confusions, ĕ confusions)
Wickelgren (1965) visual presentation of letters;
copy letters during retention interval; recall first letters presented phonological interference effects
Different codesPhonological effects with visual stimuli
Verbal code/phonological code
Verbal stimuli get coded phonologically
Different codes Release from PI
Release based on meaning of stimuli
Semantic code
(note: reflects an interaction with long- term memory)
Baddeley & Hitch (1974) -- Working memory
Long-termMemory
CentralExecutive
PhonologicalLoop
Visual-spatialSketchpad
Access meaning stored in long-term memory
Different codesStrongly visual stimuli (shapes without meaning)
Perform mental rotation taskmanipulate degree of rotation
See overhead transparencies
RT(s)
Reaction Time for “Same” Judgmentsas a Function of Angle of Rotation
Angle of Rotation (in degrees)
0 45 90 135 180
1
2
3
5
4
Different codesStrongly visual stimuli (shapes without meaning)
Perform mental rotation taskmanipulate degree of rotation
Greater degree of rotation, the longer the RT To do the task, we need a visual code
Working Memory
Why divide STM into different components?
Evidence
Dual-task paradigm
Dual-task paradigm
Do two things at once
One task – measure accuracy or RT
Second task – manipulate task or task difficulty
Dual task paradigm Baddeley & Hitch (1974)
Reasoning task – measured RTsee ABnext, get a sentence: A precedes B(respond “yes” or “no”)
Second task – do nothing (control) vs. hold a random 6-digit sequence in mind
Reas oning
Reasoning Time as a Function of Second Task
Sentence Type
1
2
3
5
4
6
Ti
me
(in seconds)
Active
Affirmative
Random digitsControl (no 2nd task)
Longer RT for dual-task condition
Only so much capacity to do mental work2nd task hurts performance on 1st task
Reasoning task – measured RT also manipulated sentence type:Affrimative vs. NegativeActive vs. Passive
AffirmativeActive: A precedes BPassive: B is preceded by A
NegativeActive: B does not precede APassive: A is not preceded by B
Reas oning
Reasoning Time as a Function of Sentence Type and Second Task
Sentence Type
1
2
3
5
4
6
Ti
me
(in seconds)
Active Passive Active Passive
Affirmative Negative
Random digitsControl (no 2nd task)
As 1st task gets harder, two things happen 1) RT increases, in general
2) Second task, if difficult, particularly hurts performance in the harder conditions of the 1st task
(e.g., 1st task, negative passive condition 2nd task, hold random digit sequence in mind)
Working Memory
Why divide STM into different components?
Evidence
Dissociations
Working Memory
DissociationsUse dual task paradigm
Reasoning 2nd task should interfere more with 1st task if
the same slave system is used for both tasks (less interference if different slave systems areused)
Working MemoryDissociations (Logie, Zucco, & Baddeley, 1990)
Measure visual spansee grid of blocksgrid change (one block different)point to change
Second taskMental additionImaging
Working Memory
Dissociations Measure visual span – visuo-spatial sketchpad
Second task Mental addition – phonological loop Imaging – visuo-spatial sketchpad
Working Memory
Dissociations Measure visual span – visuo-spatial sketchpad
Second task Mental addition – phonological loop Imaging – visuo-spatial sketchpad
Prediction – Should be a greater cost in visual span performance for the imaging task
Cost in Performance as a Function of Task Combination
Task Combination
0
70
Addition Imagery
Visual span task
Per
cent
Dro
p f
rom
Bas
elin
e
Working Memory
Dissociations Measure visual span – visuo-spatial sketchpad
Second task Mental addition – phonological loop Imaging – visuo-spatial sketchpad
Prediction upheld: Bigger cost in imaging condition
Working Memory
Dissociations Measure letter span – phonological loop
see (or hear) letters; hold letters in mind;then recall letters
Second task Mental addition – phonological loop Imaging – visuo-spatial sketchpad
Prediction – Should be a greater cost in letter span performance for the mental addition task
Cost in Performance as a Function of Task Combination
Task Combination
0
70
Addition Imagery Addition Imagery
Visual span task Letter span task
Per
cent
Dro
p f
rom
Bas
elin
e
Working Memory
Dissociations Measure letter span – phonological loop
Second task Mental addition – phonological loop Imaging – visuo-spatial sketchpad
Prediction upheld: Bigger cost in mental addition condition
Working Memory
Components
EvidenceDifferent codesDual-task paradigmDissociations