Working Memory Dr. Claudia J. Stanny EXP 4507 Memory & Cognition Spring 2009.
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Working Memory
Dr. Claudia J. StannyEXP 4507
Memory & Cognition
Spring 2009
Models of Immediate Memory
Primary & Secondary Memory (James, 1890)
“Modal Model” (Atkinson & Shiffrin, 1968)• Sensory Registers / Sensory Memory• Short-Term Memory• Long-Term Memory
Working Memory (Baddeley & Hitch, 1974)
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“Classic” Research on Working Memory
George Miller (1956)• “Magical Number Seven” article and concept of
chunking
Brown (1958) & Peterson & Peterson (1959)• Very rapid forgetting of perfectly learned
information• Recency effects & Serial position effects in the
recall of lists of words
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Brown-Peterson TaskPresent a small amount of information to
remember: e.g., a consonant trigram• X J Q
Present a 3-digit number and ask subject to count backwards by 3s during the retention interval• 987 . . . 984 . . . 981 . . . 978 . . . 975 . . . 972 . . .
Recall the consonant trigram• ???
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Recall Performance in theBrown-Peterson Task
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Serial Position Effects
Present lists of 15 or more words
Free recall of words immediately after each list
Plot the number of words recalled from each serial position in the list
Recall of all words from all lists following a filled delay produces a different pattern of recall
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Typical Serial Position Effects Data
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Characteristics of Short-Term Memory
Limited capacity (George Miller, 1956)• 7 ± 2 • Effects of chunking
Limited duration• 20 sec or less if no rehearsal is done
Type of coding: Verbal/AcousticProposed mechanism for information loss• Decay • Interference
Factors that Influence the Capacity of Working Memory
Chunking • Capacity limited to 7 plus or minus 2 chunks
Number of rehearsals & type of rehearsal usedPronunciation time• Cross-language comparisons: Digit span decreases
with longer pronunciation times
Semantic similarity• Proactive Interference• Release from proactive interference (Wickens,
1976)Claudia J. Stanny 10
Release from PI
Brown-Peterson Task Wickens (1976)
Working Memory
Conceptualizes immediate memory as a complex system with independent components
Klatzky’s (1975) STM as a workbench • Trade-off between storage capacity and
processing capacity
Working memory more than a passive storage system – management of information coding and use
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(model proposed in 1974)
Characteristics of WM ComponentsPhonological Loop• Auditory/Acoustic coding• Effects of time required to pronounce words• Effects of unattended speech• Effects of articulatory suppression
Visuospatial Sketch Pad• Visual and spatial coding• Interfering effects of competing spatial tasks
Central Executive• Regulation and coordination of specialized
systems; attentional control
Working Memory Model
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Phonological Loop
Acoustic confusion errors suggest acoustic codes• Errors in recall dominated by acoustically similar
letters
Maintain information about order and sequencing in problem-solving tasks
Supports cognitive processes for readingPhonological tasks activate frontal & left
temporal lobe
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Research on the Phonological LoopEffects of time required to pronounce words• Digit span increases as pronunciation time
decreases• Recall of single-syllable vs multi-syllable words• Limited capacity in terms of pronunciation time
Effects of unattended speech• Irrelevant speech disrupts performance on
memory for verbal stimuli Effects of articulatory suppression• Repeating an irrelevant word (doh – doh – doh)
during study disrupts memory performanceClaudia J. Stanny 17
Visuospatial Sketchpad
Visual scenes and images generated from verbal descriptions or long-term representations
Limited capacity • based on spatial characteristics
Function of the visuospatial sketchpad• Navigation• Spatial tasks (mazes, video games, etc.)
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Central ExecutiveClosely associated with conscious awarenessManages allocation and switching of attentionNot a storage system itself:• Retrieves information from specialized storage
systems, manipulates & modifies this informationSuppresses irrelevant information• Enables focus on current processing task• Random number generation task
loss of attentional control leads to predictable patterns in numbers generated
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Episodic BufferLimited capacity temporary storage area“Workspace” for working memory• Mental modeling of the environment• Problem-solving activities
Integrates and binds information from several sources using a multi-modal code• Phonological loop• Visuospatial sketch pad• Long-term memory
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Clinical Depression and Memory
Symptoms include:• Problems with concentration• Difficulty suppressing negative thoughts
Evidence of reduced function in WM:• Deficits observed related to interference during an
articulatory suppression task• Lower recall of visual information• Some evidence of reduced executive function
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