Working Memory Dr. Claudia J. Stanny EXP 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) 2Claudia J. Stanny

“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 Claudia J. Stanny3

Brown-Peterson Task Present 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 Recall the consonant trigram ??? Claudia J. Stanny4

Recall Performance in the Brown-Peterson Task Claudia J. Stanny5

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 Claudia J. Stanny6

Typical Serial Position Effects Data Claudia J. Stanny7

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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/Acoustic Proposed 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 used Pronunciation time Cross-language comparisons: Digit span decreases with longer pronunciation times Semantic similarity Proactive Interference Release from proactive interference (Wickens, 1976) Claudia J. Stanny10

Release from PI Brown-Peterson TaskWickens (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 Claudia J. Stanny12

(model proposed in 1974)

Characteristics of WM Components Phonological 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 Claudia J. Stanny15

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 reading Phonological tasks activate frontal & left temporal lobe Claudia J. Stanny16

Research on the Phonological Loop Effects 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 performance Claudia J. Stanny17

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.) Claudia J. Stanny18

Central Executive Closely associated with conscious awareness Manages allocation and switching of attention Not a storage system itself: Retrieves information from specialized storage systems, manipulates & modifies this information Suppresses irrelevant information Enables focus on current processing task Random number generation task loss of attentional control leads to predictable patterns in numbers generated Claudia J. Stanny19

Episodic Buffer Limited 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 Claudia J. Stanny20

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 Claudia J. Stanny21