Working Memory

1. Working Memory Dr. Claudia J. Stanny EXP 4507 Memory & Cognition Spring 2009

2. 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) Claudia J. Stanny

3. “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. Stanny

4. 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 • 987 . . . 984 . . . 981 . . . 978 . . . 975 . . . 972 . . . • Recall the consonant trigram • ??? Claudia J. Stanny

5. Recall Performance in theBrown-Peterson Task Claudia J. Stanny

6. 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. Stanny

7. Typical Serial Position Effects Data Claudia J. Stanny

8. Claudia J. Stanny

9. 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

10. 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. Stanny

11. Release from PI Brown-Peterson Task Wickens (1976)

12. 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. Stanny

13. (model proposed in 1974)

14. 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

15. Working Memory Model Claudia J. Stanny

16. 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. Stanny

17. 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. Stanny

18. 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. Stanny

19. 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. Stanny

20. 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. Stanny

21. 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. Stanny