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Lecture 5 – Psyco 350, B1 Winter, 2011

Lecture 5 – Psyco 350, B1 Winter, 2011. N. R. Brown. Outline. Baddeley’s Model of Working Memory Phonological Loop Visuo -spatial sketchpad Central Executive Problems w/ WM An Alternative Perspectives on WM Reading& Operation Span tasks Cowan’s Embedded Processes Mode

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Lecture 5 – Psyco 350, B1 Winter, 2011

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  1. Lecture 5 – Psyco 350, B1Winter, 2011 N. R. Brown Psyco 350 Lec #5 – Slide 1

  2. Outline • Baddeley’s Model of Working Memory • Phonological Loop • Visuo-spatial sketchpad • Central Executive • Problems w/ WM • An Alternative Perspectives on WM • Reading& Operation Span tasks • Cowan’s Embedded Processes Mode • WM Capacity as Executive Control Psyco 350 Lec #5 – Slide 2

  3. The Phonological Loop Phonological Store: holds small amount of speech based information Phonological Store Articulatory Control Process: Based on inner speech Auditory Presentation Visual Presentation Psyco 350 Lec #5 – Slide 3

  4. Phonological Loop • Speech-based System: • phonological similarity  • irrelevant speech  • articulartory suppression  • 2-s Capacity: • word length effect • cross-linguistic Δ’s • developmental Δ’s Psyco 350 Lec #5– Slide 4

  5. Evidence for the Phonological Loop Instructions: • You will see 6 letters, 1/s. • Recall them in order, at the signal. Psyco 350 Lec #5 – Slide 5

  6. Evidence for Phonological Loop • Phonological Similarity Effect similar sounding list < dissimilar sounding lists _______ vs _______ • Implies: representation is speech-based not meaning based. Psyco 350 Lec #4 – Slide 6

  7. Evidence for Phonological Loop • Irrelevant Speech Effect • Recall impaired if items are accompanied by other verbal material. • Effect found w/: same-language words, same-language non-words, foreign words. • Interpretation: “unattended (linguistic) material was gaining access to the phonological store.” -- Baddeley, p. 53 Psyco 350 Lec #4 – Slide 7

  8. Evidence for Phonological Loop • Articulartory Suppression • concurrent (overt or covert) articulation, decreases word span. (“the, the, the…” ; “one, two, three, one, two..) • concurrent articulation decreases • the phonological similarity effect • word length effect. • Interpretation: articulation of irrelevant items dominates ACP - Words cannot be “rehearsed” or recoded into phonological code Psyco 350 Lec #5 – Slide 8

  9. Evidence for Phonological Loop • Word Length Effect word span decrease as # of syllables/word increases. • Recall depends of reading rate. • # words recalled ≈ 2 * (reading rate) • reading rate = # words read / s Psyco 350 Lec #4 – Slide 9

  10. Phonological Loop – Capacity of Phono Store Baddeley et al (1975) Task: serial recall Materials:5-word lists Manipulation: syllable length Results: • recall , as syllable length  • recall predicted by reading rate. • cf. STM predictions Psyco 350 Lec #4 – Slide 10

  11. Phonological Loop – Capacity of Phono Store Baddeley et at (1975) • linear relation between reading time & recall • Interpretation: • capacity of phono loop ~ 2 s of speech materials • Reason • fast fading phono trace • rehearsal refreshes trace. • if not rehearsed within 2 s, most info lost. Psyco 350 Lec #4 – Slide 11

  12. Phonological Loop – Capacity of Phono Store Baddeley et at (1975) • Implications: • across languages, digit span should be related to mean syllable length of digits. • digit span should increase w/ age, because speech rate does. Psyco 350 Lec #4 – Slide 12

  13. Cross-Linguistic Δs in Digit SpanNaveh-Benjamin & Ayers (1986) As predicted: • span larger for languages w/ short digits than long • span ≈ 2 X reading rate Psyco 350 Lec #4 – Slide 13

  14. Age-related Δs Digit SpanHulme (1984) As predicted: • span  w/ age • span ≈ 2 X speech rate ----------------------- Overt or covert articulation serves to maintain items in the phonological store by refreshing their fading traces. The faster it can run, the longer the memory span Psyco 350 Lec #4 – Slide 14

  15. Phonological Loops: Functions • Learning to read: Children with impaired reading ability have reduced memory spans and have difficulties in tasks which require the manipulation of phonological information (e.g. given Stop, reply Top). • Language comprehension: STM patients some difficulty in comprehending verbose or complex sentences e.g. “The boys pick the apples” = OK; “The two boys pick the green apples from the tree” = Impaired • Vocabulary acquisition There is a strong correlation between non-word repetition (which strongly taxes the phonological loop) and vocabulary size (Gathercole & Baddeley, 1989) Psyco 350 Lec #4 – Slide 15

  16. Psyco 350 Lec #4 – Slide 16

  17. VSSP • Function: • “construction, maintained, & manipulation of mental images.” – Radvansky, p. 97 • Assumptions: • Independence of VSSP & Phonological Loop Psyco 350 Lec #4 – Slide 17

  18. Independence of VSSP & Phonological LoopBrooks (1968) • Dual Task Experiment • Goal to demonstrate: • spatial response mode interference w/ spatial processing • verbal response mode interferes w/ verbal processing • cross-modal tasks produce little interference Psyco 350 Lec #4 – Slide 18

  19. Independence of VSSP & Phonological LoopBrooks (1968) • Design (2X3) TASK X RESPONSE MODE image scanning pointing grammatical decision tapping vocal Psyco 350 Lec #4 – Slide 19

  20. Brooks (1968): Image Scanning Task Given a block letter & starting point: If current corner is top or bottom “yes” Otherwise ”no” Psyco 350 Lec #4 – Slide 20

  21. Brooks (1968): Response Modes While performing target task: • Vocal – say “yes”/”no” • Taping – left tap = “yes”; right tap = “no” • Pointing – point to successive “y”/”n” pairs on response sheet Psyco 350 Lec #4 – Slide 21

  22. Brooks (1968): Pointing Psyco 350 Lec #4 – Slide 22

  23. Brooks (1968): Results ≈ >> << ≈ • Spatial response mode: • interfered w/ spatial task • did not interfere w/ verbal task • Verbal response mode: • interfered w/ verbal task • did not interfere w/ spatial task Psyco 350 Lec #4 – Slide 23

  24. Brooks (1968): Interpretation • Task X Mode interaction indicates: • separate & limited pool of resources for verbal & spatial task • image scanning task & spatial response mode draw on the limited resources of the VSSP. • grammatical decision task & vocal response mode both draw on the resources of the phonological loop. Psyco 350 Lec #4 – Slide 24

  25. Visuo-spatial sketchpad Operations: • Mental rotation • Mental scanning • Boundary extension • Dynamic memory Supports: Spatial problem-solving (moving a couch Prediction of dynamic consequences. Psyco 350 Lec #5 – Slide 25

  26. Mental Rotation: VSSP @ Work Shepard & Metzler (1971) Materials: Pairs of 3-d(ish) objects in a variety of orientations. Task: timed same/different judgment Psyco 350 Lec #5 – Slide 26

  27. Mental Rotation: VSSP @ Work Shepard & Metzler (1971) Materials: Pairs of 3-d(ish) objects in a variety of orientations. Task: timed same/different judgment Psyco 350 Lec #5 – Slide 27

  28. Mental Rotation • Results: • RT  w/ angular disparity • Interpretation: “mental rotation has characteristics that mimic physical rotation….It is almost as if people are actually mentally turning the object about in their VSSP.” – Radvansky, p. 99 Psyco 350 Lec #5 – Slide 28

  29. Problems w/ Baddeley’s WM Influence of LTM on STM tasks • chunking • proactive interference (Keppel & Underwood, 1962) & release from proactive interference (Wickens, 1972). • semantic similarity can  span • span: high frequency words > low frequency words Problems with Phonological Loop • under suppression: span > 0 for visually presented words. Psyco 350 Lec #5 – Slide 29

  30. Current WM Model Psyco 350 Lec #5 – Slide 30

  31. Episodic Buffer • Information is bound together in the episodic buffer • This creates the episodic memory trace • Working memory interacts with long-term memory

  32. Central Executive (Baddeley) • Most complex and least understood component of WM • Coordinates activity of slave systems & supplements their attentional resources • Other potential roles: • coordinating retrieval strategies • temporary activation of LTM, • selective attention • suppression of habitual responses. Psyco 350 Lec #5 – Slide 32

  33. Alternatives Perspectives On WM Motivated by: • Problems w/ Baddeley’s Model • A need to better understand executive functioning • Predictive power of span task. Three Related Issue • Reading/Operation Span as a measure of “capacity” • WM contents as the active portion of LTM • WM as executive attention Psyco 350 Lec #5 – Slide 33

  34. Measuring WM Capacity • Key Idea: Performance on complex cognitive task reflects a number of different capacities • retrieval efficiency • processing efficiency • “attention-free” capacity of relevant slave system • attentional management (ability to focus on relevant info & inhibit irrelevant info. • etc. • WM span tasks developed to measure relation between WM and performance on complex cognitive tasks Psyco 350 Lec #5 – Slide 34

  35. WM Memory Span • WM span = # of words recalled • Demonstrates capacity for holding load while processing. • Large individual differences in WM span (2-6 items) • WM span measures predict performance on IQ, achievement tests (e.g., SATs), & g. • digit/word span uncorrelated with IQ/SAT tests Psyco 350 Lec #5 – Slide 35

  36. WM Memory Span – Two Interpretations • Domain Specific Capacity: Efficient processing of immediate task, leaves additional resources for maintaining load. • Accounts for dual task performance (e.g. Brooks) • Domain General Capacity: General ability to “control attention to maintain information in anactive quickly retrievable state.” Engle, 2009, p. 20. Psyco 350 Lec #5 – Slide 36

  37. An Alternative: WM as Information in an Active State Psyco 350 Lec #5 – Slide 37

  38. WM as Activation: Cowan’s Embedded Processes Model • Central Executive: directs and controls voluntary processing. • Encoding: • Incoming info activities representation in LTM Psyco 350 Lec #5 – Slide 38

  39. WM as Activation: Cowan’s Embedded Processes Model Central Notation: LTM in one of 3 states: • Dormant • Activated • fades (decays) unless reactivated • “In focus” (of attention) • limited to 4 items Psyco 350 Lec #5 – Slide 39

  40. Span from Active Perspective Two components: • read-out from focus • activated material, retrieved before decay Predictions: • factors  LTM,  span • concreteness (Walker & Hulme, 1999) • word frequency (Roodenrys & Quinlan, 2000) • Span > 0 when rehearsal suppressed Psyco 350 Lec #5 – Slide 40

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