Psyco 350 Lec #5 – Slide 1 Lecture 5 – Psyco 350, B1 Winter, 2011 N. R. Brown

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

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

Psyco 350 Lec #4 – Slide 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 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 #5 – Slide 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 #4 – Slide 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 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 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 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 13 Cross-Linguistic Δs in Digit Span Naveh-Benjamin & Ayers (1986) As predicted: span larger for languages w/ short digits than long span ≈ 2 X reading rate

Psyco 350 Lec #4 – Slide 14 Age-related Δs Digit Span Hulme (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 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 16

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

Psyco 350 Lec #4 – Slide 18 Independence of VSSP & Phonological Loop Brooks (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 19 Independence of VSSP & Phonological Loop Brooks (1968) Design (2X3) TASKXRESPONSE MODE image scanningpointing grammatical decision tapping vocal

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

Psyco 350 Lec #4 – Slide 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 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 #5 – Slide 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 26 Mental Rotation: 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 Mental Rotation: 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 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 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 30 Current WM Model

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

Psyco 350 Lec #5 – Slide 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 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 1.Reading/Operation Span as a measure of “capacity” 2.WM contents as the active portion of LTM 3.WM as executive attention

Psyco 350 Lec #5 – Slide 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 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 36 WM Memory Span – Two Interpretations 1.Domain Specific Capacity: Efficient processing of immediate task, leaves additional resources for maintaining load. –Accounts for dual task performance (e.g. Brooks) 2.Domain General Capacity: General ability to “control attention to maintain information in an active quickly retrievable state.” Engle, 2009, p. 20.

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

Psyco 350 Lec #5 – Slide 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 39 WM as Activation: Cowan’s Embedded Processes Model Central Notation: LTM in one of 3 states: 1.Dormant 2.Activated –fades (decays) unless reactivated 3.“In focus” (of attention) –limited to 4 items

Psyco 350 Lec #5 – Slide 40 Span from Active Perspective Two components: 1.read-out from focus 2.activated material, retrieved before decay Predictions: factors  LTM,  span –concreteness (Walker & Hulme, 1999) –word frequency (Roodenrys & Quinlan, 2000) Span > 0 when rehearsal suppressed