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

Psyco 350 Lec #5 – Slide 1

Lecture 5 – Psyco 350, B1Winter, 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

– WM Capacity as Executive Control


The Phonological Loop

Phonological Store

Phonological Store: holds small amount of speech based information

Articulatory Control Process: Based on inner speech

Auditory Presentation

VisualPresentation

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


Evidence for the Phonological Loop

Instructions:

• You will see 6 letters, 1/s. • Recall them in order, at the signal.


Evidence for Phonological Loop

• Phonological Similarity Effectsimilar sounding list < dissimilar sounding lists

_______ vs _______

• Implies: representation is speech-based not meaning based.



• 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



• 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



• 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


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



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.



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.


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


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


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)



VSSP

• Function:– “construction, maintained, & manipulation of

mental images.” – Radvansky, p. 97

• Assumptions:– Independence of VSSP & Phonological Loop


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


Independence of VSSP & Phonological LoopBrooks (1968)

• Design (2X3)

TASK X RESPONSE MODE

image scanning pointing

grammatical decision tapping

vocal


Brooks (1968): Image Scanning Task

Given a block letter & starting point:

If current corner is top or bottom “yes”

Otherwise ”no”


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


Brooks (1968): Pointing


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

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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.


Visuo-spatial sketchpad

Operations:

• Mental rotation

• Mental scanning

• Boundary extension

• Dynamic memory

Supports:

Spatial problem-solving (moving a couch

Prediction of dynamic consequences.


Mental Rotation: VSSP @ Work

Shepard & Metzler (1971)

Materials: Pairs of 3-d(ish) objects in a variety of orientations.

Task: timed same/different judgment


Mental Rotation: VSSP @ Work

Shepard & Metzler (1971)

Materials: Pairs of 3-d(ish) objects in a variety of orientations.

Task: timed same/different judgment


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


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.


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


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.


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 Issue1. Reading/Operation Span as a measure of

“capacity”2. WM contents as the active portion of LTM3. WM as executive attention


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


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


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.


An Alternative: WM as Information in an Active State


WM as Activation: Cowan’s Embedded Processes Model

• Central Executive: directs and controls voluntary processing.

• Encoding:– Incoming info activities

representation in LTM


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


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

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

Documents

phonological loopinstructions

phonological codepsyco

phonological store

capacity of phono loop

s capacity

syllable length recall

speech rate

language words