psyco 350 lec #6 – slide 1 lecture 6 – psyco 350, b1 winter, 2011 n. r. brown

Psyco 350 Lec #6 – Slide 1

Lecture 6 – Psyco 350, B1Winter, 2011

N. R. Brown


Outline

• An Alternative Perspectives on WM– Reading& Operation Span tasks

– Cowan’s Embedded Processes Mode

– WM Capacity as Executive Control

• LTM: Episodic-Semantic Distinction• Memory Basics: Concepts & Associations (nodes &

links)• Factors that influence Storage:

– Rehearsal • maintenance vs elaborate• massed vs spaced


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 Activation 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


WM Memory Span – Competing Interpretations

1. Domain Specific Capacity: Efficient processing of immediate task, leaves additional resources for maintaining load. Accounts for Dual-task

2. Domain General Capacity: General ability to “control attention to maintain information in an active quickly retrievable state.” Engle, 2009, p. 20.


Span as Executive Control

Main Idea:

• Active, irrelevant info infers w/ performance

• People differ in their ability to inhibited irrelevant info or remain focused on relevant info

Prediction:

Individual differences in reading/operation span predict performance on tasks that require executive control.


Three Lines of EvidenceSpan & Proactive Interference

Participants:• High-span • Low-spanMaterials & procedure:• 3 10-word lists (words from same category)• 2 s/word• 16 s Delay• 20 s recall periods


Three Lines of EvidenceSpan & Proactive Interference

Results:

• Proactive Interference

• PI worse for Low-span


Three Lines of EvidenceSpan & Anti-saccade TasK

Task: Move eyes away from cue to find taget

Measures: Distractibility

Main Finding:

Low Span worse (more distractible) than High-span


Three Lines of EvidenceSpan & The Stroop Task

• StroopTask – Name Color of font



• StroopTask – Name color of font

• General Finding: Incongruent trials (BLUE) slower than congruent trials (GREEN)

• Interpretation: Response slowed because attention required to inhibit color name.



Participants:Low Span Vs High SP

Materials:Congruence: 0%, 50%, 75%

Difficulty increases w/ congruence



Results:

• Difficulty increases w/ congruence

• Low-span worse than High-span

• Effect increase w/ congruence

Interpretation:

Inhibitory capacity particularly important when task is difficult.


WM Capacity as Executive Attention Engle (2009)

Main Claim:

WM capacity (as measure by reading & operation span) reflect individual differences in ability inhibit/exclude competing (partially active) sources of information.


Summary: Alternative View

Contents of WM

Active portion of LTM

Differences in Capacity

Reflects individual differences in ability to remain focused and inhibit irrelevant info.

Reflect in LTM and task perceptual tasks


Conclusions

• No pure measure of STM– Contents: focal info + activated LTM

• Covert Rehearsal: – one way of keeping info active

• Functional importance: – WM provides ability to access info and maintain

in active state required for thought, language, problem-solving, etc


Procedural • Knowing how

Declarative• Knowing that

Memory

Systems

DeclarativeProcedural

Episodic Semantic


Episodic-Semantic Distinction: Tulving (1972)

Episodic Memory:

• autobiographical

• temporally dated

• interference from similar episodes

• retrieval also serves as input

(i.e., episodic memory is continually being updated)


Episodic-Semantic Distinction Tulving (1972)

Semantic Memory:

• language (lexical memory)

• world knowledge

• not temporally dated

• very well-organized (organization protects memory from interference)

• not changed or modified by retrieval of information (i.e., not continually updated)


(Episodic) Memory Basics

• Content episodic memory– representation of specific events

• mini-events – “the work BOOK on List 2”• real events – “Diving in Cozumel”

• An event representation (ER) = a particular instantiation of a configuration of intersecting concepts


Memory Trace: “the word BOOK on List 2”

Event34272

BOOK List 2

WM

SM

EM


Memory Trace: “Diving in Cozumel”

Event20342

Cozumel Diving

WM

SM

EP



• Links between ER & concepts differ in strength (as do the links between concepts).

• Strength depends of:– frequency

– contiguity

– recency



• Cues in WM access conceptual information in LTM.

• Origin of cues:– environment– self-generated– provided by experimenter

• Concepts “spread activation” to linked nodes (other concepts & ERs)

• ERn activation > threshold, “ERn retrieved”


Cue word: “Cozumel”

Event20342

Cozumel Diving

WM

SM

EP

“Cozumel”


(Episodic) Memory Basic: Implications

• The stronger the link between a cued concept and an ER, the greater probability that the ER will be recalled.

[non-elaborative rehearsal]


Cue word: Cozumel w/ strong link

Event20342

Cozumel Diving

WM

SM

EP

“Cozumel”



• The more ER-to-concept links there are, the greater the probability that a given cue will serve as an effective retrieval cue. [elaboration, depth or processing]


Cue words: “Cozumel” “diving”

Event20342

Cozumel Diving

WM

SM

EP

“hurricane”

hurricane



• Context (internal & external) is encoded as part of the ER, and thus contextual features can serve as retrieval cues.

• Increasing the similarity between encoding contexts and retrieval contexts increases the probability of retrieval. [context effects, TAP]


Contextual Cue

Event20342

Cozumel Diving

WM

SM

EP

taste of t. scrimp

tequila scrimp



• Probability of recall decreases, as # of ERs linked to a cued concept increases. [interference]


Cue word: “diving” interference

Event20342

Cozumel Diving

WM

SM

EP

“diving”

Grand Banks

Event5632


Memory Processes

• Encoding:– process of storing information in memory

• Storage:– the retention (& loss) of information over time

• Retrieval:– recovery of previously stored information


Encoding Processes: Rehearsal

• Rehearsal: a set of techniques/strategies for encoding information into long-term memory

• Two kinds of rehearsal:

– Maintenance: keeps information "alive" in WM; rote recycling; little effect on LTM

– Elaboration: "promotes" information to LTM; think about and connect


Maintenance Rehearsal:Craik and Watkins (1973)

Task: • Monitor auditory list for words beginning w/ target

letter (e.g., G)• required to recall “last” target word at end of list (list

could end at any time).

• Session final recall – recall as many words as possible.

Manipulation:# of words between appearance of target word (assumed equal to amount of rehearsal).


Craik & Watkins (1973)

Results:• recall unaffected by #

of rehearsals.Interpretation:

rote (maintenance) rehearsal fails to transfer info to LTM.

Question:• What about Rundus

(1971)? • Maintenance +

(elaboration, relational coding, etc)


Rundus (1971) again

• Analysis:– # rehearsals for each

word (position)

– % recall for each word (position)

• Results:– “For a given amount of

rehearsal, items from the initial serial positions are no better recalled than items from the middle of the list” – Rundus, 1971, p. 66


Elaborative Encoding: Bradshaw & Anderson(1982)

Tasks:

Recall “target” fact

Design:

Encoding Context X Delaytarget only immediate (no delay)

target + 2 irrelevant facts 1 week

target + 2 relevant facts


Elaborative Encoding: Bradshaw & Anderson(1982)

Target only:

Newton became emotionally unstable and insecure as child.

Target+2 irrelevant facts:

Locke was unhappy as a student at Westminster.plus

Locke felt fruits were unwholesome for children.

Locke had a long history of back problems.

Target+2 relevant facts

Mozart made a long journey form Munich to Paris.plus

Mozart wanted to leave Munich to avoid a romantic entanglement.

Mozart was intrigued by musical developments in Paris.


Bradshaw & Anderson(1982): Results

• Encoding relevant facts improved recall.• Encoding irrelevant facts hampered recall.• Effect was magnified by delay.Interpretation:• relevant elaboration increases # of retrieval path• relevant facts fosters generation of appropriate cues• irrelevant facts cause interference


Spacing Effects

• Issue:– Rehearsal improves memory.

– Does the temporal distribution of rehearsals matter?

• Research Strategy– holding # of presentations constant, manipulate

the lag (delay) between presentations.


Madigan (1969): Spacing Effect• Method:

– words studied twice at 6 different lags.

• Results:– recall w/ lag

• Other findings:– spacing affects

recognition (Glenberg, 1979)

– obtained w/ textbook materials


Accounting for the Spacing Effect• Deficient Processing

– habituate to recently presented material (less “interesting”)

– short lags overestimation of learning --> decreases (or redistributed) rehearsals.

• Encoding Variability:– Recall depends in part on study context matching test

context. – Context changes w/ time– the greater the lag, the more different the encoding

contexts, and therefore the more likely that one of them will overlap with the test context.

psyco 350 lec #6 – slide 1 lecture 6 – psyco 350, b1 winter, 2011 n. r. brown

Documents

items psyco

wm span tasks

wm memory spanwm span

items wm span measures

complex cognitive tasks

brooksdomain general

dual task performance

measuring wm capacitykey