Attention (in the visual system) RESEARCH IN COGNITIVE SCIENCE Sept. 14, 2009 S. VANGKILDE CENTER...

AttentionAttention(in the visual system)(in the visual system)

RESEARCH IN COGNITIVE SCIENCE RESEARCH IN COGNITIVE SCIENCE Sept. 14, 2009Sept. 14, 2009

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

Signe A. Vangkilde, Cand.psych., Ph.d.-stip.Signe A. Vangkilde, Cand.psych., Ph.d.-stip.

University of CopenhagenUniversity of Copenhagen Center for Visual Center for Visual CognitionCognition

AttentionAttention

“Everyone knows what attention is.It is the taking possession by the mind, in clear

and vivid form, of one out of what seem several simultaneously possible objects or trains of

thought.Focalization, concentration of consciousness are

of its essence.It implies withdrawal from some things in order to

deal effectively with others, and is a condition which has a real opposite in the confused, dazed,

scatterbrain state …” (James 1890, p. 247)

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

A descriptionA description

The amount of information that impinges on our sense organs is much larger that what can be handled processed and responded to.

Attention is a way of appropriately allocating our limited resources to the relevant stimuli.

Attention facilitates the processing of relevant stimuli/thoughts/actions whereas irrelevant ones are ignored.

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Different kinds of attentionDifferent kinds of attention

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► Attention studies use a vast number of Attention studies use a vast number of different paradigms that mainly focus on:different paradigms that mainly focus on: Orientation of attentionOrientation of attention Focused attentionFocused attention Divided attentionDivided attention Sustained attentionSustained attention

► However, the distinctions could be drawn However, the distinctions could be drawn differently and the experimental and differently and the experimental and theoretical tradition that scientists adhere theoretical tradition that scientists adhere to also counts… to also counts…

Central dichotomiesCentral dichotomies

► Automatic vs. controlled processing

► Early vs. late selection

► Parallel vs. serial processing

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

Automatic Automatic Controlled Controlled

Automatic Automatic Controlled Controlled► Bottom-up► Exogeneous► Automatic

selection based on salient features: Colour Motion Etc.

► Task inspecific

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► Top-down► Endogeneous► Voluntary selection

based on current goal/task

► Task specifik

Posner’s spatial cueing paradigm (1980 )

Automatic (exogeneous) attention

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Invalid trial

Fixation Cue

Target

Valid trial

TIME

Posner’s spatial cueing paradigm (1980 )

Voluntary (endogeneous) attention

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Invalid trial

Fixation

Target

Valid trial

TIME

Cue

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SelectionSelectionEarly Early Late Late

Classical studiesClassical studies► Auditive attention

Cherry (1953) Broadbent (1958) Moray (1959) Deutch & Deutch (1963)

► Visual attention Treisman (1964) Bundesen (1990)

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Cocktail Party Effect Cocktail Party Effect (Cherry, 1953)(Cherry, 1953)

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Renoir, Le Moulin de la Galette 1876

Dichotic listening / shadowing paradigms

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► Cherry (1953) Dichotic listening: Attend to and shadow (verbally) auditive

stream in one ear – ignore stimulation in the other ear Subjects can’t report any input from the unattended ear

Early selection - Filter theoryEarly selection - Filter theory► Broadbent (1958)

All information enters a sensory buffer The physical characteristics of a stimulus decides

whether it passes through the filter and is processed further

The input that is filtered out quickly decays and doesn’t put any demands on the processing resources

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

Early selection, or?Early selection, or?► Moray (1959)

… but at a cocktail party we often react to our name or other subjectively relevant stimuli even though we are not attending to the source of these inputs

”Intrusion of the unattended”

This suggests that unattended stimuli are indeed processed semantically and not just filtered on the basis of physical features

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

Late selectionLate selection► Deutch & Deutch (1963)

Attended and ignored inputs are processed equivalently by the perceptual system, reaching a stage of semantic encoding and analysis

Only when the inputs requires a respons selection occurs limitation concerns the amount of input that can trigger a respons

Consequence: Attention does not influence processing

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The Attenuation TheoryThe Attenuation Theory► Treisman (1964)

Modification of Broadbent’s early selection Deselected stimuli are not completely gated

from higher analysis but merely attenuated Attenuation = reduction in the signal strength

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Attended input

Un-attended

input

Attenuation filter

TVATVA

A Theory of Visual AttentionA Theory of Visual Attention

Bundesen, 1990Bundesen, 1990Bundesen, Habekost & Kyllingsbæk, 2005Bundesen, Habekost & Kyllingsbæk, 2005

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TaskTask

You will be shown a matrix You will be shown a matrix of letters brieflyof letters briefly

Try to remember as many Try to remember as many letters as possible!letters as possible!

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Whole ReportWhole Report

H B C

K M W

L Y Z

E X I

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Whole ReportWhole Report

? ? ?

? ? ?

? ? ?

? ? ?

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

Sperling (1960)Sperling (1960)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 2 4 6 8 10 12 14

Display size

Mea

n s

core

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Textbook model of memoryTextbook model of memory

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Sensory storeShort-termmemory

Long-termmemory

Decay

A Theory of Visual AttentionA Theory of Visual Attention

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

Visuallong term memory

Visu

al in

puts

Visualshort term memory

RACE(between categorizations)

Processing speed in the RaceProcessing speed in the Race

Szz

xi w

wixixv ),(),(

Rj

jx jxw ),(

Rate equation

Weight equation

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Basic Assumptions of TVABasic Assumptions of TVA

►Exponential processingExponential processing►Parallel independent Parallel independent

processingprocessing►Limited Visual Short-Term Limited Visual Short-Term

MemoryMemory

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

Basic Assumptions of TVABasic Assumptions of TVA

►Exponential processingExponential processing►Parallel independent Parallel independent

processingprocessing►Limited Visual Short-Term Limited Visual Short-Term

MemoryMemory

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Single letter identificationSingle letter identification

#

Identification of a single masked letter

A10-200 ms

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Exponential ProcessingExponential ProcessingBundesen & Harms (Psychological Research 1999)Bundesen & Harms (Psychological Research 1999)

v = 77 letters/st0 = 19 ms

P(report) = 1 – exp (- v * (t - t0))

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Basic Assumptions of TVABasic Assumptions of TVA

►Exponential processingExponential processing►Parallel independent Parallel independent

processingprocessing►Limited Visual Short-Term Limited Visual Short-Term

MemoryMemory

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

S1

Type of Report

0 2 4 6 8 10 12 14 16 18

Pro

port

ion

of tr

ials

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

ObservedEstimated

S5

Type of Report

0 2 4 6 8 10 12 14 16 18

Pro

port

ion

of

tria

ls

0.00

0.05

0.10

0.15

0.20

0.25

0.30

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN Parallel Independent Parallel Independent

ProcessingProcessingKyllingsbæk & Bundesen (JEP: HPP 2007) & Kyllingsbæk & Bundesen (JEP: HPP 2007) &

Bundesen, Kyllingsbæk, & Larsen (Psychonomic Bulletin 2003)Bundesen, Kyllingsbæk, & Larsen (Psychonomic Bulletin 2003)

+ +F P + +

TIME

29 ms 500 msKeypress Report

Basic Assumptions of TVABasic Assumptions of TVA

►Exponential processingExponential processing►Parallel independent Parallel independent

processingprocessing►Limited Visual Short-Term Limited Visual Short-Term

MemoryMemory

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

The VSTM LimitationThe VSTM LimitationSperling (Psychological Monographs 1960)Sperling (Psychological Monographs 1960)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 2 4 6 8 10 12 14

Display size

Mea

n s

core

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

K VSTM capacity (elements)

C Speed of processing (elements/s)

t0 Threshold of conscious perception (s)

w Attentional weights of different locations

Relative attentional weight of distractors

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Model parametersModel parameters

TVA based assessmentTVA based assessment

► Whole report: measures attentional Whole report: measures attentional capacitycapacity

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Whole report: Whole report: General attentional capacityGeneral attentional capacity

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(shown for 10 – 200 ms)

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Whole report: Whole report: General attentional capacityGeneral attentional capacity

?

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

Whole report: Whole report: General attentional capacityGeneral attentional capacity

Example:Example:

Patient ”L4”Patient ”L4”

tt00 = 24 ms= 24 ms

CC = 16 elements / s= 16 elements / s

KK = 3.4 elements= 3.4 elements

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The whole report functionThe whole report function

TVA based assessmentTVA based assessment

► Whole report: measures attentional Whole report: measures attentional capacitycapacity

► Partial report: measures attentional Partial report: measures attentional weightingweighting

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S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

Partial report: Partial report: Filtering of distractors Filtering of distractors (”(”αα”)”)

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN

Partial report: Partial report: Filtering of distractors Filtering of distractors (”(”αα”)”)

S. VANGKILDE CENTER FOR VISUAL COGNITION UNIVERSITY OF COPENHAGEN Bilateral displays Bilateral displays

Spatial bias of attentional weightingSpatial bias of attentional weighting (”w(”windexindex”)”)

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TVA parametersTVA parameters

K VSTM capacity (elements)

C Speed of processing (elements/s)

t0 Threshold of conscious perception (s)

w Spatial bias

Distractibility

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TVA-based assessment 1999-2009TVA-based assessment 1999-2009

►Duncan et al. Duncan et al. (JEP: General, 1999)(JEP: General, 1999) Visual neglectVisual neglect►Duncan et al. Duncan et al. (Cognitive Neuropsychology 2003)(Cognitive Neuropsychology 2003) SimultanagnosiaSimultanagnosia►Habekost & Bundesen Habekost & Bundesen (Neuropsychologia 2003)(Neuropsychologia 2003) Subclinical deficits after strokeSubclinical deficits after stroke►Habekost & Rostrup Habekost & Rostrup (Neuropsychologia 2006) (Neuropsychologia 2006) Right hemisphere strokeRight hemisphere stroke►Peers et al. Peers et al. (Cerebral Cortex 2005)(Cerebral Cortex 2005) Parietal vs. frontal strokesParietal vs. frontal strokes►Habekost & Rostrup Habekost & Rostrup (Neuropsychologia 2007) (Neuropsychologia 2007) Right hemisphere strokeRight hemisphere stroke►Bublak et al. Bublak et al. (JINS 2005)(JINS 2005) Clinical testing useClinical testing use►Finke et al. Finke et al. (JINS 2005)(JINS 2005) TVA parameters in normalsTVA parameters in normals►Finke et al. Finke et al. (Brain 2006; (Brain 2006; Neuropsychologia 2007Neuropsychologia 2007)) Huntington’s diseaseHuntington’s disease►Bublak et al. Bublak et al. (Rest. Neurology & Neurosci 2006) (Rest. Neurology & Neurosci 2006) Neurodegenerative diseaseNeurodegenerative disease►Bublak et al. Bublak et al. (Neurobiology of Aging, in press)(Neurobiology of Aging, in press) Alzheimer’s and MCIAlzheimer’s and MCI►Hung et al. Hung et al. (Journal of Neuroscience 2005)(Journal of Neuroscience 2005) TMS and visual filteringTMS and visual filtering►Habekost & Starrfelt Habekost & Starrfelt (Neuropsychologia 2006)(Neuropsychologia 2006) Hemianopic alexiaHemianopic alexia►Starrfelt, Habekost, & Leff Starrfelt, Habekost, & Leff (Cerebral Cortex, 2009)(Cerebral Cortex, 2009) Pure alexiaPure alexia►Starrfelt, Habekost, & Gerlach Starrfelt, Habekost, & Gerlach (Cortex, 2009)(Cortex, 2009) Pure alexiaPure alexia►Matthias et al. Matthias et al. (JEP: HPP 2009) (JEP: HPP 2009) Cued alertingCued alerting►Matthias et al. Matthias et al. (Neuropsychologia 2009)(Neuropsychologia 2009) VigilanceVigilance