Attentional ProcessesAttentional Processes

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gs@psychology.nottingham.acgs@psychology.nottingham.ac.uk.uk

Office Hours: Thurs 11-1Office Hours: Thurs 11-1

Learning ObjectivesLearning Objectives

1.1. Early development of attention: Early development of attention: Describe maturational accounts.Describe maturational accounts.

2.2. Early development of attention: Early development of attention: Evidence for and against Evidence for and against maturation.maturation.

3.3. Later changes in attentional Later changes in attentional processing: Qualitative or gradual processing: Qualitative or gradual changes through childhood into changes through childhood into adulthood.adulthood.

4.4. Can these sources of evidence be Can these sources of evidence be integrated? How?integrated? How?

OutlineOutline Theoretical issuesTheoretical issues The early development of The early development of

selective attention:selective attention: Succession of stages, maturation of Succession of stages, maturation of

neural pathwaysneural pathways Alternatives?Alternatives?

Later development:Later development: Qualitative or Gradual changes?Qualitative or Gradual changes?

Group exercise: Conclusions Group exercise: Conclusions

Theoretical issuesTheoretical issues What is “attention”?What is “attention”? ““Every one knows what attention is. Every one knows what attention is.

It is the taking possession by the It is the taking possession by the mind, in clear and vivid form, of mind, in clear and vivid form, of one out of what seem several one out of what seem several simultaneously possible objects or simultaneously possible objects or trains of thought. […] It implies trains of thought. […] It implies withdrawal from some things in withdrawal from some things in order to deal effectively with order to deal effectively with others.” others.” (James, 1890/1950, pp. 404-5)(James, 1890/1950, pp. 404-5)

““Attention” is not well understood. So…Attention” is not well understood. So…

Theoretical issuesTheoretical issues

Disadvantages Disadvantages (interesting reading: Walsh, (interesting reading: Walsh,

2003)2003):: Too vague a Too vague a

construct to be usefulconstruct to be useful Not “localised” to Not “localised” to

any particular brain any particular brain circuit (e.g., the circuit (e.g., the parietal lobe)parietal lobe)

Mechanisms and Mechanisms and computations?computations?

Advantages:Advantages: Not so vague: Not so vague: multiple multiple

varietiesvarieties of “attention”, of “attention”, (Parasuraman, 1998)(Parasuraman, 1998)

Distinct processes Distinct processes involve different, involve different, potentially interacting potentially interacting circuits circuits (Posner & Petersen, (Posner & Petersen, 1990; Johnson, 2001)1990; Johnson, 2001)

Useful computational Useful computational models models (Braun et al. 2001)(Braun et al. 2001)

Source of Source of developmental change?developmental change?

Why study “attention”?Why study “attention”?

Theoretical issuesTheoretical issues

Why study attentional development?Why study attentional development?

1. As a “case study” in development:1. As a “case study” in development:

Does attention develop through Does attention develop through stages?stages?

Are changes in attentional Are changes in attentional performance better accounted for performance better accounted for by quantitative vs. qualitative by quantitative vs. qualitative mechanisms?mechanisms?

Theoretical issuesTheoretical issues

Why study attentional Why study attentional development?development?

2. As (one) source of developmental 2. As (one) source of developmental change change acrossacross domains: domains:

Attention influences experience of Attention influences experience of multiple types multiple types (e.g., vision, audition)(e.g., vision, audition)

Could changes in attention Could changes in attention account for some domain-specific account for some domain-specific developmental changes? developmental changes? (e.g., (e.g., number, physics)number, physics)

Early Visual Attention: Early Visual Attention: MethodsMethods

Changes in looking time as a measure of Changes in looking time as a measure of attentional effects: Video demonstrationattentional effects: Video demonstration

Findings: The newbornFindings: The newborn Saccadic pursuit tracking: step-like and lagging behind moving stimuli Saccadic pursuit tracking: step-like and lagging behind moving stimuli (Aslin, 1981)(Aslin, 1981)

Preferential orienting to the temporal field under monocular viewing conditions Preferential orienting to the temporal field under monocular viewing conditions (Braddick et al., 1992)(Braddick et al., 1992)

Externality effect: focus on external elements of a display Externality effect: focus on external elements of a display (Maurer & Young, 1983)(Maurer & Young, 1983)

Evidence of early inhibition of return (IoR) Evidence of early inhibition of return (IoR) (Valenza et al., 1994)(Valenza et al., 1994)

Findings: 1 to 3-month-oldsFindings: 1 to 3-month-olds Onset of smooth pursuit tracking Onset of smooth pursuit tracking (Aslin, 1981)(Aslin, 1981)

Increased sensitivity to nasally presented stimuliIncreased sensitivity to nasally presented stimuli Obligatory attention (“sticky” fixation): slower in disengaging Obligatory attention (“sticky” fixation): slower in disengaging

from a central stimuli from a central stimuli (Stechler & Latz, 1966; Hood & Atkinson, 1993)(Stechler & Latz, 1966; Hood & Atkinson, 1993)

Central

Stimulus

Peripheral

Stimulus+ =

1

Findings: 3 to 4-month-oldsFindings: 3 to 4-month-olds Anticipatory saccades Anticipatory saccades (Haith et al., 1988; Wentworth & Haith, (Haith et al., 1988; Wentworth & Haith,

1998)1998)

Inhibition of automatic saccades Inhibition of automatic saccades (Johnson, 1995)(Johnson, 1995)

Time

OR2

Infants decrease looking towards the cue only Infants decrease looking towards the cue only in 1. in 1.

Gradual improvements:Gradual improvements: Faster facilitation towards peripherally-cued locations Faster facilitation towards peripherally-cued locations (Johnson & Tucker, 1996)(Johnson & Tucker, 1996)

Using central cues to direct attention Using central cues to direct attention (Johnson et al., 1991)(Johnson et al., 1991)

Ability to delay orienting towards locations Ability to delay orienting towards locations (Gilmore & Johnson, 1995)(Gilmore & Johnson, 1995)

Findings: Through the 1st Findings: Through the 1st yearyear

Early Visual Attention: Early Visual Attention: AccountsAccounts

Successive maturation of Successive maturation of attentional processes and of attentional processes and of inputs to related neural inputs to related neural systems:systems:

Bronson (1974):Bronson (1974): Exogenous vs. endogenous processesExogenous vs. endogenous processes Subcortical vs. cortical mechanismsSubcortical vs. cortical mechanisms

Atkinson (1984, 2000):Atkinson (1984, 2000): Exogenous vs. endogenous processesExogenous vs. endogenous processes Subcortical and cortical mechanisms Subcortical and cortical mechanisms

for 1. eye and head movement; 2. for 1. eye and head movement; 2. reaching and grasping reaching and grasping

Johnson Johnson (1990, (1990,

2000)2000)::Maturation of Maturation of

multiple pathways multiple pathways and areas:and areas:

1.1. Retina to superior Retina to superior colliculus (SC)colliculus (SC)

2.2. V1 and Middle Temporal V1 and Middle Temporal area to SCarea to SC

3.3. Basal ganglia to SCBasal ganglia to SC4.4. Frontal eye-fieldsFrontal eye-fields5.5. Parietal cortex Parietal cortex 6.6. Dorsolateral prefrontal Dorsolateral prefrontal

cortexcortex

Early Visual Attention: Early Visual Attention: AccountsAccounts

Retina

DLPFC

FEF PC

V1

MTSC

BG

1122

33

44

5566

Johnson (1990, 2000):Johnson (1990, 2000):

Precise sequence of behaviours Precise sequence of behaviours driven by the maturational status driven by the maturational status of V1:of V1:

1.1. Not mature at birth (Pathway 1 wins over Not mature at birth (Pathway 1 wins over others)others)

2.2. Inside-out pattern of maturation and lower Inside-out pattern of maturation and lower layers project more strongly to MT layers project more strongly to MT (Pathway 2 wins over 4, 5, 6)(Pathway 2 wins over 4, 5, 6)

3.3. Frontal projections are slowest to mature Frontal projections are slowest to mature (Pathway 3 only gradually controlled by 4, (Pathway 3 only gradually controlled by 4, 5)5)

Early Visual Attention: Early Visual Attention: AccountsAccounts

Johnson (1990, 2000):Johnson (1990, 2000):Maturation of multiple pathways:Maturation of multiple pathways:

1.1. Retina to SC: Rapid eye-movements towards Retina to SC: Rapid eye-movements towards easily discriminable stimuli easily discriminable stimuli ---> newborn---> newborn

2.2. V1 and MT to SC: Driven by moving stimuli V1 and MT to SC: Driven by moving stimuli ---> ---> onset of smooth pursuit (1-3 mos)onset of smooth pursuit (1-3 mos)

3.3. BG to SC: Allows tonic inhibition of saccades to BG to SC: Allows tonic inhibition of saccades to peripheral stimuliperipheral stimuli ---> obligatory attention (1-3 ---> obligatory attention (1-3 mos)mos)

4.4. FEF: Detailed analyses of complex visual stimuli; FEF: Detailed analyses of complex visual stimuli; sequencing of eye movements sequencing of eye movements ---> gradual ---> gradual

5.5. PC: Covert orienting of attention PC: Covert orienting of attention ---> gradual---> gradual6.6. DLPFC: Control in tasks involving delays DLPFC: Control in tasks involving delays ---> --->

gradualgradual

Early Visual Attention: Early Visual Attention: AccountsAccounts

Maturational accounts: Maturational accounts: LimitationsLimitations

Onset of functioning is not all-or-Onset of functioning is not all-or-none:none: E.g., evidence of cortical processing in E.g., evidence of cortical processing in

newborns (pattern recognition, orientation newborns (pattern recognition, orientation discrimination, discrimination, e.g. reviewed in Atkinson, 2000e.g. reviewed in Atkinson, 2000))

Frontal cortices involved in perceptual Frontal cortices involved in perceptual processing early in development processing early in development (electrophysiological markers, (electrophysiological markers, Csibra et al., 2000)Csibra et al., 2000)

Prediction of sequences, rather Prediction of sequences, rather than static ages of onsetthan static ages of onset

Dynamic interactions across areas Dynamic interactions across areas are poorly understoodare poorly understood

2.

Maturational accounts: Maturational accounts: AlternativesAlternatives

1.1. Interactive Interactive specialisationspecialisation

Underlying face and Underlying face and eye-gaze direction eye-gaze direction processing processing (Halit et al., (Halit et al., 2003; Farroni et al., 2002)2003; Farroni et al., 2002)

2.2. Development as Development as expertise expertise acquisitionacquisition

Areas involved in skill Areas involved in skill learninglearning (Csibra et al., 2000) (Csibra et al., 2000)

Views of Functional Brain Views of Functional Brain Development:Development:

1.

Accounts: Summary of Accounts: Summary of EvidenceEvidence

Body of evidence: Successive Body of evidence: Successive maturation of attentional maturation of attentional processes and of inputs to related processes and of inputs to related neural systemsneural systems

However:However:

Dynamic interactions across Dynamic interactions across pathways are poorly understoodpathways are poorly understood

Growing alternatives to Growing alternatives to maturational accountsmaturational accounts

Beyond Infancy: What Beyond Infancy: What develops?develops?

Qualitative or gradual changes?Qualitative or gradual changes? Qualitative changes in specific Qualitative changes in specific

processes?processes? Orienting of attention Orienting of attention

?Invalid Valid

Beyond Infancy: What Beyond Infancy: What develops?develops?

Qualitative or gradual changes?Qualitative or gradual changes? Qualitative changes in specific Qualitative changes in specific

processes?processes? Orienting of attentionOrienting of attention (Brodeur & Enns, 1997)(Brodeur & Enns, 1997)Peripheral

CuesCentral Cues

Beyond Infancy: What Beyond Infancy: What develops?develops?

Qualitative or gradual changes?Qualitative or gradual changes? Qualitative changes in specific Qualitative changes in specific

processes?processes? EnumerationEnumeration (Trick et al., 1996)(Trick et al., 1996)

Beyond Infancy: What Beyond Infancy: What develops?develops?

Qualitative or gradual changes?Qualitative or gradual changes? Qualitative changes in specific Qualitative changes in specific

processes?processes? Visual search Visual search

Feature Conjunction

Beyond Infancy: What Beyond Infancy: What develops?develops?

Qualitative or gradual changes?Qualitative or gradual changes? Qualitative changes in specific Qualitative changes in specific

processes?processes? Visual search Visual search (Trick & Enns, 1998)(Trick & Enns, 1998)

Beyond Infancy: What Beyond Infancy: What develops?develops?

Qualitative or gradual changes?Qualitative or gradual changes? Gradual changes in attentional Gradual changes in attentional

capacitycapacity

Long-standing controversy (adults): Long-standing controversy (adults): Is attention limited in capacity?Is attention limited in capacity? Does attentional selection operate early or late Does attentional selection operate early or late

during processing?during processing?

Perceptual load determines the locus Perceptual load determines the locus of selection of selection (Lavie, 1995, 2000)(Lavie, 1995, 2000):: High: early; Low load: late selectionHigh: early; Low load: late selection

Beyond Infancy: What Beyond Infancy: What develops?develops?

Qualitative or gradual changes?Qualitative or gradual changes?

Perceptual load determines the Perceptual load determines the locus of selection locus of selection (Lavie, 1995, 2000)(Lavie, 1995, 2000):: The task: Are “X” or “N” present in the The task: Are “X” or “N” present in the

centre (ignore peripheral irrelevant stim.)?centre (ignore peripheral irrelevant stim.)?Low load: high interference from distractor that conflicts with target

High load: lower interference!

X

N

Irrelevant distractor, conflicts with central target identity

XY

T

O

Z

RF

N

Beyond Infancy: What Beyond Infancy: What develops?develops?

Gradual changes in attentional Gradual changes in attentional capacitycapacity

Perceptual load determines the locus Perceptual load determines the locus of selection through development:of selection through development: Childhood: Childhood: (Huang-Pollock et al. 2002)(Huang-Pollock et al. 2002)

Children's performance was as efficient as Children's performance was as efficient as adults' under conditions of high but not low adults' under conditions of high but not low loads: early selection engages rapidly loads: early selection engages rapidly maturing neural systems and late selection maturing neural systems and late selection engages later-maturing systems? engages later-maturing systems?

Ageing: Ageing: (Maylor & Lavie, 1998)(Maylor & Lavie, 1998)

Beyond Infancy: SummaryBeyond Infancy: Summary

Attentional capacity varies, but Attentional capacity varies, but there are also more specific there are also more specific changes occurring, suggesting changes occurring, suggesting both:both:

Qualitative changes in specific Qualitative changes in specific processesprocesses

Changes in attentional capacityChanges in attentional capacity

Not mutually exclusive mechanisms Not mutually exclusive mechanisms of changeof change

Group exercise: Group exercise: ConclusionsConclusions

Divide into groups: Researchers Divide into groups: Researchers investigating infant vs. later attentioninvestigating infant vs. later attention

Can different sources of information be Can different sources of information be integrated?integrated?

How can each group inform the other?How can each group inform the other? Methods?Methods? Experimental questions?Experimental questions? Limitations?Limitations?

Future directions?Future directions?

Tasks for next weekTasks for next week

GaiaGaia Make the points raised in the Make the points raised in the

conclusions available onlineconclusions available online

C8CCDE students:C8CCDE students: Read and evaluate:Read and evaluate:Wynn, K. (1992). Addition and subtraction by human Wynn, K. (1992). Addition and subtraction by human

infants. infants. Nature, 358,Nature, 358, 749-750. 749-750.

Cohen, L. B. & Marks, K. S. (2002). How infants Cohen, L. B. & Marks, K. S. (2002). How infants process addition and subtraction events. process addition and subtraction events. Developmental Science, 5Developmental Science, 5, 186-201., 186-201.