prosopagnosia and face-specific mechanisms brad duchaine vision sciences laboratory harvard...

Prosopagnosia andFace-Specific Mechanisms

Brad DuchaineVision Sciences Laboratory

Harvard Universityhttp://www.faceblind.org

The nature of cognitive specializations

Domain-general—mechanisms specialized for particularprocessing tasks. e.g.-recognition, reasoning.

Domain-specific—mechanisms specialized for particulartypes of content. e.g.-speech, faces.

Prosopagnosia: Acquired & Developmental

www.faceblind.org contacted by 400 prosopagnosics

Long considered an extremely rare condition

Majority are developmental

“While traveling, I had a stopover at O'Hare and I was approached by a stranger in the lounge area. It took 10-15 seconds of casual conversation before realizing who it was. It was my brother.”

Living with Prosopagnosia

“I think prosopagnosia has worsened my current depression, if it’s notthe root cause of it. This condition always affects my ability to formnormal social links to others. I prefer to be a recluse because I can’tconfidently function any other way. My avoidance of people tointeract with socially is nearly phobic.”

Explanation in prosopagnosia

Face-Specific Mechanism

Within-Class Mechanism

Configural Processing Mechanism

Curvature Mechanism

Non-Decomposable Mechanism

Rapid Expertise Mechanism

Extended Expertise Mechanism

Edward

Case History: Developmental Prosopagnosic

•General face processing impairment.

•Reports no difficulties with object recognition.

•No navigational difficulties.

•Aware of problems as a child.

•Knows of no head trauma.

•MRI showed no abnormalities.

•53-year-old right-handed man.

•Ph.D.s in physics and theology.

LJ

Case History: Acquired Prosopagnosic

•Feels lonely in world devoid of facial information.

•Impairment beginning with face detection.

•Knows of no head trauma.

•Incidents over last few years.

•16-year-old high school student.

•Incident at school dance.

LJ

Case History: Acquired Prosopagnosic

•Feels lonely in world devoid of facial information.

•Impairment beginning with face detection.

•Knows of no head trauma.

•Incidents over last few years.

•16-year-old high school student.

•Incident at school dance.

•Reports normal object recognition.

•Navigational skills are deteriorating.

•CAT, MRI, and EEG are normal.

Controls25 faces 21.6 (2.5)

Famous Face Recognition

Edward’s Face Recognition

Edward 3

Duchaine & Nakayama (2004) Neuron

LJ’s Face Recognition

Famous Face Recognition

32 faces Controls 28.8 (3.2) 1

LJ

fMRI procedure

Localizer: Block-design with 5 stimulus classes.

Faces Scenes Bodies Objects Scrambled

Controls Edward LJ

FFA: Faces - Objects

PPA: Places - Objects

Controls Edward LJ

Control Edward LJ

EBA: Bodies - Objects

% S

ign

al C

han

ge t

o F

ace

2Repetition decrease in FFA

Face 1 Face 2 Face 1 Face 2

Different Face Same Face

% S

ign

al C

han

ge S

ame

/ % S

ign

al C

han

ge D

iff

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

A mechanism isn’t working, but what is its domain?

Explanations for prosopagnosia

Predicted ImpairmentsProposed Domains

•Curved surfaces (Kosslyn et al., 1995; Laeng & Caviness, 2001)

•Within-class recognition (Damasio et al., 1982)

•Configural Information (Levine & Calvanio, 1989)

•Upright faces (Farah, 1996)

•Non-decomposable objects (Farah, 1991)

•Rapid Expert Classes (Gauthier et al., 1999)

•Extended Expert Classes (Carey & Diamond, 1986; Carey, 1992) ? ?

Mechanism for recognizing individual items.(Damasio et al., 1982)

Within-Class Mechanism

Tools Landscapes

Cars Houses

Horses Guns

Faces Sunglasses

Within-Class Mechanism

Faces: Individual Scores

A’

Response timez scores

Non-Decomposable Mechanism

Mechanism for representing objects difficult to decompose into parts (Farah, 1991)

May require holistic strategy.

Hypothesis not explicit about what objects qualify.

Curvature Mechanism

Mechanism for representing curved surfaces(Kosslyn et al., 1995; Laeng & Caviness, 2001).

Laeng & Caviness (2001): Dogs, glasses, and cars.

Upright faces activate configural processing.

Configural Processing Mechanism

Domain-general mechanism for configural processing(Levine & Calvanio, 1989)

Face-specific?

or

General purpose?

Parts

Spacing

Parts

Spacing

Spa

cing

Cha

nges

% C

orre

ct

% CorrectPart Changes

Spa

cing

Cha

nges

% C

orre

ct

% CorrectPart Changes

Configural Processing Mechanism

Demonstrates face-specific impairment.

Normal House spacing inconsistent with:

Configural processing hypothesis

Non-decomposable hypothesis

Upright vs Inverted

Non-decomposable hypothesis

Curvature hypothesis

Face Matching: Upright versus Inverted

50

60

70

80

90

100

Controls

Face Matching: Upright versus Inverted

Edward LJ

% C

orre

ct

Face Matching: Upright versus Inverted

Curvature hypothesis

Non-decomposable hypothesis

Normal inverted performance inconsistent with:

No special processing for upright faces.

Edward processes upright and inverted faces similarly.

LJ performs worse with upright faces than inverted faces.

Upright representations sent to “black hole”.

Rapid Expertise Mechanism

Mechanism for recognition of items from expert categories(Gauthier et al., 1997, 1999)

Rapid Expertise Mechanism

Edward not a face expert after 53 years.

LJ has lost his expertise with faces.

Rapid Expert Mechanism

Eight sessions of training (Gauthier & Tarr, 2002).

Sessions 1-4: Between 495-680 Test TrialsSessions 5-8: 180 Test Trials

Verification

YesTriz

No

Naming

T (for Triz)

NamingS

cale

d %

Cor

rect

Session

Naming

Session

Sca

led

% C

orre

ctNaming

Sca

led

% C

orre

ct

Session

IndividualVerification

Sca

led

% C

orre

ct

Session

IndividualVerification

Session

% C

orre

ct

FamilyVerification

% C

orre

ct

FamilyVerification

Session

Rapid Expertise Mechanism

Results are inconsistent with hypothesis

Greeble results are inconsistent with:

•Within-class hypothesis (Damasio et al., 1982)

•Curvature hypothesis (Kosslyn et al., 1995; Laeng & Caviness, 2001)

Extended Expertise Mechanism

Mechanism for recognition of items from expert categories(Diamond & Carey, 1986)

Extended Expertise Mechanism

Extended Expertise Mechanism

Extended Expertise Mechanism

Within-Class

Configural Processing

Non-Decomposable

Curved Surfaces

Rapid Expertise

Extended Expertise

Old-NewTests

Part-Spacing

InvertedMatching

GreebleTraining

BodyMatching

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

AlternativeExplanation

Explanation in prosopagnosia

Face-Specific Mechanism

Configural Processing Mechanism

Within-Class Mechanism

Curvature Mechanism

Non-Decomposable Mechanism

Rapid Expertise Mechanism

Extended Expertise Mechanism

General-purpose

“Richard Nixon?” “Richard Nixon”

Face-specific

Mr. CK:Agnosia without Prosopagnosia

CK cannot recognize objectsCK can recognize

faces

Inverted faces

(Moscovitch et al., 1997)

Faces, Domains, and Natural Categories

Results strongly support existence of what havebeen called domain-specific mechanisms

Domain-specificity and natural categories

Specialization for a natural category

Developmental Inferences

Edward never developed face-specific mechanisms.

His behavioral and fMRI results show that he developed normal object recognition mechanisms.

Functionally dissociable and developmentally dissociable.

Inferences from Edward’s case

MatureMechanisms

SpecificDevelopmental Mechanisms

Faces General Objects PlacesCore

Mechanisms

Poodle face palinopsia

Poodle face palinopsia

Session

Res

pon

se T

ime

(mse

c)

Expertise Criterion: Comparable Verification RTs

Session

Res

pon

se T

ime

(mse

c)

Expertise Criterion: Comparable Verification RTs

FFA: Faces – Objects

EdwardRight

ControlRight

FFA

PPA: Scenes - Objects

Edward

Right

Control

Right

PPA

EBA: Bodies - Objects

Control

Edward

EBA

EdwardRight

-4.0

-3.0

-2.0

-1.0

0.0

1.0

2.0

3.0

1 2 3 4 5 6 7 8

TR (2 sec)

% s

ignal change

Face

Object

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1 2 3 4 5 6 7 8

TR (2 sec)

% s

ignal change

FaceObject

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1 2 3 4 5 6 7 8

TR (2sec)

% s

ignal change

FaceObject

PPA

EBA

Edward Control

Structural MRI showed no obvious abnormalities.

Imaging Results

Cambridge Test of Face Memory

Examples

Test item with identical images

Test item with novel images

Test item with novel imageswith noise

Duchaine & Nakayama (under review) Neuropsychologia

Item Number

Cu

mu

lati

ve S

core

Introduction Novel images Novel images with noise

Future Directions

Developmental ProsopagnosiaNeural basis

Dissecting face processingEtiology

Genetic basis of face perceptionAutism & prosopagnosia

Plasticity/TherapiesDevelopmental Topographagnosia?

PsychophysicsFace recognition test

Training with inverted facesActivation of face recognition

Rapid Expertise Hypothesis

50

60

70

80

90

100

Upright Inverted

Sequential Face Matching

% C

orre

ct

Ed

Tina

Gayle

Frank

Maureen

Dana

Joe

0

10

20

30

40

50

60

70

80

90

100

Famous Faces

% C

orre

ct (

n =

25)

EdTinaGayleFrankMaureenDanaJoe

Mr. CK:Agnosia without Prosopagnosia

CK cannot recognize objectsCK can recognize

faces

Inverted faces

(Moscovitch et al., 1997)

Face OIT

Faces #1

Faces #2

Warrington

Famous Faces

Profiles

-10 -8 -6 -4 -2 0 2 4 6 8 10

Accuracy

Response Time

Z values forNM’s scores

Duchaine et al., 2003 Perception

Face OIT

Faces #1

Faces #2

Warrington

Famous Faces

Profiles

Emotion Hexagon

Eyes Test

Emotion Matching

Emotional Intensity

-10 -8 -6 -4 -2 0 2 4 6 8 10

-10 -8 -6 -4 -2 0 2 4 6 8 10

Accuracy

Response Time

Z values forNM’s scores

Duchaine et al., 2003 Perception

Configural Processing Hypothesis

Predicts that Edward will be impaired.

# C

orre

ct

Non-selective response to faces vs. objects

Face - FixationObject - Fixation

+

-

RT criterion is dependent on proportions of differenttrial types.

It says nothing aboutproficiency.

Past results show that RT criterion does not work.

1

3

3

2

(Gauthier et al., 1998)

Problems with RT criterion

(Gauthier et al., 1998)

Greeble Transfer or Task Learning?

1. No evidence of a large inversion effect.

2. Part-whole difference between experts & novices.

3. Part-in-original vs. part-in-whole effects: --Gauthier et al. (1998)—No effects. --Gauthier et al. (2002)—Two effects in opposite directions.

4. Composite effect: --Gauthier et al. (1997)—No effect. --Gauthier et al. (1998)—No effect. --Gauthier et al. (2002)—No effect.

Putative holistic/configural effects are not face-like

Low- and Mid-Level Vision

Are Edward’s face processing impairments due to problemswith low-level or mid-level vision?

Visual acuityNear vision NormalFar vision Corrected-to-normal

Pelli-Robson Contrast Sensitivity Test Normal

Birmingham Object Recognition BatteryLength match NormalSize match NormalOrientation match NormalPosition of gap match Normal

Paradigmatic Examples:Language and Face Recognition

Chomsky—Rules and RepresentationsFodor—Modularity of MindPinker—Language Instinct

Cowie—What’s within? Bates et al—Rethinking Innateness

Language is a difficult test case.

Face recognition more tractable ability.

Face-specific hypothesis(Farah, 1996; Moscovitch et al., 1997)

Other than faces, no examples of classes for which everyone has expertise.

Unclear how to test either hypothesis with Edward or LJ.

Extended expertise hypothesis (Diamond & Carey, 1986; Carey, 1992) ??

Remaining Hypotheses

Little evidence that expertise leadsto face-like processing.

Edward: Normal inversion effect for face detection

Low Density High Density

Upright

Inverted

Remaining Hypotheses: Double Dissociation

Mr. CK: Airplane & toy soldier expert(Moscovitch et al., 1997)

RM: Car expert (Sergent & Signoret, 1992)

Remaining Hypotheses: Critical Period

FaceConfigural

Face configural processing does not developwithout input during the first months of life.

(Le Grand et al., 2001)

No critical period for non-face expertise.

Remaining Hypotheses

Face-specific Hypothesis(Farah, 1996; Moscovitch et al., 1997)

Extended Expertise Hypothesis (Carey & Diamond, 1986; Carey, 1992) ??