prosopagnosia and face-specific mechanisms
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Prosopagnosia and Face-Specific Mechanisms. Brad Duchaine Vision Sciences Laboratory Harvard University http://www.faceblind.org. The nature of cognitive specializations. Domain-specific—mechanisms specialized for particular types of content. e.g.-speech, faces. - PowerPoint PPT PresentationTRANSCRIPT
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
igna
l Cha
nge
to F
ace
2Repetition decrease in FFA
Face 1 Face 2 Face 1 Face 2
Different Face Same Face
% S
igna
l Cha
nge
Sam
e / %
Sig
nal C
hang
e 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
Spac
ing
Cha
nges
% C
orre
ct
% CorrectPart Changes
Spac
ing
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)
NamingSc
aled
% C
orre
ct
Session
Naming
Session
Scal
ed %
Cor
rect
Naming
Scal
ed %
Cor
rect
Session
IndividualVerification
Scal
ed %
Cor
rect
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 PlacesCoreMechanisms
Poodle face palinopsia
Poodle face palinopsia
Session
Res
pons
e T
ime
(mse
c)
Expertise Criterion: Comparable Verification RTs
Session
Res
pons
e T
ime
(mse
c)
Expertise Criterion: Comparable Verification RTs
FFA: Faces – Objects
EdwardRight
ControlRight
FFA
PPA: Scenes - Objects
EdwardRight
ControlRight
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
igna
l cha
nge
FaceObject
-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
igna
l cha
nge
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
igna
l cha
nge
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
Cum
ulat
ive
Scor
e
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 InvertedSequential Face Matching
% C
orre
ct
EdTinaGayleFrankMaureenDanaJoe
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 HexagonEyes Test
Emotion MatchingEmotional 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 HypothesisPredicts 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) ??