The changing face of face research

Vicki Bruce

School of Psychology

Newcastle University

and many, many more......

STRUCTURAL ENCODING

FACE RECOGNITION UNITS

PERSON IDENTITY NODES

NAME GENERATION

COGNITIVE SYSTEM

EXPRESSION ANALYSIS

FACIAL SPEECH ANALYSIS

DIRECTEDVISUAL PROCESSING

Bruce & Young (1986)

(Selective) developments since 1986

• Simple ‘box and arrow’ outline replaced in 1990s by computer model – Interactive Activation with Competition

• Much better ideas about the kinds of visual representations that form the core of the ‘FRUS’ or equivalent

• Development of cognitive neuroscience models (Haxby and many others)

• Emergence of ‘social cognition’ and central role played by gaze

Simple ‘box and arrow’ outline replaced in 1990s

by computer model – Interactive Activation

with Competition

Burton, Bruce and Johnston (1990)

• IAC - Interactive activation with competition (cf early McClelland & Rumelhart)

• Pools of units for features, FRUs, PINS, SIUs

• Excitation between pools, inhibition within pools

• Familiarity decisions when PIN reaches threshold

Provides good simulations of• Repetition priming - via strengthened

connections (so long-lasting, but not cross domain)

• Associative priming - via temporary activation (so short-lasting but crosses domains)

• Covert recognition in prosopagnosia

• Predicted face-name matching in patient ME

Name retrieval in IAC?

• Burton and Bruce (1992) proposed names like other semantic information but with fewer connections.

Name retrieval in IAC?

• This position, however, has not stood up to empirical test.

• E.g. Bredart et al (1995) showed that you were not slower (actually faster) to name people about whom you knew a lot rather than a little information.

After Bredart et al (1995) QJEP

Much better ideas about the kinds of visual

representations that form the core of the ‘FRUS’ or

equivalent

Burton, Bruce & Hancock (1999)

Cognitive Science• IAC model of person

recognition (familiar)• FRUs driven by

distributed reps - PCA• Look at how model

behaves in recognition and priming now using real faces as input.

Data set

• 50 young men• all captured in a neutral expression and

2 or 3 other expressions

In total• 50 neutral faces + 136 expressive faces

Results

Face recognition

Correct PIN identified Neutralfaces (/50)

Expressingfaces (/136)

Shape-free (50-bit) 50 129 (95%)

Raw image (50 bit) 50 113 (83%)

Shape-free plus shape (70 bit) 50 131 (96%)

Distinctiveness

Human subjects rated neutral versions of faces.(1=typical, 15=distinctive)

Correlation between human rating and cycles-to-reach-PIN

= - 0.31

Semantic primingPairs defined as sharing 2 semantic units

Mean cycles to threshold for test faces

Unrelated prime Related prime

Face prime 65 38

Name prime 63 41

Repetition priming

Procedure:1. Present prime face2. Cycle model & Hebb update3. ISI - present lots more faces (c. 100) 4. Present test face (same or different view)

Mean cycles to threshold for test faces

Unprimed Primed with sameimage

Primed withdifferent image

78.6 60.1 64.8

Burton, Bruce & Hancock, 1999

How do we represent familiar faces?

• Just the average of each distinct image we see of them?

• See Burton, A.M., Jenkins, R., Hancock, P.J.B. & White, D. (2005) Robust representations for face recognition: The power of averages. Cognitive Psychology, 51 (3), 256-284

• Jenkins, R. & Burton, A.M. (2008), Science, 319, p.435.

Face Recognition Units?

What about Face Space?

• Valentine (1991) and later

• Adaptation studies (Rhodes et al..)

• PCA dimensions can be thought of as forming the dimensions of ‘face space’ (though this is not the only possible model)

Development of cognitive neuroscience models

(Haxby)

Diagram from Calder & Young (2005)

After Bruce & Young (1986)

After Haxby et al, 2000

Are faces special?

Or, is face recognition special?

• Innateness (congenital prosopagnosia, congenital cataracts suggest sensitive period)

• Localisation (FFA active even in congenital Ps)

• Specificity (still debated...)

Exciting hot topics...Gaze

• Information from dynamic patterns

• Interactions between systems

• Gaze and social cognition: certainly eyes are special..

• But why eyes?

STRUCTURAL ENCODING

FACE RECOGNITION UNITS

PERSON IDENTITY NODES

NAME GENERATION

COGNITIVE SYSTEM

EXPRESSION ANALYSIS

FACIAL SPEECH ANALYSIS

DIRECTEDVISUAL PROCESSING

Bruce & Young (1986)-dynamics-interactions-gaze!

Eyes important for..Social reasons

• We look at other people’s eyes for

• Intimacy

• Control

• Regulating conversational turns etc

Cognitive reasons• We look at other people’s eyes to

– Mind-read (Baron-Cohen)– Establish shared attention– Dogs do this too..(Miklosi et al, 2003)

• Can’t ignore what another person gazes at– Gaze cuing– But sometimes we must look away (gaze

aversion)

• Different gaze patterns in different genetic learning disorders

From D. Riby & Hancock (2008) Neuropsychologia

So, why eyes?

• We need to look at them/use them for other social and cognitive purposes

• They tell us about gaze and also other expressions

• They don’t change when other facial features do.

• Probably explains why representations of familiar faces are weighted to the eyes.

And if you don’t want to be recognised?

Summing up

• Bruce and Young (1986) mapped broad relationships between different processes of face perception.

• In past 25 years we have begun to understand the mechanisms.

• Social cognition is the new hot topic, and there’s plenty left to learn.

School of Psychology