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 DIRECTED VISUAL 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 expressive faces

Results Face recognition Correct PIN identified

Distinctiveness Human subjects rated neutral versions of faces. (1=typical, 15=distinctive) Correlation between human rating and cycles-to- reach-PIN =

Semantic priming Pairs defined as sharing 2 semantic units Mean cycles to threshold for test faces

Repetition priming Procedure: 1. Present prime face 2. Cycle model & Hebb update 3. ISI - present lots more faces (c. 100) 4. Present test face (same or different view) Mean cycles to threshold for test faces

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), 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 DIRECTED VISUAL 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