Essay PLAN - FACE Perception PDF

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FACE PERCEPTION  

Sensation = information about the environment picked up from sensory receptors and transmitted to brain Perception = interpretation by the brain of these inputs

VISUAL ACUITY  Poor at birth, rapid increase in first 6 months  Near adult levels by 1 year VISUAL SCANNING  Younger than 2 months = can’t track object smoothly  1 month = focus on limited features of a shape e.g outside edges  2 months = start to focus on internal features COLOUR VISION  New-borns can distinguish between red and white but no other colours  1 month = look longer at bright bold colour  4 months = similar to adult abilities HOW DO WE TEST PERCEPTUAL ABILITIES?  Preference tests  Habituation tests  Conditioning PREFERENCE TESTS  Present 2 stimuli and measure how long baby looks at each – if looks at one for longer = has s preference and can distinguish between the 2 stimuli Fantz (1961)  Looked at orange longer than white circle, looked at face longest, and next text detail

HABITUATION TESTS  Shown interesting stimulus repeatedly (eventually infant loses interest = habituation)  Change to a different stimulus – infant shows renewed interest and looks again (dishabituation)  Shows infant can tell the difference CONDITIONING  Repeatedly reward target behaviour (increased sucking rate – get specific stimuli)  Infant becomes habituated to stimulus, stimulus is altered  If infant does not increase sucking rate, treats 2 stimuli the same  Does increase sucking rate = distinguishes between the 2 stimuli Moulson et al (2009, p.1)  “Faces are arguably the most important visual stimulus used in human social communication” Face perception = crucial ability for successful social life (can depict species, sex, race, identity, mood etc)

THEORETICAL APPROACHES

Nature vs nurture  Nativism: abilities from birth – innate, inborn o Descartes (1638/1965) and Kant (1781/1958) argued that infants’ capacity to perceive space is innate o Gestalt school – (early 20th century) – certain perceptual abilities were present at birth because of the structural characteristics of the NS – the infant actively tries to create order and organisation in their perceptual world  Empiricism: acquire overtime through experience – learned o William James (1890) – to the infant sensory inputs become fused into “one blooming, buzzing confusion” – only later through experience that children can discriminate among them o John Locke - tabula rasa (blank slate) on which experience is imprinted Special perceptual process for faces  Organised at birth Perceive faces as the perceive other objects  Becomes specialised after experience

Fantz (1961) - Innate face preference  1-15 weeks old = prefer complex patterns  2 faces with facial features were preferred to blank face

Maurer & Barrera (1981) – add controls for complexity  1 month = no difference in looking times  2 months = looked longer at ‘natural’ face

Goren et al (1975)  Used moving stimuli instead of static  New-borns tracked schematic face more than the other two

EARLY FACE PREFERENCE? Johnson et al (1991)  Replicated effect with new-borns  By 3 months – no longer track face more  Why does this face preference vanish?

Johnson & Morton (1991) – 2 process model  CONSPEC = early system (subcortical structures) biases infants to orient towards face  CONLEARN = later taken over by more mature system (visual cortex) and more precise recognition

NEW-BORN ABILITIES  Recognise identity of novel individuals (Turati, 2008)  Recognise eye-gaze – look more at direct than averted eyes (Farroni, 1982)

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Recognise expressions – infants dishabituated when expression changes (Field, 1982) Prefer attractive faces – new-borns < 1 week old, looked longer at attractive faces (Slater, 2000) Discriminate mother’s face – 1-4 days old sucked more to keep mother’s face on video (Walton, 1992) Pascalis (1995) – disappearance for mother’s face disappeared when outside of face/hairline was masked, new-borns use outer features to identify)

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Turati (2006) – could use both outer and inner features, but better with full-face condition with inner and outer features present or just outer features alone compared to inner features alone

Suggests face perception must be innate to some extent in new-borns  Support: Sugita (2008) - monkeys not exposed to faces for first few months of life still preferred them (early maturation support)

EFFECT OF ENVIRONEMNT – EARLY SOCIAL EXPERIENCE 

As we get older face perception skills become more specialised (narrowing of perpetual window)

Pascalis (2002)  6m old infants could discriminate between monkey faces and human faces (dishabituate)  9m old and adults could only discriminate between human faces

“OTHER RACE EFFECT”  Adults are poorer at discriminating faces of races different from their own  Tanaka (2004) – driven by environment, due to exposure to similar races in one’s environment  3m old (not new-borns) prefer own race face (Kelly, 2005) Sangrigoli (2005)  Korean adults adopted between 3-9months into Caucasian families  More accurate with Caucasian faces (distinguishing)

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Better at discriminating and recognising female faces (effect of exposure to primary care giver?) Preference for female faces in 3m old infants, not new-born (Quinn, 2008) Fathers as primary caregivers = preference for male faces (Quinn, 2002)

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Institutionalised children showed deficits in identifying emotions in faces (Wismer Fries & Pollack, 2004) Children raised in an abusive environment show bias for angry faces (Polack, 2000)

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BEYOND INFACNY – CONTINUING DEVELOPMENT IN ADULTS    

Recognise faces as familiar in 0.5s Retain information about a large number of faces 90% recognition of yearbook photos (class size up to 300, 35 years later) Some research suggests expertise (face learning/recognition) doesn’t fully emerge until 30+ years

LATE MATURATION VS EARLY MATURATION Two key theories:  Face specific perceptual development theory = ongoing development of face-specific perception mechanisms continue to develop into late childhood/adolescence SUPPORT: Susilo, 2013  Tested over 2,000 18-33-year olds  Positive association between age and facial recognition abilities, other abilities increase over time  Controlled for non-face visual recognition, sex, own-race bias 

General cognitive development theory = face perception matures early (4-5 years), performance increases later as general cognitive mechanisms improve

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Holistic/configural processing = integration of information from all regions of the face, code spacing between face and features

ABORMAL FACE PERCEPTION  ASD = deficits in social cognition (recognising familiar people, remembering faces, interpreting eyegaze/emotions)  William’s syndrome = process unfamiliar face atypically, prolonged face gaze (Riby, 2008)  Prosopagnosia (face blindness) = damage or abnormalities in right fusiform gyrus, congenital prosopagnosia (from birth, appears to run in families) – differs in severity (e.g might not recognise own face) PASCALIS (2011) •

Tzourio-Mazoyer et al – using PET technique found brain activation in 2-month-old infants presented with faces in brain regions that are activated by faces in an adult population in both fMRI and PET studies.

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Golarai et al - compared recognition of objects and faces in children (ages 7–11), teenagers, and adults. o found similar activation in the same areas for the three age groups for objects. o For faces - demonstrated that FFA is three times larger in adults than in children which may explain why some studies could not find it in young children.

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Viewing a face triggers at least two automatic and fast processes o categorization of the stimulus as a face belonging or not belonging to our own group or species o recognition of the face at an individual level Bruce and Young - stepwise model where categorization of faces according to their race, gender, and other social attributes happens at an early stage of ‘structural encoding’, before the ‘face recognition units’ or the ‘person identity nodes’ are involved

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