face perception

Question 1

what are the practical applications of research into face perception?

Answer 1

CCTV and police

passports and customs/immigration

security of your devices

Facebook photo tagging

Question 2

what sort of object is a face?

Answer 2

one with extremely similar distractors - within-class not between-class recognition

a very changeable one - rigid transforms (head movement, viewpoint), non-rigid (expressions, speech), shape and texture (aging), colour (emotion, health, temperature, tan)

Question 3

are we good at facial recognition?

Answer 3

yes - very good

even when extremely distorted, we recognise faces

even see faces when there are none - pareidolia - studies suggest all you need is a symmetrical noise pattern with a natural distribution of spatial frequencies

Question 4

what does BOLD stand for?

Answer 4

Blood Oxygenation Level Dependent Signal

Question 5

how is BOLD signal used in fMRI to see brain activity?

Answer 5

when neurons in a brain area become active, they need more energy which comes from oxygen in our blood

oxygen-rich blood flows to active areas

MRI detects difference between blood that has a lot of oxygen and blood that has less - turns these differences into images showing which brain areas are most active

fMRI results always a difference between conditions to remove background or unrelated brain activity and highlight areas specifically involved in the task

Question 6

where are faces processed?

Answer 6

Fusiform Face Area (FFA) - face selective region

Question 7

what is the contrast study evidence for the FFA?

Answer 7

Kanwisher et al (1997)

compared BOLD signals for faces vs other objects

highlighted regions had higher signals for faces

Question 8

what is the evidence from physiology for the FFA?

Answer 8

Desimone et al (1984)

neural signalling in monkey FFA was highest for faces (of same species)

when scrambled or partially obscured, the response went done

Question 9

what is the domain specificity hypothesis?

Answer 9

faces are special

we are born with dedicated mechanisms for facial recognition which operate differently to those that serve typical object recognition

Question 10

what is neonatal face discrimination?

Answer 10

is there an innate ability to recognise faces?

newborn babies prefer to look at face-like patterns more than non-face-like patterns - might be broader preference for top-heavy patterns

but babies as young as 1-4 day sold seem to be able to tell mother’s face from that of a stranger

Question 11

how is neonatal facial discrimination studied?

Answer 11

using habituation

show the baby photos of its mother until they get bored

see how long it looks at a new photo (of a stranger)

if it looks for longer, it is inferred that the baby was more interested because the face was new

Question 12

what is prosopagnosia?

Answer 12

some people cannot recognise (exclusively) faces

often have different gaze patterns

acquired - damage to occipital-temporal regions

although very rarely isolated completely to faces

Question 13

who was patient GG?

Answer 13

after a right ischemic stroke was unable to recognise faces but had no problem with objects and animals

Question 14

what is developmental prosopagnosia?

Answer 14

can be heredity

reported that 2% of the population has developmental prosopagnosia

can be very isolated to face

large-scale studies reported that people with developmental prosopagnosia show lower performance when tested on difficult object recognition tasks

Question 15

what are super-recognisers?

Answer 15

people who are very good at distinguishing faces

explained by genetic factors

Question 16

what is the inversion effect in bistable ambigram face drawings?

Answer 16

easier to see the second face when right way up

Question 17

what is the inversion effect?

Answer 17

pareidolia is orientation specific

inversion disrupts configural more than featural evidence

change one part (the mouth) and the whole face looks different

evidence of holistic processing - the inability to attend to one part of the face

Question 18

what is the Thatcher effect (Thompson, 1980?

Answer 18

don’t seem to notice there is something wrong with the image on the left because we are more attuned to faces that are the correct orientation

Question 19

how does the inversion effect affect sensitivity to facial configuration?

Answer 19

disrupts configural information more than featural

procedure - target face appears for 200ms, second face shown, task - are they the same face or different

on the top two, spacings between features (configuration) has been changed

on the bottom two, same spacings but features (eyes, mouth) have been changed

Question 20

what was Tanaka & Farah’s (1993) study into the part-whole effect?

Answer 20

sub-parts of faces are not independently recognisable

training phase - participants given a face to remember, either whole or scrambled

testing phase - participants given a distinguishing task where one thing (nose) had been changed, given these in configuration and on its own

results - participants trained on whole face better at identifying whole face, participants trained on scrambled faces better at identifying individual parts

evidence that when given the whole face to learn, it was processed holistically

when trained on scrambled face, face-specific mechanisms were not activated and component parts were processed individually

Question 21

what is the composite effect?

Answer 21

we can’t help but see the whole face (Young, Hallawell & Hay, 1987)

measured reaction time for identifying top and bottom faces, either aligned or misaligned, upright or inverted

composite effect slows reaction time for aligned faces, but only when they are upright

more evidence of compulsory holistic processing for upright races

perhaps we can’t encode configural relationships in upside down faces

Question 22

what are the advantages of domain specificity hypothesis?

Answer 22

information on specific features of faces can be misleading because different faces might share similar features or because face features can change

integration could rely on parallel processing and ensure a faster recognition of a highly relevant stimulus - we can classify a face as familiar or unfamiliar in 200ms

Question 23

what is the expertise hypothesis?

Answer 23

faces are not special

face perception simply shows us how general object recognition mechanisms work for objects we are extremely well-practiced at observing

Question 24

what is the effect of (un)familiarity?

Answer 24

so much better at identifying people we have already seen (Jenkins et al, 2011)

two women are Dutch celebrities so more familiar to Dutch participants than British participants

facial recognition is heavily dependent on familiarity - you have practiced identifying these particular faces

Question 25

how can the effect of (un)familiarity be used against the expertise hypothesis?

Answer 25

unlike other objects, for which experts can recognise both familiar and unfamiliar instances with high accuracy, humans are much better at recognising familiar faces than unfamiliar ones suggests that facial recognition might involve specialised processes

Question 26

what is the "other race" effect?

Answer 26

sensitivity to differences between faces seems to require specific experience (Shepherd et al, 1974) people are better at remembering, more accurate at matching and can make finer discriminations amongst faces of their own race rather than another Asian children adopted into European Caucasian families show the same recognition pattern as native Caucasian people more evidence of the importance of practice and familiarity

Question 27

what is object inversion in experts?

Answer 27

orientation more critical in situations where participant has extensive practice in making subtle object discrimination (Diamond & Carey, 1986) tested experts in dog breeds on subtle differences in pictures of dogs, upright and inverted both experts and non-experts were worse at recognising faces when they were upside down but only dog experts were worse at recognising dogs when they were inverted so the inversion effect applies to all things we are good at recognising

Question 28

what was Gauthier & Tarr's (2002) study into the part-whole effect in objects?

Answer 28

parts are often recognised better in their original context, not just faces trained participants to recognise Greebles (not really faces, but face-like) showed them a target Greeble and told which part to attend to then shown that part either in isolation or in its trained configuration was that part the same or different to that part of the target Greeble? accuracy was much better when the parts were in situ so the part-whole effect exists for objects too

Question 29

what was the FFA activation in car experts?

Answer 29

FFA may simply be an area responding to expertise - FFA activation as a response to faces, animals, cars, planes most voxels preferred faces but the amount of voxels were activated by cars (vs animals) was correlated with how expert the person was on cars so the FFA may aid the perception of images in which we are experts

Question 30

what does the expertise hypothesis say about prosopagnosia?

Answer 30

brain damage in prosopagnosia might affect areas associated with expertise in general rather than faces evidence that some participants with acquired prosopagnosia have problems recognising objects in, for examples, cars which suggests they might have general expertise-related deficits however, individuals with developmental prosopagnosia can become experts, showing an independent mechanism for faces and expertise in objects