High level perception - Face perception

Question 1

Hierarchal processing of visual information

Answer 1

Hubel and Wiesel’s findings in Visual cortex

Simple —> complex —> hyper complex —> ?????

Question 2

What is the problem with hierarchal processing ?

Answer 2

we question where it is supposed to end

Question 3

grandmother cells

Answer 3

Hierarchal processing led to the speculation of grandmother cells - a cell that only reacts to your grandmother. Things that respond to every individual thing

Question 4

Peri-Stimulus Time Histogram PSTH

Answer 4

Reveals how neurons respond to stimuli by showing when they fire more or less.

Question 5

In monkeys what responds to faces

Answer 5

Monkey temporal cortex cells (IT, STS) respond to faces

Question 6

What did PSTH experiments identify

Answer 6

a cell that activates in responds to faces even if the content is very different

Question 7

What is the idea of increasing specificity?

Answer 7

Generalisation (respond to different instances of your grandmother)

Question 8

Problems with increasing specificity theory

Answer 8

Not enough cells in the brain? but every 1mm3 contains 1,000,000 cells & most people only recognize 20,000 words

• Death of cell results in inability to recognize grandmother
• Evidence of population coding in temporal cortex
• Unlikely ever to find them…

Question 9

how are faces processed upright?

Answer 9

Features analysed holistically

Question 10

how are inverted faces processed?

Answer 10

Holistic face processing impaired, Features analysed independently, Each feature coded relative to gravity

Question 11

internal facial features

Answer 11

eyes nose mouth

Question 12

external facial features

Answer 12

hair

Question 13

what are external features more important for?

Answer 13

unfamiliar faces

Question 14

what are internal features more important for

Answer 14

famous/familiar faces

Question 15

The cell for perceiving eyes / internal features

Answer 15

• Whole face = lots of spikes (80)
• Only the eyes = a small drop in spikes but lots of spikes
• When the eyes are removed and the rest is there - barley any activity
  This suggests that this cell responds to internal features

Question 16

evidence of cell responding to external features

Answer 16

• there will be spikes for whole face and when eyes are removed but not when there is just eyes

Question 17

do cells only respond to internal vs external

Answer 17

Other cells will respond to a combination of features - could be both internal and external

Question 18

our ability to recognise faces is argued to be a what process?

Answer 18

learned

Question 19

can we recognise faces of an ingroup or outgroup more?

Answer 19

its thought that we recognise people of our own race more easily - combined face study

Question 20

Short-Term Learning: Face Adaptation

Answer 20

Rhodes’ Study: Participants were exposed to average Caucasian or Asian faces for 5 minutes.
After adaptation, they were better at discriminating faces of that race.
This suggests that even brief exposure to faces can enhance recognition ability.

Question 21

What does Face Adaptation tell us?

Answer 21

Face cells “get used to” faces, like cells for motion or tilt.

After staring at one face, similar ones look different (e.g., after a wide nose, normal looks narrow).

This “suppression” helps your brain focus on changes or new faces, which could be more important (like a stranger vs. your best friend).

Suggests different brain cells code different identities.

Helps tune vision to common social faces.

Question 22

Neural Mechanism (Adaptation Hypothesis)

Answer 22

Adaptation reduces the responses of neurons coding common facial properties.
This makes the differences between faces more pronounced, aiding discrimination.

Question 23

How do we work out where people are attending to in the environment

Answer 23

Cells respond to different positions and angles at which you see the head

Question 24

intermediate views

Answer 24

45 degrees

Question 25

view centred coding

Answer 25

matters where you see this person from

Question 26

object centred coding

Answer 26

some respond to all views

Question 27

what may cells use to know peoples position

Answer 27

gaze or posture

Question 28

what study demonstrates gaze importance in telling peoples position

Answer 28

when the eyes are removed and they cant see where the gaze is focusing.

Question 29

posture

Answer 29

downwards attention as soon as their head looks forward - less of a response Some cells even integrate posture and where the body posture is - need eye gaze or where head is positioned

Question 30

hierarchy

Answer 30

Importance: eyes > head > body. Tuning consistent with attention direction. Social attention

Question 31

how is the physiological hierarchy aligned with social interactions

Answer 31

Monkeys follow the head and gaze direction of others. Autistic children have problems following the gaze of others

Question 32

emission

Answer 32

Cross cultural similarity of expressions and causes Deaf and blind children’s expressions are normal Therefore production of expressions is innate (Darwin)

Question 33

comprehension

Answer 33

Universal interpretation of 6 basic emotions (Ekman)

Question 34

darwins 6 emotions

Answer 34

happy, sad, angry, fear, surprise, disgust, Fear

Question 35

what does fear activate?

Answer 35

Amygdala is activated when we experience fear and it is also activated when you observe others experiencing fear When stimulated you experience a moment of fear.

Question 36

what does disgust activate?

Answer 36

Disgust experiences activate the insular cortex and when you see others who looked disgusted - when you feel disgusted too

Question 37

do all emotions activate the same area?

Answer 37

Different emotions activate different brain regions and damage to this regions can impair emotion range, and how they can recognise emotion in other people

Question 38

what makes a face attractive?

Answer 38

1. symmetry 2. avargeness 3. secondary sexual traits 4. skin health 5. hormone levels

Question 39

symmetry

Answer 39

One half of the face is the same as the other Results from successful development – good genes Potentially a signal of the quality of the individual

Question 40

averageness

Answer 40

Averageness - non-normal face = genotypes that are homozygous for deleterious alleles

Question 41

secondary sexual traits

Answer 41

econdary sexual traits - shape and hair - good genes for offspring

Question 42

skin health

Answer 42

Skin health and colour - healthy = more attractive - artificially more attractive - makeup and tanning and Beta carotene - eating fruit and vegetable

Question 43

when do women prefer masculine or feminine men?

Answer 43

female preferences for males is affected by female hormone levels at ovulation women prefer male faces - most fertile - taking oral contraceptives disrupts the above effect

Question 44

What does Perrett et al. (1983) show about face identity?

Answer 44

Different neurons respond to different face identities. One neuron may respond strongly to "Face PS" but weakly to others, and vice versa. Shows our brain has identity-specific face cells, not just general face detectors.

Question 45

what cells are sensitive to view of the face?

Answer 45

STS CELLS can be more responsive to the side of the head or the front etc

Question 46

which cortex are these face cells in?

Answer 46

temporal cortex

Question 47

when the face is pointing right but eyes forward - would a right view cell be responsive?

Answer 47

No they respond to the face and eyes being right - would respond if you removed the eyes entirely and the face was looking right

Question 48

for a down focused cell ? would it respond if body facing down (like childs pose) but head is forward facing?

Answer 48

No, whole body would need to be down

Question 49

why is face perception biased to the left side of the face

Answer 49

Left half of the face projects to right hemisphere which is specialised in face perception

Question 50

Flashed Face Distortion Effect (FFDE)

Answer 50

Definition: Brief exposure to faces (less than a second) causes them to appear distorted or altered. Cause: The brain struggles to process facial details quickly, leading to unrecognizable or warped features. Key Brain Area: Fusiform face area (FFA), responsible for face recognition. Significance: Reveals how the brain processes faces under time pressure and limited information.

Question 51

Face Adaptation & Own-Race vs. Other-Race Recognition

Answer 51

Fact: We adapt to familiar faces, especially those of our own race, making us less responsive to their features. Explanation: Face adaptation reduces sensitivity to familiar faces, helping us focus on novel stimuli. This makes us highly efficient at recognizing familiar faces but less sensitive to small changes. Other-Race Effect: We are more sensitive to differences in faces of other races due to less adaptation, but we still struggle to distinguish them because we're less practiced in recognizing those faces.

Question 52

Population Coding in Face Perception

Answer 52

Fact: The brain uses a group of neurons to process faces. Explanation: Multiple neurons work together to encode different aspects of faces (eyes, mouth, shape), contributing to face recognition.

Question 53

Face Adaptation and Neuronal Sensitivity

Answer 53

Fact: Prolonged exposure to a face changes how we perceive faces. Explanation: Adaptation effects show that neurons adjust their sensitivity to facial features, supporting the idea of population coding.