perceptual organisation, gestalt psychology and face perception

Question 1

Low level vision

Answer 1

Extracts local information about lines, bars and edges

Question 2

Mid level vision

Answer 2

Joins together isolated features into larger groups

Question 3

High level vision

Answer 3

Forms the basis for object recognition

Question 4

Ventral stream

Answer 4

What stream
Object identification

Question 5

Dorsal stream

Answer 5

Where stream
Viso-spatial information processing

Question 6

No strict separation in visual processing

Answer 6

Complex connectivity in the visual system
No strict anatomical or functional separation of what and where streams (Konen & Kaster, 2008)

Question 7

Overcoming ambiguity in grouping

Answer 7

We need constraining principles
We use prior knowledge and assumptions about the input

Question 8

Gestalt principles of perceptual organisation

Answer 8

Described a set of laws or principles of perceptual organisation
Relationships between elements are critical for perception and that’s what’s important
Early Gestalt psychologists recognised the easy ones, newer ones are less easy to understand intuitively

Question 9

Principle of proximity

Answer 9

Group things based on where they are
Pieces of information that are close together in space are bound together

Question 10

Principle of similarity

Answer 10

Pieces of information that are similar in some way are bound together
Can see when principle of proximity takes over, in the case of the different coloured dots

Question 11

Principle of common fate

Answer 11

Things that move together are bound together as a concept
Assumes that features that move together come from same object

Question 12

Principle of good continuation

Answer 12

Most natural objects smooth continuation in orientation
Our brain assumes that smooth lines mean they are connected

Question 13

Face perception

Answer 13

Many factors found in the face tell us lot about an individual
Face is important in telling us about characteristics that can change quickly
Gaze direction particularly important in understanding how we interact with the environment
Faces processed very efficiently

Question 14

Brain areas of face processing

Answer 14

Have specific brain areas that are relatively dedicated to facial processing

Question 15

Three main areas

Answer 15

Inferior occipital gyri
(Also known as occipital face area - specifically dedicated for facial processing)
Superior temporal sulcus
Lateral fusiform gyrus

Question 16

Domain specific account for face perception

Answer 16

Mechanisms operate independently of general object perception
We only use certain areas just for faces, nothing else

Question 17

Expertise account for face perception

Answer 17

Mechanisms derive from general object perception but have become finely tuned due to extensive experience
We are good at detecting faces because we have used the skills so much
Exposed to faces so much that our object processing system can become an expert

Question 18

Holistic processing

Answer 18

Representing features and their relationship as one unit

Question 19

Part-whole effect

Answer 19

Features are easier to identify when presented as part of a face (Tanaka & Fara, 1993)

Question 20

Face inversion effect

Answer 20

Inversion disrupts processing of fine details and relationships between features
Specialised mechanisms only kick in when we see a configuration we recognise

Question 21

Thatcher illusion (Thompson, 1980)

Answer 21

Holistic processing won’t kick in if the face with swapped eyes and mouth are upside down

Question 22

Prosopagnosia

Answer 22

Failure to identify or distinguish between faces despite otherwise normal visual and cognitive ability
Patients can identify other object categories
Prosopagnosia patients will still be able to identify that a familiar individual is familiar but be unable to identify

Question 23

Opposite of prosopagnosia?

Answer 23

Capgras syndrome

Question 24

Norm-Based Code

Answer 24

Facial features are represented as deviations from the average face
In our brain, we have stored the average face
We judge all of the other faces based on that average face
Further away from the norm, the easier it should be to recognise the face

Question 25

After-effects in High level vision

Answer 25

If we change the way we think about the norm, the way in which we perceive faces would be very different
1. Change your norm by looking at one face in the Bush/Obama illusion
2. Neurons that code for facial features adapt to specific characteristics of adaptor face
3. As a consequence, perception of subsequent faces are biased away from adaptor characteristics