Disorders of Visual Perception - 3

Question 1

What is prosopagnosia?

Answer 1

• Losing the ability to distinguish between faces

- People know they know the person, they just don’t know who they are or where they are from

Question 2

Why are faces so important?

Answer 2

• Subject of intense research
• For surveillance
• Social recognition
• Survival

Question 3

What are the two types of prosopagnosia?

Answer 3

• Apperceptive

- Associative

Question 4

What is apperceptive?

Answer 4

-Cannot perceive face

Question 5

What is associative?

Answer 5

-Cannot recognise faces they perceive

Question 6

What do Kanwisher and colleagues argue regarding face processing?

Answer 6

• Argue that the fusiform gyrus is specialised for the detection and identification of faces.
• Basically detects specific faces

Question 7

What do Gauthier and colleagues argue?

Answer 7

• Argue that face recognition involves expert discrimination of visually similar objects, with fusiform gyrus being specialised at this general function
• Basically detects similarities in faces to distinguish

Question 8

What damage is usually associated with regarding impaired face recognition?

Answer 8

-Usually associated with bilateral damage of the fusiform gyrus

Question 9

What are the consequences of RH damage to fusiform gyrus?

Answer 9

• Sufficient to produce prosopagnosia whilst sparing object recognition of equal difficulty.
• So able to distinguish between certain things such as cars but not faces

Question 10

What is the face inversion effect?

Answer 10

-If faces are show upside-down, the speed and accuracy of recognition is reduced

Question 11

What evidence does face inversion provide?

Answer 11

• That inverted faces are processed differently from upright faces.
• Upright faces processed as a unique pattern, rather than as components.

Question 12

What is the effect of The inversion Effect on general objects?

Answer 12

-Same effect not found as it is for faces

Question 13

What is the evidence suggesting that there are two different processes to recognise objects and faces?

Answer 13

-Patient CK (see Tovée, 1998) – severe object agnosia (can’t recognise objects) but unimpaired face recognition (can recognise faces).

Question 14

What is unique about prosopagnosia?

Answer 14

• Human face specific disorder

- However, can distinguish between items within different categories such as sheep

Question 15

What is the evidence for the fact that prosopagnosia is a human disorder?

Answer 15

• WJ (NcNeil & Warrington, 1993)
• Able to recognise own sheep (36 sheep)
• But not 10 famous faces
• Cannot be attributed to sheep task being easier than human faces – controls found sheep difficult to recognise (‘they all look the same’).
• WJ suffers face-specific problem whilst remaining able to recognise other visually difficult and confusable stimuli.

Question 16

Are there processes specialised in facial recognition?

Answer 16

• Perhaps yes, evidence does indicate this
• However, this could be a component of a general object processing system that is divided into specialised domains (e.g. tools, animals, faces, buildings, words), rather than a specialised system.
• So the domain of human faces is just unrecognisable