Object And Face Recognition

Question 1

Challenges of object recognition

Answer 1

• different classes of things recognised
• from different angles-partly occluded
• occurs rapidly and mostly without error

Question 2

Computers vs humans

Answer 2

Computers start with pixels and build up (bottom up) and people take info at multiple scales (top down)

Question 3

Process of recognising an object

Answer 3

• See the basic features in the scene
• Perceive organisation in features
• perceive shape
• compare the shape percent to memory
• make a decision about whether the object is familiar

Question 4

Template matching

Answer 4

Comparing the whole object to stored representations to find a match

Question 5

Feature analysis

Answer 5

Break shapes down into critical features

- these critical features are recognised and assembled into objects and shapes that are compared to mental templates

Question 6

Strengths of feature analysis

Answer 6

Reduces the number of representations the mind must store in order to process everything to be recognised

Question 7

Marr and Nishiharas model of 3 levels

Answer 7

1. Edge image -edges colours and blobs
2. 2 1/2 D sketch - depth and orientation
3. 3D model representation - relative positions

Better at explaining how computers are programmed than recognition in humans

Question 8

Motion perception

Answer 8

We must be able to pick up changes in a stimulus over quite brief time intervals and recognise the same stimulus in different positions

Question 9

Face recognition

Evidence that it is “special”

Answer 9

1) Developmental- newborns averaging 8 minutes old oriented towards upright face stimuli
2) Configural processing- see very specific spatial relationships between features
3) Mechanistic - special brain areas devoted to face processing - Fusiform Face Area (FFA)

Question 10

Prosopagnosia =face blindness

Answer 10

• brain damage to face processing regions

- harder to do as involves making finer distinctions

Question 11

Capgras Syndrome

Answer 11

A person holds delusions that friends and family have been replaced by an identical looking imposter
- damage of emotional pathway -people might “look” real to you but not “feel” real

Question 12

Implications of face recognition.

Answer 12

• facial attractiveness related to more lenient court decisions for crimes where attractiveness is a factor e.g. Con artist
• “criminal” faces rated as less trustworthy and more dominant