Object Recognition

Question 1

What is mental chronometry?

Answer 1

Time course of a cognitive process

Question 2

What is Donder’s Law?

Answer 2

Two types of reaction time:
- Simple: response to stimulus
- Choice: decision of response to stimulus
Difference reveals how long it takes to produce a response

Question 3

What two key systems are involved in object recognition?

Answer 3

ventral and dorsal systems

Question 4

Describe Marr’s computational theory

Answer 4

Different representations constructed in object recognition:
1. Grey level - compares intensity of light accross retina
2. Primal sketch - patterns based on spatial patterns of light intensity, size, density and distance groupings
3. 2D sketch - viewer centered, attachement of vectors to surface edges
4. 3D sketch - allows viewer to imagine objects in a rotated position
(bottom up)

Question 5

What is Biderman’s theory of object recognition?

Answer 5

• Objects composed of basic shapes/components known as geons
• 36 variations
• Bottom-up

Question 6

What processes are behind Biderman’s theory of object recognition?

Answer 6

• Extraction
• Segmentation of objects into parts
• Deciding which edge information is invariant across viewing angles
• construction of geons
• comparison with LTM

Question 7

What is the evidence for Biderman’s theory of object recognition?

Answer 7

• Object recognition is harder when contours showing information about concavity are missing
• Also harder when geon is changed
  However: viewpoint dependence in novel objects

Question 8

What do Tarr & Bulthoff (1995) + Milivojevic (2012) argue?

Answer 8

That perception can be viewpoint dependent or viewpoint invariant depending on whether it is categorisation (invariant) or identification (dependent)

Question 9

What did Varnie (2002) argue?

Answer 9

Complexity influences whether object recognition is viewer invariant or viewer dependent

Question 10

What brain areas are associated with object recognition?

Answer 10

• The inferotemporal cortex has neurons with high and low invariance
• Different section of the inferotemporal cortex appear to be specialised for different categories of objects
• Dorsal stream also contributes to object recognition

Question 11

What evidence is there for top down recognition?

Answer 11

• Forward and backward projecting neurons
• Goolkasian & Woodberry (2010) show priming gives bias on interpretation of ambiguous figures
• Bar et al (2006) masking figures produces activation in the orbitofrontal cortex before recognition related areas of the temporal lobe

Question 12

What are the 3 types of visual agnosia?

Answer 12

1. Apperceptive
2. Association
3. Integrative

Question 13

What are the characteristics of associative visual agnosia?

Answer 13

• Normal response when objects are presented verbally

- Problems recognising objects visually and providing structural descriptions from LTM