Chapter 4: Object Recognition. What do various disorders of shape recognition tell us about object recognition? - Apperceptive visual agnosia (Ch. 2) - Associative visual agnosia - Perceptual categorization deficit What do neuroimaging studies tell us about object recognition?
- Apperceptive visual agnosia (Ch. 2)
- Associative visual agnosia
- Perceptual categorization deficit
Farah (2000) – Fig. 4.1
From Banich (2004)
Upper row: Control PET scan (resting while looking at static fixation point) is subtracted from looking at a flickering checkerboard stimulus positioned 5.5° from fixation point.
Middle row: Subtraction procedure produces a somewhat different image for each of 5 subjects.
Bottom row: The 5 images are averaged to eliminate noise, producing the image at the bottom.
Sequence of trial events
Passive Viewing Task:
Are stimuli comparable (e.g., size, complexity)
Mind is not a vacuum
Active Viewing Task:
What is task?
What is response?
1. Object-centered coordinate system
2. A cluster of multiple viewer-centered object representations plus the ability to transform one representation to another as necessary (a la Multiple Views model of Tarr, 1995).
Symbolic Model vs Neural net