Size Perception

Size Perception
More involved influences from surrounding scene
33
Size Perception Affected by Depth Perception
http://www.olemiss.edu/courses/psy214/Readings/Illusions/ImageSizeAdjustmentTheory.htm
Lecture Outline
• Size Perception is Hard
✦
Retinal image size vs. Depth (the
Problem of Size Constancy)
• Size-Distance Scaling
✦
Emmert’s Law
• Other Effects on Size Perception
✦
Relative Size
✦
Conflicting Cues?
✦
Occlusion
Figure 8.25
How to approximate the visual angle spanned by an object.
Figure 8.26
The Problem of Size Constancy
Figure 8.25
The Problem of Color Constancy
Figure 7.23
The Problem of View Invariance
Figure 5.6
Lecture Outline
• Size Perception is Hard
✦
Retinal image size vs. Depth (the
Problem of Size Constancy)
• Size-Distance Scaling
✦
Emmert’s Law
• Other Effects on Size Perception
✦
Relative Size
✦
Conflicting Cues?
✦
Occlusion
Size Distance Scaling (Emmert’s Law)
Figure 8.25
Afterimage Stimulus
Size Distance Scaling (Emmert’s Law)
S=K(RxD)
S=perceived size, R=retinal image size,
D=distance, K=constant
Figure 8.31
Depth Information vs. Retinal Image Size
Holway & Boring (1941)
Figure 8.24
Depth Information vs. Retinal Image Size
Normal
One eye closed
Peephole
Draped
Hallway
Figure 8.28
Lecture Outline
• Size Perception is Hard
✦
Retinal image size vs. Depth (the
Problem of Size Constancy)
• Size-Distance Scaling
✦
Emmert’s Law
• Other Effects on Size Perception
✦
Relative Size
✦
Conflicting Cues?
✦
Occlusion
Other Effects on Size Information
Figure 8.32
Relative Size
Muller-Lyer Illusion
Figure 8.34
Muller-Lyer Illusion Explained?
Figure 8.34
Misapplied
Size-Constancy Scaling
S=K(RxD)
Figure 8.35
But.......
Figure 8.36
Figure 8.37
Conflicting Cues Theory (Day, 1989)
Figure 8.36
Length perception depends on:
Length of line
Length of figure
Occlusion: Non-occluded Part Seems Bigger
Occlusion: Occluded Part Seems Smaller
Some mysteries remain...
Ebbinghaus Illusion
Lecture Outline
• Size Perception is Hard
✦
Retinal image size vs. Depth (the
Problem of Size Constancy)
• Size-Distance Scaling
✦
Emmert’s Law
• Other Effects on Size Perception
✦
Relative Size
✦
Conflicting Cues?
✦
Occlusion