1. How do we maintain a stable perceptual world despite moment-to-moment variations in input stimulation?
Distal vs. Proximal Stimulus
Unconscious inference vs. higher-order patterns in the stimulus
Lightness Constancy
Shape Constancy
Size Constancy

2. Sensory physiology Physiological psychology Psychophysics creativity
Perception
Sensory
physiology
Physiological
psychology
Psychophysics
Physical
Stimulus
Physical
Stimulus
Physiological
Response
Sensory
Experience
Sensory
Experience
creativity
memory
motivation
attention
learning

3. Lightness constancy Shape constancy Size constancy
One’s judgment of an object’s lightness remains constant under varying levels of illumination.
Shape constancy
One’s judgment of an object’s shape remains constant at varying viewing angles.
Size constancy
One’s judgment of an object’s size remains constant at varying distances.

4. The Gelb effect: dim ceiling light screen black disk white disk unseen
The observer ignorant of the spotlight will judge the black and white discs to have equal brightness.
unseen
spot
light
(on)
observer
sits
here

5. The Gelb effect: dim ceiling light screen black disk white disk unseen
white piece of paper
screen
black
disk
white
disk
unseen
spot
light
(on)
The observer ignorant of the spotlight will judge the black and white discs to have equal brightness.
A piece of paper thrust into the light beam, however, makes it obvious that the left disc is black.
observer
sits
here

6. Incident light (illumination)
Reflected light (luminosity)
Albedo =
Incident light (illumination)

7. Observer has matched this stimulus that is under low illumination to the target on the left that is under high illumination

8. The observer’s matched stimulus exactly as before, now under the same bright illumination

9. Trapezoid or flat rectangle?

13. Cues for distance or depth
(depth perception)
1. Binocular cues
Convergence
(oculomotor)*
Retinal disparity
*…involves kinesthetic feedback

14. Convergence as a binocular depth cue:
(The role of kinesthetic feedback)

15. 2. Monocular cues Non-motion Motion Motion parallax Optic flow
Accommodation
(oculomotor)*
*…involves kinesthetic feedback
Pictorial (static)
cues
Interposition
Texture gradients
Light and shadow
Linear perspective
Aerial perspective
Horizon

16. Interposition (occlusion)

17. Texture gradient as a monocular depth cue

18. Light and shadow as a monocular depth cue

19. Linear perspective

20. Aerial perspective as a monocular depth cue

21. (Appears farther)
(Appears closer)
(Appears closer)
(Appears farther)