1. Perceptual Organization
PSYCHOLOGY
Perceptual Organization

2. Perceptual Illusions

3. Objectives Understand how illusions help us understand perception
Understand perceptual organization principles

4. Outline A. Intro & illusions B. Organizational Principles
Form perception
Figure/Ground
Gestalt grouping
Depth perception
Binocular cues - retinal dispartity, convergence
Monocular cues - 8
Motion Perception - stroboscopic, phi phenomemon
Perceptual Constancy - size & shape, size & distance, light, color

5. Perception
What can we learn from looking at the visual illusions #1-6 in your textbook?
Illusion reveal the ways we normally organize and interpret sensation.

6. Perceptual Illusions

7. Perceptual Organization: Muller-Lyer Illusion

8. Illusions Muller-Lyer Illusion
We interpret the arrows as cues for distance & length
The arrows at the ends of the lines make them appear of different lengths

9. Room Illusion

10. Room Illusion

11. Perceptual Organization: Size-Distance Relationship

12. Illusions What assumptions do we make about rooms? 90 degree angles
Size & distance (we make the false assumption that they are the same distance way)
To fool us they distorted the shape of the room

13. St. Louis Arch
Taller than wider?
Wider than taller?

14. Perceptual Organization: Depth Perception
Relative Height

15. St. Louis Arch Explanation:
Relative Height - we perceive objects higher in our field of vision as farther away

16. Perceptual Illusions

17. Illusions Hans- Wallach’s - glowing blue worm
Gestalt principles grouping principles lead you astray in this puzzle
Apply grouping principles like - continuity

18. Perceptual Illusions

19. Illusions Hoffman - ripple illusion
It is a shading technique using light & shadows

20. Perceptual Illusions

21. Illusions People tend to overestimate distance in the fog
Light & Shadow issues
Relative Clarity issues
Where can this information be useful in the real world?

22. Perceptual Illusions

23. Perception
What can we learn from looking at the visual illusions #1-6 in your textbook?
Illusion reveal the ways we normally organize and interpret sensation.

24. Which sense dominates? Visual Capture
tendency for vision to dominate the other senses
Ex. - movie theater, roller coaster

25. Perceptual Organization: Gestalt
Our brains do more then just register info, we filter & infer to make sense
Gestalt = whole
tendency to integrate pieces of information into meaningful wholes

26. Necker Cube The whole may exceed the sum of the parts
8 circles - people tend not to notice the circles but the whole box

27. Perceptual Organization: Illusory Contours

28. Fig. 15.2 Is there really a line down the middle?
Your eye perceives one

29. Outline M15
A. Intro & illusions
B. Organizational Principles
Form perception
Figure/Ground
Gestalt grouping
Depth perception
Binocular cues - retinal dispartity, convergence
Monocular cues - 8
Motion Perception - stroboscopic, phi phenomemon
Perceptual Constancy - size & shap, size & distance, light

30. Form perception
Our brains do more then just register info, we filter & infer to make sense by discriminating what it is - form
We organize and interpret meaning

31. What is it?

32. Perceptual Organization
Form perception
Figure and Ground--organization of the visual field into objects (figures) that stand out from their surroundings (ground);
Reversible figures

33. What is it?

34. What is it?

35. Perceptual Organization: Gestalt
Grouping
the perceptual tendency to organize stimuli into coherent groups

36. Gestalt grouping prin. Grouping Principles
proximity--group nearby figures together
similarity--group figures that are similar
continuity--perceive continuous patterns
closure--fill in gaps
connectedness--spots, lines, and areas are seen as unit when connected

37. Perceptual Organization: Grouping Principles

38. Perceptual Organization: Closure
Gestalt grouping principles are at work here.

39. Perceptual Organization: Grouping Principles
Gestalt grouping principles are at work here

40. Perceptual Organization: Grouping Principles
Impossible doghouse

41. Perceptual Organization:
Depth Perception
ability to see objects in three dimensions
allows us to judge distance
Somewhat innate ability as shown by infants

42. Perceptual Organization: Depth Perception
Visual Cliff

43. Depth perception 1. Binocular cues retinal disparity
images from the two eyes differ
closer the object, the larger the disparity
(floating finger sausage)
convergence
neuromuscular cue - two eyes move inward for near objects

44. 2. Monocular Cues relative size smaller image is more distant
b) Interposition (overlay)
closer objects blocks distant object

45. Perceptual Organization: Depth Perception
Relative Size

46. Perceptual Organization: Depth Perception
Interposition

47. Monocular cues c) relative clarity hazy object seen as more distant
d) texture
coarse --> close
fine --> distant

48. Perceptual Illusions

49. Monocular cues
e) relative height
higher objects seen as more distant

50. Perceptual Organization: Depth Perception
Relative Height

51. Monocular cues f) relative motion g) linear perspective
closer objects seem to move faster
g) linear perspective
parallel lines converge with distance
h) relative brightness
closer objects appear brighter

52. Perceptual Organization: Depth Perception
Light and Shadow

53. Perceptual Organization: Depth Perception
Perspective Techniques

54. Perceptual Organization: Depth Perception
Illusory Depth

55. Perceptual Organization: Depth Perception
Illusory Depth Explanation

56. Motion Perception
Stroboscopic movement - still pictures can be perceived as moving ( cartoons & film)
Phi phenomenon - 2 adjacent stationary lights blink on/off in succession are perceived as moving

57. Perceptual Constancy Perceptual Constancy
perceiving objects as unchanging even as illumination and retinal image change
color
shape
size

58. Size & distance p.239

59. Monster & Ponzo illusions
Monster - linear perspective, relative height; cues to distance & size
Ponzo - we perceive the bar as farther away as being larger based on experience

60. Moon illusion
Moon looks larger at the horizon then it does high in the sky
Explanation: cues to objects distances at the horizon make the moon seem farther away
Similar to the monster & ponzo illusion

61. Perceptual Organization-Brightness Contrast

62. Perceptional Constancy
Shape
Size & distance
Color
Lightness/Brightness

63. Concentrate on the 4 dots in the middle for 30 sec.

64. Which is line is longer?