1. Thinking About Psychology: The Science of Mind and Behavior
Charles T. Blair-Broeker
Randal M. Ernst

2. Perception
Module 10

3. Perception
The process of organizing and interpreting sensory information
Top Down Processing

5. Organizational Principles
Module 10: Perception

6. Selective Attention
Perceptions about objects change from moment to moment. We can perceive different forms of the Necker cube; however, we can only pay attention to one aspect of the object at a time. (Other examples: dichotic listening)
OBJECTIVE 1| Describe the interplay between attention and perception.
Necker Cube

7. SELECTIVE ATTENTION Our brain can only focus on 1 thing at a time
Stress narrows attention
OTHER EXAMPLES:
Cell phones in car ?

8. Count the number of times the ball is passed:

9. Change Blindness

10. Gestalt
The “whole,” or the organizational patterns that we tend to perceive
Gestalt psychologists stressed that the whole is greater than the sum of its parts.
By breaking experiences into their basic parts, something important is lost.
Ex. Butter, eggs, flour, sugar, salt, brown sugar, baking soda, vanilla, chocolate chips

11. Organizational Principles: Figure-Ground Relationships
Module 10: Perception

12. Figure-Ground
The perceptual tendency to organize stimuli into objects (the figures) that stand out from their surrounding (the ground) - doesn’t have to be visual
The figure is the object(s) that stands out or draws one’s attention.
The ground is the background.
Right now, what is the “figure”?

13. What’s the “figure” now?

14. Organizational Principles: Grouping Principles
Module 10: Perception

15. Grouping
The perceptual tendency to organize stimuli into understandable groups
Several principles of grouping include:
Similarity
Proximity
Closure
Continuity

16. Grouping - Similarity
The tendency to place items that look similar into a group

18. Draw what you just saw.

19. Grouping - Proximity
The tendency to place objects that are physically close to each other in a group

21. Draw what you just saw

22. Grouping – Closure
The tendency to look at the whole by filling in gaps in a perceptual field

24. Draw what you just saw

25. Grouping – Continuity
The tendency to perceive that movement of an object continues once it appears to move in a particular direction

27. Draw what you just saw

28. Depth Perception
Module 10: Perception

29. Depth Perception
The ability to see in three dimensions and judge distances
How does this happen?
Inverted, 2 dimensional image projected on retina

30. Visual Cliff
A laboratory device for testing depth perception in infants and young animals
Infants are reluctant to crawl past the “edge” of the visual cliff
Other animals had similar results.
Suggests that depth perception, to some extend, is inborn

31. Visual Cliff

32. Depth Perception: Binocular Depth Cues
Module 10: Perception

33. Binocular Cues
Depth cues that require the use of both eyes – allows us to see 3 dimensions

34. Retinal Disparity
A binocular depth cue resulting from slightly different images produced by the separation of the retinas in the left and right eye
Is most effective when the item is quite close to the person

35. Binocular Depth Cues: Finger Sausage

36. Convergence
A binocular depth cue related to the tension in the eye muscles when the eyes track inward to focus on objects close to the viewer
The more tension in the eye muscle, the closer the object is
Works best at close distances

37. Depth Perception: Monocular Depth Cues
Module 10: Perception

38. Monocular Cues Depth cues that require the use of only one eye
Monocular depth cues include: relative size, relative motion, interposition, relative height, texture gradient, relative clarity, and linear perspective.

39. Monocular Depth Cues – Relative Size
Using the perceived size of a familiar object to determine depth
The larger the object appears, the closer the object is to the viewer

40. Relative Size: Which Pencil is farther away?
Monocular Cues
Relative Size: Which Pencil is farther away?
OBJECTIVE 7| Explain how monocular cues differ from binocular cues, and describe several monocular cues for perceiving depth.

41. Monocular Depth Cues – Relative Motion
A person who is moving can determine depth by focusing on a distant object.
Objects further away than the object of focus will appear to move in the same direction as the subject is moving.
Objects closer than the object of focus will appear to move in the opposite direction.

42. Relative Motion

43. Monocular Depth Cues – Interposition
Method of determining depth by noting that closer objects partially obstruct the more distant objects
Also called “overlap”

44. Monocular Cues
Interposition: Objects that occlude (block) other objects tend to be perceived as closer.
Rene Magritte, The Blank Signature, oil on canvas,
National Gallery of Art, Washington. Collection of
Mr. and Mrs. Paul Mellon. Photo by Richard Carafelli.

45. Monocular Depth Cues – Relative Height
Method of determining depth by noting that distant objects appear higher in your field of vision than do closer objects

46. Relative height

47. In this picture, is the arch taller or wider?
Tall Arch
In this picture, is the arch taller or wider?
Rick Friedman/ Black Star

48. Monocular Depth Cues – Texture Gradient
Method of determining depth by noting that distant objects have a smoother texture than nearby objects

49. Monocular Cues
Texture Gradient: Indistinct (fine) texture signals an increasing distance.
© Eric Lessing/ Art Resource, NY

50. Texture Gradient

51. Monocular Depth Cues – Relative Clarity
Method of determining depth by noting that distant objects are less clear than nearby objects
Tends to work outdoors

52. Monocular Cues
Relative Clarity: We perceive hazy objects to be farther away than those objects that appear sharp and clear.

53. Monocular Depth Cues–Linear Perspective
Method of determining depth by noting that parallel lines appear to converge in the distance
The lines appears to eventually merge on the horizon.

54. Monocular Cues
Linear Perspective: Parallel lines, such as railroad tracks, appear to converge in the distance. The more the lines converge, the greater their perceived distance.
© The New Yorker Collection, 2002, Jack Ziegler
from cartoonbank.com. All rights reserved.

55. Motion Perception
Module 10: Perception

56. Stroboscopic Motion
The illusion of motion by the rapid projection of slightly changing images
The concept a motion picture uses

57. Apparent Motion
Phi Phenomenon: When lights flash at a certain speed they tend to present illusions of motion. Neon signs use this principle to create motion perception.
One light jumping from one point to another: Illusion of motion.
Two lights flashing one after the other.

58. Perceptual Constancy
Module 10: Perception

59. Perceptual Constancy
Perceiving the size, shape, and lightness of an object as unchanging, even as the retinal image of the object changes
The understanding that objects usually remain the same

60. Perceptual Constancy: Size Constancy
Module 10: Perception

61. Size Constancy
A person’s understanding that as an object moves further or closer to them its actual size stays the same
As an object appears to become larger we realize it is getting closer, not bigger.
As an object appears to become smaller we realize it is moving farther away, not getting smaller.

62. Size Distance Relationship

63. Size Distance Relationship

64. Size Distance Relationship

65. Perceptual Constancy: Shape Constancy
Module 10: Perception

66. Shape Constancy
The understanding that an object’s shape remains the same even though the angle of view makes the shape appear changed

67. Shape Constancy

68. Perceptual Constancy: Lightness Constancy
Module 10: Perception

69. Light Constancy
The ability to see an object as having a constant level of lightness no matter how the lighting conditions change

70. Illusion of the Camera
Play “Lights, Camera, Magic!” (12:53) Segment #10 from Scientific American Frontiers: Video Collection for Introductory Psychology (2nd edition).

71. Perceptual Set
Module 10: Perception

72. Perceptual Set
A mental predisposition to perceive one thing and not another. What you see in the center picture is influenced by flanking pictures.
OBJECTIVE 14| Define perceptual set, and explain how it influences what we do or do not perceive. Right half the class should close their eyes and the left half of the class should see the saxophonist for about 20 seconds. Then the left half of the class should close the eyes and the right half should see the woman’s face. All of them should then write their responses while watching the middle picture. Responses are compared to show perceptual set.
From Shepard, 1990.

73. Perceptual Set
A mental predisposition to perceive something one way and not another
Example of top-down processing
Influence of the “power of suggestion” (subliminal perception)
Guided by schemas: concepts or mental frameworks that organize and interpret information

74. What do these letters spell?
f o l k

75. What do these letters spell?
c r o a k

76. What do these letters spell?
s o a k

77. What do we call the white of an egg?

78. Subliminal Perception
Play “Studying the Effects of Subliminal Stimulation on the Mind” (4:46) Segment #9 from The Mind: Psychology Teaching Modules (2nd edition).

79. Context
Module 10: Perception

80. Context
The setting or environment in which we interpret sensory stimuli
EX. – If sad music is playing and you read homophones to people, they will write “mourning” and “die”. If they hear happy music, they will write “morning” and “dye”.

81. Illusions
Module 10: Perception

82. Illusions Misinterpreting sensory stimuli
Help researchers understand how sensation and perception normally works

83. Müller-Lyer Illusion

84. Müller-Lyer Illusion
Most people think segment AB equals BC. In reality AB is much longer than BC.

85. Müller-Lyer Illusion

86. Müller-Lyer Illusion

87. Müller-Lyer Illusion

88. Müller-Lyer Illusion
Insert “Müller-Lyer Illusion” Video #4 from Worth’s Digital Media Archive for Psychology.
Instructions for importing the video file can be found in the ‘Readme’ file on the CD-ROM.

89. Ames Room Illusion: Secret Revealed

90. The End