1. Perceiving &
Recognizing
Objects (Chapter 5)

2. Wilhelm Wundt (1879):
Our PERCEPTION is constructed from the combinations of our SENSATIONS

3. What is this object?
Copyright © 2002 Wadsworth Group. Wadsworth is an imprint of the Wadsworth Group, a division of Thomson Learning

4. Can you “reverse frame?”
1. Cube floating over dark circles?
Cube seen through (or behind) holes or perforations?

5. Gestalt Psychology
In response to Wilhelm Wundt (1879) who proposed that “perception” was a function of “sensation”
Gestalt psychologists were struck by the many ways in which our perceptions transcend the simple sensations from which they are built… and the importance of the “organization of perception”
"The whole is different/greater than the sum of the parts"

6. How do we “organize” (i. e
How do we “organize” (i.e., cluster, group, give meaning, prioritize) our sensations into perception?

7. How do we “organize” (i. e
How do we “organize” (i.e., cluster, group, give meaning, prioritize) our sensations into perception?

8. Gestalt Psychology - Perceptual Organization
"The whole is different than the sum of the parts"

9. Six Gestalt Laws of Perceptual Organization
1. “Pragnanz” – the law of “good figure,” “law of closure” or “law of simplicity”
“Every stimulus pattern is seen in such a way that the resulting structure is as simple as possible”
Related to the scientific concept of “parsimony:” In selecting a criterion for deciding among scientific theories or explanations, one should always choose the simplest explanation of a phenomenon, the one that requires the fewest leaps of logic.

10. Gestalt Laws
Pragnanz - good figure or simplicity

11. Gestalt Laws
Pragnanz - good figure or simplicity

12. Gestalt Laws
Pragnanz - good figure or simplicity

13. Good fit, closure, simplicity

14. Six Gestalt Laws of Perceptual Organization
2. Law of Similarity
“Similar things appear to be grouped together”
Circles and squares are evenly spaced both horizontally and vertically, yet we “see” vertical columns. Why? Because we group things that are similar.

15. Law of Similarity

16. Six Gestalt Laws of Perceptual Organization
3. Law of good continuation –
“Points that, when connected, result in straight or smoothly curving lines are seen in such a way as to follow the smoothest path.”
“Perceptual path of least resistance”
What defines these lines?
a  c? or a  b?
c  b? or c d?
Determined by smoothness

17. Six Gestalt Laws of Perceptual Organization
4. Law of proximity (or nearness) –
“Things that are near to each other appear to be grouped together”
This guy doesn’t “belong”

18. Law of Proximity

19. Proximity defines propinquity (kinship)

20. Six Gestalt Laws of Perceptual Organization
5. Law of Common Fate
“Things that are moving in the same direction appear to be grouped together” – choreography of movement

21. Six Gestalt Laws of Perceptual Organization
6. Law of familiarity (or meaningfulness) – “Things are more likely to form groups if the groups appear familiar or meaningful”

22. Meaningfulness (Familiarity)

23. Six Gestalt Laws of Perceptual Organization
6. Law of familiarity (or meaningfulness) – “Things are more likely to form groups if the groups appear familiar or meaningful” What do you see below?

24. Six Gestalt Laws of Perceptual Organization
6. Law of familiarity (or meaningfulness) – “Things are more likely to form groups if the groups appear familiar or meaningful” Find the hidden faces below

25. Six Gestalt Laws of Perceptual Organization
6. Law of familiarity (or meaningfulness) – “Things are more likely to form groups if the groups appear familiar or meaningful” There are allegedly 12 faces

26. Elaborations of the “laws:” Palmer and Rock
Principle of common region
Principle of element connectedness
Principle of synchrony

27. Elaborations of the “laws:” Palmer and Rock
Principle of common region
Principle of element connectedness
Principle of synchrony

28. Elaborations of the “laws:” Palmer and Rock
Principle of common region
Principle of element connectedness
Principle of synchrony

29. Elaborations of the “laws:” Palmer and Rock
Principle of common region
Principle of element connectedness
Principle of synchrony

30. Elaborations of the “laws:” Palmer and Rock
Principle of common region
Principle of element connectedness
Principle of synchrony

31. Gestalt Principles are “Heuristics:” the difference between algorithms and principles (i.e., best guess, rule-of-thumb, source of hypothesis testing)
Likelihood principle - von Helmholtz
-we will perceive an object that is most likely
the cause of our sensory stimulation
(hypothesis testing)

32. How do we perceive objects in our world? Summary of Gestalt rules
Good fit, closure, simplicity
Similarity
Good continuity
Proximity
Common fate
Familiarity (meaningfulness)
Common region
Connectedness
Synchrony
Classical Gestalt “laws”
Modern Gestalt “laws”

33. Remember, How do we perceive objects is dependent on how we separate (segment, segregate) objects

34. Fundamental Gestalt question: How do we separate (segment, segregate) objects
Understanding “Figure-Ground”
Are there properties of figure and ground?

35. Figure-Ground segregation
The figure is more “thing-like” than the ground

36. Figure-Ground segregation
What is this?

37. Figure-Ground segregation
“Figure” is perceived as being “in front” of the ground
“Ground” tends to be perceived in the surrounding pattern
“Figure” is perceived as the smaller object
“Surroundedness”

38. Figure -Ground Segregation
Small things generally are seen as figure

39. Figure against the ground

40. Figure-Ground segregation
The ground is seen as unformed material and seems to extend behind the figure…
The contour (i.e., lines/edges/endings) separating the figure from the ground appears to belong to the figure.

41. Figure -Ground Segregation
Symmetrical areas tend to be seen as figure

42. Figure -Ground Segregation
Symmetry (i.e., both sides convex or concave) generally is seen as figure

43. Symmetry is indicated in “parallelism”

44. Figure -Ground Segregation
Meaningful things generally are seen as figure

45. Figure -Ground Segregation
Meaningful things generally are seen as figure

46. Properties of Figure and Ground?
“Thing-like” appearance
Figure is perceived as “in front” of ground
Ground is perceived by a surrounding stimulus (“surroundedness”)
Figure is perceived as the smaller object
Ground is unformed
Contour “belongs” to the figure
Figure is seen in the symmetry of forms (opposite-mirror images or parallel images “belong” together)
Meaningfulness of information can infer figure-ground

47. Alternative models (alternative “levels of analysis”) to how we “construct” objects in perception David Marr (1982) Vision “Computational Approach” to object perception
Individual
Features
Groups of
Features
Objects
Scenes
Extrastriatal “cross-talk” & synchrony (IT, MT, Parietal lobe, feedback to LGN, etc.)
Retina, LGN, Cortical Hyper-columns analyses
Extrastriate Cortical regions (Inferotemporal lobe, V4 (color), etc.)

48. Object Perception in Stages
Anne Treisman's "feature integration theory" (FIT)
Preattentive Stage
Focused Attention Stage
identify
Primitives
(line/edge)
preattentive
"automatic"
processing
attentional
devise
-focus on
some
features
combine
features
or primitives
Perception
of three
dimensional
world
Chapter 6: Attention and Experiencing a Coherent World
Pages
Compare to memory
Identify Object

49. Object Perception in Stages
Treisman's "feature integration theory" (FIT)
identify
primitives
preattentive
"automatic"
processing
Preattentive Stage:
Visual system (retina, LGN, Hypercolumns) analyzes features such as curvature, orientation, length, color, movement, etc.
“Non-conscious processes”

50. Preattentive Stage: Identify and analyze “primitives” (i.e., features)
How do we see features? Method 1 “pop-out” boundaries
Example of when pop-out occurs: when there are texturally different fields

51. Example of when pop-out occurs: when there are different texture fields

52. O Items that POP OUT are visual primitives
- line orientation, curvature, color, depth, line ends, motion etc. O
Why doesn't the red vertical bar POP OUT?
Because it requires attention and analysis

53. Object Perception in Stages
Treisman's "feature integration theory" (FIT)
Focused attention:
Narrows the range of what an individual attends to in the wider visual array
identify
primitives
preattentive
"automatic"
processing
attentional
devise
-focus on
some
features

54. Object Perception in Stages
Treisman's "feature integration theory" (FIT)
Focused attention:
Narrows the range of what an individual attends to in the wider visual array
With narrowed attention, features are combined and object is perceived
identify
primitives
preattentive
"automatic"
processing
attentional
devise
-focus on
some
features
combine
features
or primitives

55. Object Perception in Stages
Treisman's "feature integration theory" (FIT)
identify
primitives
preattentive
"automatic"
processing
attentional
devise
-focus on
some
features
combine
features
or primitives
Perception
of three
dimensional
world
Compare to memory
Identify Object

56. Focused Attention Stage: What if the stimulus doesn’t just “pop-out?”
How do we see features? Method 2 visual search and “back-end” processing of Feature Integration Theory
Need for combining & perceiving objects & using cognitive processes (i.e., comparing to memory)

57. Focused Attention Stage: What if the stimulus doesn’t just “pop-out?”
How do we see features? Method 2 visual search and “back-end” processing of Feature Integration Theory
Combining & perceiving (c) requires both Ventral (“what is it?”) and Dorsal (“where is it?”) pathways and cross-talk of both

58. Example of when pop-out does NOT occur: when comparison to memory is involved

59. Pop-Out in Visual Search - Anne Treisman
5 distractors
10 distractors
2 distractors V O V O V O T L T L T L

60. To find a red vertical bar amongst green vertical bars
# of distractors
Reaction Time 2 5 10
# of distractors
Reaction Time 2 5 10
To find an "L" amongst "T"s

61. Anne Treisman’s conclusions about Basic Features
Pop-out occurs with stimuli such as:
Curvature
Orientation
Line ends/lengths
Movement
Brightness
Direction of illumination
These types of stimuli are processed largely at the “beginning” of visual processing
The preattentive stage
Not yet at the stage to “form objects” per se
Probably processed by the Retina, LGN & Striate cortex (V1)

62. Anne Treisman’s conclusions about “non-Basic” Features
Stimuli that don’t pop-out require more elaborate analyses:
Ventral “what is it” pathway
Dorsal “where/how” pathway
Influenced by attentional factors
Influenced by motivational and circumstantial factors
Reliant on higher memory
These types of stimuli are processed largely at the “end” of visual processing:
Attentional factors involve several brain areas
At the stage of “formed objects” from combining features
Probably processed largely by the Extrastriatal areas
Cross-talk among several higher brain areas

63. 3 1 4 2 3 5 5 Biederman's Recognition-by-Components (RBC)
“geons” – limited set of elements of geometric shapes 4 2 3 5 5

64. Biederman's Recognition-by-Components (RBC)

65. Biederman's Recognition-by-Components (RBC)

66. Cells in the Inferotemporal Lobe differentially respond to different geometric shapes

67. If you can see most of the geons, you can
identify the object.

68. How do we parse our perceptual world?
Neurological
Dorsal (“where”) pathway
Ventral (“what”) pathway
Gestalt grouping rules
Segregate, separate
Figure-Ground
Experience & knowledge
Faces
Geons
Viewpoint Effect
How we pay attention
Modifications of the Neurology

69. 69

70. You can read this upside down!70

71. VIEWPOINT EFFECT & VIEWPOINT CONSTANCY
Viewpoint effects: ability to perceive an object from a different perspective (i.e., rotated or turned version from the original object).
Each image perceived activates a different set of receptors on the retina;
however, we perceive the different images as representing the same object. 71

72. View-Based Theories (Template theories)
we mentally rotate the image until it matches a similar representation already in our memory
the representations in our memory that we already have are simple (and/or abstract, i.e., what do you think of when you think “dog”)
should take longer for the perceiver to recognize the same object the more that it is rotated from its normal and most common representation.
VIEWPOINT DEPENDENT 72

73. Notice anything different about these two pictures
Notice anything different about these two pictures? It’s the same person, with one small difference.
One image has been altered, but most people won’t see how until they’re viewed upright.
Thank you Jon D.

74. This is one example of the “inversion effect”
it’s harder for the brain to process upside-down objects than upright objects
Effect is particularly strong for the perception of faces

75. How do we “organize” (i. e
How do we “organize” (i.e., cluster, group, give meaning, prioritize) our sensations into perception?
Partly by non-conscious analysis of features
Partly by conscious analysis of features
Partly by what drives attention & memory
Partly by what we “know” about what we are perceiving

76. How we direct attention: Stimulus Salience

77. How we direct attention: Stimulus Salience
Attentional Capture:
Analogous to Treisman’s “preattentive” stage:
Lights, movements, sounds, contours, etc.

78. How we direct attention: Cognitive Factors
Active cognitive processes drive our attention

79. How we direct attention: Cognitive Factors
Active cognitive processes drive our attention

80. How we direct attention: Cognitive Factors
Active cognitive processes drive our attention: where is Justin Beiber?

81. How we direct attention: Cognitive Factors
Active cognitive processes drive our attention: where is Justin Beiber?
And: Miley Cyrus
Or Rihanna?

82. Attention – Think of attention as a highlighter –
a concept of how we actively process information present in our environment
Think of attention as a highlighter –
As we read through a book, the highlighted section draws us in, causing us to focus on that area
Attention allows us to “tune-out” information, sensations and perceptions that are not relevant at the moment, and instead focus on “important” information.

83. “Spotlight” of Attention
Overt Attention: directing a sense organ at a stimulus.
Reading the words on this slide
Covert Attention: processing information outside of your direct focus.
Pointing your eyes toward this slide while watching someone in your peripheral vision

84. How do we parse our perceptual world?
Neurological
Dorsal (“where”) pathway
Ventral (“what”) pathway
Gestalt grouping rules
Segregate, separate
Figure-Ground
Experience & knowledge
Faces
Geons
Viewpoint Effect
How we pay attention
Modifications of the Neurology

85. The “knowledge” problem
Perception is more than just interpreting sensation
How far have we come in the last 100+ years?
Not very far (Gestalt “laws” still hold up)
Exception is in the understanding of the neurophysiology
What’s missing: understanding the interplay between “attention,” “knowledge” and “perception”