Unit 8

Question 1

What is Perceptual Organization?

Answer 1

It is the process by which elements in the environment become grouped to create our perception of objects.

Question 2

Perceptual Organization involves…

Answer 2

• Grouping - putting together individual elements into an object
• Segregation - separating one object from another

Question 3

Structuralism - Wilhelm Wundt

Answer 3

Distinguishes between:
-Sensations: elementary processes that occur in response to stimulation of the senses
-Perception: More complex conscious experiences

Perception: result of individual sensations combining

Question 4

Gestalt Psychologists

Answer 4

Rejected structuralism.

Question 5

Gestalt Psychologists: Max Wertheimer - The Stroboscopic Effect

Answer 5

light - dark - light in another location.
Our perceptual system perceives it as a moving object through space.
Conclusions:
- The resulting perception CANNOT be the sum of individual sensations as our senses are not being stimulated by movement
- The whole is different to the sum of its parts

Question 6

Gestalt Psychologists: Illusory Contra Effect

Answer 6

The perception of a triangle is not the sum of sensations because if we remove one of the pacmans the perception of the triangle disappears.

Question 7

Gestalt Psychologists Conclusion

Answer 7

Perception is not the sum of sensations, but how the individual sensations are organized

Question 8

Perceptual Organization - Grouping (Principles = 9)

Answer 8

These principles help bring order and coherence:
- Principle of Pragnaz
- Principle of good continuation
- Principle of similarity
- Principle of proximity
- Principle of common fate
- Principle of closure
- Principle of symmetry
- Principle of common region
- Principle of uniform connectedness

Question 9

Grouping: Principle of Pragnaz

Answer 9

We perceive the simplest possible configuration of individual elements

Question 10

Grouping: Principle of good continuation

Answer 10

Elements that follow smooth uninterrupted lines are grouped

Question 11

Grouping: Principle of similarity

Answer 11

similar things appear to be grouped together

Question 12

Grouping: Principle of proximity

Answer 12

elements close together are likely to be perceived as one unit

Question 13

Grouping: Principle of common fate

Answer 13

Objects moving in the same direction are perceived as a unit

Question 14

Grouping: Principle of closure

Answer 14

we group individual elements of fragmented objects to perceive a whole object

Question 15

Grouping: Principle of common region

Answer 15

Elements within the same region are grouped

Question 16

Grouping: Principle of uniform connectedness

Answer 16

A group of connected objects that have a constant property are perceived as a unit

Question 17

Segregation: Figure-ground

Answer 17

It is not possible to hold both perceptions at once so we switch in between both perceptions.
The fact that we can switch proves the constructive (top-down) nature of perception
- Figure: distinct shape / in front /border ownership
- Ground: lacks form / extend behind the figure

Question 18

Segregation: which areas are more likely to be perceived as figure?

Answer 18

• Vercera et al. -> areas lower in the visual field.
• upper-lower configuration: lower area - figure
  *left-right configuration: equal
• Convex (curving outwards) more likely to be perceived as figure than concave (curving inwards)

Question 19

The Role of knowledge in perception: Gestalt psychologists

Answer 19

They deemphasized the importance of part experience, knowledge and learning in the perceptual process
- Knowledge and experience do Not play a role in perception
- The principles of organization are innate

Question 20

The Role of knowledge in perception: Gestalt psychologists - Wertheimer

Answer 20

M and W configuration
depending on the configuration, we perceive the letters thanks to our knowledge about the alphabet

Question 21

The Role of knowledge in perception: Gestalt psychologists - Barense et al

Answer 21

Presented familiar and unfamiliar objects to amnesia patients and healthy controls:
- Healthy controls: judged the black region of images to be figure more often when they were familiar
- Amnesia patients showed no difference
This suggests that figure-ground segregation depends on past experiences and knowledge

Question 22

scene schema

Answer 22

The knowledge of what a specific context contains is a scene schema, and it can influence our perception of objects

Question 23

scene schema - Palmer

Answer 23

Presented subjects with a scene and then rapidly presented visual objects they had to quickly identify.
- 80% if it belongs to the scene schema
- 40% if it did not belong
Therefore, knowledge of what the scene schema contains helped participants to perceive objects.

Question 24

Illusion of depth and size

Answer 24

The information detected by sensory receptors is not necessarily what we perceive in our minds. We use sensory info to construct a perceptual representation

Question 25

Illusion of depth and size: Müller-Lyer Illusion

Answer 25

Our visual receptors detect vertical lines of identical length but we perceive one as longer

Question 26

Illusion of depth and size: Gregory

Answer 26

He suggests our system is confused by the Müller-Lyer Illusion because it is misapplying “size constancy scaling”, which helps us maintain stable perceptions of objects regardless of their distance by making us perceive nearby objects as small, and further away objects as big

Question 27

Illusion of depth and size: Ponzo Illusion

Answer 27

Misapplied “size constancy scaling”
The converging vertical lines give depth info: the top seems further away than the bottom. Therefore, an objects placed at the top appears further away. Therefore, we unconsciously apply size constancy scaling, any object placed at the top will appear bigger