Unit 8

Question 1

What is perceptual organisation?

Answer 1

Process by which elements in the environment become grouped together or separated to create our perception of objects

Question 2

Which processes are involved in perceptual organisation?

Answer 2

Grouping and segregation

Question 3

Grouping

Answer 3

Putting together individual elements into an object or groups of objects

Question 4

Segregation

Answer 4

Separating an object from another/ areas from another

Question 5

Structuralism

Answer 5

Proposed by Wilhelm Wundt
one of the earliest approaches to understanding the organisation of individual elements to form perception of an object

Question 6

Sensations

Answer 6

Elementary process that occurs in response to stimulation of the senses

Question 7

What is perception according to structuralists?

Answer 7

Result of individual sensations combining
Like atoms adding up to create complex molecules

Question 8

What was the issue Gestalt psychologists had with this idea of perception?

Answer 8

Perceptions aren‘t just the summation of sensations

Question 9

Stroboscopic effect

Answer 9

Rapidly alternating two images produces illusion of movement
-> there is however nothing actually moving

Question 10

When does the stroboscopic effect occur?

Answer 10

When one light flashes followed by period of darkness and the flashing of another light in another location

Question 11

Why dont we see the period of darkness?

Answer 11

Perceptual system adds perception of an object moving

Question 12

Which conclusions did the stroboscopic effect lead to?

Answer 12

1) Perception cant be sum of individual sensations -> senses arent being stimulated
2) Whole is different to sum of parts -> perception of movement created without movement being present

Question 13

What is the illusory contour effect?

Answer 13

Three Pac-man like objects create perception of triangle
-> no physical edges stimulating visual receptors
=> perception of triangle can‘t be sum of sensations

Question 14

What was the focus of Gestalt psychologists?

Answer 14

How are individual sensations or elements organised

Question 15

What are the principles of perceptual organisation used for (in general)?

Answer 15

Explain how elements in a scene are perceived
Explore mental processes that help assume things about environment while perceptions are created
-> bring order and coherence out of potentially confusing stimuli

Question 16

The most relevant laws of perceptual organisation

Answer 16

Principle of pragnanz
Principle of good continuation
Principle of similarity
Principle of proximity
Principle of common fate
Principle of closure
Principle of symmetry

Question 17

Principle of Prägnanz

Answer 17

aka principle of simplicity
Most fundamental/ over-arching principle
Tendency to perceive simplest possible configuration of individual elements
(E.g. olympic rings)

Question 18

Principle of good continuation

Answer 18

Elements that follow smooth, uninterrupted lines are grouped together as whole object or group of objects

Question 19

Principle of similarity

Answer 19

Similar things appear to be grouped together

Question 20

Principle of proximity

Answer 20

Elements close together are likely to be perceived as one unit

Question 21

Principle of common fate

Answer 21

Objects moving in same direction perceived as one unit

Question 22

Principle of closure

Answer 22

Tendency to group individual elements of fragmented or incomplete objects together
-> to perceive whole objects
Objects perceptually closed

Question 23

Principle of symmetry

Answer 23

Elements that are symmetrical to each other tend to be perceived as unified group

Question 24

Which additional principles were added later?

Answer 24

Principle of common region
Principle of uniform connectedness

Question 25

Principle of common region

Answer 25

Palmer 1992 Elements within same region or space appear to be grouped together

Question 26

Principle of uniform connectedness

Answer 26

Palmer& Rock 1994 Group of connected objects with constant property are perceived as single unit

Question 27

What helps with understanding segregation?

Answer 27

Studying the properties of figure ground

Question 28

The Figure-ground problem

Answer 28

Involves figure (object) and the ground (background)

Question 29

Why are perceptions alternated in an ambiguus picture involving the figure-ground problem?

Answer 29

Its impossible to hold both perceptions at same time

Question 30

How does the fact that we alternate our perceptions prove the constructive nature of perception?

Answer 30

If we only engaged in bottom-up processing we would always experience the same perception

Question 31

Which characteristics does the perceived figure have in comparison to the ground?

Answer 31

Distinct form/ shape Figure perceived as in front of ground -> ground extends behind figure Border ownership -> contour separating figure and ground belongs to figure

Question 32

What did Vecera et al. prove?

Answer 32

Areas lower in visual field are more likely to be perceived as figure than other areas of visual field

Question 33

Vecera et al. Experiment

Answer 33

Subjects shown image (~150ms) -> quickly decide which area was figure

Question 34

Results of Vecera et al. experiment

Answer 34

Image presented in upper-lower configuration -> subjects more likely to judge lower area as figure Image presented in left-right configuration -> equally likely to judge left or right area as figure

Question 35

Peterson & Salvagio

Answer 35

Proved that convex regions are more likely to be perceived as figures than concave regions

Question 36

Peterson & Salvagio experiment

Answer 36

Visual display presented -> decide whether red dot was „on“ or „off“ perceived figure -> subjects judged convex regions to be figure 89% of trials

Question 37

The impact of gestalt psychology on cognitive psychology

Answer 37

Almost all principles of organisation concerning grouping and segregation have stood up to research and are considered valid

Question 38

What was the issue with Gestalt psychologists and their theories?

Answer 38

Descriptions of perceptual effects largely without explanations of how they occur Deemphasised importance of past experience, knowledge and learning => principles of organisation innate concepts that over-ride experience and knowledge

Question 39

How did Wertheimer „prove“ that innate concepts dominate knowledge?

Answer 39

Figure A -> perceived as W on top of M Figure B -> not perceived as letters => principle of good continuation dominates knowledge when creating perception

Question 40

What did Barense at al. prove in 2012 regarding the figure-ground segregation?

Answer 40

Figure ground relation depends on past experience and knowledge

Question 41

How did Barense et al. prove that figure-ground segregation relies on knowledge?

Answer 41

Familiar and unfamiliar objects shown to healthy controls and amnesia patients -> healthy controls judged regions of images to be figure more often when said regions were familiar objects -> amnesic patients showed no difference

Question 42

What is a scene schema?

Answer 42

The knowledge of what a specific context contains

Question 43

What are semantic regularities?

Answer 43

Characteristics we associate with specific contexts

Question 44

How did Palmer demonstrate that the knowledge of scene schemas can influence our perception of objects?

Answer 44

Subjects presented a scene (e.g. kitchen) Rapidly presented visual objects which needed to be identified quickly Subjects correctly identified loaf of bread 80% of the time (belongs to kitchen scene schema) Objects that didn‘t belong to scene schema only identified 40% of the time => knowledge of what kitchen contains seemed to help participants perceive objects

Question 45

What are perceptual illusions useful for?

Answer 45

Demonstrate how we perceive objects Suggest that information detected isnt necessarily what we perceive

Question 46

What is an example for a perceptual illusion?

Answer 46

Illusory contour effect: perception of triangle suggests what we are somehow constructing the image of a triangle

Question 47

Müller Lyer illusion

Answer 47

Right vertical line perceived as longer than left line even though they are the same length Constructed perception: right line perceived as longer, even though visual receptors detect lines of identical length

Question 48

What did Gregory suggest in the context of the Müller-Lyer illusion?

Answer 48

Perceptual system confused because it misapplies size constancy scaling

Question 49

What does size constancy scaling help us with?

Answer 49

Maintaining stable perception of objects regardless of distance

Question 50

How does size constancy scaling confuse us in the Müller-Lyer illusion?

Answer 50

Fins of left line look like exterior corner of a room Fins of right line look like interior corner of a room ->exterior corners stick out towards us while interior corners recede away -> right line appears further away than left line => we think it should be relatively bigger

Question 51

Ponzo illusion

Answer 51

Converging vertical lines appear to give depth information -> top of lines look further away than bottom lines => objects placed at top of lines appear further away and thus bigger than objects at bottom of lines

Question 52

Why was Gregory‘s explanation of Müller-Lyer illusion challanged?

Answer 52

Same perceptual effect occurs if image contains no obvious cues for depth or distance