Final: Object Perception

Question 1

What are visual illusions?

Answer 1

Erroneous perception due to incomplete, ambiguous, or contradictory visual information.

Question 2

Many of the “geometric” illusions involve ambiguous or misleading _____________.

Answer 2

monocular depth cues

Question 3

What are 4 famous examples of geometric illusions?

Answer 3

1) Muller-Lyer illusion
2) Hering Illusion
3) Wundt Illusion
4) Zollner Illusion

Question 4

If 2 objects create the same retinal image size, but one is believed to be farther away, the object that is believed to be farther will be perceived as _____.

Answer 4

Larger

Question 5

Describe reversible or multistable perception. Give example.

Answer 5

They are a psychophysical phenomenon in which one unique interpretation alternates spontaneously every few seconds between two or more interpretations of the same sensory input.

Example: An image of duck, but you may see a rabbit, or both changing back and forth.

Question 6

True or false:

If you change the background, it can change what you perceive as the object.

Answer 6

True;
an example of this is the vase with the dark face outlines. If nothing in background, you could perceive the faces as the object. If putting the vase in light in a room, you’d view the vase as object and not the faces.

Question 7

Feature analysis has been labeled “________”. What does this mean?

Answer 7

Bottom up

This means it starts with a sensation and then gets sent to the brain.

Question 8

What are two subgroups of feature analysis?

Answer 8

Structuralism

Visual “alphabet” / “geons”

Question 9

Global Processing has been labeled “_______”. What does this mean?

Answer 9

The brain already has certain information in mind and it brings that information to the situation when looking at the object.

Question 10

One subgroup of global processing (top down approach). What does it try to explain?

Answer 10

Gestalt Organizing Principles.

It tries to explain why an object may seem to be more than the sum of its parts.

Question 11

What are computational models?

Answer 11

Computer models that stimulate something about vision and it tries to match how human vision works.

Question 12

What are 3 theoretical approaches to object perception?

Answer 12

1) Feature Analysis (Bottom Up)
2) Global Processing (Top Down)
3) Computational Models

Question 13

Describe Structuralism theory. What are some characteristics taken into account in this theory? What are some problems with this theory?

Answer 13

Analytical Introspection- Identify the smallest set of “primary sensations” (visual sensations) necessary to uniquely identify any object.

The object characteristics taken into account are color, size, shape, texture etc.

Problems:
-Lack of agreement upon which sensations are
(or are not) “primary”

-Explosion of the number of “primary sensations” 
(> 40,000) that were identified

Question 14

What is an example of structuralism?

Answer 14

Example:
Many dots on a paper to form an image of a face.

(a number of sensations adds up to create our perception)

Question 15

What is feature analysis?

Answer 15

Perceptual identification of an “object” by the simpler components comprising it. (Distinctive features help distinguish patterns as different.)

Question 16

Preference of _________ for orientation used to support feature analysis theories.

Answer 16

Cortical cells

Question 17

Describe the 3 “demons” for Oliver Selfridge’s Pandemomonium model.

Answer 17

Feature ‘demons’ find vertical lines, acute angles, etc.

Cognitive ‘demons’ (one for each letter) have ideas about the features of their letters.

Decision ‘demon’ identifies the
letter based on which cognitive
demon ‘yells the loudest’.

Question 18

What is a problem with feature analysis theory?

Answer 18

It does not explain how features of a pattern are
 organized.

Question 19

What did Beiderman believe with his variation of recognition by components theory? Has research. supported his theory? What is a problem with this theory?

Answer 19

He assumed Recognition of 3D objects involves the use of 24 different 3D shapes (GEONS–for Geometrical Ions)‏

Research has generally supported this theory.

Problem: People poor at identifying objects in unusual angles or orientations

Question 20

What are geons? What is the theory called that geons are associated with?

Answer 20

Geometric Icons.

• Non-accidental features’, so they
should be equally recognizable regardless of
orientation.
• Structures composed of geons, then, should also be ‘viewpoint invariant’.
• Certain neurons in IT of monkey (equivalent
to LOC of humans) respond well to basic shapes.

Theory of “Recognition by Components”

Question 21

What does the Kanizsa Figure tell us?

Answer 21

Brain perceives more than the sum of the sensory parts.

we can see a 2D outline of house but the objects given looked like man pac man figures

Question 22

The perceptual whole is (more than/less than) the sum of its sensory parts.

Answer 22

More than

Question 23

Explain Bottom Up process. Example of this.

Answer 23

Information processed at the lower levels without
 influence from higher levels.

Example: learning to read progresses from children learning the parts of language to understand whole text

Question 24

Explain Top Down process

Answer 24

Information at the higher levels (via guessing, 
 predicting) may influence processing at the lower levels

Question 25

What are the 3 basic components of Bottom up process?

Answer 25

1) Features: Information on retina is processed in different areas of visual cortex. They work together to identify particular features. Then, they are passed on to the next stage.
2) Patterns: The features detected in previous stage are combined to form complex patterns. Different patterns built on top of
 the elementary features begin to emerge.
3) Objects: The sets of patterns are filtered out into reduced set of visual objects that retain information to the scene. These visual objects are stored in a so
 called visual working memory that is not capable of maintaining more
than three objects at a time.

Question 26

What is the top down process driven by? Give example.

Answer 26

Driven by attention and a goal.

Example: You want to find a pineapple within a group of fruit.

The neurons specialized in detecting the features & 
 patterns associated with a pineapple will have their 
 sensitivity enhanced (and the neurons that respond to “non-
pineapple” features will be actively inhibited).

Question 27

Describe the Gestalt (shape) Principles of Visual Perception

Answer 27

His principles suggest we see objects as well organized patterns rather than separate components. Based on a concept called “grouping”

“The whole is greater than the sum of it’s parts.”

Question 28

Describe the Gestalt organizing principle called Pragnanz (good figure).

Answer 28

Every stimulus is interpreted in its simplest form.

“Keep it simple stupid”

Question 29

Describe the Gestalt organizing principle called Similarity. What characteristics can be grouped base on similarity?

Answer 29

Similar things are grouped together.

You can group things based on color, size, orientation, and aspects of shape.

Question 30

Describe the Gestalt organizing principle called Good Constitution.

Answer 30

Connected points resulting in straight
or smooth curves belong together.

Question 31

Describe the Gestalt organizing principle called Proximity. Give example.

Answer 31

Items near each other are more likely to group together than items more widely separated.

Example: Vertical rows vs. Horizontal rows. Based on spacing it determines the orientation of the rows.

Question 32

Describe the Gestalt organizing principle called Common region.

Answer 32

If two features appear to be part of the same larger region, they will be grouped
together.

Question 33

Describe the Gestalt organizing principle called Connectedness.

Answer 33

If two items are connected, then they probably belong together.

Question 34

Describe the Gestalt organizing principle called Context or Meaning.

Answer 34

Things form groups if they appear meaningful or familiar.

Question 35

Describe the Gestalt organizing principle called Closure.

Answer 35

We tend to see complete figures even when 
 part of the information is missing.

Question 36

Describe the Gestalt organizing principle called Synchrony.

Answer 36

Elements changing at the same time are
seen as belonging together.

Question 37

Conclusion of Gestalt Organizing Principles

Answer 37

Common Fate:

• elements of a scene that share the same direction and speed of motion tend to be perceived as a unit.
• Spatial structure from temporal structure

Question 38

_________ (meaning) and ________ (order) clues are two other types of contextual clues that also help us to interpret the meaning of missing, scrambled, or displaced text.

Answer 38

Semantic; syntactic

Question 39

Describe the Popout concept.

Answer 39

Give an image to person and ask if anything pops out to them.

If something immediately pops out to them, it is a bottom up process. If it takes a while for it to pop out for them and they have to look for it, it is a top down process.

Question 40

Describe the response from a Popout of a bottom up (Pre-attentive) result.

Answer 40

• Rapid “popout”
• Biases attention to novel stimuli
• Info. processed in different, parallel “channels“
• Does not require conscious thought; attention caused by an external stimulus.

Question 41

Describe the response from a Popout of a Top-Down (Attentive) result.

Answer 41

• Slow “popout”
• Requires serial search (conscious thought), analysis of details
• Info. processed within the same “channel

Question 42

Search times can be influenced by ________.

Answer 42

Set size; smaller the objects, the harder to find a pop-out.

Question 43

Describe the feature-integration theory of object perception.

Answer 43

Different visual features
are coded in parallel, in 
 separate feature maps.

Question 44

What is a conjunction search? Is this more or less difficult?

Answer 44

When you have observer look for two things at the same time (looking for blue and red circles). Visual search becomes more difficult because attentional spotlight can only be deployed locally. The viewer then must shift attention to other places to keep searching.

Question 45

What is a serial search? When does the search stop? If target is present, on average, how many items needed to be examined before we find object? If object is absent, how many items will be examined?

Answer 45

Assumes items are examined one items at a time. Search ends when the target is found or all items have been examined. On average we would have to look at half the items to find the object.

If object is absent, all objects would have been examined.

Question 46

What is “The Binding Problem”?

Answer 46

How can different visual characteristics of an object be “held together”?

How can a bouncing blue ball keep its shape, color, and “ballness” together while moving across one’s visual field?