chapter 5: perceiving objects and scenes

Question 1

what is the process of object recognition

Answer 1

detecting objects in an image and matching those objects with existing, stored representations of what those objects are

Question 2

what is the inverse projection problem

Answer 2

task of determining the object responsible for a particular image on the retina

Question 3

define viewpoint invariance

Answer 3

ability to recognize an object seen from different viewpoints

Question 4

what are the three problems machines face when perceiving objects

Answer 4

1. inverse projection problem (ex. shadow illusion)
2. objects can be hidden or blurred
3. objects are often viewed from different angles

Question 5

define perceptual organization

Answer 5

process by which elements in a person’s visual field become perceptually grouped and segregated to create a perception

Question 6

what are the two components involved in perceptual organization?

Answer 6

• grouping: visual scene are “put together” into coherent units or objects
• segregation: separating one area or object from another

Question 7

define structuralism

Answer 7

sensations combine to create complex perceptions

Question 8

what is apparent movement

Answer 8

although movement is perceived, nothing is actually moving

Question 9

what are the two conclusions drawn from the phenomenon of apparent movement

Answer 9

1. apparent movement can’t be explained by sensation alone
2. the whole is different than the sum of its parts, because the perceptual system creates the perception of movement where there actually is none

Question 10

what are illusory contours

Answer 10

illusion that there are physical edges present when there are none

Question 11

what are gestalt principles of perceptual organization

Answer 11

1. principle of good continuation
2. principle of good figure
3. principle of similarity
4. principle of proximity
5. principle of common fate
6. principle of common region
7. principle of uniform connectedness

Question 12

what is reversible figure-ground

Answer 12

when the front and the background can be alternated

Question 13

what are some properties of figure and ground

Answer 13

1. figure is more “thinglike”
2. figure is in front of ground
3. ground is seen as unformed material, without a specific shape, and seems to extend behind the figure
4. border ownership

Question 14

name the figural cues that determine figure-ground

Answer 14

1. lower areas in viewfield are more likely to be perceived as figure
2. convexity
3. symmetry
4. smaller region

Question 15

describe the gestalt ideas about the role of meaning and past experience in determining figure-ground segregation

Answer 15

• segregation of figure from the ground
• figure must stand out from the ground before it can be recognized and assigned a meaning

Question 16

describe gibson and peterson’s experiment that showed that meaning can play a role in figure-ground segregation

Answer 16

• black figure that looked like a standing women on white background
• when figure flipped upside down, Ps were less likely to see that area as being the figure
  conclusion: since meaningfulness influences the assignment of an area as figure, process of recognition must be occurring before or at the same time as figure segregation

Question 17

define the recognition by components theory (RBC)

Answer 17

objects are comprised of individual geometric components called geons, and we recognize objects based on the arrangement of those geons

Question 18

According to Biederman, what are examples of geons and how many are there

Answer 18

three-dimensional shapes like pyramids, cubes and cylinders
- 36 different geons that can be assembled to form different objects

Question 19

why does the RBC theory account for viewpoint invariance

Answer 19

because whether you see an object from the side or from the front, it is still comprised of the same geons, so it should still be recognized as the same object

Question 20

what are 3 aspects that the RBC theory could not explain

Answer 20

1. doesn’t account for grouping or organization like the Gestalt principle
2. some objects can’t be represented by assemblies of geons (clouds)
3. doesn’t allow for distinguishing between objects within a given category

Question 21

what is the definition of a scene

Answer 21

view of a real-world environment that contains
1. background elements
2. multiple objects that are organized in a meaningful way relative to each other and to the background

Question 22

define what the gist of a scene is

Answer 22

being able to identify important properties of most scenes after viewing them for only a fraction of a second

Question 23

what is the phenomenon called persistence of vision

Answer 23

the perception of a visual stimulus continues for about 250 ms after the stimulus is extinguished

Question 24

how can persistence of vision be eliminated

Answer 24

by presenting a masking stimulus, a random pattern that covers the original stimulus

Question 25

what enables observers to perceive the gist of a scene. name 5 of them

Answer 25

global image features: information that can be perceived rapidly and is associated with specific types of scenes
- degree of naturalness
- degree of openness
- degree of roughness
- degree of expansion
- color

Question 26

what are regularities in the environment

Answer 26

characteristics of the environment that are frequent, such as:
- the color blue being associated with an open sky
- landscapes are often green and smooth
etc

Question 27

what are the two types of regularities and explain them

Answer 27

physical: regularly occurring physical properties of the environment
semantic: characteristics associated with activities that are common in different types of scenes

Question 28

define scene schema

Answer 28

knowledge of what a given scene typically contains

Question 29

describe Palmer’s experiment of scene schema

Answer 29

1. presents context scene
2. presents target objects, one that fits with scene and others that don’t
3. asked Ps to identify target objects.
   - 80% time can identify object that fits with scene
   - 40% time can identify object that doesn’t fit with scene

Question 30

what is the “multiple personalities of a blob”

Answer 30

a blob can be perceived as different objects depending on its orientation and the context within which it is seen

Question 31

define retinal ambiguity

Answer 31

particular pattern of stimulation on the retina can be caused by many different possible objects in the environment

Question 32

what is the likelihood principle

Answer 32

we perceive the object that is most likely to have caused the pattern of stimuli we have received

Question 33

what is Helmholtz’s theory of unconscious inference

Answer 33

our perceptions are the result of unconscious assumptions, or inferences, that we make about the environment

Question 34

what is the Bayesian inference and what are the two factors that determine it

Answer 34

our estimate of the probability of an outcome is determined by
1. prior probability
2. likelihood: extend to which the available evidence is consistent with the outcome

Question 35

define predictive coding

Answer 35

theory that describes how the brain uses our past experiences to predict what we will perceive

Question 36

according to predictive coding, what happens when new incoming visual input reaches the receptors?

Answer 36

it is sent upward in the visual system, and is compared to the predictions flowing downward from higher levels.
- brain determines whether what we’re seeing matches with what we expect to be seeing

Question 37

when is the lateral occipital complex (LOC) activated

Answer 37

when looking at objects, regardless of their size, orientation, position or other basic feature

Question 38

true or false? the LOC can differentiate between types of objects

Answer 38

false

Question 39

what is the role of the fusiform face area (FFA)

Answer 39

specialized to respond to faces

Question 40

what is prosopagnosia

Answer 40

inability to recognize faces

Question 41

when is the extrastriate body area (EBA) activated

Answer 41

activated by pictures of bodies and parts of bodies, but not by faces or other objects

Question 42

what is the amygdala responsible for

Answer 42

emotional reactions and familiarity

Question 43

what is the frontal lobe responsible for

Answer 43

evaluation of attractiveness

Question 44

what is the superior temporal sulcus (STS) responsible for

Answer 44

gaze direction, mouth movements, and general face movements

Question 45

explain what neural representation is

Answer 45

a representation that goes beyond modules.
combination of modular and distributed representation appears to underlie our perception of objects and faces

Question 46

what is the function of the parahippocampal place area (PPA)

Answer 46

responds to places, not objects or faces
spatial layouts

Question 47

what does the spatial layout hypothesis entail about the PPA/PHC

Answer 47

PPA/PHC responds to the surface geometry or geometric layout of a scene

Question 48

define binocular rivalry

Answer 48

observer perceives either the left-eye image or the right-eye image, but not both at the same time

Question 49

what is neural mind reading

Answer 49

use of neural response to determine what a person is perceiving or thinking

Question 50

describe the neural mind-reading procedure

Answer 50

1. measure brain’s response to different stimuli to determine relationship between stimulus and voxel pattern
2. creates decoder
3. decoder is tested by measuring brain activation as a person is looking at different stimuli

Question 51

what is the expertise hypothesis

Answer 51

idea that our proficiency in perceiving faces, and the large face response in the FFA, can be explained by the fact that we have become “experts” in perceiving faces since we’ve been exposed to them for our entire lives