From visual shapes to objects

Question 1

Low-level (early) vision

Answer 1

extracting basic features from the image (e.g., dots in retina and lines in V1)

Question 2

Mid-level (middle) vision

Answer 2

a stage of visual processing that comes after early vision and before object recognition and scene understanding (high-level vision)

Question 3

Perceptual organization

Answer 3

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

Question 4

Grouping

Answer 4

the process by which elements in a visual scene are grouped into coherent units or objects

Question 5

Segregation

Answer 5

the process of separating one area or object from another

Question 6

recognition-by-components (RBC) theory

Answer 6

objects consisted of geometric component called geons. We recognize objects on the basis of the arrangement of these geons. Geons are a set of basic geometric objects that are sufficient to constitute any object

Question 7

holistic processing

Answer 7

processing based on analysis of the entire object or scene (instead of based on adding together a set of smaller parts of features). This type of processing is evident in face recognition: faces are not recognized by recognizing features (e.g., eye, nose, and mouth) and then combining them into a face. Instead, faces are processed as a single object

Question 8

Illusory contours

Answer 8

contours that are perceived even though nothing changes from one side of the contour to the other

Question 9

Structuralism

Answer 9

a paradigm that comple perceptions are the sum of basic units of perception (e.g., color, orientation etc.). The presence of illusory contours challenge the structuralist view because there is no basic part representing the edge of an illusory contour

Question 10

Gestalt theory

Answer 10

states that the perceptual whole is more than the sum of its parts (opposite of structuralism)

Question 11

Gestalt grouping rules

Answer 11

a set of rules describing which elements in a picture tend to group together

Question 12

Contour completion

Answer 12

we tend to see similarly oriented lines as part of the same contour

Question 13

Principle of good continuation

Answer 13

2 points are likely to be grouped together if they seem to lie on the same straight or smoothly curving line. Lines tend to be seen in such a way as to follow the smoothest path

Question 14

Closure

Answer 14

the visual system prefers closed contours to open contours

Question 15

Texture segmentation

Answer 15

separating an image into regions of common texture properties

Question 16

Principle of similarity

Answer 16

image chunks that are similar to each other will be more likely to group together

Question 17

Principle of proximity

Answer 17

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

Question 18

Principle of common region

Answer 18

elements that are within the same region of space appear to be grouped together

Question 19

Principle of uniform connectedness

Answer 19

a connected region of the same visual properties (eg., lightness, color, texture, motion) is perceived as a single unit

Question 20

Parallelism

Answer 20

parallel contours are likely to be grouped together

Question 21

Symmetry

Answer 21

symmetrical regions are more likely to be grouped together

Question 22

Principle of Prägnanz

Answer 22

every stimulus pattern is seen in such a way that the resulting structure is as simple as possible

Question 23

Principle of common fate

Answer 23

objects that are moving in the same direction appear to be grouped together, e.g., a flock of birds all flying together is usually perceived as a single unit

Question 24

Inverse projection problem

Answer 24

the retinal image is ambiguous: any two-dimensional retinal image can be created by an infinite number of objects located at different distances

Question 25

Ambiguous figure

Answer 25

a visual stimulus that gives rise to 2 or more interpretations of its identity or structure

Question 26

Accidental viewpoint

Answer 26

a viewing position that produces some regularity in a visual image that is not present in the world (e.g., the sides of 2 independent objects lining up perfectly)

Question 27

Helmholtz's theory of unconscious inference

Answer 27

in the case of ambiguous retinal imates, we use likelihood principle to infer what is perceived.

Question 28

Likelihood principle

Answer 28

we perceive the object that is most likely to have caused the retinal image. This judgment results from a process called unconscious inference, in which our perceptions are the result of unconscious assumptions that we make about the environment

Question 29

Figure-ground assignment

Answer 29

the process of determining which regions of an image belong to a foreground object (figure) and which to the background (ground)

Question 30

Figural cues

Answer 30

cues within the image that determine which areas are perceived as figure and which as ground

Question 31

Surroundedness

Answer 31

if one region is entirely surrounded by another, it is likely that the surrounded region is the figure

Question 32

Size

Answer 32

the smaller region is likely to be the figure

Question 33

Symmetry

Answer 33

a symmetrical region is more likely to be seen as figure

Question 34

Parallelism

Answer 34

regions with parallel contours are more likely to be seen as figure

Question 35

Scene

Answer 35

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

Question 36

gist of a scene

Answer 36

a general description of the type of scene. People are able to perceive the gist of a scene in less than 1 second

Question 37

Global image features

Answer 37

features that can be perceived holistically and rapidly and are associated with specific types of scenes

Question 38

physical regularities

Answer 38

regularly occuring physical properties in the environment, e.g., there are more vertical & horizontal than oblique orientation in the environment

Question 39

light-from-above assumptions

Answer 39

we usually assume that light is coming from above, because sunlight and most articifical light does so

Question 40

semantic regularities

Answer 40

environmental properties associated with activities that are common in scenes

Question 41

scene schemas

Answer 41

schemas about what different scenes contain

Question 42

Relatability

Answer 42

the degree to which 2 line segments appear to be part of the same contour

Question 43

Nonaccidental features

Answer 43

a feature of an object that is not dependent on an accidental viewing position of the observer

Question 44

Global superiority effect

Answer 44

the properties of whole objects take precedence over the properties of object parts

Question 45

Extrastriate cortex

Answer 45

a set of visual areas of V1- V2, V3, V4 & V5. From V1, the dorsal (where/how) pathway does to parietal lobe. It plays a role in the processing of object location and generating actions to interact with objects. The ventral (what) pathway goes to the temporal lobe and is important for object recognition

Question 46

Inferotemporal (IT) cortex

Answer 46

contains cells with large receptive fields that respond to specific stimuli

Question 47

Free-forward process

Answer 47

a computation that is performed one step after the other, without need for feedback from a later stage to an earlier stage (e.g., one-way information transmission retina-LGN-V1-extrastriate)

Question 48

Reverse-hierarchy theory

Answer 48

argues that feed-forward processes can provide a crude impression of objects in the world based on activity in higher-level visual cortex

Question 49

Predictive coding theory

Answer 49

our brain's predictions about the world are represented at higher levels of the visual system

Question 50

border ownership

Answer 50

when an object is sitting on a background, the edges defining the border between object & background belong to the object

Question 51

V2

Answer 51

cells that respond to illusory contours

Question 52

V4

Answer 52

respond to more complex attributes, but the perfect set of stimuli for them has not been determined yet

Question 53

Fusiform face area (FFA)

Answer 53

contains neurons that respond to faces. It has been proposed that different parts of the FFS are important for different aspects of face processing: a two-pathway model has been proposed

Question 54

Lateral occipital cortex (LOC)

Answer 54

an area within the ventral visual pathway that contains neurons that respond to any kind of object but not to texture or scrambled object parts

Question 55

Parahippocampal place area (PPA)

Answer 55

contains neurons that respond to indoor and outdoor scenes

Question 56

Extrastriate body area (EBA)

Answer 56

contains neurons that responds strongly to images of bodies and body parts

Question 57

Visual word form (VWFA)

Answer 57

contains neurons that respond strongly to written words more than any other visual stimuli - faces, objects, houses, even Arabic numerals

Question 58

Pure alexia

Answer 58

inability to recognize words, even though the patient and listen to, speak and write language. It can be caused by damage to the VWFA

Question 59

Neuronal recycling hypothesis

Answer 59

cultural inventions always involve the recycling of older cerebral structures that had other evolutionary-determined functions, but manage to shift toward a novel cultural use

Question 60

Mirror invariance

Answer 60

the ability to recognize mirror-symmetrical images