Chapter 10

Question 1

Absolute disparity

Answer 1

The visual angle between the images of an object on the two retinas. When images of an object fall on corresponding points, the angle of disparity is zero. When images fall on non corresponding points, the angle of disparity indicates the degree of non correspondence

Question 2

Accretion

Answer 2

A cue that provides information about the relative depth of two surfaces. Occurs when the father object is uncovered by the nearer object due to sideways movement of an observer relative to the objects. A cue that provides information about the relative depth of two surfaces. Deletion occurs when a farther object is due to sideways movement of an observer relative to the objects.

Question 3

Ames Room

Answer 3

A distorted room, first built by adelbert Ames, that creates an erroneous perception of the sizes of people in the room. The room is constructed so that two people at the far wall of the room appear to stand at the same distance from an observer. In actuality, one of the people is much farther away than the other

Question 4

Angle of disparity

Answer 4

The visual angle between the images of an object on the two retinas. When images of an object fall on corresponding points, the angle of disparity is zero. When images fall on non corresponding points, the angle of disparity indicates the degree of noncorrespondence.

Question 5

Angular size contrast theory

Answer 5

Explanation of the moon illusion that states that the perceived size of the moon is determined y the sizes of the objects that surround it. According to this idea, the moon appears small when it is surrounded by large objects, such as the expanse of the sky when the moon is overhead.

Question 6

Apparent distance theory

Answer 6

An explanation of the moon illusion that is based on the idea that the horizon moon, which is viewed across the filled space of the terrain, should appear farther away than the zenith moon, which is viewed through the empty space of the sky. This theory states because the horizon and zenith moons have the same visual angle but are perceived to be at different distances, the farther appearing horizon moon should appear larger.

Question 7

Atmospheric perspective

Answer 7

A depth cue. Objects that are farther away look more blurred and bluer than objects that are closer because we look through more air and particles to see them

Question 8

Binocular depth cells

Answer 8

A neuron in the visual cortex that responds best to stimuli that fall on points separated by a specific degreee of disparity on the two retinas. Also called disparity-selective cell

Question 9

Binocularly fixate

Answer 9

Directing the two fovea’s to exactly the same spot

Question 10

Conflicting cues theory

Answer 10

A theory of visual illusions. States that our perception of line length depends on a an integration of the actual line length and overall figure length

Question 11

Correspondence problem

Answer 11

The problem faced by he visual system, which must determine which parts of the images in the left and right eyes correspond to one another. Another way of stating the problem is: How does the visual system match up the images in the two eyes? This matching of the images is involved in determining depth perception using the cue of binocular disparity

Question 12

Corresponding retinal points

Answer 12

The points on each retina that would overlap if one retina were slid on top of the other. Receptors at corresponding points send their signals to the same location in the brain.

Question 13

Crossed disparity

Answer 13

Disparity that occurs when one object is being fixated, and is therefore on the Homoptera and another object is located in front of the Homoptera closer to the observer.

Question 14

Cue approach to depth perception

Answer 14

The approach to explaining depth perception that focuses on identifying information in the retinal image that is correlated with depth in the scene. Some of the depth cues that have been identified are overlap, relative height, relative size, atmospheric perspective, convergence, and accommodation

Question 15

Deletion

Answer 15

A cue that gives information about the relative depth of two surfaces. Deletion occurs when a farther object is covered by a nearer object due to sideways movement of an observer relative to the objects (Accretion)

Question 16

Disparity-selective cell

Answer 16

A plot of neurons response versus the degree of disparity of a visual stimulus. The disparity to which a neuron responds best is an important property of disparity selective cells, which are also called binocular depth cells

Question 17

Disparity tuning curve

Answer 17

A plot of a neurons response versus the degree of disparity of a visual stimulus .The disparity to which a neuron responds best is an important property of disparity selective cells, which are also called binocular depth cells.

Question 18

Echolocation

Answer 18

Locating objects by sending out high frequency pulses and sensing the echo created when these pulses are reflected from objects in the environment. Echolocation is used by bats dolphins.

Question 19

Emmert’s Law

Answer 19

A law stating that the size of an afterimage depends on the distance of the surface against which the afterimage is viewed. The farther away the surface, the larger the afterimage appears.

Question 20

Familiar size

Answer 20

A depth cue in which judgement of distance is based on knowledge of the sizes of objects. Epstein coin experiment illustrated the operation of the cue of familiar ice by showing that th e relative sizes of the coins influenced perception of the coins distance.

Question 21

Frontal eyes

Answer 21

Eyes located in front of the head, so the views of the two eyes overlap

Question 22

Horopter

Answer 22

An imaginary surface that passes through the point of fixation. Images caused by a visual stimulus on this surface fall on corresponding points on the two retinas

Question 23

Lateral eyes

Answer 23

Eyes located on opposite sides of an animal’s head, as in the pigeon and the rabbit, so the views of the two eyes do not overlap or overlap only slightly.

Question 24

Misapplied size constancy scaling

Answer 24

A principle, proposed by Richard Gregory, that when mechanisms that help maintain size constancy in the three-dimensional world are applied to two- dimensional pictures, an illusion of size sometimes resluts.

Question 25

Monocular cue

Answer 25

Depth cue- such as overlap, relative size, relative height, familiar size, linear perspective, movement parallax, and accommodation- that can work when we use only one eye.

Question 26

Moon illusion

Answer 26

An illusion in which the moon appears to be larger when it is on or near the horizon than when it is high in the sky.

Question 27

Motion parallax

Answer 27

A depth cue. As an observer moves, nearby objects appear to move rapidly across the visual field whereas far objects appear to move more slowly.

Question 28

Muller-Lyer illusion

Answer 28

An illusion in which two lines of equal length appear to be of different lengths because of the addition of fins to the ends of the lines.

Question 29

No corresponding points

Answer 29

Two points, one on each retina, that would not overlap if the retinas were slid onto each other. Also called disparate points.

Question 30

Occlusion

Answer 30

Depth cue in which one object hides or partially hides another object from view, causing the hidden object to be perceived as a being farther away. A monocular depth cue.

Question 31

Oculomotor cue

Answer 31

Depth cue that depends on our ability to sense the position of our eyes and the tension in our eye muscles. Accommodation and convergence are oculomotor cue.

Question 32

Perspective convergence

Answer 32

The perception that parallel lines in the distance converge as distance increases

Question 33

Pictorial cue

Answer 33

Monocular depth cue, such as overlap, relative height, and relative size, that can be depicted in pictures .

Question 34

Ponzu illusion

Answer 34

An illusion of size in which two objects of equal size that are positioned between two converging lines appear to be different in size. Also called the railroad track illusion

Question 35

Random-dot stereogram

Answer 35

A pair of stereoscopic images made up of random dots. When one section of this pattern is shifted slightly in one direction, the resulting disparity causes the shifted section to appear above or below the rest of the pattern when the patterns are viewed in a stereoscope

Question 36

Relative disparity

Answer 36

The difference between two objects absolute disparities

Question 37

Relative height

Answer 37

A monocular depth cue. Objects that have bases below the horizon appear to be farther away when they are higher in the field of view. Objects that have bases above the horizon appear to be farther away when they are lower in the field of view.

Question 38

Relative size

Answer 38

A cue for depth perception. When two objects are of equal size, the one that is farther away will take up less of the field of view.

Question 39

Size constancy

Answer 39

Occurs when the size of an object is perceived to remain the same even when it is viewed from different distances.

Question 40

Size distance scaling

Answer 40

A hypothesized mechanism that helps maintain size constancy by taking an objects perceived distance into account. According to this mechanism, an objects perceived size, s, is determined by multiplying the size of the retinal image, R, by the objects perceived distance, D.

Question 41

Stereopsis

Answer 41

The impression of depth that results from binocular disparity— the difference in the position of images of the same object on the retinas of the two eyes.

Question 42

Stereoscope

Answer 42

A device that presents pictures to the left and the right eyes so that the binocular disparity a person would experience when viewing an actual scene is duplicated. The result is a convincing illusion of depth.

Question 43

Stereoscopic depth perception

Answer 43

The perception of depth that is created by input from both eyes.

Question 44

Stereoscopic vision

Answer 44

Two-eyed depth perception involving mechanisms that take into account differences in the images formed on the left and right eyes.

Question 45

Strabismus

Answer 45

Misalignment of the eyes, such as crossed eyes or walleyes, in which the visual system suppresses vision in one of the eyes to avoid double vision, so the person sees the world with only one eye at a time.

Question 46

Texture gradient

Answer 46

The visual pattern formed by a regularly textured surface that extends away from the observer. This pattern provides information for distance because the elements in a texture gradient appear smaller as distance from the observer increases.

Question 47

Uncrossed disparity

Answer 47

Disparity that occurs when one object is being fixated, and is therefore on the horopter, and another object is located behind the horopter, farther from the observer.

Question 48

Visual angle

Answer 48

The angle of an object relative to an observers’ eyes. This angle can be determined by extending two lines from the eye— one to one end of an object and the other to the other end of the object. Because an objects visual angle is always determined relative to an observer, its visual angle changes as the distance between the object and the observer changes.