Definitions Part 2

Question 1

Binocular Rivalry

Answer 1

A situation in which one image is presented to the left eye and a different image is presented to the right eye, and perception alternates back and forth between the two images.

Question 2

Border ownership

Answer 2

When two areas share a border, as occurs in figure–ground displays, the border is usually perceived as belonging to the figure.

Question 3

Figure

Answer 3

When an object is seen as separate from the background (the “ground”), it is called a figure. See also figure–ground segregation.

Question 4

Figure-ground segregation

Answer 4

The perceptual separation of an object from its background

Question 5

Gestalt Psychology

Answer 5

An approach to psychology that developed as a reaction to structuralism. The Gestalt approach proposes principles of perceptual organization and figure–ground segregation and states that “the whole is different than the sum of its parts.”

Question 6

Gist of a scene

Answer 6

General description of a scene. People can identify most scenes after viewing them for only a fraction of a second, as when they flip rapidly from one TV channel to another. It takes longer to identify the details within the scene.

Question 7

Global image features

Answer 7

Information that may enable observers to rapidly perceive the gist of a scene. Features associated with specific types of scenes include degree of naturalness, degree of openness, degree of roughness, degree of expansion, and color.

Question 8

Ground

Answer 8

In object perception, the background is called the ground.

Question 9

Grouping

Answer 9

In perceptual organization, the process by which visual events are “put together” into units or objects.

Question 10

Illusory Contour

Answer 10

Contour that is perceived even though it is not present in the physical stimulus.

Question 11

Inverse projection problem

Answer 11

The idea that a particular image on the retina could have been caused by an infinite number of different objects. This means that the retinal image does not unambiguously specify a stimulus.

Question 12

Light from above assumption

Answer 12

The assumption that light usually comes from above, which influences our perception of form in some situations.

Question 13

Likelihood principle

Answer 13

The idea proposed by Helmholtz that we perceive the object that is most likely to have caused the pattern of stimuli we have received.

Question 14

Organizing principles

Answer 14

In Gestalt psychology, the rules that determine how elements in a scene become grouped together.

Question 15

Perceptual organization

Answer 15

The process by which small elements become perceptually grouped into larger objects.

Question 16

Perceptual segregation

Answer 16

Perceptual organization in which one object is seen as separate from other objects.

Question 17

Persistence of vision

Answer 17

A phenomenon in which perception of any stimulus persists for about 250 ms after the stimulus is physically terminated.

Question 18

Physical regularities

Answer 18

Regularly occurring physical properties of the environment. For example, there are more vertical and horizontal orientations in the environment than oblique (angled) orientations.

Question 19

Principle of common fate

Answer 19

A Gestalt principle of perceptual organization that states that things that are moving in the same direction appear to be grouped together.

Question 20

Principle of common region

Answer 20

A modern Gestalt principle that states that elements that are within the same region of space appear to be grouped together.

Question 21

Principle of good continuation

Answer 21

A Gestalt principle of perceptual organization that states that points that, when connected, result in straight or smoothly curving lines are seen as belonging together, and that lines tend to be seen in such a way as to follow the smoothest path.

Question 22

Principle of good figure

Answer 22

A Gestalt principle of perceptual organization that states that every stimulus pattern is seen in such a way that the resulting structure is as simple as possible. Also called the principle of pragnanz or the principle of simplicity.

Question 23

Principle of pragnaz

Answer 23

A Gestalt principle of perceptual organization that states that every stimulus pattern is seen in such a way that the resulting structure is as simple as possible. Also called the principle of good figure or the principle of simplicity.

Question 24

Principle of proximity

Answer 24

A Gestalt principle of perceptual organization that states that things that are near to each other appear to be grouped together. Also called the law of nearness.

Question 25

Principle of similarity

Answer 25

A Gestalt principle stating that similar things appear to be grouped together.

Question 26

Principle of simplicity

Answer 26

A Gestalt principle of perceptual organization that states that every stimulus pattern is seen in such a way that the resulting structure is as simple as possible. Also called the principle of good figure or the principle of pragnanz.

Question 27

Principle of uniform connectedness

Answer 27

A modern Gestalt principle that states that connected regions of a visual stimulus are perceived as a single unit.

Question 28

Regularities in the environment

Answer 28

Characteristics of the environment that occur regularly and in many different situations.

Question 29

Reversible figure-ground

Answer 29

A figure–ground pattern that perceptually reverses as it is viewed, so that the figure becomes the ground and the ground becomes the figure. The best-known reversible figure–ground pattern is Rubin’s vase–face pattern.

Question 30

Scene

Answer 30

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

Question 31

Segregation

Answer 31

The process of separating one area or object from another.

Question 32

Semantic encoding

Answer 32

A method for analyzing the patterns of voxel activation recorded from visual areas of an observer’s brain, based on the relationship between voxel activation and the meaning or category of a scene.

Question 33

Semantic regularities

Answer 33

Characteristics associated with the functions associated with different types of scenes. These characteristics are learned from experience. For example, most people are aware of the kinds of activities and objects that are usually associated with kitchens.

Question 34

Sensations

Answer 34

Elementary elements that, according to the structuralists, combine to create perceptions.

Question 35

Structural encoding

Answer 35

A method for analyzing the patterns of voxel activation recorded from visual areas of an observer’s brain, based on the relationship between voxel activation and structural characteristics of a scene, such as lines, contrasts, shapes, and textures.

Question 36

Structuralism

Answer 36

According to structuralism, a number of sensations (represented by the dots) add up to create our perception of the face. The approach to psychology, prominent in the late 19th and early 20th centuries, that postulated that perceptions result from the summation of many elementary sensations. The Gestalt approach to perception was, in part, a reaction to structuralism.

Question 37

Theory of unconscious inference

Answer 37

The idea proposed by Helmholtz that some of our perceptions are the result of unconscious assumptions that we make about the environment.

Question 38

Viewpoint invariance

Answer 38

The condition in which object properties don’t change when viewed from different angles. Responsible for our ability to recognize objects when viewed from different angles.

Question 39

Visual masking stimulus

Answer 39

A visual pattern that, when presented immediately after a visual stimulus, decreases a person’s ability to perceive the stimulus. This stops the persistence of vision and therefore limits the effective duration of the stimulus.

Question 40

Attention

Answer 40

The process of focusing on some objects while ignoring others. Attention can enhance the processing of the attended object.

Question 41

Attentional capture

Answer 41

Occurs when stimulus salience causes an involuntary shift of attention. For example, attention can be captured by movement.

Question 42

Autism

Answer 42

A serious developmental disorder in which one of the major symptoms is the withdrawal of contact from other people. People with autism typically do not make eye contact with others and have difficulty telling what emotions others are experiencing in social situations.

Question 43

Balint’s syndrome

Answer 43

A condition resulting from damage to a person’s parietal lobe. One characteristic of this syndrome is an inability to focus attention on individual objects.

Question 44

Binding

Answer 44

The process by which features such as color, form, motion, and location are combined to create our perception of a coherent object. Binding can also occur across senses, as when sound and vision are associated with the same object.

Question 45

Binding problem

Answer 45

The problem of how neural activity in many separated areas in the brain is combined to create a perception of a coherent object.

Question 46

Change blindness

Answer 46

Difficulty in detecting differences between two visual stimuli that are presented one after another, often with a short blank stimulus interposed between them. Also occurs when part of a stimulus is changed very slowly.

Question 47

Conjunction search

Answer 47

A visual search task in which it is necessary to search for a combination (or conjunction) of two or more features on the same stimulus to find the target. An example of a conjunction search would be looking for a horizontal green line among vertical green lines and horizontal red lines.

Question 48

Covert Attention

Answer 48

Attention without looking. Seeing something “out of the corner of your eye” is an example of covert attention.

Question 49

Dishabituation

Answer 49

An increase in looking time that occurs when a stimulus is changed. This response is used in testing infants to see whether they can differentiate two stimuli.

Question 50

Dual-task procedure

Answer 50

An experimental procedure in which subjects are required to carry out simultaneously a central task that demands attention and a peripheral task that involves making a decision about the contents of a scene.

Question 51

Feature integration theory

Answer 51

A theory proposed by Treisman to explain how an object is broken down into features and how these features are recombined to result in a perception of the object.

Question 52

Feature search

Answer 52

A visual search task in which a person can find a target by searching for only one feature. An example would be looking for a horizontal green line among vertical green lines.

Question 53

Fixation

Answer 53

The brief pause of the eye that occurs between eye movements as a person scans a scene.

Question 54

Focused attention stage (of perceptual processing)

Answer 54

The stage of processing in feature integration theory in which the features are combined. According to Treisman, this stage requires focused attention.

Question 55

Habituation

Answer 55

Paying less attention to the same stimulus that is presented repeatedly. For example, infants look at a stimulus less and less on each successive trial.

Question 56

High-load task

Answer 56

Task that involves more processing resources and that therefore uses more of a person’s perceptual capacity.

Question 57

Illusory conjunction

Answer 57

Illusory combination of features that are perceived when stimuli containing a number of features are presented briefly and under conditions in which focused attention is difficult. For example, presenting a red square and a blue triangle could potentially create the perception of a red triangle.

Question 58

Inattentional blindness

Answer 58

A situation in which a stimulus that is not attended is not perceived, even though the person is looking directly at it.

Question 59

Load theory of attention

Answer 59

Lavie’s proposal that the amount of perceptual capacity that remains as a person is carrying out a task determines how well the person can avoid being distracted by task-irrelevant stimuli. If a person’s perceptual load is close to perceptual capacity, the person is less likely to be distracted by task-irrelevant stimuli.

Question 60

Overt attention

Answer 60

Attention that involves looking directly at the attended object.

Question 61

Perceptual capacity

Answer 61

The resources a person has for carrying out perceptual tasks.

Question 62

Perceptual completion

Answer 62

The perception of an object as extending behind occluding objects.

Question 63

Perceptual load

Answer 63

The amount of a person’s perceptual capacity needed to carry out a particular perceptual task.

Question 64

Preattentive stage (of perceptual processing)

Answer 64

An automatic and rapid stage of processing, proposed by Treisman’s feature integration theory, during which a stimulus is decomposed into individual features.

Question 65

Precueing

Answer 65

A procedure in which a cue stimulus is presented to direct an observer’s attention to a specific location where a test stimulus is likely to be presented. This procedure was used by Posner to show that attention enhances the processing of a stimulus presented at the cued location.

Question 66

Saccadic eye movement

Answer 66

Rapid eye movement between fixations that occurs when scanning a scene.

Question 67

Saliency Map

Answer 67

A “map” of a visual display that takes into account characteristics of the display such as color, contrast, and orientation that are associated with capturing attention.

Question 68

Same-object advantage

Answer 68

The faster responding that occurs when enhancement spreads within an object. Faster reaction times occur when a target is located within the object that is receiving the subject’s attention, even if the subject is looking at another place within the object.

Question 69

Scene schema

Answer 69

An observer’s knowledge about what is contained in typical scenes. An observer’s attention is affected by knowledge of what is usually found in the scene.

Question 70

Scene statistics

Answer 70

The probability of various things occurring in the environment.

Question 71

Stimulus salience

Answer 71

Characteristics such as bright colors, high contrast, and highly visible orientations that cause stimuli to stand out and therefore attract attention.

Question 72

Task-irrelevant stimuli

Answer 72

Stimuli that do not provide information relevant to the task at hand.

Question 73

Visual scanning

Answer 73

Moving the eyes to focus attention on different locations on objects or in scenes.

Question 74

Visual search

Answer 74

A procedure in which a person’s task is to find a particular element in a display that contains a number of elements.

Question 75

Affordance

Answer 75

The information specified by a stimulus pattern that indicates how the stimulus can be used. An example of an affordance would be seeing a chair as something to sit on or a flight of stairs as something to climb.

Question 76

Audiovisual mirror neuron

Answer 76

Neuron that responds to actions that produce sounds. These neurons respond when a monkey performs a hand action and when it hears the sound associated with this action.

Question 77

Ecological approach to perception

Answer 77

This approach focuses on specifying the information in the environment that is used for perception, emphasizing the study of moving observers to determine how their movement results in perceptual information that both creates perception and guides further movement.

Question 78

Focus of expansion FOE

Answer 78

The point in the flow pattern caused by observer movement in which there is no expansion. According to J. J. Gibson, the focus of expansion always remains centered on the observer’s destination.

Question 79

Gradient of flow

Answer 79

In an optic flow pattern, a gradient is created by movement of an observer through the environment. The “gradient” refers to the fact that the optic flow is rapid in the foreground and becomes slower as distance from the observer increases.

Question 80

Invariant information

Answer 80

Environmental properties that do not change as the observer moves relative to an object or scene. For example, the spacing, or texture, of the elements in a texture gradient does not change as the observer moves on the gradient. The texture of the gradient therefore supplies invariant information for depth perception.

Question 81

Landmarks

Answer 81

Objects on a route that serve as cues to indicate where to turn; a source of information for wayfinding.

Question 82

Mirror neuron

Answer 82

Neuron in the premotor area of the monkey’s cortex that responds when the monkey grasps an object and also when the monkey observes someone else (another monkey or the experimenter) grasping the object. There is also evidence for mirror neuron-like activity in the human brain.

Question 83

Optic ataxia

Answer 83

A condition in which individuals with parietal lobe damage have trouble pointing to visual stimuli.

Question 84

Optic flow

Answer 84

The flow of stimuli in the environment that occurs when an observer moves relative to the environment. Forward movement causes an expanding optic flow, whereas backward movement causes a contracting optic flow. Some researchers use the term optic flow field to refer to this flow.

Question 85

Parietal reach region PRR

Answer 85

A network of areas in the parietal cortex that contains neurons that are involved in reaching behavior.

Question 86

Self produced information

Answer 86

Generally, environmental information that is produced by actions of the observer. An example is optic flow, which occurs as a result of a person’s movement and which, in turn, provides information that can be used to guide that movement.

Question 87

Visual direction strategy

Answer 87

A strategy used by moving observers to reach a destination by keeping their body oriented toward the target.

Question 88

Visuomotor grip cell

Answer 88

A neuron that initially responds when a specific object is seen, and then also responds as a hand grasps the same object.

Question 89

Wayfinding

Answer 89

The process of navigating through the environment. Wayfinding involves perceiving objects in the environment, remembering objects and their relation to the overall scene, and knowing when to turn and in what direction.

Question 90

Akinetopsia

Answer 90

A condition in which damage to an area of the cortex involved in motion perception causes blindness to motion.

Question 91

Aperature problem

Answer 91

Occurs when only a portion of a moving stimulus can be seen, as when the stimulus is viewed through a narrow aperture. This can result in misleading information about the direction in which the stimulus is moving.

Question 92

Apparent motion

Answer 92

An illusion of movement that occurs when two objects separated in space are presented rapidly, one after another, separated by a brief time interval.

Question 93

Attentional capture

Answer 93

Occurs when stimulus salience causes an involuntary shift of attention. For example, attention can be captured by movement.

Question 94

Biological motion

Answer 94

Motion produced by biological organisms. Most of the experiments on biological motion have used walking humans with lights attached to their joints and limbs as stimuli.

Question 95

Coherence

Answer 95

In research on movement perception in which arrays of moving dots are used as stimuli, the degree of correlation between the direction of the moving dots. Zero percent coherence means all of the dots are moving independently; 100 percent coherence means all of the dots are moving in the same direction.

Question 96

Comparator

Answer 96

A structure hypothesized by the corollary discharge theory of movement perception. The corollary discharge signal and the sensory movement signal meet at the comparator to determine whether movement will be perceived.

Question 97

Corollary discharge signal

Answer 97

A copy of the motor signal that is sent to the eye muscles to cause movement of the eye. The copy is sent to the hypothetical comparator of corollary discharge theory.

Question 98

Corollary discharge theory

Answer 98

The theory that explains motion perception as being determined both by movement of the image on the retina and by signals that indicate movement of the eyes.

Question 99

Event

Answer 99

A segment of time at a particular location that is perceived by observers to have a beginning and an ending.

Question 100

Event boundary

Answer 100

The point in time when one event ends and another begins.

Question 101

Global optic flow

Answer 101

Information for movement that occurs when all elements in a scene move. The perception of global optic flow indicates that it is the observer that is moving and not the scene.

Question 102

Illusory motion

Answer 102

Perception of motion when there actually is none.

Question 103

Image displacement signal

Answer 103

In corollary discharge theory, the signal that occurs when an image moves across the visual receptors.

Question 104

Implied motion

Answer 104

When a still picture depicts an action that involves motion, so that an observer could potentially extend the action depicted in the picture in his or her mind based on what will most likely happen next.

Question 105

Induced motion

Answer 105

The illusory movement of one object that is caused by the movement of another object that is nearby.

Question 106

Local disturbance in the optic array

Answer 106

Occurs when one object moves relative to the environment, so that the stationary background is covered and uncovered by the moving object. This local disturbance indicates that the object is moving relative to the environment.

Question 107

Microstimulation

Answer 107

A procedure in which a small electrode is inserted into the cortex and an electrical current passed through the electrode activates neurons near the tip of the electrode. This procedure has been used to determine how activating specific groups of neurons affects perception.

Question 108

Motion aftereffect

Answer 108

An illusion that occurs after a person views a moving stimulus and then sees movement in the opposite direction when viewing a stationary stimulus immediately afterward.

Question 109

Motor signal MS

Answer 109

In corollary discharge theory, the signal that is sent to the eye muscles when the observer moves or tries to move his or her eyes.

Question 110

Optic array

Answer 110

The structured pattern of light created by the presence of objects, surfaces, and textures in the environment.

Question 111

Point-light walker

Answer 111

A biological motion stimulus created by placing lights at a number of places on a person’s body and having an observer view the moving-light stimulus that results as the person moves in the dark.

Question 112

Real motion

Answer 112

The physical movement of a stimulus

Question 113

Real motion neuron

Answer 113

Neuron in the monkey’s cortex that responds when movement of an image across the retina is caused by movement of a stimulus, but does not respond when movement across the retina is caused by movement of the eyes.

Question 114

Reichardt detector

Answer 114

A neural circuit that results in neurons firing to movement in one direction. Excitation and inhibition are arranged so that movement in one direction creates inhibition that reduces or eliminates neural responding, whereas movement in the opposite direction creates excitation that enhances neural responding.

Question 115

Representational momentum

Answer 115

Occurs when motion depicted in a still picture continues in an observer’s mind.

Question 116

Shortest path constraint

Answer 116

In the perception of apparent motion, the principle that apparent movement tends to occur along the shortest path between two stimuli.

Question 117

Waterfall illusion

Answer 117

An aftereffect of movement that occurs after viewing a stimulus moving in one direction, such as a waterfall. Viewing the waterfall makes other objects appear to move in the opposite direction.

Question 118

Achromatic colour

Answer 118

Color without hue. White, black, and all the grays between these two extremes are achromatic colors.

Question 119

Additive colour mixture

Answer 119

The creation of colors that occurs when lights of different colors are superimposed.

Question 120

Anomalous trichromat

Answer 120

A person who needs to mix a minimum of three wavelengths to match any other wavelength in the spectrum but mixes these wavelengths in different proportions from a trichromat.

Question 121

Cerebral anchromatopsia

Answer 121

A loss of color vision caused by damage to the cortex.

Question 122

Chromatic adaptation

Answer 122

Exposure to light in a specific part of the visible spectrum. This adaptation can cause a decrease in sensitivity to light from the area of the spectrum that was presented during adaptation.

Question 123

Chromatic colour

Answer 123

Color with hue, such as blue, yellow, red, or green.

Question 124

Colour blindness

Answer 124

A condition in which a person perceives no chromatic color. This can be caused by absent or malfunctioning cone receptors or by cortical damage.

Question 125

Color constancy

Answer 125

The effect in which the perception of an object’s hue remains constant even when the wavelength distribution of the illumination is changed. Partial color constancy occurs when our perception of hue changes a little when the illumination changes, though not as much as we might expect from the change in the wavelengths of light reaching the eye.

Question 126

Colour deficiency

Answer 126

People with this condition (sometimes incorrectly called color blindness) see fewer colors than people with normal color vision and need to mix fewer wavelengths to match any other wavelength in the spectrum.

Question 127

Colour matching experiment

Answer 127

A procedure in which observers are asked to match the color in one field by mixing two or more lights in another field.

Question 128

Desaturated

Answer 128

Low saturation in chromatic colors as would occur when white is added to a color. For example, pink is not as saturated as red.

Question 129

Deuteranopia

Answer 129

A form of red–green color dichromatism caused by lack of the middle-wavelength cone pigment.

Question 130

Dichromat

Answer 130

A person who has a form of color deficiency. Dichromats can match any wavelength in the spectrum by mixing two other wavelengths. Deuteranopes, protanopes, and tritanopes are all dichromats.

Question 131

Double-opponent neurons

Answer 131

Neurons that have receptive fields in which stimulation of one part of the receptive field causes an excitatory response to wavelengths in one area of the spectrum and an inhibitory response to wavelengths in another area of the spectrum, and stimulation of an adjacent part of the receptive field causes the opposite response. An example of double-opponent responding is when the response of one part of a receptive field is L+ M- and the response of an adjacent part is L- M+.

Question 132

Hue

Answer 132

The experience of a chromatic color such as red, green, yellow, or blue or combinations of these colors.

Question 133

Illumination edge

Answer 133

The border between two areas created by different light intensities in the two areas.

Question 134

Ishihara plate

Answer 134

A display of colored dots used to test for the presence of color deficiency. The dots are colored so that people with normal (trichromatic) color vision can perceive numbers in the plate, but people with color deficiency cannot perceive these numbers or perceive different numbers than someone with trichromatic vision.

Question 135

Lightness

Answer 135

The perception of shades ranging from white to grey to black

Question 136

Lightness constancy

Answer 136

The constancy of our perception of an object’s lightness under different intensities of illumination.

Question 137

Memory colour

Answer 137

The idea that an object’s characteristic color influences our perception of that object’s color.

Question 138

Metamerism

Answer 138

The situation in which two physically different stimuli are perceptually identical. In vision, this refers to two lights with different wavelength distributions that are perceived as having the same color.

Question 139

Metamers

Answer 139

Two lights that have different wavelength distributions but are perceptually identical.

Question 140

Monochromat

Answer 140

A person who is completely color-blind and therefore sees everything as black, white, or shades of gray. A monochromat can match any wavelength in the spectrum by adjusting the intensity of any other wavelength. Monochromats generally have only one type of functioning receptors, usually rods.

Question 141

Neutral point

Answer 141

The wavelength at which a dichromat perceives gray.

Question 142

Opponent neuron

Answer 142

A neuron that has an excitatory response to wavelengths in one part of the spectrum and an inhibitory response to wavelengths in the other part of the spectrum.

Question 143

Opponent-process theory of colour vision

Answer 143

A theory originally proposed by Hering, which claimed that our perception of color is determined by the activity of two opponent mechanisms: a blue–yellow mechanism and a red–green mechanism. The responses to the two colors in each mechanism oppose each other, one being an excitatory response and the other an inhibitory response. In addition, this theory also includes a black–white mechanism, which is concerned with the perception of brightness.

Question 144

Partial colour constancy

Answer 144

A type of color constancy that occurs when changing an object’s illumination causes a change in perception of the object’s hue, but less change than would be expected based on the change in the wavelengths of light reaching the eye. Note that in complete color constancy, changing an object’s illumination causes no change in the object’s hue.

Question 145

Penumbra

Answer 145

The fuzzy border at the edge of a shadow.

Question 146

Protanopia

Answer 146

A form of red–green dichromatism caused by a lack of the long-wavelength cone pigment.

Question 147

Ratio principle

Answer 147

A principle stating that two areas that reflect different amounts of light will have the same perceived lightness if the ratios of their intensities to the intensities of their surroundings are the same.

Question 148

Reflectance

Answer 148

The percentage of light reflected from a surface.

Question 149

Reflectance curve

Answer 149

A plot showing the percentage of light reflected from an object versus wavelength.

Question 150

Reflectance edge

Answer 150

An edge between two areas where the reflectance of two surfaces changes.

Question 151

Saturation (colour)

Answer 151

The relative amount of whiteness in a chromatic color. The less whiteness a color contains, the more saturated it is.

Question 152

Selective reflection

Answer 152

When an object reflects some wavelengths of the spectrum more than others.

Question 153

Selective transmission

Answer 153

When some wavelengths pass through visually transparent objects or substances and others do not. Selective transmission is associated with the perception of chromatic color.

Question 154

Simultaneous colour contrast

Answer 154

The effect that occurs when surrounding one color with another changes the appearance of the surrounded color. Occurs for chromatic and achromatic stimuli.

Question 155

Single-opponent neuron

Answer 155

Neurons that increase firing to long wavelengths presented to the center of the receptive field and decrease firing to short wavelengths presented to the surround (or vice versa).

Question 156

Subtractive colour mixture

Answer 156

The creation of colors that occurs when paints of different colors are mixed together.

Question 157

Trichromat

Answer 157

A person with normal color vision. Trichromats can match any wavelength in the spectrum by mixing three other wavelengths in various proportions.

Question 158

Trichromatic theory of colour vision

Answer 158

A theory proposing that our perception of color is determined by the ratio of activity in three receptor mechanisms with different spectral sensitivities.

Question 159

Tritanopia

Answer 159

A form of dichromatism thought to be caused by a lack of the short-wavelength cone pigment.

Question 160

Unilateral dichromat

Answer 160

A person who has dichromatic vision in one eye and trichromatic vision in the other eye. People with this condition (which is extremely rare) have been tested to determine what colors a dichromats perceive by asking them to compare the perceptions they experience with their dichromatic eye and their trichromatic eye.

Question 161

Young-Helmholtz theory of colour vision

Answer 161

A theory proposing that our perception of color is determined by the ratio of activity in three receptor mechanisms with different spectral sensitivities.

Question 162

Absolute disparity

Answer 162

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 noncorresponding points, the angle of disparity indicates the degree of noncorrespondence.

Question 163

Accretion

Answer 163

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

Question 164

Active method (3D TV)

Answer 164

A method used to create 3-D television images. The active method alternates the left-eye and right-eye images on the screen 30 or more times a second. This method is called active because the viewing glasses have a shutter system that is synchronized with the alternating images on the TV screen.

Question 165

Ames room

Answer 165

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 166

Angle of disparity

Answer 166

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 noncorresponding points, the angle of disparity indicates the degree of noncorrespondence.

Question 167

Angular size contrast theory

Answer 167

An explanation of the moon illusion that states that the perceived size of the moon is determined by 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 168

Apparent distance theory

Answer 168

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 that 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 169

Atmospheric perspective

Answer 169

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

Question 170

Binocular depth cell

Answer 170

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

Question 171

Binocular disparity

Answer 171

Occurs when the retinal images of an object fall on disparate points on the two retinas.

Question 172

Binocular fixate

Answer 172

Directing the two foveas to exactly the same spot.

Question 173

Conflicting cues theory

Answer 173

A theory of visual illusions proposed by R. H. Day, which states that our perception of line length depends on an integration of the actual line length and the overall figure length.

Question 174

Correspondence problem

Answer 174

The problem faced by the 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 175

Corresponding retinal points

Answer 175

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 176

Cue approach to depth perception

Answer 176

The approach to explaining depth perception that identifies information in the retinal image, and also information provided by aiming and focusing the eyes on an object 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 177

Deletion

Answer 177

A cue that provides 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.

Question 178

Disparity tuning curve

Answer 178

A plot of a neuron’s 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 179

Disparity-selective cell

Answer 179

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

Question 180

Echolocation

Answer 180

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 and dolphins.

Question 181

Emmert’s law

Answer 181

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 182

Familiar size

Answer 182

A depth cue in which judgment of distance is based on knowledge of the sizes of objects. Epstein’s coin experiment illustrated the operation of the cue of familiar size by showing that the relative sizes of the coins influenced perception of the coins’ distances.

Question 183

Frontal eyes

Answer 183

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

Question 184

Horopter

Answer 184

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 185

Lateral eyes

Answer 185

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

Question 186

Lenticular projection

Answer 186

A method used to create 3-D television images. The screen is coated with a film containing two sets of lenses, which results in different images reaching the left and right eyes. An example being those postcards that show different images depending on the angle held.

Question 187

Muller-Lyer illusion

Answer 187

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 188

Misapplied size constancy scaling

Answer 188

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 results.

Question 189

Monocular cue

Answer 189

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 190

Moon illusion

Answer 190

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 191

Motion parallax

Answer 191

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 192

Noncorresponding points

Answer 192

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

Question 193

Occlusion

Answer 193

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

Question 194

Oculomotor cue

Answer 194

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 cues.

Question 195

Passive method (3DTV)

Answer 195

A method used to create 3-D television images. Polarized light is used to create left and right images—one image is polarized so its vibration is vertical, and the other is polarized so its vibration is horizontal. The TV is viewed through polarizing lenses, which let vertically polarized light into one eye and horizontally polarized light into the other eye, creating the disparity that results in three-dimensional perception.

Question 196

Perspective convergence

Answer 196

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

Question 197

Pictoral cue

Answer 197

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

Question 198

Ponzo illusion

Answer 198

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 199

Random dot stereogram

Answer 199

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 200

Relative disparity

Answer 200

The difference between two objects’ absolute disparities.

Question 201

Relative height

Answer 201

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 202

Relative size

Answer 202

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 203

Size constancy

Answer 203

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

Question 204

Size distance scaling

Answer 204

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

Question 205

Stereopsis

Answer 205

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 206

Stereoscope

Answer 206

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 207

Stereoscopic depth perception

Answer 207

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

Question 208

Stereoscopic vision

Answer 208

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

Question 209

Strabismus

Answer 209

Misalignment of the eyes, such as crossed-eyes or walleyes (outward looking eyes), 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 210

Texture gradient

Answer 210

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 211

Visual angle

Answer 211

The angle of an object relative to an observer’s 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 object’s visual angle is always determined relative to an observer, its visual angle changes as the distance between the object and the observer changes.

Question 212

Acoustic prism

Answer 212

The way the cochlea separates frequencies entering the ear to create activity at different places along the basilar membrane.

Question 213

Amplitude

Answer 213

In the case of a repeating sound wave, such as the sine wave of a pure tone, amplitude represents the pressure difference between atmospheric pressure and the maximum pressure of the wave.

Question 214

Apex of the cochlea

Answer 214

The end of the cochlea farthest from the middle ear.

Question 215

Attack

Answer 215

The buildup of sound energy that occurs at the beginning of a tone.

Question 216

Audibility curve

Answer 216

A curve that indicates the sound pressure level (SPL) at threshold for frequencies across the audible spectrum.

Question 217

Auditory canal

Answer 217

The canal through which air vibrations travel from the environment to the tympanic membrane.

Question 218

Auditory response area

Answer 218

The psychophysically measured area that defines the frequencies and sound pressure levels over which hearing functions. This area extends between the audibility curve and the curve for the threshold of feeling.

Question 219

Base of the cochlea

Answer 219

The part of the cochlea nearest the middle ear.

Question 220

Basilar membrane

Answer 220

A membrane that stretches the length of the cochlea and controls the vibration of the cochlear partition.

Question 221

Characteristic frequency

Answer 221

The frequency at which a neuron in the auditory system has its lowest threshold.

Question 222

Cilia

Answer 222

Fine hairs that protrude from the inner and outer hair cells of the auditory system. Bending the cilia of the inner hair cells leads to transduction.

Question 223

Cochlea

Answer 223

The snail-shaped, liquid-filled structure that contains the structures of the inner ear, the most important of which are the basilar membrane, the tectorial membrane, and the hair cells.

Question 224

Cochlear amplifier

Answer 224

Expansion and contraction of the outer hair cells in response to sound sharpens the movement of the basilar membrane to specific frequencies. This amplifying effect plays an important role in determining the frequency selectivity of auditory nerve fibers.

Question 225

Cochlear implant

Answer 225

A device in which electrodes are inserted into the cochlea to create hearing by electrically stimulating the auditory nerve fibers. This device is used to restore hearing in people who have lost their hearing because of damaged hair cells.

Question 226

Cochlear partition

Answer 226

A partition in the cochlea, extending almost its full length, that separates the scala tympani and the scala vestibuli. The organ of Corti, which contains the hair cells, is part of the cochlear partition.

Question 227

Decay

Answer 227

The decrease in the sound signal that occurs at the end of a tone.

Question 228

Decibel dB

Answer 228

A unit that indicates the pressure of a sound stimulus relative to a reference pressure: dB=20 log (p/po) where p is the pressure of the tone and po is the reference pressure.

Question 229

Eardrum

Answer 229

Another term for the tympanic membrane, the membrane located at the end of the auditory canal that vibrates in response to pressure changes. This vibration is transmitted to the bones of the middle ear.

Question 230

Effect of the missing fundamental

Answer 230

Removing the fundamental frequency and other lower harmonies from a musical tone does not change the tone’s pitch.

Question 231

Equal loudness curve

Answer 231

A curve that indicates the sound pressure levels that result in a perception of the same loudness at frequencies across the audible spectrum.

Question 232

First harmonic

Answer 232

A pure tone with frequency equal to the fundamental frequency of a complex tone.

Question 233

Frequency

Answer 233

The number of times per second that pressure changes of a sound stimulus repeat. Frequency is measured in Hertz, where 1 Hertz is one cycle per second.

Question 234

Frequency spectrum

Answer 234

A plot that indicates the amplitudes of the various harmonics that make up a complex tone. Each harmonic is indicated by a line that is positioned along the frequency axis, with the height of the line indicating the amplitude of the harmonic.

Question 235

Frequency tuning curve

Answer 235

Curve relating frequency and the threshold intensity for activating an auditory neuron.

Question 236

Fundamental

Answer 236

A pure tone with frequency equal to the fundamental frequency of a complex tone. See also fundamental frequency.

Question 237

Fundamental frequency

Answer 237

The first harmonic of a complex tone; usually the lowest frequency in the frequency spectrum of a complex tone. The tone’s other components, called higher harmonics, have frequencies that are multiples of the fundamental frequency.

Question 238

Hair cell

Answer 238

Neuron in the cochlea that contains small hairs, or cilia, that are displaced by vibration of the basilar membrane and fluids inside the inner ear. There are two kinds of hair cells: inner and outer.

Question 239

Harmonics

Answer 239

Pure-tone components of a complex tone that have frequencies that are multiples of the fundamental frequency.

Question 240

Hertz

Answer 240

The unit for designating the frequency of a tone. One Hertz equals one cycle per second.

Question 241

Higher harmonics

Answer 241

Pure tones with frequencies that are whole-number (2, 3, 4, etc.) multiples of the fundamental frequency.

Question 242

Incus

Answer 242

The second of the three ossicles of the middle ear. It transmits vibrations from the malleus to the stapes.

Question 243

Inner Ear

Answer 243

The innermost division of the ear, containing the cochlea and the receptors for hearing.

Question 244

Inner Hair cell

Answer 244

Auditory receptor cell in the inner ear that is primarily responsible for auditory transduction and the perception of pitch.

Question 245

Leisure noise

Answer 245

Noise associated with leisure activities such as listening to music, hunting, and woodworking. Exposure to high levels of leisure noise for extended periods can cause hearing loss.

Question 246

Level

Answer 246

Short for sound pressure level or sound level. Indicates the decibels or sound pressure of a sound stimulus.

Question 247

Loudness

Answer 247

The quality of sound that ranges from soft to loud. For a tone of a particular frequency, loudness usually increases with increasing decibels.

Question 248

Malleus

Answer 248

The first of the ossicles of the middle ear. Receives vibrations from the tympanic membrane and transmits these vibrations to the incus.

Question 249

Middle ear

Answer 249

The small air-filled space between the auditory canal and the cochlea that contains the ossicles.

Question 250

Middle-ear muscles

Answer 250

Muscles attached to the ossicles in the middle ear. The smallest skeletal muscles in the body, they contract in response to very intense sounds and dampen the vibration of the ossicles.

Question 251

Noise-induced hearing loss

Answer 251

A form of sensorineural hearing loss that occurs when loud noises cause degeneration of the hair cells.

Question 252

Octave

Answer 252

Tones that have frequencies that are binary multiples of each other (2, 4, etc.). For example, an 800-Hz tone is one octave above a 400-Hz tone.

Question 253

Organ of Corti

Answer 253

The major structure of the cochlear partition, containing the basilar membrane, the tectorial membrane, and the receptors for hearing.

Question 254

Ossicles

Answer 254

Three small bones in the middle ear that transmit vibrations from the outer to the inner ear.

Question 255

Outer ear

Answer 255

The pinna and the auditory canal.

Question 256

Outer hair cell

Answer 256

Auditory receptor cells in the inner ear that amplify the response of inner hair cells by amplifying the vibration of the basilar membrane.

Question 257

Oval window

Answer 257

A small, membrane-covered hole in the cochlea that receives vibrations from the stapes.

Question 258

Periodic tone

Answer 258

A tone in which the waveform repeats

Question 259

Periodicity pitch

Answer 259

The constancy of a complex tone’s pitch when the fundamental frequency and other lower harmonics are eliminated.

Question 260

Phase locking

Answer 260

Firing of auditory neurons in synchrony with the phase of an auditory stimulus.

Question 261

Pinna

Answer 261

The part of the ear that is visible on the outside of the head.

Question 262

Pitch

Answer 262

The quality of sound, ranging from low to high, that is most closely associated with the frequency of a tone.

Question 263

Pitch neurons

Answer 263

Neurons that respond to stimuli associated with a specific pitch. These neurons fire to the pitch of a complex tone even if the first harmonic or other harmonics of the tone are not present.

Question 264

Place theory of hearing

Answer 264

The proposal that the frequency of a sound is indicated by the place along the organ of Corti at which nerve firing is highest. Modern place theory is based on Békésy’s traveling wave theory of hearing.

Question 265

Presbycusis

Answer 265

A form of sensorineural hearing loss that occurs as a function of age and is usually associated with a decrease in the ability to hear high frequencies. Since this loss also appears to be related to exposure to environmental sounds, it is also called sociocusis.

Question 266

Pure tone

Answer 266

A tone with pressure changes that can be described by a single sine wave.

Question 267

Resonance

Answer 267

A mechanism that enhances the intensity of certain frequencies because of the reflection of sound waves in a closed tube. Resonance in the auditory canal enhances frequencies between about 2,000 and 5,000 Hz.

Question 268

Resonant frequency

Answer 268

The frequency that is most strongly enhanced by resonance. The resonance frequency of a closed tube is determined by the length of the tube.

Question 269

Sound perceptual

Answer 269

The perceptual experience of hearing. The statement “I hear a sound” is using sound in that sense.

Question 270

Sound physical

Answer 270

The physical stimulus for hearing. The statement “The sound’s level was 10 dB” is using sound in that sense.

Question 271

Sound level

Answer 271

The pressure of a sound stimulus, expressed in decibels.

Question 272

Sound pressure level SPL

Answer 272

A designation used to indicate that the reference pressure used for calculating a tone’s decibel rating is set at 20 micropascals, near the threshold in the most sensitive frequency range for hearing.

Question 273

Sound wave

Answer 273

Pattern of pressure changes in a medium. Most of the sounds we hear are due to pressure changes in the air, although sound can be transmitted through water and solids as well.

Question 274

Stapes

Answer 274

The last of the three ossicles in the middle ear. It receives vibrations from the incus and transmits these vibrations to the oval window of the inner ear.

Question 275

Tectorial membrane

Answer 275

A membrane that stretches the length of the cochlea and is located directly over the hair cells. Vibrations of the cochlear partition cause the tectorial membrane to bend the hair cells by rubbing against them.

Question 276

Temporal coding

Answer 276

The connection between the frequency of a sound stimulus and the timing of the auditory nerve fiber firing.

Question 277

Timbre

Answer 277

The quality that distinguishes between two tones that sound different even though they have the same loudness, pitch, and duration. Differences in timbre are illustrated by the sounds made by different musical instruments.

Question 278

Tip links

Answer 278

Structures at the tops of the cilia of auditory hair cells, which stretch or slacken as the cilia move, causing ion channels to open or close.

Question 279

Tone chroma

Answer 279

The perceptual similarity of notes separated by one or more octaves.

Question 280

Tone height

Answer 280

The increase in pitch that occurs as frequency is increased.

Question 281

Tonotopic map

Answer 281

An ordered map of frequencies created by the responding of neurons within structures in the auditory system. There is a tonotopic map of neurons along the length of the cochlea, with neurons at the apex responding best to low frequencies and neurons at the base responding best to high frequencies.

Question 282

Traveling wave

Answer 282

In the auditory system, vibration of the basilar membrane in which the peak of the vibration travels from the base of the membrane to its apex.

Question 283

Tympanic membrane

Answer 283

A membrane at the end of the auditory canal that vibrates in response to vibrations of the air and transmits these vibrations to the ossicles in the middle ear.

Question 284

Acoustic shadow

Answer 284

The shadow created by the head that decreases the level of high-frequency sounds on the opposite side of the head. The acoustic shadow is the basis of the localization cue of interaural level difference.

Question 285

Architectural acoustics

Answer 285

The study of how sounds are reflected in rooms. An important concern of architectural acoustics is how these reflected sounds change the quality of the sounds we hear.

Question 286

Auditory localization

Answer 286

The perception of the location of a sound source.

Question 287

Auditory receiving area A1

Answer 287

The area of the cortex, located in the temporal lobe, that is the primary receiving area for hearing.

Question 288

Auditory scene

Answer 288

The sound environment, which includes the locations and qualities of individual sound sources.

Question 289

Auditory scene analysis

Answer 289

The process by which sound stimuli produced by the different sources in an auditory scene become perceptually organized into sounds at different locations and into separated streams of sound.

Question 290

Auditory space

Answer 290

Perception of where sounds are located in space. Auditory space extends around a listener’s head in all directions, existing wherever there is a sound.

Question 291

Auditory stream segregation

Answer 291

The effect that occurs when a series of sounds that differ in pitch or timbre are played so that the tones become perceptually separated into simultaneously occurring independent streams of sound.

Question 292

Azimuth

Answer 292

In hearing, specifies locations that vary from left to right relative to the listener.

Question 293

Belt area

Answer 293

Auditory area in the temporal lobe that receives signals from the core area and sends signals to the parabelt area.

Question 294

Binaural cue

Answer 294

Sound localization cue that involves both ears. Interaural time difference and interaural level difference are the primary binaural cues.

Question 295

Cochlear nucleus

Answer 295

The nucleus where nerve fibers from the cochlea first synapse.

Question 296

Coincidence detectors

Answer 296

Neurons in the Jeffress neural coincidence model, which was proposed to explain how neural firing can provide information regarding the location of a sound source. A neural coincidence detector fires when signals from the left and right ears reach the neuron simultaneously. Different neural coincidence detectors fire to different values of interaural time difference.

Question 297

Cone of confusion

Answer 297

A surface in the shape of a cone that extends out from the ear. Sounds originating from different locations on this surface all have the same interaural level difference and interaural time difference, so location information provided by these cues is ambiguous.

Question 298

Core area

Answer 298

The area in the temporal lobe that includes the primary auditory cortex (A1) and some nearby areas. Signals from the core area are transmitted to the belt area of the auditory cortex.

Question 299

Direct sound

Answer 299

Sound that is transmitted directly from a sound source to the ears.

Question 300

Distance

Answer 300

How far a stimulus is from the observer. In hearing, the distance coordinate specifies how far the sound source is from the listener.

Question 301

Elevation

Answer 301

In hearing, sound locations that are up and down relative to the listener.

Question 302

Indirect sound

Answer 302

Sound that reaches a listener’s ears after being reflected from a surface such as a room’s walls.

Question 303

Inferior colliculus

Answer 303

A nucleus in the hearing system along the pathway from the cochlea to the auditory cortex. The inferior colliculus receives inputs from the superior olivary nucleus.

Question 304

Interaural level difference ILD

Answer 304

The difference in the sound pressure (or level) between the left and right ears. This difference creates an acoustic shadow for the far ear. The ILD provides a cue for sound localization for high-frequency sounds.

Question 305

Interaural time difference ITD

Answer 305

When a sound is positioned closer to one ear than to the other, the sound reaches the close ear slightly before reaching the far ear, so there is a difference in the time of arrival at the two ears. The ITD provides a cue for sound localization.

Question 306

ITD tuning curve

Answer 306

A plot of the neuron’s firing rate against the ITD (interaural time difference).

Question 307

Jeffress model

Answer 307

The neural mechanism of auditory localization that proposes that neurons are wired to each receive signals from the two ears, so that different neurons fire to different interaural time differences (ITD).

Question 308

Location cue

Answer 308

In hearing, characteristics of the sound reaching the listener that provide information regarding the location of a sound source.

Question 309

Medial geniculate nucleus

Answer 309

An auditory nucleus in the thalamus that is part of the pathway from the cochlea to the auditory cortex. The medial geniculate nucleus receives inputs from the inferior colliculus and transmits signals to the auditory cortex.

Question 310

Melodic channeling

Answer 310

An illusion that occurs when successive notes of a scale are presented alternately to the left and right ears. Even though each ear receives notes that jump up and down in frequency, smoothly ascending or descending scales are heard in each ear.

Question 311

Melody schema

Answer 311

A representation of a familiar melody that is stored in a person’s memory. Existence of a melody schema makes it more likely that the tones associated with a melody will be perceptually grouped.

Question 312

Metrical structure

Answer 312

The underlying beat of music

Question 313

Monaural cue

Answer 313

Sound localization cue that involves one ear.

Question 314

Multisensory interaction

Answer 314

Use of a combination of senses. For example, for vision and hearing, seeing a person’s lips move while listening to the person speak.

Question 315

Parabelt area

Answer 315

Auditory area in the temporal lobe that receives signals from the belt area.

Question 316

Precedence effect

Answer 316

The effect that occurs when two identical or very similar sounds reach a listener’s ears separated by a time interval of less than about 50 to 100 ms, and the listener hears the first sound that reaches his or her ears.

Question 317

Primary auditory cortex A1

Answer 317

An area of the temporal lobe that receives signals via nerve fibers from the medial geniculate nucleus in the thalamus.

Question 318

Reverberation time

Answer 318

The time it takes for a sound produced in an enclosed space to decrease to 1/1,000th of its original pressure.

Question 319

Rhythmic pattern

Answer 319

In music, the series of changes across time (a mixture of shorter and longer notes) in a temporal pattern.

Question 320

Scale illusion

Answer 320

An illusion that occurs when successive notes of a scale are presented alternately to the left and right ears. Even though each ear receives notes that jump up and down in frequency, smoothly ascending or descending scales are heard in each ear. Also called melodic channeling.

Question 321

Signal to noise ratio

Answer 321

The level of a sound signal in decibels minus the level of background noise in decibels.

Question 322

Spectral cue

Answer 322

In hearing, the distribution of frequencies reaching the ear that are associated with specific locations of a sound. The differences in frequencies are caused by interaction of sound with the listener’s head and pinnae.

Question 323

Subcortical structure

Answer 323

Structure below the cerebral cortex. For example, the superior colliculus is a subcortical structure in the visual system. The cochlear nucleus and superior olivary nucleus are among the subcortical structures in the auditory system.

Question 324

Superior olivary nucleus

Answer 324

A nucleus along the auditory pathway from the cochlea to the auditory cortex. The superior olivary nucleus receives inputs from the cochlear nucleus.

Question 325

Two flash illusion

Answer 325

An illusion that occurs when one flash of light is presented, accompanied by two rapidly presented tones. Presentation of the two tones causes the observer to perceive two flashes of light.

Question 326

Ventriloquism effect

Answer 326

When sound is heard coming from a seen location, even though it is actually originating somewhere else. Also called visual capture.

Question 327

Vestibular system

Answer 327

The mechanism in the inner ear that is responsible for balance and sensing the position of the body.

Question 328

Visual capture

Answer 328

When sound is heard coming from a seen location, even though it is actually originating somewhere else. Also called the ventriloquism effect.

Question 329

Acoustic signal

Answer 329

The pattern of frequencies and intensities of the sound stimulus.

Question 330

Acoustic stimulus

Answer 330

The pattern of frequencies and intensities of the sound stimulus.

Question 331

Aphasia

Answer 331

Difficulties in speaking or understanding speech due to brain damage.

Question 332

Articulator

Answer 332

Structure involved in speech production, such as the tongue, lips, teeth, jaw, and soft palate.

Question 333

Audiovisual speech perception

Answer 333

A perception of speech that is affected by both auditory and visual stimulation, as when a person sees a tape of someone saying /ga/ with the sound /ba/ substituted and perceives /da/. Also called the McGurk effect.

Question 334

Broca’s aphasia

Answer 334

Language problems, caused by damage to Broca’s area in the frontal lobe, characterized by labored and stilted speech and short sentences.

Question 335

Broca’s area

Answer 335

An area in the frontal lobe that is important for language perception and production. One effect of damage is difficulty in speaking.

Question 336

Categorical perception

Answer 336

In speech perception, perceiving one sound at short voice onset times and another sound at longer voice onset times. The listener perceives only two categories across the whole range of voice onset times.

Question 337

Coarticulation

Answer 337

The overlapping articulation that occurs when different phonemes follow one another in speech. Because of these effects, the same phoneme can be articulated differently depending on the context in which it appears. For example, articulation of the /b/ in boot is different from articulation of the /b/ in boat.

Question 338

Dual-stream model of speech perception

Answer 338

Model that proposes a ventral stream starting in the temporal lobe that is responsible for recognizing speech, and a dorsal stream starting in the parietal lobe that is responsible for linking the acoustic signal to the movements used to produce speech.

Question 339

Formant

Answer 339

Horizontal band of energy in the speech spectrogram associated with vowels.

Question 340

Formant transition

Answer 340

In the speech stimulus, the rapid shift in frequency that precedes a formant.

Question 341

Indexical characteristic

Answer 341

Characteristic of the speech stimulus that indicates information about a speaker, such as the speaker’s age, gender, or emotional state.

Question 342

McGurk effect

Answer 342

A perception of speech that is affected by both auditory and visual stimulation, as when a person sees a tape of someone saying /ga/ with the sound /ba/ substituted and perceives /da/. Also called audiovisual speech perception.

Question 343

Motor theory of speech perception

Answer 343

A theory that proposes a close link between how speech is perceived and how it is produced. The idea behind this theory is that when we hear a particular speech sound, this activates the motor mechanisms that are responsible for producing that sound, and it is the activation of these motor mechanisms that enable us to perceive the sound.

Question 344

Multimodal

Answer 344

The involvement of a number of different senses in determining perception. For example, speech perception can be influenced by information from a number of different senses, including audition, vision, and touch.

Question 345

Phoneme

Answer 345

The shortest segment of speech that, if changed, changes the meaning of a word.

Question 346

Phonemic restoration effect

Answer 346

An effect that occurs in speech perception when listeners perceive a phoneme in a word even though the acoustic signal of that phoneme is obscured by another sound, such as white noise or a cough.

Question 347

Phonetic boundary

Answer 347

The voice onset time when perception changes from one speech category to another in a categorical perception experiment.

Question 348

Shadowing

Answer 348

Listeners’ repetition aloud of what they hear as they are hearing it.

Question 349

Sound spectrogram

Answer 349

A plot showing the pattern of intensities and frequencies of a speech stimulus.

Question 350

Speech segmentation

Answer 350

The process of perceiving individual words from the continuous flow of the speech signal.

Question 351

Statistical learning

Answer 351

The process of learning about transitional probabilities and other characteristics of the environment. Statistical learning for properties of language has been demonstrated in young infants.

Question 352

Transitional probabilities

Answer 352

In language, the chances that one sound will follow another sound. Every language has transitional probabilities for different sounds. Part of learning a language involves learning about the transitional probabilities in that language.

Question 353

Voice cells

Answer 353

Neurons in the temporal lobe that respond more strongly to same-species voices than to calls of other animals or to “non-voice” sounds.

Question 354

Voice onset time (VOT)

Answer 354

In speech production, the time delay between the beginning of a sound and the beginning of the vibration of the vocal chords.

Question 355

Wernicke’s aphasia

Answer 355

An inability to comprehend words or arrange sounds into coherent speech, caused by damage to Wernicke’s area.

Question 356

Wernicke’s area

Answer 356

An area in the temporal lobe involved in speech perception. Damage to this area causes Wernicke’s aphasia, which is characterized by difficulty in understanding speech.

Question 357

Word deafness

Answer 357

Occurs in the most extreme form of Wernicke’s aphasia, when a person cannot recognize words, even though the ability to hear pure tones remains intact.

Question 358

Active touch

Answer 358

Touch in which the observer plays an active role in touching and exploring an object, usually with his or her hands.

Question 359

Affective (emotional) component of pain

Answer 359

The emotional experience associated with pain—for example, pain described as torturing, annoying, frightful, or sickening.

Question 360

Cutaneous senses

Answer 360

The ability to perceive sensations, such as touch and pain, that are based on the stimulation of receptors in the skin.

Question 361

Direct pathway model of pain

Answer 361

The idea that pain occurs when nociceptor receptors in the skin are stimulated and send their signals to the brain. This model does not account for the fact that pain can be affected by factors in addition to stimulation of the skin.

Question 362

Duplex theory of texture perception

Answer 362

The idea that texture perception is determined by both spatial and temporal cues that are detected by two types of receptors. Originally proposed by David Katz and named the “duplex theory” by Hollins.

Question 363

Endorphin

Answer 363

Chemical that is naturally produced in the brain and that causes analgesia.

Question 364

Epidermis

Answer 364

The outer layers of the skin, including a layer of dead skin cells.

Question 365

Exploratory procedures EPs

Answer 365

People’s movements of their hands and fingers while they are identifying three-dimensional objects by touch.

Question 366

Gate control model

Answer 366

Melzack and Wall’s idea that perception of pain is controlled by a neural circuit that takes into account the relative amount of activity in nociceptors, mechanoreceptors, and central signals. This model has been used to explain how pain can be influenced by factors in addition to stimulation of receptors in the skin.

Question 367

Grating Acuity

Answer 367

In the cutaneous senses, a measure of acuity on the skin that is the narrowest spacing of a grooved surface on the skin for which orientation can be accurately judged. Can also be applied to detecting the orientation of a visual grating stimulus

Question 368

Haptic perception

Answer 368

The perception of three-dimensional objects by touch.

Question 369

Homunculus

Answer 369

Latin for “little man”; refers to the topographic map of the body in the somatosensory cortex.

Question 370

Inflammatory pain

Answer 370

Pain caused by damage to tissues, inflammation of joints, or tumor cells. This damage releases chemicals that create an “inflammatory soup” that activates nociceptors.

Question 371

Kinesthesis

Answer 371

The sense that enables us to feel the motions and positions of the limbs and body.

Question 372

Mechanoreceptor

Answer 372

Receptor that responds to mechanical stimulation of the skin, such as pressure, stretching, or vibration.

Question 373

Medial lemniscal pathway

Answer 373

A pathway in the spinal cord that transmits signals from the skin toward the thalamus.

Question 374

Meissner corpuscle RA1

Answer 374

A receptor in the skin, associated with RA1 mechanoreceptors. It has been proposed that the Meissner corpuscle is important for perceiving tactile slip and for controlling the force needed to grip objects.

Question 375

Merkel receptor

Answer 375

A disk-shaped receptor in the skin associated with slowly adapting fibers and the perception of fine details.

Question 376

Multimodal nature of pain

Answer 376

The fact that the experience of pain has both sensory and emotional components.

Question 377

Naloxone

Answer 377

A substance that inhibits the activity of opiates. It is hypothesized that naloxone also inhibits the activity of endorphins and therefore can have an effect on pain perception.

Question 378

Neuropathic pain

Answer 378

Pain caused by lesions or other damage to the nervous system.

Question 379

Nociceptive pain

Answer 379

This type of pain, which serves as a warning of impending damage to the skin, is caused by activation of receptors in the skin called nociceptors.

Question 380

Nociceptor

Answer 380

A fiber that responds to stimuli that are damaging to the skin.

Question 381

Opioid

Answer 381

A chemical such as opium, heroin, and other molecules with related structures that reduce pain and induce feelings of euphoria.

Question 382

Pacinian corpuscle RA2 or PC

Answer 382

A receptor with a distinctive elliptical shape associated with RA2 mechanoreceptors. It transmits pressure to the nerve fiber inside it only at the beginning or end of a pressure stimulus, and is responsible for our perception of vibration and fine textures that are perceived when moving the fingers over a surface.

Question 383

Pain matrix

Answer 383

The network of structures in the brain that are responsible for pain perception.

Question 384

Passive touch

Answer 384

A situation in which a person passively receives tactile stimulation.

Question 385

Proprioception

Answer 385

The sensing of the position of the limbs.

Question 386

Rapidly adapting RA receptor

Answer 386

Mechanoreceptors that respond with bursts of firing just at the onset and offset of a pressure stimulus. The Meissner corpuscle and the Pacinian corpuscle are rapidly adapting receptors.

Question 387

Ruffini cylinder

Answer 387

A receptor structure in the skin associated with slowly adapting fibers. It has been proposed that the Ruffini cylinder is involved in perceiving “stretching.”

Question 388

Secondary somatosensory cortex S2

Answer 388

The area in the parietal lobe next to the primary somatosensory area (S1) that processes neural signals related to touch, temperature, and pain.

Question 389

Sensory component of pain

Answer 389

Pain perception described with terms such as throbbing, prickly, hot, or dull.

Question 390

Slowly adapting SA receptor

Answer 390

Mechanoreceptors located in the epidermis and the dermis that respond with prolonged firing to continued pressure. The Merkel receptor and the Ruffini cylinder are slowly adapting mechanoreceptors.

Question 391

Somatosensory receiving area S1

Answer 391

An area in the parietal lobe that receives inputs from the skin and the viscera associated with somatic senses such as touch, temperature, and pain.

Question 392

Somatosensory system

Answer 392

The system that includes the cutaneous senses (senses involving the skin), proprioception (the sense of position of the limbs), and kinesthesis (sense of movement of the limbs).

Question 393

Spatial cue

Answer 393

In tactile perception, information about the texture of a surface that is determined by the size, shape, and distribution of surface elements such as bumps and grooves.

Question 394

Spinothalamic pathway

Answer 394

One of the nerve pathways in the spinal cord that conducts nerve impulses from the skin to the somatosensory area of the thalamus.

Question 395

Surface texture

Answer 395

The visual and tactile quality of a physical surface created by peaks and valleys.

Question 396

Synesthesia

Answer 396

A condition in which stimulation of one modality (such as vision) results in an experience in another modality (such as touch). For example a person with synesthesia who observes another person being touched may experience touch on the same part of his or her own body.

Question 397

Tactile acuity

Answer 397

The smallest details that can be detected on the skin.

Question 398

Temporal cue

Answer 398

cue In tactile perception, information about the texture of a surface that is determined by the rate of vibrations that occur as we move our fingers across the surface.

Question 399

Transmission cell (Tcell)

Answer 399

According to gate control theory, the cell that receives + and – inputs from cells in the dorsal horn. T-cell activity determines the perception of pain.

Question 400

Two-point threshold

Answer 400

The smallest separation between two points on the skin that is perceived as two points; a measure of acuity on the skin.

Question 401

Ventrolateral nucleus

Answer 401

Nucleus in the thalamus that receives signals from the cutaneous system.

Question 402

2-deoxyglucose technique

Answer 402

A procedure that involves injecting a radioactive 2-deoxyglucose (2DG) molecule into an animal and exposing the animal to oriented stimuli. The 2DG is taken up by neurons that respond to the orientation. This procedure is used to visualize orientation columns in the cortex.

Question 403

Across fiber patterns

Answer 403

The pattern of nerve firing that a stimulus causes across a number of neurons. Also referred to as distributed coding.

Question 404

Amiloride

Answer 404

A substance that blocks the flow of sodium into taste receptors.

Question 405

Amygdala

Answer 405

A subcortical structure that is involved in emotional responding and in processing olfactory signals.

Question 406

Anosmia

Answer 406

Loss of the ability to smell due to injury or infection.

Question 407

Bimodal neuron

Answer 407

A neuron that responds to stimuli associated with more than one sense.

Question 408

Calcium imaging

Answer 408

A method of measuring receptor activity by using fluorescence to measure the concentration of calcium inside the receptor. This technique has been used to measure the activation of olfactory receptor neurons.

Question 409

Chemotopic map

Answer 409

The pattern of activation in the olfactory system in which chemicals with different properties create a “map” of activation based on these properties. For example, there is evidence that chemicals are mapped in the olfactory bulb based on carbon-chain length.

Question 410

Detection threshold

Answer 410

The minimum amount of energy that can be detected. The detection threshold for smell is the lowest concentration at which an odorant can be detected. This threshold is distinguished from the recognition threshold, which requires a higher concentration of odorant.

Question 411

Flavour

Answer 411

The perception that occurs from the combination of taste and olfaction.
Frontal operculum cortex An area in the frontal lobe of the cortex that receives signals from the taste system.

Question 412

Glomeruli

Answer 412

Small structures in the olfactory bulb that receive signals from similar olfactory receptor neurons. One function of each glomerulus is to collect information about a small group of odorants.

Question 413

Insula

Answer 413

An area in the frontal lobe of the cortex that receives signals from the taste system and is also involved in the affective component of the perception of pain.

Question 414

Macrosmatic

Answer 414

Having a keen sense of smell; usually important to an animal’s survival.

Question 415

Microsmatic

Answer 415

Having a weak sense of smell. This usually occurs in animals like humans, in which the sense of smell is not crucial for survival.

Question 416

Nasal pharynx

Answer 416

A passageway that connects the mouth cavity and the nasal cavity.

Question 417

Neurogenesis

Answer 417

The cycle of birth, development, and death of a neuron. This process occurs for the receptors for olfaction and taste.

Question 418

Nontaster

Answer 418

A person who cannot taste the compound phenylthiocarbamide (PTC).

Question 419

Nucleus of the solitary tract

Answer 419

The nucleus in the brain stem that receives signals from the tongue, the mouth, and the larynx transmitted by the chorda tympani, glossopharyngeal, and vagus nerves.

Question 420

Odor map

Answer 420

The pattern of activation in the olfactory system in which chemicals with different properties create a “map” of activation based on these properties. For example, there is evidence that chemicals are mapped in the olfactory bulb based on carbon-chain length. Also called chemotopic map or odotoptic map.

Question 421

Odor object

Answer 421

The source of an odor, such as coffee, bacon, a rose, or car exhaust.

Question 422

Odotoptic map

Answer 422

The pattern of activation in the olfactory system in which chemicals with different properties create a “map” of activation based on these properties. For example, there is evidence that chemicals are mapped in the olfactory bulb based on carbon-chain length. Also called chemotopic map or odor map.

Question 423

Olfaction

Answer 423

The sense of smell. Usually results from stimulation of receptors in the olfactory mucosa.

Question 424

olfactometer

Answer 424

A device that presents olfactory stimuli with great precision.

Question 425

Olfactory bulb

Answer 425

The structure that receives signals directly from the olfactory receptors. The olfactory bulb contains glomeruli, which receive these signals from the receptors.

Question 426

Olfactory mucosa

Answer 426

The region inside the nose that contains the receptors for the sense of smell.

Question 427

Olfactory receptor

Answer 427

A protein string that responds to odor stimuli.

Question 428

Olfactory receptor neurons ORNs

Answer 428

Sensory neurons located in the olfactory mucosa that contain the olfactory receptors.

Question 429

Optical imaging

Answer 429

A technique that has been used to measure the activity of large areas of the olfactory bulb by measuring the intensity of red light reflected from the bulb.

Question 430

Oral capture

Answer 430

The condition in which sensations from both olfaction and taste are perceived as being located in the mouth.

Question 431

Orbitofrontal cortex

Answer 431

An area in the frontal lobe, near the eyes, that receives signals originating in the olfactory receptors. Also known as the secondary olfactory cortex.

Question 432

Papillae

Answer 432

Ridges and valleys on the tongue, some of which contain taste buds. There are four types of papillae: filiform, fungiform, foliate, and circumvallate.

Question 433

Pheromone

Answer 433

Chemical signal released by an individual that affects the physiology and behavior of other individuals.

Question 434

Piriform cortex

Answer 434

An area under the temporal lobe that receives signals from glomeruli in the olfactory bulb. Also called the primary olfactory cortex.

Question 435

Primary olfactory area

Answer 435

A small area under the temporal lobe that receives signals from glomeruli in the olfactory bulb. Also called the piriform cortex.

Question 436

Proust effect

Answer 436

The elicitation of memories through taste and olfaction. Named for Marcel Proust, who described how the taste and smell of a tea-soaked madeleine cake unlocked childhood memories.

Question 437

Recognition profile

Answer 437

The pattern of olfactory activation for an odorant, indicating which ORNs (olfactory receptor neurons) are activated by the odorant.

Question 438

Retronasal route

Answer 438

The opening from the oral cavity, through the nasal pharnyx, into the nasal cavity. This route is the basis for the way smell combines with taste to create flavor.

Question 439

Secondary olfcatory area

Answer 439

An area in the frontal lobe, near the eyes, that receives signals originating in the olfactory receptors. Also known as the orbitofrontal cortex.

Question 440

Sensory specific satiety

Answer 440

The effect on perception of the odor associated with food eaten to satiety (the state of being satiated or “full”). For example, after eating bananas until satiety, the pleasantness rating for vanilla decreased slightly (but was still positive), but the rating for banana odor decreased much more and became negative.

Question 441

Supertaster

Answer 441

A person who is especially sensitive to 6-n- propylthiouracil (PROP), a bitter substance.

Question 442

Taste bud

Answer 442

A structure located within papillae on the tongue that contains the taste cells.

Question 443

Taste cell

Answer 443

Cell located in taste buds that causes the transduction of chemical to electrical energy when chemicals contact receptor sites or channels located at the tip of this cell.

Question 444

Taste pore

Answer 444

An opening in the taste bud through which the tips of taste cells protrude. When chemicals enter a taste pore, they stimulate the taste cells and result in transduction.

Question 445

Taster

Answer 445

A person who can taste the compound phenylthiocarbamide (PTC).

Question 446

Video microscopy

Answer 446

A technique that has been used to take pictures of papillae and taste buds on the tongue.