Perception - Exam 2

Front 1

The tendency of neurons in the striate cortex to respond optimally to certain orientations and less to others.

Back 1

Orientation Tuning

Front 2

edit

Back 2

Filter

Front 3

The property of the receptive fields of striate cortex neurons by which they demonstrate a preference responding more rapidly when a stimulus is presented in one eye than when it is presented in the other.

Back 3

Ocular Dominance

Front 4

A cortical neuron with clearly defined excitatory and inhibitory regions.

Back 4

Simple Cells

Front 5

A neuron whose receptive field characteristics can't be easily predicted by mapping with spots of lite.

Back 5

Complex Cells

Front 6

The process by which a cell in the cortex first increases its firing rate as the bar length increases to fill up its receptive field and then decreases its firing rate as the bar is lengthened further.

Back 6

End Stopping

Front 7

edit

Back 7

Columns

Front 8

A 1mm block of the striate cortex containing two sets of columns, each covering every possible orientation (0-180 degrees) with one set preferring input from the right eye.

Back 8

Hypercolumn

Front 9

edit

Back 9

Cytochrome Oxidase (CO)

Front 10

A reduction in response caused by prior or continuing stimulation (gives psychologists a non-invasive electrode they can use to probe the human brain).

Back 10

Adaptation

Front 11

The perpetual illusion of tilt, produced by adaptation to a pattern of a given orientation.

Back 11

Tilt Aftereffect

Front 12

A pattern analyzer implemented by an ensemble of cortical neurons, in which each set of neurons is tuned to a limited range of spatial frequencies.

Back 12

Spatial-Frequency Channel

Front 13

A misalignment of the two eyes such that a single object in space is imaged on the fovea of one eye and on a nonfoveal area of the other (turned) eye.

Back 13

Strabismus

Front 14

A developmental disorder that is characterized by reduced spatial vision in an otherwise healthy eye, even with proper correction for refractive error.

Back 14

Amblyopia / "Lazy Eye"

Front 15

A loosely defined stage of visual processing that comes after basic features have been extracted from the image (early vision) and before object recognition and scene understanding (high-level vision).

Back 15

Middle (or mid-level) Vision

Front 16

A contour that is perceived, even though nothing changes from one side of the contour to the other in the image.

Back 16

Illusory Contours

Front 17

A school of thought believing that complex objects or perceptions could be understood by analysis of the components.

Back 17

Structuralism

Front 18

Theory that holds that the perceptual whole is more than the sum of its sensory parts.

Back 18

Gestalt Theory

Front 19

A set of rules describing which elements in an image will appear to group together.

Back 19

Gestalt Grouping Rules

Front 20

A Gestalt grouping principle stating that two elements will tend to group together if they seem to lie on the same contour.

Back 20

Good Continuation

Front 21

Carving an image into regions of common texture properties.

Back 21

Texture Segments

Front 22

A Gestalt grouping rule stating that the tendency of two features to group together will increase as the similarity between them increases (colour, size, orientation, form).

Back 22

Similarity

Front 23

A Gestalt grouping rule stating that the tendency of two features to group together will increase as the distance between them decreases.

Back 23

Proximity

Front 24

A rule for figure-ground assignment stating that symmetrical regions are more likely to be seen as a group.

Back 24

Symmetry

Front 25

A rule for figure-ground assignment stating that parallel contours are likely to belong to the same figure.

Back 25

Parallelism

Front 26

A Gestalt grouping rule stating that two features will tend to group together if they appear to be part of the same larger region.

Back 26

Common Region

Front 27

A Gestalt grouping rule stating that two items will tend to group together if they are connected.

Back 27

Connectedness

Front 28

A visual stimulus that gives rise to two or more interpretations of its identity or structure.

Back 28

Ambiguous Figure

Front 29

An outline that is perceptually bi-stable unlike the situation with most stimuli, two interpretations continually battle for perceptual dominance.

Back 29

Necker Cube

Front 30

A viewpoint position that produces some regularity in the visual image that is not present in the world (the sides of two independent objects lining up perfectly).

Back 30

Accidental Viewpoint

Front 31

The process of determining that some regions of an image belong to a foreground object and other regions are part of the background.

Back 31

Figure-Ground Assignment

Front 32

A rule for figure-ground assignment stating that if one region is entirely surrounded by another, it's likely that the surround region is the figure.

Back 32

Surroundness

Front 33

The degree to which two line segments appear to be a part of the same contour.

Back 33

Relatability

Front 34

Mental shortcut; "Rule of Thumb"

Back 34

Heuristic

Front 35

A feature of an object that is not dependent on the exact (or accidental) viewing position of the observer.

Back 35

Non-accidental Features

Front 36

The finding in various experiments that the properties of the whole object take precedence over the properties of parts of the object.

Back 36

Global Superiority Effect

Front 37

The proposal that the visual system recognizes objects by matching the neural representation of the image with a stored representation of the same "shape" in the brain.

Back 37

Naive Template Theory

Front 38

A description of an object in terms of the nature of its constituent parts and the relationships between those parts.

Back 38

Structural Description

Front 39

In Biederman's "recognition by components" model. the geometric ions out of which perceptual objects are built (specified as collections of non-accidental features).

Back 39

Geons

Front 40

Biederman's model of object recognition, which holds that objects are recognized by the identities and relationships of their component parts.

Back 40

"Recognition by Components" Model

Front 41

1. Aproperty of an image that doesn't change when observer viewpoint changes. 2. A class of theories of object recognition that proposes representations of objects that do not change when viewpoint changes.

Back 41

View-Point Invariance

Front 42

For an object, the label that comes to mind most quickly when we identify the object (bird, dog, chair).

Back 42

Entry-Level Category

Front 43

An inability to recognize faces (resulting from damage with specific areas in the temporal lobe).

Back 43

Phosopagnosia

Front 44

The phenomenon in which one of two functions, such as sight and hearing, can be damaged without harm to the other and vice versa.

Back 44

Double Dissociation

Front 45

The region of cortex bordering the primary visual cortex and containing multiple areas involved in visual processing.

Back 45

Extrastriate Cortex

Front 46

1. A region of damaged brain. 2. To destroy a section of the brain.

Back 46

Lesioned

Front 47

A failure to recognize objects in spite of the ability to see them (typically due to brain damage).

Back 47

Agnosia

Front 48

Part of the cerebral cortex in the lower portion of the temporal lobe, important in object recognition.

Back 48

Inferotemporal (IT) Cortex

Front 49

Brain regions that appear to have similar functions in different species.

Back 49

Homologous Regions

Front 50

A process that carries out a computation one neural step after another, without need for feedback from a later stage to an earlier stage.

Back 50

Feed-Forward Process

Front 51

The fact that an infinite set of different wavelength-intensity combinations can elicit exactly the same response from a single type of photoreceptor. One photoreceptor type cannot make color discriminations based on wavelength.

Back 51

Problem of Univariance

Front 52

Light intensities that are bright enough to stimulate the rod receptors but too dim to stimulate the cone receptors.

Back 52

Scotopic

Front 53

Light intensities that are bright enough to stimulate the cone receptors and bright enough to saturate the rod receptors (i.e. drive them to their maximum responses).

Back 53

Photopic

Front 54

A cone that is preferentially sensitive to short wavelengths; colloquially (but not entirely accurately) known as a "Blue-Cone".

Back 54

S-cone

Front 55

A cone that is preferentially sensitive to to middle wavelengths; colloquially (but not entirely accurately) know as a "green cone").

Back 55

M-cone

Front 56

A cone that is preferentially sensitive to long wavelengths; colloquially known as "red cone".

Back 56

L-cone

Front 57

The theory that the color of any light is defined in our visual system by the relationships of three numbers, the outputs of three receptor types now known to be the three cones.

Back 57

Trichromatic Theory of Color Vision/ Trichromancy/ Young-Helmholtz Theory

Front 58

Different mixtures of wave-lengths that look identical. More generally, any pair of stimuli that are perceived as identical in spite of physical differences.

Back 58

Metamers

Front 59

A mixture of lights. If light A and light B are both reflected from a surface to the eye, in the perception of color the effects of those two lights add together.

Back 59

Additive Color Mixture

Front 60

A mixture of pigments. If pigments A and B mix, some of the light shining on the surface will be subtracted by A and some by B. Only the remainder contributes to to the perception of color.

Back 60

Subtractive Color Mixtures

Front 61

The three-dimentional space, established because color perception is based on the outputs of three cone types, that describes the set of all colors.

Back 61

Color Space

Front 62

The chromatic (colorful) aspect of color (red, blue, green, yellow and so on).

Back 62

Hue

Front 63

The chromatic strength of a hue. White has zero saturation, pink is more saturated and red is fully saturated.

Back 63

Saturation

Front 64

The distance from black (zero brightness) in color space).

Back 64

Brightness

Front 65

A structure in the thalamus, part of the mid-brain, that receives input from the retinal ganglion cells and has input and output connections to the visual cortex.

Back 65

Lateral Geniculate Nucleus (LGN)

Front 66

A neuron whose output is based on a difference between sets of cones.

Back 66

Color-Opponent Cells

Front 67

The theory that perception of color is based on the output of three mechanisms, each of them based on an opponency between two colors: red-green, blue-yellow, and black-white.

Back 67

Opponent Color Theory

Front 68

A blue that has no red or green tint.

Back 68

Unique Blue

Front 69

Any of four colors that can be described with only a single color term: red, yellow, green, blue. Other colors (e.g. purple or orange) can be described as compounds (reddish blue, reddish yellow).

Back 69

Unique Hue

Front 70

A visual image seen after the stimulus has been removed.

Back 70

Afterimage

Front 71

A stimulus whose removal produces a change in visual perception or sensitivity.

Back 71

Adapting Stimulus

Front 72

An afterimage whose polarity is the opposite of the original stimulus. Light stimuli produce dark negative afterimages. Colors are complementary; for example, red produces green, yellow produces blue.

Back 72

Negative Afterimage

Front 73

The point at which an opponent color mechanism is generating no signal. If red-green and blue-yellow mechanisms are at their neutral points, a stimulus will appear achromatic. (The black-white process has no neutral point.)

Back 73

Neutral Point

Front 74

An inability to perceive colors that is caused by damage to the central nervous system.

Back 74

Achromatopsia

Front 75

An individual who suffers from color blindness that is due to the absence of M-cones.

Back 75

Deuteranope

Front 76

An individual who suffers from color blindness that is due to the absence of L-cones.

Back 76

Protanope

Front 77

An individual who suffers from color blindness due to the absence of S-cones.

Back 77

Tritanope

Front 78

A better term for what is usually called "color-blindness". Most "color-blind" individuals can still make discriminations based on wavelength. Those discriminations are different from the normal.

Back 78

Color-Anomalous

Front 79

An individual with only one cone type; are truly color blind.

Back 79

Cone Monochromats

Front 80

An individual with no cones of any type. In addition to being truly color blind, ___ are badly visually impaired in bright light.

Back 80

Rod Monochromats

Front 81

A failure to recognize objects in spite of the ability to see them; typically due to brain damage.

Back 81

Agnosia

Front 82

An inability to name objects in spite of the ability to see and recognize them (as shown by usage); typically due to brain damage.

Back 82

Anomia

Front 83

In sensation and perception, the idea that basic perceptual experiences (e.g. color perception) may be determined in part by the cultural environment.

Back 83

Cultural Relativism

Front 84

A color that can be experienced in isolation.

Back 84

Unrelated Color

Front 85

A color, such as brown or grey, that is seen only in relation to other colors. A "grey" patch in complete darkness appears white.

Back 85

Related Color

Front 86

The light that illuminates a surface.

Back 86

Illuminant

Front 87

The function relating the wavelength of light to the percentage of that wavelength that is reflected from a surface.

Back 87

Spectral Reflection Function

Front 88

The physical energy in a light as a function of wavelength.

Back 88

Spectral Power Distribution

Front 89

The tendency of a surface to appear the same color under a fairly wide range of illuminants.

Back 89

Color Constancy

Front 90

The percentage of light hitting a surface that is reflected and not absorbed into the surface. Typically ___ is given as a function of wavelength.

Back 90

Reflectance

Front 91

A philosophical position arguing that there is a real world to sense.

Back 91

Realism

Front 92

A philosophical position arguing that all we really have to go on is the evidence of the senses, so the world might be nothing more than an elaborate hallucination.

Back 92

Positivism

Front 93

Referring to the geometry of the world, so named in honor of Euclid, the ancient Greek geometer of the third century BCE. Parllel lines remain parallel lines as they are extended in space, objects maintain the same size and shape as they move around in space, the internal angles of a triangle always add to 180 degrees, and so forth.

Back 93

Euclidean

Front 94

The combination (or summation) of signals from each eye in ways that make performance on many tasks better with both eyes than with either eye alone.

Back 94

Binocular Summation

Front 95

The differences between the two retinal images of the same scene. The basis for stereopsis, a vivid perception of the three-dimensionality of the world that is not available with monocular vision.

Back 95

Binocular Disparity

Front 96

With one eye.

Back 96

Monocular

Front 97

The ability to use binocular disparity as a cue to depth.

Back 97

Stereopsis

Front 98

Information about the third dimension (depth) of visual space. May be monocular or binocular.

Back 98

Depth Cues

Front 99

A depth cue that is available even when the world is viewed with one eye alone.

Back 99

Monocular Depth Cue

Front 100

A depth cue that relies on information from both eyes. Stereopsis is the primary example in humans, but convergence and the ability of two eyes to see more of an object than one eye sees are also ___.

Back 100

Binocular Depth Cues

Front 101

A cue to relative depth order in which, for example, one object obstructs the view of part of another object.

Back 101

Occlusion

Front 102

A depth cue that provides information about the depth order (relative depth) but not depth magnitude (e.g. his nose is in front of his face).

Back 102

Nonmetrical Depth Cue

Front 103

A depth cue that provides quantitative information about distance in the third dimension.

Back 103

Metrical Depth Cue

Front 104

For purposes of studying perception of the three-dimensional world, the geometry the describes the transformations that occur when the three-dimensional world is projected onto a two-dimensional surface. For example, parallel lines do not converge in the world, but they do in the two-dimensional projection.

Back 104

Projective Geometry

Front 105

A comparison of size between items without knowing the absolute size of either one.

Back 105

Relative Size

Front 106

A depth cue based on the geometric fact that items of the same size form smaller images when they are farther away. An array of items that will change in size across the image will appear to firm a surface in depth.

Back 106

Texture Gradient

Front 107

As a depth cue, the observation that objects at different distances from the viewer on the ground plane will form images at different heights in the retinal image. Objects farther away will be seen as higher in the image.

Back 107

Relative Height

Front 108

A depth cue based on knowledge of the typical size of objects like humans or pennies.

Back 108

Familiar Size

Front 109

A depth cue that could specify, for example, that object A was twice as far away as object B without providing information about the absolute distance to either A or B.

Back 109

Relative Metrical Depth Cue

Front 110

A depth cue that provides absolute information about the distance in the third dimension (e.g. his nose sticks out 4 centimeters in front of his face).

Back 110

Absolute Metrical Depth Cue

Front 111

A depth cue based on the implicit understanding that light is scattered by the atmosphere. More light is scattered when we look through more atmosphere. Thus, more distant objects are subject to more scatter and appear fainter, bluer, and less distinct.

Back 111

Aerial Perspective (or Haze)

Front 112

A depth cue based on the fact that lines that are parallel in the three-dimensional world will appear to converge in a two-dimensional image.

Back 112

Linear Perspective

Front 113

The apparent point at which parallel lines receding in depth converge.

Back 113

Vanishing point

Front 114

A cue to distance or depth used by artists to depict three-dimensional depth in two-dimensional pictures.

Back 114

Pictorial Depth Cues

Front 115

Use of rules of linear perspective to create a two-dimensional image so distorted that it looks correct only when viewed from a special angle or with a mirror that counters the distortion.

Back 115

Anamorphosis (or Anamorphic Projection)

Front 116

An important depth cue that is based on head movement. The geometric information obtained from an eye in two different positions at two different times is similar to the information from two eyes in different positions in the head at the same time.

Back 116

Motion Parallax