CH 4, 5, 6
Gestalt
"form" the perceptual whole can be greater than apparent sum of sensory parts
The superior colliculus: how many?
- 2 superior colliculi ( one on each side of the brain)
What happens once the optic tract has left the chasm?
- 90% of axons have made their way to LGN of the thalamus - the pathway then leads to the visual cortex - 10% of the axons from the optic tract go to other locations in the brain -May go to superior colliculus
MT (V5) - middle temporal
- Area to the occipital lobe in the dorsal pathway - Specifc to motion detection and perception - cells are sensitive to the direction and speed of motion
Gestalt Psychologists- Wertheimer, Koffka, Kohler
- Claimed brain is holistic with self organizing tendencies - higher levels of organization take precedence over lower levels - thought stimuli could be interpreted directly
Parvocellular layers specialize in what functions?
- Foveal - color, acuity, texture, and depth
Ipsilateral Organization
- Same side organization - each eye sends a signal to each hemisphere
The parahippocampal place area (PPA)
- an area within the inferotemporal cortex - specific function of scene recognition: recognition of spatial landscapes, both indoor and outdoor
Prosopagnosia
- an inability to recognize the faces of familiar people - Happens when there is damage to the FFA
Areas in parietal lobe that are part of dorsal pathway
- anterior intraparietal - lateral intraparietal - medial intrapariretal involved with the visual guidance of action reaching and grasping for objects
Receptive fields of the LGN are more like retinal ganglion cells than receptors- Why
- center surround organization - some LGN cells respond maximally to stimuli that are present in the center of the cell's receptive field but absent outside the center ( or reserved) - LGN neurons show specific responding to edges spots and gratings
How are Stimulus- specific cells organized?
- complex, but predictable columns - this sensitivity can be mapped into predictable patterns
Superior colliculus
-Midbrain structure that sits below the LGN - important structure in eye movements
Parvocellular Pathways
-P pathway - characterized by the retinal ganglion cells known as midget retinal ganglion cells -Midget retinal ganglion cells usually receive input from a single cone in the fovea of the retina - carry detailed info necessary for visual acuity - When stimulated, the cells continue to fire throughout the time period when a stimulus is present - sensitive to wavelength
V2
-the second area in the visual cortex that receives input - considered the area that starts with visual associations rather than processing the input - Sometimes called the pre striate cortex
The maximum distance for which vergence is a reliable depth cue is:
2 m.
at ___ months of age, stereopsis develops rapidly in human infants
4
Color Contrast
A color perception effect in which the color of one region induces the opponent color in a neighboring region
Color Assimilation
A color perception effect in which two colors bleed into each other, each taking on some of the chromatic qualities of the other
Unrelated Color
A color that can be experienced in isolation
Related Color
A color that is seen only in relation to other colors ex. brown or grey
L-Cone
A cone that is preferentially sensitive to long wavelengths - "red cone"
M-Cone
A cone that is preferentially sensitive to middle wavelengths - "green cone"
S-Cone
A cone that is preferentially sensitive to short wavelengths - "blue cone"
Agnosia
A failure to recognize objects in spite of the ability to see them
rod monochromat
A person who has a retina in which the only functioning receptors are rods.
Adapting Stimulus
A stimulus whose removal produces a change in visual perception or sensitivity
Surfaces that reflect all light equally are called what? and what does that mean?
Achromatic- which means that with out color bc we do not see them as containing color
Single cell studies discovered what?
Adjacent cells in the LGN that respond to visual stimuli that excite adjacent cells in the retina
Why is seeking out faces important in human evolution?
Adults need to be able to recognize familiar kin and distinguish them from dangers
How is the left optic tract formed?
Axons from ganglion cells in the left half of the right retina and the left half of the left retina combine, forming the left optic tract
Why is the LGN thought of as a relay center?
Because it holds an intermediate position between the retinae of the eyes and the visual cortices
Parvocellular Layers
Cells are somewhat smaller
Retinal ganglion cells may be what?
Collecting input from many or more receptor cells
V3 and V4
Color processing
Main function of superior colliculus
Control of rapid eye movements
As frequency increases.. wavelength?
Decreases
Metemers
Different mixtures of wavelengths that look identical. More generally, any pair of stimuli that are perceived as identical in spite of physical differences.
Receptor fields of V1 cells: Hubel and Wiesel found what?
Different types of cells that had differing sensitivities to objects in their receptive fields
The rock band Foreigner scored a Top 10 single in 1978 with the song, "Double Vision." Were the members of the band vision scientists, the song might have been titled:
Diplopia
"Where/How" pathway
Dorsal pathway to Parietal Lobe - object oriented action - input from Magnocellular cells/layers - location, motion, space
What does spectral reflectance mean?
Every object has particular characteristics that permit it to absorb some wavelengths of light and reflect other wavelengths of light.
In the illustration, higher PSE scores indicate better color-matching abilities than lower PSE scores.
False
subtractive color mixing
Formation of colors by removing some wavelengths of light, leaving less light than was originally there.
Good Continuation
Gestalt grouping principle stating 2 elements will tend to group together if they seem to lie on the same contour
Proximity
Gestalt grouping principle stating that the tendency of grouping increases as distance decreases
Common Fate
Gestalt grouping principle that states when objects are moving in the same direction at the same speed we tend to perceive them as being together
Closure
Gestalt principle stating that a CLOSED contour is preferred to an OPEN contour
Similarity
Gestalt principle stating that the tendency of 2 features to group together will increase as similarity increases
What did Looser find with EEG technology?
Gounf that they could indeitfy an event related potential wave that occur after recognizing faces, real or inanimate, but not other stimuli
cone monochromat
Have only one cone type; truly color-blind
V2 cells also combine what?
Input from both eyes
Which layers do the retinal ganglion cells connect with?
Koniocellular and parvocellular layers
Simple cells found where?
Layer 4B of V1
Visual signals that leave V1 go in different directions. What's a a main one
Major pathway is from V1 to V2
The three distinct regions of V2 match with what?
Match directly up with the three different types of cells in V1
V5
Motion detection area
Layer 4B cells respond well to what?
Moving stimuli and stimuli of low contrast
The color orange (565 nm) activates
M‐cones and L‐cones.
Photopic
Referring to light intensities that are bright enough to stimulate the cone receptors and bright enough to "saturate" to rod receptors
Scotopic
Referring to light intensities that are bright enough to stimulate the rod receptors but too dim to stimulate the cone receptors
Where does vision come together?
Region has not been found where pathways come together
How do we tell a who from a what? How can we distinguish human faces from doll and mannequin faces?
Research done by Wheatley states that dolls draw us in and repels us simultaneously is that they have faces. Humans are drawn to seek out faces
Many experiments use what animal as research participants?
Rhesus Macaques : Monkey - their visual brains are very similar to ours
What do we see when a monochromatic light reflects off of a white surface?
See that surface as the color associated with that wavelength
Layer 4B - thick stripes
Sensitive to motion
Interblobs - interstripes
Sensitive to shape and position
Retinal Ganglion cells emerge from where?
Specific locations along the retina
Saturation
Strength of the hue
LGN is part of what?
Thalamus
Visual Spectrum
The band wavelength from 400 to 700 nm that people with normal vision can detect
Hue
The chromatic (colorful) aspect of color
Problem of Univariance
The fact that an infinite set of different wavelength intensity combinations can elicit exactly the same response from a single type of photoreceptor
Law of Simularity
The gestalt grouping law that element that are similar to one another tend to be perceived as a unified group - can refer to color, orientation, size, or motion
Cultural Relativism
The idea that basic perceptual experiences may be determined in part by the cultural environment
Illuminant
The light that illuminates a surface
The main pathway is directly from where? What does it do?
The main pathway is directly from the retinal ganglion cells to the superior colliculus. - it allows it to produce quick eye movements - blindsight
1 million retinal ganglion cells form what?
The optic nerve of each eye
Luminance
The perceived intensity of the color
Spectral Reflectance Function
The percentage of a particular wavelength that is reflected from a surface
Neutral Point
The point at which an opponent color mechanism is generating no signal
Univarience
The problem that an infinite set of different wavelength-intensity combinations can elicit exactly the same response from a single type of photoreceptors. One photoreceptor type cannot make color discriminations based on wavelength.
When you walk out of a dim building and into the bright sunshine, everything appears overly bright and washed out. _________________ and ______________ will occur so that you adjust to the new lighting conditions.
The pupils will constrict; light adaptation
Spectral reflectance
The ratio of light reflected by an object at each wavelength
Strong evolutionary pressures led to what?
The special module for face and recognition that exists in the FFA of the IT lobe, which allows us to quickly recognize familiar faces
Small number of these axons also head where?
They head to the frontal eye field region
How do objects get their color characteristics?
They reflect light as particular wavelengths
Looser used electroencephalogrphic ( EEG) technology for what?
To look at responses to photographs of real faces and photographs of dolls and mannequins. The EEG responses were averaged to look at characteristic wave patterns, known as event related potentials in response to these face stimuli
In the visual system, the nasal retina projects where?
To the opposite side of the brain
Color-Anomalous
Typically have three cone photopigments, but two of them are so similar that these individuals experience the world much the same way as individuals with only two cone types
Simple Cells
V1 neurons that respond to stimuli with particular orientations to objects within their receptive field - have clear excitatory and inhibitory regions - orientation selectivity
Reflectance of white clothes vs blue jeans
White clothes reflect wavelengths equally where as blue jeans absorb most wavelengths but reflect light at about 450 nm which we perceive as blue
Is it possible to generate a metamer for a pure wavelength light?
Yes, as long as a person has control over three independent lights.
Hypercolumn
a 1mm blof V1 containing both the ocular dominance and orientation columns for a particular region in visual space
Ocular Dominance Column
a column within V1 that is made up of neurons that receive input from only the left eye or only the right eye - perpendicular to orientation columns
Orientation Column
a column within V1 that is made up of neurons with similar responses to the orientation of a shape presented to those neurons
virtual reality
a computer-generated photograph, image, or environment that can be interacted with in an apparently real way
anomalous trichromacy
a condition in which all three cone systems are intact, but one or more has an altered absorption pattern, leading to different metameric matches than in the most common type of trichromatic individuals
Synchrony
a coordinated, rapid, and smooth exchange of responses
shadows
a depth cue arising because an object is in front of its shadow; the angle of the shadow can provide information about how far the object is in front of the background
Orienting tuning curve
a graph that demonstrates the typical response of a simple cell to stimuli or different orientations
Gelb effect
a phenomenon whereby an intensely lit black object appears to be gray or white in a homogeneously dark space
Retinotopic map
a point by point relation between the retina and V1
What type of lighting conditions occurs during the daytime in full sunlight? a. Photopic b. Mesopic c. Biopic d. Monopic e. Scotopic
a. Photopic
Which photoreceptors are most active when looking at a blue sky? a. S-cones b. M-cones c. L-cones d. M- and L-cones e. Rods
a. S-cones
Cone-opponent cells are found in the lateral-geniculate nucleus, but color-opponent cells are found in V1 of the cerebral cortex. a. True b. False
a. True
Double-opponent cells are thought to be particularly useful for detecting ______. a. color edges by enhancing color divisions at the edges of objects b.the subtle variations of hues that are close on the color wheel c. unique colors by having two receptors to discern them d. the edges of achromatic colors that do not activate normal opponent cells
a. color edges by enhancing color divisions at the edges of objects
Older 3D movies generally use _____ stereograms.
anaglyph
Stereograms are created by taking still photographs from two cameras separated by about 6 cm. In _____ stereograms, the two photographs are printed in different colors.
anaglyph
unique hue
any of four colors that can be described with only a single color term: red, yellow, green, blue
Fusiform Face Area (FFA)
area of the brain involved in facial processing
Interblob
areas sensitive to the orientation of an object
Blobs
areas within V1 that are sensitive to color
What physical feature of the human eye lends important support to the trichromatic theory of color vision? a. the optic nerve b. the various types of cones in the retina c. the lens d. the muscles that control the pupil
b. the various types of cones in the retina
In subtractive color mixing, a combination of the primary colors (cyan, magenta, and yellow) results in
black paint
The color of an object is determined by what?
by what wavelengths is reflects the most
A light of 485 nm is presented to a person's visual system. Which of the following is the best description of what happens next? a. A cone system that responds to specific wavelength will respond, while other cone systems will be silent. b. The light will not be responded to at all because that wavelength is invisible. c. All three cone systems will respond at varying strengths. Color is perceived from the mix of those responses. d. Only the S-cone will respond to this light, as it is out of the range of sensitivity for the other cone systems.
c. All three cone systems will respond at varying strengths. Color is perceived from the mix of those responses.
Which photoreceptor are most active when looking at a beautiful sunset? a. S-cones b. M-cones c. L-cones d. Rods e. S-cones and rods
c. L-cones
Texture Segmentation
carving of an image into regions of common texture properties ** not for combinations of features **
Koniocellular layers also specialize in what?
color
Decoding Method
determine the nature of a stimulus from pattern of responses in a brain or artificial network - can be external stimulus OR internal state (dreaming) ** doesn't prove area is a locus of recognition** ** just shows object identity info is present in area **
Dichomate
dogs and most mammals. Similar to R and G colorblind in humans.
Extrastriate Body Area (EBA)
extrastriate region of visual cortex activated by images of the body
Tetrachromats
have four cone types and can see 100 times as many colors as a normal trichromat
V4
higher level visual processing cortex - typically sensitive to/prefers color
Simple cells receive input from mainly where?
layer 4C
Superordinate-Level Category
less specific label for identified object EX) animal
monochromatic light
light consisting of one wavelength
photopic
light intensities that are bright enough to stimulate the cone receptors and bright enough to "saturate" the rod receptors
monochromatic light
light of only one wavelength or a very narrow band of wavelengths
cortical achromatopsia
loss of color vision due to damage to the occipital lobe
Stereopsis may be simulated using:
motion parallax.
color opponent cells
neurons that are excited by one color in the center and inhibited by another color in the surround, or neurons that are inhibited by one color in the center and excited by another color in the surround
non corresponding points
refers to a situation in which a point on the left retina and a point on the right retina would not coincide if the two retinae were superimposed
Area 17 and BA 17
refers to the area's position on the Brodmann charts
Striate Coretx
refers to the way the brain cells in this area look under certain straining conditions - appear striated
Some fibers go to pineal gland and do what?
regulate circadian rhythms
Parallelism
rule for figure-ground assignment stating that parallel contours are likely to belong to the same figure
Symmetry
rule for figure-ground assignment stating that symmetrical regions are more likely to be seen as a figure
constancy
the ability to perceive an object as the same under different conditions
color constancy
the ability to perceive the color of an object despite changes in the amount and nature of illumination
lightness constancy
the ability to perceive the relative reflectance of objects despite changes in illumination
Cortical Magnification
the allocation of more space in the cortes to some sensory receptors than to others example: the fovea has a larger cortical area than the periphery
visual angle
the angle of an object is relative to the observer's eye
visual spectrum
the band of wavelengths from 400 to 700 nm that people with the most common classes of cones vision can detect
Geons
the geometric ions out of which objects are built according to Biederman's Recognition-By-Components Model
Location of FFA
the ventral surface of the temporal lobe
Smooth Pursuit
voluntary tracking eye movements
Parvocellular layer 4 and 6
Receive input from contralateral eye
Retinal ganglion cells close to the fovea do what?
Receive input from few or just one receptor cell
Achromatic
Referring to any color that lacks a chromatic component ex. black, white, grey
Brightness
The perceptual consequence of the physical intensity of a light ex. the sun appears brighter than the moon
Spectral Power Distribution
The physical energy in a light as a function of wavelength
Perceptual Organization
The process by which multiple objects in the environment are grouped, allowing us to identify multiple objects in complex scenes - permits use to group what we see into coherent perceptions - needed to group some objects and separate others
Color Constancy
The tendency of a surface to appear the same color under a fairly wide range of illuminates
opponent color theory
The theory that perception of color is based on the output of three mechanisms, each of them resulting from an opponency between two colors: red-green, blue-yellow, and black-white.
Opponent Color Theory
The theory that perception of color is based on the output of three mechanisms, each of them resulting from an opponent between two colors: red-green, blue-yellow, and black-white
Trichromatic Theory of Color Vision
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 three cones
Color Space
The three-dimensional space that describes the set of all colors
Lateral Geniculate Nucleus (LGN)
A structure in the thalamus that receives input from the retinal ganglion cells and has input and output connections to the visual cortex
Afterimage
A visual image seen after the stimulus has been removed
Object Agnosia
An acquired deficit in identifying and recognizing objects even though though vision remains intact
Negative Afterimage
An afterimage whose polarity is the opposite of the original stimulus
Anomia
An inability to name objects in spite of the ability to see and recognize them
Achromatopsia
An inability to perceive colors that is caused by damage to the central nervous system
Protanope
An individual who suffers from colorblindness that is due to the absence of L-cones
Deuteranope
An individual who suffers from colorblindness that is due to the absence of M-cones
Tritanope
An individual who suffers from colorblindness that is due to the absence of S-cone
Rod Monochromat
An individual with no cones of any type
Cone Monochromat
An individual with only one type - truly color blind
Single-Opponent Cell
Another way to refer to cone-opponent cells, in order to differentiate them from double-opponent cells
Unique Hue
Any of four colors that can be described with only a single color term: red, green, yellow, blue - other colors can be described as compounds
additive color mixing
Formation of colors by superimposing lights, putting more light in the mixture than exists in any one light by itself.
Where else does the superior colliculus receive input?
From other systems - auditory and somatosensory
Difference between neurons in the IT area verses neurons in V1 and V4 area
IT neurons have larger receptive fields IT neurons detect particular kinds of objects anywhere in the visual field rather than specific features in specific places
Viewpoint Invariant
Identification does not depend on the particular view we have of the object
What does the LGN preserve?
Information about both where the visual world information is coming from and which eye is detecting that info
Which of the following is a motion depth cue?
accretion
Agnosias
acquired sensory deficits that occur without any loss of sensation
By using two squares within the ISLE illustration, what changes do you need to make to transform fire-engine red to mint green?
adjust the hue, decrease the saturation
Why is edge detection critical to perception?
allows the visual system to determine where one object ends and where the next object begins
The left- and right-eye retinal images are fused for objects located:
along the horopter and within Panum's area.
Object agnosia
an acquired deficit in identifying and recognizing objects even though vision remains intact
Frontal eye field region
an area in the frontal lobe also in instrumental in eye movements
The Fusiform Face Area (FFA)
an area in the inferotemporal area of the temporal lobe that specializes in recognizing familiar faces
v4
an area of the brain involved in both color vision and shape perception
Scotoma
an area partially or completely destroyed cells, resulting in a blind spot in particular region of the visual field - blindsight may exist within the scotoma region
Extrastriate Body Area
an area within the inferotemporal cortex that is activated when its cells view bodies or body parts, but not faces
hue cancellation
an experiment in which observers cancel out the perception of a particular color by adding light of the opponent color
Inferotemporal Cortex (IT)
cerebral cortex in lower Temporal Lobe involved in object recognition - shapes and images > spots and lines ** cells said to have plasticity in monkeys' homologous regions**
Border Ownership
characteristic og extrastriate neurons - edges between object and background belong to the object
The physical stimulus is?
the wavelength of the light entering our eye
trichromatic theory
theory of color vision that proposes three types of cones: red, blue, and green
There are more connections from the cortex back to the LGN than.. ??
there are from the LGN to the cortex
subtractive color mixing
color mixing in which a new color is made by the removal of wavelengths from a light with a broad spectrum of wavelengths -mix substances w/ different absorption patterns
Blobs to thin stripes
color response
In the spectrum we see different wavelengths as different...
colors
complementary colors
colors on the opposite side of the color wheel that when added together in equal intensity give a white or gray or black
unique colors
colors that can be described only with a single term-red, green, blue, and yellow
hofeldt and hoefle (1993)
compared professional baseball players in the highest profession league with the minor league -measured stereopsis abilities. -major league players were better findings: -binocular information is important for baseball batting and baseball batters do have a dominant eye,
achromatopsia
complete color blindness
Low-level Vision
consists of basic features from retinal input - luminance - spots - bars - orientation - center-surround receptive fields RETINA / LGN / V1
Extrastriate Cortex
cortex beyond the primary visual cortex (V1) involved in visual processing of higher order features - neurons show preferences ... "border ownership"
movement based cues
cues about depth that can be seen with a single eye in which the inference of distance comes from motion
In the _____ depth cue called _____, parallel lines appear to converge with distance.
monocular; linear perspective
stereopsis
the sense of depth we perceive from the visual system's processing of the comparison of the two different images from each retina
zero disparity
the situation in which retinal images fall along the corresponding points, which means that the object is along the horopter
Engram
the specific location of a specific memory, such as the visual identity of your cat or your grandma
Preferred orientation of a simple cell
the stimulus orientation that produces the strongest response
Representation
the storage and reconstruction of info in memory when that info is not in use
Individuals lacking short-wavelength cones are called __________ and have difficulty seeing __________.
tritanope, blue
Deep Neural Networks
type of ""machine learning" in AI where a computer is programmed to learn something; can provide answers for stimuli never before seen based on known answers to similar stimuli - layered processing of features
The color violet
unique because it is a pure spectral color and it has a very short wavelength.
Subtraction Method
use of functional magnetic imaging to compare brain activity in 2 conditions: 1. WITH process of interest 2. WITHOUT process of interest to show areas involved in a specific mental process
Cole's eyes rotate outward as his focus moves from a text message on the phone in his hand an image on the television screen across the room. The movement of his eyes is called:
vergence
Pictorial depth cues include each of the following EXCEPT:
vergence
Subordinate-Level Category
more specific label for identified object EX) eagle (instead of entry-level "bird")
Saccade
most common and rapid - sudden eye movements and are used to look from one object to another
color-opponent cells
neurons that are excited by one color in the center and inhibited by another color in the surround, or neurons that are inhibited by one color in the center and excited by another color in the surround
cone opponent cells
neurons that are exited by the input from one cone type in the center but inhibited by the input from another cone type in the surround
End- stopped neurons
neurons that respond to stimuli that end within the cell's receptive field
V2
next "level" of visual processing cortex
Accidental Viewpoints
viewing position that produces some regularity in the visual image not present in world - assumptions based on implicit understandings
Critical locus in the thalamus for what?
visions
afterimages
visual images that are seen after an actual visual stimulus has been removed
Occlusion
visual system assumes another contour must be occluding another line of a complete image
Gestalt Grouping Principles
visual system's interpretation of the raw retinal image that describes which elements of the image will be grouped together - good continuation - closure - texture segmentation - similarity - proximity - parallelism - symmetry - camouflage
The hue of an object is most closely associated with the _____________ of the reflected light.
wavelength
Metamers are a psychophysical color match between two patches of light that have different sets of _______________.
wavelengths
How do we detect faces that have minds attached?
when we see a face it instantly activates face- sensitive areas of the brain such as FFA. However animate face recognition requires an additional step: to associate the face with a moving living animate being, thus we make an additional step to go from face to mind
Heterochromatic Light
white light, consisting of many wavelengths
heterochromatic light
white light, consisting of many wavelengths
In the additive color mixing illustration, a combination of the primary colors (red, green and blue) results in _____.
white light.
What color is generated when M-cones and L-cones are equally activated?
yellow
The horopter is an imaginary line connecting points corresponding to _____ retinal image disparity.
zero
Objects appear to change in size as we move toward or away from them. This is a motion depth cue called:
optic flow.
A change in position is called:
parallax
Trichomats
people (and cats) who have normal color vision
Illusory Contour
perceived contour despite no change on either side in image
color consistency
perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
Bayesian Approach
perception is a combination of current stimulus and our knowledge about conditions (likelihood of hypothesis) ** can use mathematical ways to model how implicit knowledge can constrain interpretations ** 1. Prior Probability 2. Consistence with observation
Global Superiority Effect
properties of the WHOLE OBJECT take precedence over properties of the PARTS of the object
Individuals lacking long-wavelength cones are called __________ and have difficulty seeing __________.
protanope, red
Parvocellular layer 3 and 5
receive input from ipsilateral eye
Magnocellular Layer 1
receives input from contralateral side
Magnocellular Layer 2
receives input from the ipsilateral eye
Right superior colliculus function
receives input from the left visual world
Left superior colliculus function
receives input from the right visual world
Viewpoint Dependent
recognition may be affected by orientation of object
In the airplane simulation, when the light entering the cockpit becomes darker, the automated program ______________ of the display, thereby _____________ perceived by the pilot.
reduces the intensity; increasing the contrast
Scotopic
referring to light intensities that are bright enough to stimulate the rod receptors but too dim to stimulate the cone receptors
corresponding points
refers to a situation in which a point on the left retina and a point on the right retina would coincide if the two retinae were superimposed
In the illustration, if you move the cursor dot toward the center of the color wheel, the _________ of the sample square changes.
saturation
Structuralism/Structuralists
school of thought stating that complex objects/perceptions could be understood by analysis of components (structure of image)
V4
sends info to inferotemporal cortex - sensitive to binocular disparity - critical to color vision and shape recognition
Tritanopia
an inherited form of defective color vision in which hues with short wavelengths are confused; "blue" cones are either lacking or faulty
Deuteranopia
an inherited form of defective color vision in which red and green hues are confused; "green" cones are filled with "red" cone opsin
Homologous Regions
areas that share a majority of the same/similar functions between species EX) IT cells in monkeys (and humans)
LGN has an organization oriented to the visual world- how
as adjacent areas in the visual world are picked up by adjacent areas of the retina, which are in turn projects to adjacent areas of the LGN
Contour Completion
assumptions made by the brain to complete contours despite the fact that nothing has changed from one side of the contour to the other in an image (Illusory Contours)
Where is Superior colliculus?
at the top of the brainstem, just beneath the thalamus
The Blue Ridge Mountains in Virginia and the Smoky Mountains in Tennessee are aptly named given their appearance to a distant observer. The names of these ranges reflect the monocular depth cue:
atmospheric perspective.
Suppose you have a red surface and want it to seem as red as possible. What sort of background should you put behind it, according to the color contrast effect? a. Red b. Green c. Blue d. Yellow e. Orange
b. Green
Which photoreceptors are most active when looking at a green forest? a. S-cones b. M-cones c. L-cones d. Rods e. All cones would be equally active.
b. M-cones
The principle of univariance refers to the fact that we have three types of cones in our visual system. b. an infinite set of different wavelength-intensity combinations can elicit the same response from a single type of photoreceptor. c. an infinite set of different wavelength-intensity combinations can elicit the same response from three different types of photoreceptors that are compared to each other. d. many shades of colors appear the same under certain lighting conditions. e. an infinite set of cones can record the same response from a single wavelength.
b. an infinite set of different wavelength-intensity a.
Neurons that respond best when they are excited by the input from one cone type in the center, but inhibited by the input from another cone type in the surround, are known as ______ cells. a. chromatic b. cone-opponent c. trichromatic d. color-inhibition
b. cone-opponent
Hurvich and Jameson (1957) developed an experiment in which observers cancel out the perception of a particular color by adding light of the opponent color. This procedure is known as ______. a. afterimage detection b. hue cancellation c. simultaneous color contrast d. spectral reflectance
b. hue cancellation
If you stare at a bright incandescent light bulb for even a short time and then close your eyes, you will continue to see an afterimage of that light bulb for a relatively brief period. But you will notice that even though the light bulb has a yellowish hue, your afterimage will appear somewhat blue. This phenomenon supports the ______ theory of color vision? a. trichromatic b. opponent-process c. competitive d. ancillary
b. opponent-process
cue approach to depth perception
the system whereby depth perception results from three sources of information, monocular cues to depth present in the image, binocular cues from the comparison of images in each eye, and cues from focusing the eyes, such as vergence and accommodation
Viewpoint Invariance
the perception that an object does not change when an observer sees the object from a new vantage point
linear perspective
the pictorial depth cue that arises from the fact that parallel lines appear to converge as they recede into the distance
Blindsight
the presence of visual abilities in the absence of the visual cortex - Example: the patient claims to be blind but makes visual response
unilateral dichromacy
the pressence of dichromacy in one eye but trichromatic vision in the other
univariance
the principle whereby any single cone system is color-blind, in the sense that different combinations of wavelength and intensity can result in the same response from the cone system
correspondence problem (depth perception)
the problem of determining which image in one eye matches the correct image in the other eye
Grouping
the process by which elements in a figure are brought together into a common unit or object
dishabiutation
the process in which, after habitation has occurred, changing the stimulus causes the organism to respond again
Segregation
the process of distinguishing two objects as being distinct or discrete
lightness
the psychological experience of the amount of light that gets reflected by a surface
saturation
the purity of light
spectral reflectance
the ratio of light reflected by an object at each wavelength
horopter
the region in space where the two images from an object fall on corresponding locations on the two retinae
Inferotemporal (IT) area
the region in the temporal lobe that receives input from the visual pathway; one of its functions is object identification
Panum's area of fusion
the region of small disparity around the horopter where the two images can be fused into a single perception
opponent-process theory of color perception
the theory that color perception arises from three opponent mechanisms, for red-green, blue-yellow, and black-white
In the hue cancellation experiments described in the textbook, if the starting color were too reddish, you would add a. yellow. b. blue. c. green. d. purple. e. orange.
c. green.
size-distance invariance
the relation between perceived size and perceived distance, whereby the perceived size of an object depends on its perceived distance, and the perceived distance of an object may depend on its perceived size
In the figure below, the two inner circles are identical physically. That the surroundings make them appear to have different colors is an example of ______. a. hue cancellation b. spectral reflectance c. simultaneous color contrast d. afterimage detection
c. simultaneous color contrast
What primarily differentiates the three types of cone photoreceptors in the retina? a. the type of nerve leading from them to the brain b. the way they are shaped c. the wavelength of light they are sensitive to d. the section of the retina where they are found
c. the wavelength of light they are sensitive to
According to the _______ theory, the color of any light is defined in our visual system by the relationships among three numbers of a set. a. univariance b. saturation c. trichromacy d. opponent color e. subtractive color mixing
c. trichromacy
trichromatic theory of color
the theory that the color of any light is determined by the output of the three cone systems in our retinae
The principle whereby any single cone system is colorblind, in the sense that different combinations of wavelength and intensity can result in the same response from the cone system, is known as ______. a. cone specificity b. color deficient theory c. univariance d. deuteranopia
c. univariance
double opponent cells
cells that have a center, which is excited by one color and inhibited by the other; in the surround, the pattern is reversed -useful for detecting color edges
Grandmother Cells
cells that respond better to whole objects/images - downstream visual processing - cells in human Temporal Lobe shown using electrodes to respond well to highly specific objects/shapes
Lateral Geniculate Nucleus-
a bilateral structure that relates info from the optic nerve to the visual cortex - one present in each hemisphere - each layer receives input from only one eye
binocular disparity
a binocular depth cue because our two eyes are in different locations in our head and therefore have slightly different views of the world.
color contrast
a color perception effect in which the color of one region induces the opponent color in a neighboring region
color assimilation
a color perception effect in which two colors bleed into each other, each taking on some of the chromatic quality of the other
protanopia
a lack of L-cones, leading to red-green deficiency; this trait is sex-linked and thus more common in men
tritanopia
a lack of S-cones, leading to blue-yellow color deficiency; this trait is rare and not sex linked
Thalamus
a large structure that serves as a relay station for a number of sensory systems, including both vision and audition
motion parallax
a monocular cue depth cue arising from the relative velocities of objects moving across the retinae of a moving person
texture gradient
a monocular depth cue that occurs because textures become finer as they recede in the distance
optic flow
a motion depth cue that involves the relative motion of objects as an observer moves forward or backward in a scene
simultaneous color contrast
a phenomenon that occurs when our perception of one color is affected by a color that surrounds it
atmospheric perspective
a pictorial depth cue that arises from the fact that objects in the distance appear blurred and tinged with blue
Top - down processing
a process whereby our existing knowledge of objects influences how we perceive them
Bottom - Up processing
a process whereby physical stimuli influence how we perceive them
Edge Detection
a process whereby the boundaries of shapes or objects are detected within an image - may use Illusory Contours
metamer
a psychophysical color match between two patches of light that have different sets of wavelengths
Ames Room
a specially constructed room where two people of the same size standing in the two back corners will look very different in height
binocular cells
cells with two receptive fields, one for each eye; their main function is to match the images coming to each eye
quality
a value that changes but does not make the value larger or smaller
relative height
a visual cue in which objects closer to the horizon are seen as more distant
occulusion
a visual cue that occurs when one object partially hides or obstructs the view of a second object; we infer that the hidden object is farther away from us than the object that obstructs it
Ambiguous Figures
a visual stimulus that gives 2 or more interpretations of identity or structure of an object EX) Necker Cube ** Visual Angle is proportionate to viewing distance and physical size **
What theory proposes that all colors on the color circle can be represented by the following pairs of opposing mechanisms: blue-yellow, red-green, and black-white? a. opponent-process theory of color vision b. competitive theory of color vision c. Hering-Osbourne theory of color vision d. trichromatic theory of color vision
a. opponent-process theory of color vision
Figure-Ground Assignment/Segmentation
ability to distinguish figures (objects in foreground) from ground (surface or object behind)
Heuristics
Mental shortcuts or "rules of thumb" that often lead to a solution (but not always)
Pandemonium Model
"noise and chaos" Oliver Selfridge's model of object (letter) recognition that states features are extracted/identified (by feature demons) and organized (by cognitive demons) so that information from all features can be pooled (by the decision demon) based upon strength of signal from each cognitive demon
During sleep, the thalamus is inhibited by what? Why?
- Complex neural circuitry in the brain - a person;s eyes can be open during sleep, but they will not see, bc the info does not leave the LGN
Mid-level Vision
- EDGE DETECTION stage of visual processing where basic features are organized - NO MEANING UP UNTIL THIS POINT - BEFORE object recognition and scene understanding V2 / V4
Grandmother Cells and Specific Coding in the IT Cortex
- How specific brain regions are to function and to particular stimuli? - Is there an area in the brain, or more specifically, in the IT cortex, that codes for your grandmother, but no other person? - quest has been labeled the search for the engram
Bistratisfied Retinal Ganglion Cells
- K cells - project to koniocelllar layer of LGN - represent 10 % of ganglion cells, possess low sensitivity to light and are sensitive to wavelength
Koniocellular Pathway
- K pathway - starts with bistratisfied retinal ganglion cells and projects to the koniocellular layers of the LGN \ - cells recieve input from cones - more convergence among these cells - lower acuity than the P pathways - cells show some role in color vision
Parasol retinal ganglion cells
- M cells - project to the magnocellular layer of the LGN -represent 10% of ganglion cells and possess high sensitivity to light
Magnocellular pathway
- M pathway - starts with the parasol retinal ganglion cells and projects to the magnocellular layers of the LGN
Lateral Geniculate nucleus cells
- Parasol retinal ganglion cells (m cells) - midget retinal ganglion cells ( pcells) - Bistratified Retinal ganglion cells ( k cells)
Receives feed back from the the visual cortex and what?
- Projects to areas of the visual cortex beyond the primary visual cortex - Also projects to the koniocellular levels of the LGN
Two kinds of voluntary eye movements
- Smooth Pursuit - Saccade
What happens as a result of retinal ganglion cells connecting?
- The retinal ganglion cells connect with with the Koniocellular and parvocellular layers of the LGN, which in turn project to V1 Layers 2 and 3, and 4B - From V1, signal is sent to other visual area in the occipital cortex and then to the inferotemporal cortex - V1 to V2 to V3 and V4
Topographic agnosia
- a deficit in recognizing spatial landscapes - related to damage to the parahippocampal place area
Occipital face area
- an area in the brain in the occipital lobe associated with recognizing faces as distinct from other objects - making the initial identification of a face being a face regardless of its familiarity
Our ability to detect objects must overcome three aspects for the environment
- image clutter - Object variety - Variable views
The primary visual cortex (V1)
- in occipital lobe -the area of the cerebral cortex that receives input from the LGN - first area of the cortex to receive information
Achromatic surfaces
- judged to be white to gray to black - what matters is the proportion of ambient light they reflect
Magnocellular layers
- layers 1 and 2 - cell layers are larger
LGN is divided into 6 layers
- magnocellular layers: layers 1 and 2 - Parvocellular layers: layers 3-6
Magnocellular layers are sensitive to?
- motion - light detection - sudden changes in the visual image
Complex Cells
- neurons in V1 that respond optimally to stimuli with particular orientations - unlike simple cells, they respond to a variety of stimuli across different locations , particularly to moving stimuli
Torsten Wiesel and David Hubel
- noble prize for work on the anatomy and physiology of visual cortex - discovered that areas of the visual brain, including areas in the thalamus and areas in the occipital cortex, are specifically sensitive to certain kinds of stimuli
Organization of V1
- ocular dominance column - Hypercolumn
Contralateral Representation of Visual Space
- opposite side organization - left optic tract receives info from the right visual world
Contralateral organization
- opposite side organization -
Rules that govern what we see as figure and what we see as ground
- perceived depth affects it - a figure is more likely to be perceived as being the foreground if it is perceived to be on the convex side of a border - symmetry affects figure ground organization - convex affects it - convex or concave bands affect it
In magnocellular pathways the cells...?
- receive input from photoreceptors ( both rods and cones) - have large receptive fields and are sensitive to light, but not color - lower acuity - helps with visual functions such as light detection and motion detection
Wavelength
- refers to the distance between two peaks of light energy - the inverse of frequency
Neurons in each layer of the LGN show retinotopic organization- What does this mean
- retinal ganglion cells from adjacent regions of the retina connect to cells in adjacent areas of LGN
Areas like the _______ makes it possible to make ____________
- superior colliculus - visual responses
Ventral Pathway ( P pathway)
- the "what" - starts with the bistratified and midget retinal ganglion cells and continues through the visual cortex into the inferotemporal cortex in the temporal lobe - as it codes for object identification as well as color vision - critical for shape recognition
Dorsal Pathway ( M pathway)
- the "where" - starts with the parasol ganglion cells, which then project to magnocellular cells - Pathway then lead to layer 4 in V1 - Then projects to V2 and then ends up in the parietal cortex - After it leaves V@, it is sent to MT - Once it leaves MT, it is sent across the occipitoparietal junction into the parietal lobe
LGN receives input from where?
- the cortex - the brainstem - other loci in the thalamus - within the LGN itself
We divide the world into two elements
- the figure that is the objet of regard - ground or background
Optic Tract
- the optic nerve starting at the optic chasm and continuing into the brain - then proceeds to the right hemisphere of the brain
Neurons in the brain have specific _______ fields. The cells respond to what?
- visual -the cells respond to some patterns of stimuli but not others
Midget Retinal Ganglion cells
-P cells - project to the parvocellular layer of LGN - represent 80 % of ganglion cells, posses low sensitivity to light, and are sensitive to wavelength
Mondrian experiments by Edwin Land (1977)
-three lights w/ different wavelength compose different colored rectangles -adjusted wavelengths, and asked participants what color the rectangle is. -supports the idea that color constancy is achieved by an implicit comparison across different objects in a scene, each object reflecting a different wavelength, allowing the visual system to extract the illumination from known reflective properties
Additive Color Mixture
1. A mixture of LIGHTS 2. 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 ex. computer screens
Subtractive Color Mixture
1. A mixture of PIGMENTS 2. 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 the perception of color ex. colored filters over theatre lights
Metamers
1. Different mixtures of wavelengths that look identical 2. Any pair of stimuli that are perceived a identical in spite of physical differences
The short system of cones is optimally sensitive to ___________ wavelengths of light.
420 nm
color-anomalous
A better term for what is usually called "color-blind." Most "color-blind" individuals can still make discriminations based on wavelength.
Cone-Opponent Cell
A cell type that, in effect, subtracts one type of cone input fro another
Double-Opponent Cell
A cell type, found in the visual cortex, in which one region is excited by one cone type, combination of cones, or color and inhibited by the opponent cones or color
double-opponent cell
A cell type, found in the visual cortex, in which one region is excited by one cone type, combination of cones, or color and inhibited by the opponent cones or color (e.g., R+/G-). Another adjacent region would be inhibited by the first input and excited by the second (thus, in this example, R-/G+).
Object Recognition in the inferotemporal (IT)
Information in the ventral pathway leaves the occipital lobe and heads into the IT area of the temporal lobe
Integral to understanding object perception
Memory and Perception
Development of the visual system
Nature Vs. Nurture
Binocular Disparity
The binocular depth cue that arises from the fact that the images of most objects that are in the visual scene do not fall on the same location of the retinae of the two eyes
Saturation
The chromatic strength of a hue ex. white as no saturation, pink has some saturation, red is fully saturated
Disparity
The measure of this difference in the position of the images on the two retinae - helps recognize 3D objects in space
Reflectance
The percentage of light hitting a surface that is reflected and not absorbed into the surface
Reflectance
The percentage of light reflected from a surface.
"What" pathway
Ventral pathway to Temporal Lobe - object recognition - input from Parvocellular cells/layers - form, color, objects
Koniocellular Layers
Very thin layers between each of the two magnoceelular levels and the four parvocellular layers - very small cells - six layers
Which of the following correctly lists the color-opponent pairs coded by the visual system? a.Blue versus red; yellow versus green; black versus white b. Blue versus white; yellow versus green; black versus red c. Blue versus green; red versus yellow; black versus white d. Blue versus yellow; red versus green; black versus white e. Blue versus yellow; red versus green; gray versus white
d. Blue versus yellow; red versus green; black versus white
Which of the following is the least common of the cones that are found in the retinae? a. R-cone b. M-cone c. L-cone d. S-cone
d. S-cone
Double-opponent cells are ______. a. neurons that are excited by one color but multiplied when combined with another color b. neurons that have a center, which is excited by one color, and a surround, which is inhibited by the opposite of that color c.neurons that are excited by the input from rods, but not by inputs from cones d. neurons that have a center, which is excited by one color and inhibited by its opposite, while in the surround, the pattern is reversed
d. neurons that have a center, which is excited by one color and inhibited by its opposite, while in the surround, the pattern is reversed
A green square surrounded by red looks more green than if surrounded by a neutral color. Similarly, a yellow square looks more yellow when surrounded by a blue background than a neutral background. These phenomena support which view of color perception? a. competitive theory of color vision b. trichromatic theory of color vision c. complementary theory of color vision d. opponent-process theory of color vision
d. opponent-process theory of color vision
Lesion
damage to area(s) of the brain causing deficit in sensation & perception abilities and/or behavior - may lead to agnosia if in temporal lobe
FFA- Fusiform face area
dedicated to recognizing familiar faces
Relatability
degree to which 2 line segments appear to be part of the same structure/contour
monocular depth cues
depth cues that require only one eye
Structural Description
description of an object in terms of its constituent parts and relationship between parts - viewpoint INVARIANT
Reverse-Hierarchy Theory
details of visual space come from Re-entrant processing - general info comes from feed-forward processing
Morgan, Adam, Mollon (1992) study
dichromats can see through some forms of color camouflage that completely mask objects to color trichromats -participants had to locate a square of horizontal rectangles in a field of vertical rectangles. if the dots are all one color, the square is easier to find for all of us. dichromats are better at this task bc they can see less colors and can see the square among dots more easily.
Diplopia
double image, or seeing two copies of the same images; usually results from the images of an object having too much disparity to lead to fusion
Which of the following is a related color? a. Orange b. Purple c. Blue d. Green e. Brown
e. Brown
According to the principle of univariance, which genetic difference in color vision would cause someone to be truly color-blind? a. Deuteranope b. Protanope c. Tritanope d. Color-anomalous e. Cone monochromat
e. Cone monochromat
Which of the following is not a unique hue? a. Red b. Blue c. Green d. Yellow e. Magenta
e. Magenta
Negata et al
examined the use of depth information in jumping accuracy in a species of spiders known as jumping spiders -examined how these spiders perceive depth -they perceive depth w/ retina that have 4 layers
Parahippocampal Place Area (PPA)
extrastriate region specifically activated by places
Congenital Prosopagnosia
face blindness present from birth
Agnosia
failure to recognize objects that can be seen - Kluver & Bucy
Feed-forward Process
flow of information to downstream structures without need for feedback/communication from "later" structures back to earlier structures - general info; categorical impression; implicit EX) retina - occipital - temporal
pathway codes
for place and movement
V3, V4, and V5 receive input from where?
from only some of the cell types in V1 and V2 - V1 and V2 send info in parallel to these regions
Face Inversion Effect
inability to detect facial features that are inverted on an inverted face (i.e., the features would be upside down, and very obvious, if the face were turned right-side up), because we are so used to processing faces in the upright orientation.
Prosopagnosia
inability to recognize faces; usually associated with lesions to the right inferior temporal cortex
The angle formed by the lines of sight of the two eyes _____ as a focal object becomes closer. This change is _____ dramatic with greater separation between the two eyes.
increases; more
pictorial cues
information about depth that can be inferred from a static picture
Feed-back/Reentrant Process
information coming in from "later" structures back to "earlier" structures - modulate activity - provide specific details; explicit
Templates/ Naive Template Model
internal representations of a stimulus used to recognize the stimulus in the world - not expected to look exactly alike - more applicable to TASTE and SMELL
Inferotemporal cortex
involved in object recognition and is the region of the temporal lobe that receives input from the ventral visual pathway - neurons are sensitive to highly specific kinds of shapes
Dichromats are usually _______ because genes controlling color vision are located on the _____ chromosome(s).
male, X
High-level Vision
meaning assigned to visual information - gain understanding of scene and recognize objects
Perceptual Committees
metaphor used to describe competition for domination over perception between various grouping principles - honor physics - avoid accidents
Ocular Dominance
some cells prefer to respond to inputs from one eye, while other cells prefer to respond to the other eye
random-dot stereograms
stereograms in which the images consist of a randomly arranges set of black and white dots, with the left eye and right eye images arranges identically except that some of the dots are moved to the left or the right in one for the images, creating either a crossed or an uncrossed disparity
Mark just bought a new house. He paints his living room sage green, a color which he mixes himself. This is an example of
subtractive color mixing.
Recognition-by-Components Model
suggest that objects are recognized by GEONS and relationships between geons regardless of its orientation
Recognition
the ability to match a presented item with an item in memory - the perceptual matching of something currently present to our visual system with a stored representation in memory
Extrastriate Cortex ( secondary visual cortex)
the collective term for visual areas in the occipital lobe other than V1
hue
the color quality of light, corresponding to the color names we use, such as orange, green, indigo, and cyan. ___ is the quality of the color.
color deficiency
the condition of individuals who are missing one or more of their cone systems
L cone
the cone with its peak sensitivity to long-wavelength light, around 565 nm (yellow)
m cone
the cone with its peak sensitivity to medium wavelength light, around 535 nm (green)
s cone
the cone with its peak sensitivity to short-wavelength light, around 420 nm (blue)
additive color mixing
the creation of new color by a process that adds one set of wavelengths to another set of wavelengths -used in television -pointillism - artist uses small dots of simple primary colors as the basis of a painting. from a distance, the dots of colors blend together through a process similar to additive color mixing to form a rich array of colors. colors are created by keeping each dot a specific color so that the dots blent together in a person's vision when viewed at a distance
familiar size
the cue whereby knowing the retinal size of a familiar object at a familiar distance allows us to use that retina size to infer distance
Hue
the dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth
crossed disparity
the direction of disparity for objects closer to the viewer than the horopter (the image in the left eye is to the right of the image of the object in the right eye)
uncrossed disparity
the direction of disparity for objects that are farther from the viewer than the horopter (the image of the object in the left eye is to the left of the position of the image of the object in the right eye)
Figure Ground Organization
the experience viewers have as to which part of an image is in front and which part of an image is in the background of a particular scene
relative size
the fact that the more distant an object is, the smaller the image will be on the retina
Law of good continuation
the gestalt grouping law stating that elements that are close together tend to be perceived as a unified group - if objects are farther apart they are less likely to be grouped together
Law of common fate
the gestalt grouping law that staes that elements that are moving together tend to be perceived as a unified group
Law of symmetry
the gestalt grouping law that states that elements that are symmetrical to one another tend to be perceived as a unified group - more likely to be grouped together if symmetrical
deletion
the gradual occlusion of a moving object as it passes behind another object
accretion
the gradual reappearance of a moving object as it emerges from behind another object
Ponzo illusion
the illusion in which two horizontal lines are drawn one above the other; both lines are on top of two inwardly angled vertical lines; the top line, where the two vertical lines are closer together, look larger
Muller-Lyer Illusion
the illusion where a line that has two lines going away at an angle looks longer than a line of the same length but the end lines angle back across the main line
Moon illusion
the illusion where the moon looks larger when it is near the horizon than it does when overhead
vergence
the inward bending of the eyes when looking at closer objects
Entry-Level Category
the label that comes to mind most quickly when we identify it EX) Bird
deuteranopia
the lack of m cones, leading to red-green deficiency; this trait is sex-linked and more common in men
habituation
the learning process in which animals stop responding to a repeated stimulus
brightness
the perceived intensity of the light present
size constancy
the perception of an object as having a fixed size, despite the change in the size of the visual angle that accompanies changes in distance
