PERCEPTION MIDTERM EXAM
what is the equation to find the spectral power distribution of the reflectance?
(SPD of illuminant) * (reflectance)
what is the equation to find reflectance?
(SPD of reflectance)/(SPD of illuminant)
what is VVeber's law?
(change in I)/I=k
what is necessary to create a psychophysics formula?
- a "zero point" - a unit of measure
what is the support for distributed coding
- a computer could predict which class of object the person was looking at without looking at the main responsive area
what are geons?
- a geometric icon - a basic, non-accidental, 3D shape
what is the iris
- a set of muscles that contract/dilate to change pupil size - the colored part of the eye
what do simple cells respond to?
- a wide range of orientations of a line or edge
what are the consequences of convergence?
- acuity - sensitivity
what determines the size of pupils
- amount of light - how interested you are - tension - drugs
the pupil changes its size depending on...
- amount of light present - how much attention a person is paying to a visual sense - whether they have taken certain drugs
what are the rules to assigning border ownership?
- assign using depth - assign it to the thing that is not the ground - the figure has dingstoff
What is the S cone sensitive to
- blue hues - small wavelengths
what happens when there is a dorsal lesion on the brain?
- can't do the landmark test - can say what an object is, but not where it is
what happens when there is a ventral lesion on the brain?
- can't do the object task - can say where an object is, but not what it is
what are the explanations for opponent process theory?
- chromatic adaptation - discounting the illuminant
why are cones so insenstive?
- cones require many photons in order to send a signal - they are highly acute
what are the benefits of the staircase method
- doesn't take as many trials - very precise
examples of heterochromatic light
- fluorescent - incandescent - sunlight
what are the benefits to MEG?
- good time course - useful for looking inside the folds of the brain
What is the M cone sensitive to
- green hues - medium wavelengths
what is the benefit to EEG
- has excellent time resolution (measures 1000 times per second
what is the procedure for the method of constant stimuli
- have 5-7 stimuli - present each stimuli in a random order and ask if it was perceived - repeat the process hundreds of times - calculate the percent of times in which each constant was perceived
what is the adjustment threshold procedure for the method of adjustment
- have the participant change a single stimulus (dim a lightbulb) until they just notice a difference
what is the difference threshold procedure for the method of adjustment
- have the participant change one of 2 stimuli until they just notice a difference between the two
what are the pupils
- hole in the middle of the iris
how can you tell if your eye is accommodating?
- if the muscles attached to the lens are relaxed, you are looking at something far away - if the muscles feel contracted, you are looking at something close
why is depth perception hard?
- info on the retina is 2D - different scenes and objects can have the same retinal image
what are the costs of a rod being so sensitive?
- less acute - monochromatic
what are Fechner's three measurements?
- methods of adjustment - methods of constant stimuli - method of limits
what are the rules for integrating depth cues?
- no single depth cue dominates all situations - no single depth cue is necessary for all situations - it is automatic - more depth cues leads to more accuracy
what are the problems with the method of adjustment?
- not very precise - estimates aren't very accurate
what is object recognition
- organizing the visual image so we can recognize a particular image/object
what are the retinal layers?
- outer nuclear layer - inner nuclear layer - ganglion cell layer
some neurons in V4 respond to...
- particular curvatures (curve orientation) - concavity vs convexity
what is the procedure for the staircase method?
- present stimulus 1 and ask if they see it - continue to present increasing intensity of stimulus until they say they can perceive it - reverse and lower the intensity until they say they cannot see it - make threshold estimates at each reversal point - take an average of the estimates
what are the gestalt principles of perceptual grouping
- proximity - similarity of color - good continuation and common fate
what are superior colliculi involved in?
- rapid eye movements to orient the eyes toward a stimulus - the how/where system rather than the what system
what is the L cone sensitive to
- red hues - longer wavelengths
what are the three layers of the eye
- sclera - choroid - retina
what is the problem with EEG?
- spatially limited (it measures billions of neurons at once, so we don't know exactly which space is the cause) - not a very fine level of detail - doesn't do well measuring inside the folds of the brain
the optic tract projects onto what two structures in each hemisphere?
- superior colliculus - lateral geniculate nuclei
what does the magnocellular layer do?
- tells us about motion - flicker!
what is color vision
- the ability to see differences between lights of different wavelengths
what are the assumptions of Fechner's law?
- the absolute threshold corresponds to a psychological intensity of 0 - each difference threshold is psychologically equivalent
if a simple cell has a low rate of neural activity, that could be due to...
- the edge having an orientation similar to, but not equal to the preferred orientation - the edge having a small difference in intensity between the brighter and darker parts of the edge
why can we not see the black dot when directly at the intersection of the Hermann grid?
- the fovea tends to have smaller receptive fields - the retinal ganglion cells have a small receptive field that completely fits within the intersection
where does the left visual field go?
- the left visual hits the medial left eye and the temporal right eye
what does the univariance principle state?
- the photoreceptors wither absorb the photons, or they don't - if we look at a single type of photoreceptor, we cannot distinguish between the amplitude of light and the wavelength of light in determining the cause of the photoreceptor's response
what is a difference threshold?
- the unit of measure for relation between psychological and physical worlds - how different 2 stimuli have to be in order for a person to reliably perceive them
what is the spectral power distribution?
- the wavelengths and their intensities from the source of illumination - the amplitude of each wavelength that is found in each illuminant
what did the Jen Aniston study find?
- there are certain neurons that respond to certain images, both the image and the words!
why is there inherent redundancy in the integration of depth cues?
- there is always a back up - ex: even if you aren't move (no motion parallax), you can still depend on other cues
why can we see a black dot when not looking directly at the intersection?
- there is less neural activity
the proximity gestalt principle says...
- things/edges that are closer together are more likely to be grouped together
when will simple cells have the highest rate of neural activity
- to their preferred orientation
what does the lateral occipital cortex and inferiotemporal cortex give information about
- understanding and interpreting the object - the what pathway
what are the 2 theories about object recognition
- viewpoint invariance - viewpoint secificity
what are the explanations for light constancy?
- wallach's ratio principle - non-uniformly illuminated areas
what are the physical properties of light?
- wavelength - amplitude - purity
the good continuation and common fate gestalt principle says...
- we want to perceive lines as continuous in the direction that they are going - things that undergo change together are grouped together
how is the method of constant stimuli different with the difference threshold?
- you go through the same process, but add a fixed constant stimulus
motion parallax relies on what 3 pieces of information?
1. objects closer than fixation appear to move in the opposite direction as the observer 2. objects farther than fixation appear to move in the same direction as the observer 3. the greater the distance from fixation, the greater the motional of retinal image
what are the steps to perceptual organization
1. represent edges of visual stimulus 2. border ownership 3. group the regions that have similar properties 4. perceptual interpolation
what is cortical magnification?
1/2 of the visual cortex is devoted to a very small area of the retina - there is a high density of cones on the fovea! - needs a lot of the cortex in order to process all of the information
how much does black paper reflect
10%
opponent process theory states that we have ___ color channels coming out of the eye
2
perceptual interpolation likely occurs in V_
2
how many LGN's do we have?
2 - 1 in each hemisphere
According to VVeber's law, if a person can just notice a difference between a light with intensity 10 and a light with an intensity of 11, they should be able to just notice that a light with intensity 20 is just noticeable different than a light with an intensity of...
22
how many dimensions are there in color perception
3
how many types of cones are there?
3
when performing a metameric match, a normal human has to be able to adjust the intensity/intensities of ____ lights, widely spaced wavelengths
3
color is a ____ structure in perception
3D
a normal human can perceive wavelengths that are between ______ and ______ nm
400-700
what is the visible color spectrum for humans
400-700 nm
what is the most sensitive wavelength for S cone curves
443 nm
how many preferred orientations do simple cells typically have?
5-7
what is the maximum sensitivity of a rod
500 nm - shorter wavelengths
what is the most sensitive wavelength for M cone curves
543 nm
what is the most sensitive wavelength for L cone curves
574 nm
how many layers are there in the LGN?
6
how much does white paper reflect
80%
what does fMRI use instead of radiation?
BOLD signals
what are after color image pairs for each color? Blue Green Red Yellow
Blue : yellow green : red red : green yellow : blue
which test would allow a researcher to measure the activity of the brain every millisecond?
EEG
T/F each type of cone is sensitive to only a single wavelength of light
F
T/F monocular depth cues do not work when both eyes are open
F
T/F the axons of the photoreceptors are bundled together and form the optic nerve
F
T/F the separation of the figure from the ground is never ambiguous
F
T/F? All humans with normal color vision have approximately the same number of L cones
F
T/F? If object A is surrounded by object B, object B is usually the figure and owns the border
F
T/F if the light reflecting off of two objects has a very different spectral properties and the visual system will always perceive the color of the two objects as different
F color and light constancy
prosopagnosia is a result from damage to the...
FFA
when n<1, which law should you use?
Fechner's or Steven's ... it doesn't matter
who studied simple cells?
Hubel and VVeisel
protanope means you're missing the ____ cone
L
what are the 3 types of cones
L cone M cone S cone
deuteranope means you're missing the ____ cone
M
what is the abbreviation for medial temporal area
MT or V5
can you be both acute and sensitive?
NO, it's one or the other
topographic agnosia is a result from damage to the...
PPA
what is Fechner's law?
Psych Intensity = klog(I/Io)
tritanope means you're missing the ____ cone
S
is the SC or LGN phylogenetically older?
SC
when n>1, which law should you use?
Steven's
T/F adjacent areas of the retina are associated wit hadjacent areas in the LGN
T
T/F other species can sense things that humans cannot sense
T
T/F steven's power law gives better results than Fechner's law when n>1
T
T/F? Two objects at different distances from the observer can cast the same exact image on the retina
T
T/F? compared to asymmetrical objects, symmetrical objects usually are perceived as the figure and own the border
T
T/F? convex curves are more likely to own the border than are concave curves
T
where are simple cells located?
V1
where does perceptual interpolation occur?
V2
which visual area has neurons that respond to particular curvatures and whether the curvature is concave/convex?
V4
what is the color circle
a 2D depiction in which hue varies around the circumference and saturation varies along the radius
what is a color solid
a 3D depiction in which hue varies around the circumference, saturation varies along the radius, and brightness varies vertically
what are grandmother cells?
a cell that is tuned to a particular object and responds to it vigorously, regardless of viewpoint
what is the ishihara test
a circle of colored dots with a number/letter inside
the neurons in the IT cortex respond to...
a combination of contour fragments
what would cast the LARGEST image on the retina?
a large object that is close to the observer
what is heterochromatic
a light with many different wavelengths
when the lens is not curved, does it bend a little or a lot of light
a little
when the lens is curved, does it bend a little or a lot of light?
a lot
what is a single cell recording neuroimaging
a microelectrode is implanted in a single neuron to monitor electrical activity in that neuron
what is the test patch in metameric matches
a monochromatic light with a fixed intensity
what is protanomaly
a mutated L cone spectral sensitivity toward the smaller wavelengths
what is color?
a perceptual experience evoked by wavelengths of light reaching our eyes
the S-cones are most sensitive to...
a shorter wavelength of light (usually perceived as blue)
what is a photoreceptor?
a specialized neuron that transduces/changes light into a neurological event
what indicates partial occlusion?
a t-junction
how does monochromatic light appear on the spectral power distribution
a vertical spike
how many geons are there?
about 36
what are the two types of thresholds
absolute and difference
A researcher measures how hard she must touch a person's arm in order for the person to just notice that they have been touched. This is a(n)...
absolute threshold
what do photoreceptors do?
absorb light and change it into a neurological event that the brain can understand
what are the subcategories of oculomotor cues
accommodation and convergence
when you uncover parts of the background as you walk around, you are taking part in...
accretion
if we reflect all wavelengths equally, we will perceive the objects as _________
achromatic (white/black/grey)
what happens if you damage your V4
achromatopsia
what is the function of aqueous humor?
acts as blood, but is clear so that we can see
what makes a color more desaturated?
adding extra wavelengths (especially in the same amounts) - adding more white!
what way should we think of mixtures in terms of light?
additive
light reaching the retina obeys the principle of...
additive mixtures
If a stimulus stimulates adjacent parts of the LGN, it will stimulate _______ areas of each layer of the retina
adjacent
the concept of a retinotopic map states that...
adjacent areas of the retina are represented in adjacent areas of V1
what does the participant do in a metameric experiment?
adjust the intensities of the comparison patch in order to make it perceptually identical to the test patch
when can akinetopsia happen?
after a stroke
what happens with damage to the MT
akinetopsia
why is the cornea clear
allows light to enter the eye
what is the comparison patch in metameric matches
an additive mixture of 3 monochromatic lights (red, blue, green)
the region of each area that is the brightest is called the _____ and is perceived as ____
anchor white
which chamber is the cornea located in
anterior
what are the chambers of the eye
anterior posterior vitreous
According to the accommodation depth cue, when the lens is flat, the fixated object is how far away?
any distance beyond about 2 meters from the observer
How do non-corresponding points relate to the fixated object?
any object that falls on a non-corresponding point will either be farther away or closer than fixation
what is chromatic adaptation?
any sensory neuron that has prolonged exposure to its preferred stimulus becomes fatigued/bleached and wants to respond at lower than baseline level
what is a depth cue?
any source of information that the visual system can use in order to recreate the perception of depth
what is the name of the liquid in the anterior chamber
aqueous humor
the FFA is part of the...
area IT
what is the common name for lateral occipital cortex and inferiotemporal cortex
area IT
if a person had a normal set of photoreceptors in his retina but was cortically blind, the person would most likely have damage to his...
area V4
what does RAS control?
arousal and attention
how can light be seen
as a particle or as a wave
when the shadow detaches from the object, how is the object perceived?
as floating/jumping/flying
when the shadow is attached to the object, how is the object perceived?
as rolling across the floor
why can all combinations of hue, saturation, and brightness not be possible?
as you reach the extremes of brightness, there is a very small range of saturation
where are rods located?
at the center of the eye - highest density is around the fovea
when do the consequences of conversion occur?
at the retinal level before the information hits the brain
Which depth cue claims that distant objects appear more fuzzy and bluish than nearby objects
atmospheric perspective
posterior
back
where is the posterior chamber located
behind the bulge of the cornea
where is the lens
behind the pupil
what is the purpose of the lens?
bends light
where do the konicellular layers receive their information?
bistratified retinal ganglion cells
if all the wavelengths are absorbed equally, what kind of achromatic light will we perceive?
black
what are bold signals?
blood oxygenation level differences that tell us how active the brain is
which color has the shortest wavelength?
blue
in additive mixtures, when would you get white light?
blue + yellow
objects that are protruding into the picture plane have shadows on their _____
bottom
ventral
bottom
knowing the retinal image size of an object is _____-_____ processing
bottom-up
if all wavelengths are reflected equally, what kind of achromatic light will we perceive?
bright white
in an additive mixture of two lights, the mixture is (darker/brighter) and (more/less) saturated than the individual pigments
brighter less saturated
what does amplitude correspond with?
brightness
how could we drive the rate of neural activity in a simple cell down?
by lowering the contrast of the stimulus
what did fechner do
came up with 3 distinct ways of measuring thresholds
what is akinetopsi
can't perceive motion
what is the downside to MEG?
can't pinpoint exactly where something is
you (can/cannot) see color well when using your peripherals
cannot
what does the ganglion cell layer do?
carries information from photoreceptors to the cortex
what is transduction?
changing of physical stimulus into a neurological event
at the optic _______, information from the right eye's right visual field crosses over to join the information from the left eye's right visual field
chiasm
the optic ______ is where the information crosses over at a midpoint
chiasm
which layer of the human eye provides the blood supply to the innermost layer
choroid
what does the choroid give way to?
ciliary body
do we assign borders to things that are closer or farther from you?
closer
if the texture is relatively uniform, the larger the visual angle of the texture, the (closer/farther) the texture unit is to you
closer
a person is looking at an object. part of the object has a specular highlight on its upper part and the lower part is dark. the person will perceive this part of the object as...
closer to the person than the rest of the object
what are corresponding points
coinciding points on each of the retinae
what does the inner nuclear layer do?
collect information from the photorecetors and feed it to the retinal ganglion cells
if you only have 2 of the 3 cones, you are considered to be...
color deficient
bistratified retinal ganglion cells play a role in...
color perception
how is brightness represented
color solid
information from the left visual field hits the medial side of the left eye. this information will become... contralateral/ipsilateral
contralateral
when information hits the MEDIAL side of an eye, it becomes...
contralateral - it must cross over to get to the opposite hemisphere
the closer an object gets to your eye, the more (convergent/divergent) your eyes become
convergent
do we assign borders to convex or concave structures?
convex
are the fovea corresponding or non-corresponding
corresponding
what is achromatopsia
cortical blindness
V1 undergoes _______ ___________
cortical magnification
how do you maximally excite a single opponency neuron?
cover the entire visual field with the excitation wavelength!
in terms of center-surround antagonism, which setup would give you the highest rate of neural activity?
covering the surround
what was the goal of psychophysics?
create a formula to help us relate a physical trait of the outside world to the psychological representation of that physical property
the magnitude of disparity is related to how much the image is...
crossed or uncrossed
what are oculomotor cues?
cues coming from the eye muscles
what are visual cues
cues that depend on the amount of light that reaches the retina
what does V4 correspond with
curvature and color information
in humans, when looking at something very close, the lens is...
curved
when you are close to an object, is your lens curved or flat
curved
some neurons in V4 receive input from several V1 neurons, the receptive fields of which each have slightly different preferred orientation and slightly different location on the retina. These V4 neurons are tuned to a...
curved line (or edge)
is a human choroid light or dark?
dark
in a subtractive mixture of two different pigments, the mixture is (darker/brighter) and (more/less) saturated than the individual pigments
darker more saturated
when you systematically cover things up that are behind you as you walk, you are taking part in...
deletion
which part of a neuron receives information from other neurons
dendrites
what do neurons use to send information to each otehr
dendrites or cell bodies
some cortical neurons receive information from both the left and right eye. these neurons would most likely be involved in the perception of...
depth
A bright pink object would be considered to be...
desaturated
pastel colors are considered to be...
desaturated
the closer you get to the center of the color circle, the more (saturated/desaturated) the color becomes
desaturated
the location of a color within the color circle is close to the center of the circle. The color is...
desaturated
simple cells with the same receptive field respond to the same area of the retina, but have...
different responses depending on their preferred orientation
the figure has "thingness." this is called...
dingstoff
if you want to see color, should you look directly at the object, or slightly to the side of it?
directly at it
what is the static monocular principle of atmospheric pressure
distant objects appear fuzzier and more bluish than nearby objects
the fact that a computer can very accurately identify the class of object that a person is looking at by looking at neural activity across the cortex even if activity in areas such as the FFA and PPA are removed, supports which coding theory?
distributed
once we get past V1, the visual system splits into what 2 pathways
dorsal and ventral
what is viewpoint invariance
each object has a single representation that is activated for all different viewpoints - 1 single neural representation of all viewpoints of that object
what is viewpoint specificity
each object has multiple representations, each from a different viewpoint
what is a receptive field?
each retinal ganglion cell has their own part of the retina that they are responsible for responding to
how does EEG work
each sensor measures electrical activity
what does the physiological evidence from retinal densitometry say?
early color vision processing is trichromatic and that trichromatic theory is correct in at least the early stages of color perception
the FFA likes _____ faces
entire/whole
what is shape constancy?
even though the object may be slanted and look different, our visual system accommodates and keeps the perceived shape constant
what is color constancy?
even when the illuminant changes, the color perception does not vary
messages to and from neurons can be considered ______ or ______
excitatory or inhibitory
which procedure would allow a researcher to measure the activity of the brain with the greatest spatial resolution
fMRI
T/F a rod can sense color of a light that is shining on it
false
T/F all neurotransmitters are excitatory -- they increase the likelihood that the post-synaptic neuron will depolarize
false
T/F humans have only 5 senses
false
T/F sensation and perception are synonyms
false
T/F the receptive fields of all retinal ganglion cells are approximately the same size
false
in object perception, the figure is said to have dingstoff. Dingstoff refers to the fact that the...
figure is a thing while the ground sometimes is not
what is perceptual interpolation
filling in missing information when there is something blocking an image
what is border ownership?
finding out what the line/edge belongs to
what is an absolute threshold critical for?
finding the zero point
senses in other species: fish? birds? bees?
fish = electrical fields birds = magnetic fields bees = polarization of light
when you are far away from something, is your lens curved or flat
flat
what is the static monocular principle of relative size?
for objects known to be approximately the same size, the larger the retinal image, the closer the object is
a person is looking directly at a tree. the image of the tree falls on the...
fovea
when you look directly at an object, where does it's image go?
fovea
anterior
front
what are the 4 lobes of the brain
frontal parietal temporal occipital
how do we decide which parts of the brain are active during certain actions?
functional neuroimaging
FFA stands for
fusiform face area
what does FFA stand for
fusiform face area
what is the layer closest to the eye?
ganglion cell layer
according the recognition by components, objects are represented by _____
geons
what is sensation
getting information into the brain Ex: changing light/sound into something you can see/hear
what does a dark choroid do for humans?
gives us greater aquity
a retinal ganglion cell that has a high rate of convergence will have ____ sensitivity and _____ acuity
good sensitivity poor acuity
a __________ cell is a cell that is tuned to a particular object or person that responds vigorously regardless of the viewpoint
grandmother
the farther an object is from the horopter, the (smaller/greater) the disparity is
greater
a light with a medium amplitude and a wavelength of 540 nm would be...
green
the sense of taste is technically called _____
gustation
high amplitude = _____ brightness
high
high convergence = ____ sensitivity
high
low convergence = ______ acuity
high
quick changes in contrast correspond to ____ spatial frequency
high
the smaller the receptive field, the _____ the spatial frequency that the retinal ganglion cells will respond to
higher
what does the anterior chamber do?
holds the aqueous humor
what is the role of the sclera
holds the shape of the eye
what is included in the inner nuclear layer?
horizontal, bipolar, and amacrine cells
what is convergence in the oculomotor cues?
how much the eyes are pointed toward the nose
what is accomodation?
how much the lens changes its curvature based on how far the object is from the eye
what is the amplitude
how tall a wave is
psychophysics is the study of...
how the physical world relates to the psychological world
the dorsal pathway processes information about...
how you might interact with the object
as we stretch the wavelength and make distance from the crests longer, the perceived _____ changes
hue
what does wavelength correspond to?
hue
which perceptual characteristic of color is most closely associated with the wavelength of light
hue
what are the 3 dimensions of color perception
hue, saturation, and brightness
_____ are equally represented at the center of the color solid
hues
what does the FFA do
identifies faces
what does the PPA do
identifies familiar places
what is the static monocular principle of shading
if shadow is underneath, the object is protruding if the shadow is on top, the object is recessing
what does wallach's ratio principle state?
if we increase the intensity of the illuminant, the amount of light reflected from an object increases equally
why might you have to wear glasses?
if your cornea is curved too much/not enough
what are the konicellular layers?
in between the magnocellular and parvocellular layers
where does transduction happen?
in photoreceptors
when is trichromatic theory present?
in the early stages of vision (the retina and photoreceptors)
agnosia
inability to do tasks that are very easy for normal people
visual agnosia
inability to name objects
topographic agnosia
inability to recognize buildings and spatial layouts
prosopagnosia
inability to recognize faces
myelination _______ the rate of neural transmission once the information has left the eye
increases
brightness ____ as you move up the color solid and _____ as you move down the color solid
increases as you go up decreases as you go down
what information does the ipsilateral fibers of the right eye carry
information about the left visual field
how does PET work?
inject radioactive glucose into the blood and follow it to the brain
the extraocular eye muscles that control the positions of the eye are ________
innervated
how would we use cues to make the best estimate about depth of an object?
integrate as many depth cues as possible
how to we find out the photons absorbed by a photoreceptor?
intensity x sensitivity
proprioception sense is the sense of
internal bodily senses
information from the left visual field hits the temporal side of the right eye. this information becomes... contralateral/ipsilateral
ipsilateral - it is already on the right side!
when information hits the TEMPORAL side of an eye, it becomes...
ipsilateral - it is already on the side of the hemisphere that it should be!
why is a rod so sensitive?
it can transduce a single photon of light under ideal situations into a neurological event - as sensitive as a neuron can be
how does pupil size determine the depth of field?
it decides the range of distance for which objects will be focused
why are protanopia and deuteranopia more prevalent in males?
it is a sex linked trait
what is the downside to single cell recording
it is destructive to tissues and damages the neurons which have electrodes implanted in them
why doesn't the vitreous chamber need its own blood source?
it is right next to the choroid
what is the optic tract
it is the same optic nerve, just rearranged and renamed
what is the purpose of the vitreous humor
it keeps the eye inflated
why do we use scotopic vision in the dark?
it needs very few photons to work
what does it mean for the retina to be 2D?
it only has width and height... no depth!
as you increase and decrease the brightness, what happens to saturation in the color solid?
it shrinks
fechner's law can be written as...
klog(I/Io)
what is the static monocular principle of familiar size?
knowing the actual size of an object and its retinal image size allows you to calculate distance
what is top-down information?
knowledge, expectations, etc.
which layers of the LGN are involved in the perception of color
koniocellular and parvocellular
if the disparity is far away from the fovea, you will have a (small/large) magnitude
large
when you go outside and it is completely dark, what size are your pupils?
large
when you are interested in a conversation, what size are your pupils
large (dilated)
the larger the visual angle, the (smaller/larger) the retinal image
larger
the smaller your pupils are, the (smaller/larger) your depth of field is
larger
what does LGN stand for
lateral geniculate nucleus
the magnocellular layer is comprised of how many layers
layer 1 layer 2
the parvocellular layer is comprised of how many layers?
layer 3 layer 4 layer 5 layer 6
all of the information from the right visual field projects to the ______ hemisphere
left
a dark choroid makes humans _____ sensitive to light, but we need to have ____ light to see (more or less)
less more
what does the static monocular principle of shading assume
light comes from above
what is achromatic light
light containing wavelengths from across the visible spectrum, with no really dominant wavelengths
what is monochromatic light
light that consists of a single wavelength
what is a metamer
lights appearing identical to the observer, despite their physical differences and the different spectral power distributions
_____ perspective is a depth cue that states that parallel lines appear to meet in the distance (at the vanishing point on the horizon)
linear
what is a population code?
looking at the output across a group of simple cells that have the same receptive field
how does the MEG work
looks at the magnetic activity of a large section of the brain
when there is high convergence, do we lose or gain spatial information?
lose it - there are so many photoreceptors hitting one RGC that we can't decide where things are coming from
a dark blue light would have what kind of amplitude
low
high convergence = ______ acuity
low
low contrast of stimulus = _____ neural activity
low
low convergence = _____ sensitivity
low
large receptive fields = ___ acuity = ____ sensitivity
low acuity high sensitivity
the larger the receptive field is, the ______ the spatial frequencies the RCG will respond to
lower
what is the deepest layer in the LGN
magnocellular
which layers of the LGN are involved in the perception of motion and flicker?
magnocellular
what is a visual angle
measurement of how large the retinal image is
where does the right visual field go?
medial right eye and temporal left eye
a person is looking straight ahead but sees a dog far to the left of where they are looking. The image of the dog falls on the...
medial side of the left eye the temporal side of the right eye
which method usually yields the least accurate measure of the threshold?
method of adjustment
______ retinal ganglion cells usually have small receptive field types
midget
where does the parvocellular layer receive their information
midget retinal ganglion cells - very small receptive fields - good at telling information about acuity!
the 3 dimensions of color are reasonably independent for ______ brightness
moderate
the fusiform face area is evidence for ______ coding
modular
the existence of the PPA and the topographical agnosia that occurs when the PPA are damaged supports which coding theory?
modular coding
the LGN receives information from the reticular activating system (or reticular formation). this allows the LGN to...
modulate the amount of attention paid to a stimulus
what is RAS important for?
modulation of the amount of information that gets passed to the cortex
when you are missing 2 cones, you are considered to be...
monochromatic
is motion parallax monocular or binocular?
monocular
what are the subcategories of visual cues
monocular and binocular cues
the farther an object is from fixation, the (more/less) the object moves across the eye
more
how is achromatic light perceived?
more or less colorless (shades of grey)
Dynamic depth cues must have ____ in order for them to work
motion
the vestibular sense if the sense of _________
motion
vestibular sense is the sense of
motion
what do dynamic cues require
motion
superior colliculi have ___________ neurons
multisensory
what is deuteranomaly
mutated M cone spectral sensitivity toward the longer wavelengths
when the optic nerve leaves the eye, it becomes ______
myelinated
each retinal ganglion cell is covered in ________
myelination
what are binocular cells?
neurons in V1 that receive information from both eyes
axon terminals have _________ in them
neurotransmitters
are all binocular cells in the same location
no
can you perceive color with rods?
no
does the optic disk have photoreceptors?
no
if light is not shining on a cell's receptive field, does the retinal ganglion cell perceive it?
no
when the size of the retinal image changes, does the perception of the size of the object change?
no
does each type of cone have the same spectral sensitivity?
no - each have their own different spectral sensitivity curve that allows us to see color
can the FFA recognize scrambled faces optimally?
no!
for on-center, off-surround receptive fields, will the receptive field change based on the orientation of the line?
no!
is there depth at the level of the photoreceptors and the early stages of vision?
no!
do receptive fields come in only one size?
no, approximately 5-7 sizes
do V4 neurons respond to curves only at a specific point in their visual field?
no, they respond equally to its preferred curve, no matter the placement in the visual field
can we look at individual simple cells to investigate it's preferred orientation?
no, unless we know the contrast of the stimulsu
when the object is closer than the horopter, they are _______ points and _______ disparity
non-corresponding crossed
when the object is farther than the horopter, they are _____ points and ______ disparity
non-corresponding un-crossed
what is prosopangosia
not able to recognize faces
what do static cues require?
nothing - motion is not required!
what is the static monocular principle of relative height?
objects closer to the horizon or line of sight appear to be farther away than objects that are farther from the horizon
the gestalt principle of common fate states...
objects that undergo the same transformation tend to be grouped together
which lobe of the human brain is most posterior
occipital
where is V1 located?
occipital lobe
fechner day is celebrated on...
october 22
what are the two main categories of depth cues
oculomotor and visual cues
single and double opponency neurons have what type of receptive field?
on-center, off-surround
if a person is monochromatic, how many lights are needed in the metameric matches experiment
one light
People have a very difficult time thinking about color mixtures of opponent colors. What theory does this support?
opponent color theory
which theory do the retinal ganglion cells follow when perceiving information about color?
opponent process theory
what do dendrites receive info from
other cells
what allows us to see color?
our 3 types of cones
where are photoreceptors found
outer nuclear layer of the retina
does information travel faster outside the eye or inside the eye?
outside
what does PPA stand for
parahippocampal place area
what does the static monocular principle of linear perspective state
parallel lines which converge at the horizon are farther away
______ retinal ganglion cells tend to have large receptive fields
parasol
what is the most useful depth cue?
partial occlusion
why do distant objects appear fuzzier?
partial occlusion with particulate matter in the air
akinetopsia is an inability to...
perceive motion
what is the size-distance invariance principle
perceived size is proportional to the product of perceived distance and retinal image ssize
what is the last step in perceptual organization?
perceptual interpolation
what is the last step of perceptual grouping
perceptual interpolation
what is the earliest stage of object recognition
perceptual organization
when reading, you need a ________ visual system
photopic
which visual system do the cones follow
photopic
what does the optic disk lack?
photoreceptors
what does the outer nuclear layer contain?
photoreceptors
if you want to have the greatest visual acuity of an object, you should use _______ visual systems and look ________ at the object
phototopic look directly at the object
the parahippocampal place area (PPA) is tuned to...
places
the ambiguity of the response of a simple cell can be removed by using a...
population code
what animals also use stereopsis?
praying mantis and cuttlefish
what does the MT do
process motion information
what happens with a damaged FFA
prosopangosia
what are the three types of dichromatic deficiencies
protanope deuteranope tritanope
according to the gestalt principle of ______, objects that are placed close together are likely to be perceived as a group
proximity
what is Steven's Power Law?
psych intensity = cIⁿ
what does the superior colliculi play a role in?
rapid movements of the eye
according to the optic flow cue, images of things that are far away from fixation move (slightly/rapidly) on the retina
rapidly
prospagnosia is the inability to...
recognize faces
which color has the longest wavelength?
red
parvocelluar layers give information about _____ and _____ hues while the bistratified RGC gives information about _____ and _____ hues
red/green blue/yellow
what are the 2 color channels coming out of our eye?
red/green and blue/yellow
rods are more common in the...
retina
what is the innermost layer of the eye
retina
what is the innermost layer of the eye?
retina
where are the photoreceptors found?
retina
opponent process theory happens at the _____ and ______ levels
retinal and cortical not the Photoreceptors!!
V1 maintains _______ maps
retinotopic
all of the information from the left visual field crosses over to project to the ______ hemisphere
right
when the observer moves from left to right, the object is perceived as moving...
right to left
are rods or cones more numerous?
rods
are rods or cones more sensitive?
rods
what are the 2 types of photoreceptors?
rods and cones
what are the axons of the photoreceptors?
rods and cones
when you have high convergence, are you dealing mostly with rods or cones? Photopic or scotopic vision?
rods and scotopic
are monochromatic colors saturated or desaturated?
saturated
what does purity correlate with?
saturation
what must be kept the same in all dots in order for the Ishihara test to work?
saturation and brightness
which visual system do the rods follow
scotopic
if you wanted to have maximal visual sensitivity, you should use _______ visual systems and look ________ at the object
scotopic just a little the the left/right of the object
example of proprioception senses
sensing gas in your body muscle aches hunger
objects of very different ______ and _______ can all project the same exact image on the retina
shapes, differences
+S means that the neuron is excited by ______ wavelengths
short
which functional neuroimaging is rarely used in humans
single cell recording
example of vestibular sense
sit and spin
visual angle depends on what?
size and distance
if the disparity is close to the fovea, you will have a (small/large) magnitude
small
when you go outside and there is a lot of sun, what size are your pupils?
small
small/low amplitude = ____ hues large/high amplitude = ___ hues
small amplitude = dark hues large amplitude = bright hues
monocular cues are further broken down into...
static and dynamic cues
what is another term for binocular disparity?
stereopsis
what is another name for after color images
successive color contrast
what light is closest to the idealized white light?
sunlight
the visual system detects partial occlusion based on...
t-junctions
what kind of information does the parvocellular layer give us?
texture depth form color
what is accomodation
the ability of the lens to change its curvature
what is Io?
the absolute threshold intensity of the stimulis
what is brightness
the amplitude of the wavelengths in the light
why does a person perceive an apple as red?
the apple primarily reflects long wavelengths of light
how does size influence visual angles?
the bigger the object is, the bigger the visual angle is the bigger the visual angle is, the bigger the retinal image is
what are dendrites
the branching structure of a neuron that comes off the cell body
what is the optic nerve?
the bundle of fibers of retinal ganglion cell axons at the optic disk
how does a neuron decide whether or not to send a message?
the cell body sums up all of the excitatory and inhibitory messages
what is the cornea
the clear bulge on the eye
how does distance influence visual angle
the closer the object is, the bigger the visual angle is the bigger the visual angle is, the bigger the image is on the retina
what does the sclera consist of
the cornea
how is the lens different than the cornea?
the cornea cannot accomodate
what is a wavelength
the distance between 2 adjacent peaks or troughs
what does it mean for simple cells to have a preferred orientation?
the edge on the retina must be oriented at a certain degree in order to maximally excite one of the simple cells
what is distributed coding
the entire brain is involved in all of the information processing
where is the highest density of cones?
the fovea
which part of the eye has the greatest amount of acuity?
the fovea it has the most photoreceptors per unit area
what is the ponzo illusion?
the front object looks smaller than the back object, even though they are the same size
what must be changed in the dots of the Ishihara test for it to work
the hue
what is optic flow
the image of things that are close to fixation only move slightly across the retina
what is the static monocular principle of texture gradients?
the larger the visual angle of the unit of texture is, the closer the object is
what is the fovea
the line of sight
what is the strong psychological evidence that we have three types of cones
the metameric matches experiment
what is the absolute threshold?
the minimum amount of stimulus needed to just perceive the stimulus approximately 50% of the time
when people were asked to identify a rotated structure, what were the results?
the more the object was rotated, the longer it took for the participant to recognize it
in vision, cortical magnification states that...
the most acute area of the retina has a disproportionately (based on its area) larger number of V1 neurons devoted to it
what happens when a neuron sends a message?
the neuron depolarizes its axon until it reaches the axon terminals
where is V1?
the occipital lobe
why can't every single photoreceptor leave information on the optic disk?
the optic disk would have to be much, much larger
what is perception
the organization of sensory information - how we organize/recognize sensory information - ex: is the sound coming from the right or the left?
which layer is closest to the choroid
the outer nuclear layer
what is the sclera
the outermost layer (whites of the eye)
where does the magnocellular information receive its information
the parasol retinal glands - they have large receptive fields - the do not tell us much about acuity
what is the visual field
the part of the outside world that enters the eye and occupies your vision
why do distant objects look as if they have a bluish-gray tint to it?
the particulate matter floating in the atmosphere has larger wavelengths than the short (blue) wavelengths, so when the blue light hits the particles, it scatters
where does color perception begin?
the parvocellular layer
what happens when pieces of the retina break off?
the pieces float in the vitreous humor and when light hits the floaters, it casts a shadow on the retina
what is a threshold
the point of going from the outside world to the inside world
what is spectral sensitivity function
the probability that a cone's photopigment will absorb a photon of light of any given wavelength
what is spectral reflectance
the proportion of light that a surface reflects at each wavelength
what is convergence?
the reduction of information that leaves the eye at the optic disk
how does additive color mixture work?
the reflected light contains the sum of the wavelengths in the overlapping regions
where do the lateral geniculate nuclei receive their information
the reticular activating system (RAS)
if you have been sitting in a very dark room for about an hour, are the cones or the rods active? or both?
the rods are active, but the cones are not
what is the horopter?
the set of points that are equally distant from the two eyes
what does the static monocular principle of cast shadows
the shadow can be attached or detached from the object
what do you need to know in order to calculate distance?
the size of the object and the visual angle
pupillary reflex
the size of the pupil respond to the amount of light
why do the illusory dots in the intersections of the Hermann grid disappear when you look directly at them?
the size of the receptive field is small enough to fit entirely within the intersection when the intersection is foveal
what is a photon
the smallest, indivisible part of a particle
what does each layer of the LGN preserve?
the spatial layout (topography) of the retina
what does the optic nerve preserve?
the spatial layout information of the retina
psychophysics
the study of relating the outside world to the mental perception of that outside world - the study of perception!
what is discounting the illuminant?
the visual system determines the spectral power distribution of the illuminant and can use it to give an approximation of the SPD of light
what is saturation
the vividness/purity/richness of a hue
what is the problem with the ganglion cell layer?
there are 120-130 million photoreceptors in each eye, but only 1 million ganglion cells - we have to reduce the information!
why is it hard to distinguish what an object is without recreating depth?
there are an infinite number of objects that can project the same image on the retina
what did the V4 study on monkeys show us?
there are neurons in V4 that respond optimally to a certain type of curve
why is there no information processing at the optic chiasm?
there are no synapses
what is modular coding
there is a certain module (piece) of the brain dedicated to processing a particular type of information
what does double dissociation tell us about the visual pathway?
there is strong evidence that the ventral pathway is the what pathway and the dorsal pathway is the where pathway
why are simple cells ambiguous?
they are tuned to line orientation as well as contrast of the stimulus - we never know if the reaction of a simple cell is due to contrast or orientation
explain the receptive fields of binocular cells
they have a receptive field in each eye
how do enchroma glasses work?
they selectively remove some wavelengths of light where the M and L cone sensitivity overlap
M cones are about twice as sensitive to 540 nm light than they are to 500 nm light. If a person used only their M cones, how should they adjust a 500 nm light of intensity 100 ti be a metameric match to a 540 nm light of intensity?
they should make the 500 nm light more bright
why are edges important?
they signify where the object ends and the background begins
who do enchroma glasses benefit?
those with anomalous trichromacy
for the metameric matches experiment, if a person has normal vision, how many colors do they need in the comparison patch?
three
when you are not interested in a conversation, what size are your pupils?
tiny
dorsal
top
with respect to the human brain, dorsal means...
top
in partial occlusion, the object with the ___ of the T covers the object with the ____ of the T
top, stem
knowing the actual size of an object is _____-_____ processing
top-down
objects that are receding from the picture plane have shadows on their _____
tops
cones are ____chromatic
tri
which dichromatic deficiency is rare
tritanope
T/F? topographic agnosia is the inability to recognize building and spatial layouts
true
T/F? two different objects can cast the same exact image on the retina
true
how does fMRI work?
turns on high levels of magnetism, causing iron to align and give off signals
what is required to do the metameric match experiment with 2 photoreceptors
two lights
according to the _______ principle, a single photoreceptor can only signal that at least one photon has been captured and cannot distinguish between the wavelength and intensity of light
univariance
what do we use to remove the ambiguity of a simple cell
use a population code
how do we recreate depth?
using depth perception cues
how do you maximally excite the receptive field of double opponent neurons?
using edges! - cover the entire center, right up to the edge
what is another name for the choroid
vascular tunic
which class of theory of object recognition claims that there is a single neural representation of an object, no matter where the object is viewed from?
viewpoint invariance
which chamber occupies approximately 2/3 of the eye
vitreous chamber
what substance is within the vitreous chamber
vitreous humor
if you look at a single photoreceptor type, you cannot distinguish...
wavelength and intensity
the symmetry and parallelism gestalt principle says...
we group things together when they are symmetrical or parralel
what is binocular disparity?
we have two different viewpoints because the eyes are in slightly different locations
what is light constancy?
we perceive the lightness of a reflected object as constant, no matter how bright the illuminant is
the object task is the "_____" task
what
if a person suffered a stroke in her ventral pathway, she would most likely be unable to identify...
what an object is
what is hue
what people think of as color
what does depth perception allow us to figure out?
what the object is and how far away it is
what is low convergence
when a RGC gets information from a small amount of photoreceptors
what is high convergence
when a RGC gets information from hundreds of photoreceptors
when does color opponency kick in?
when color is interpreted by the retinal ganglion cells
when is the retinal image of an object largest?
when it is close/large
when are Fechner and Steven's power laws equally good at describing psychophysical relation for brightness?
when n is below 1
when can wallach's ratio principle applied?
when objects are uniformly illuminated
when is partial occlusion present?
when one object is partially covered by another
what is the partial occlusion principle of depth?
when one object partially covers up/occludes another object, the object that is occluding is closer to you than the object that is being occluded
why do sorting experiments support color opponency theory rather than trichromatic theory
when people are given a stack of various colors and sort them into as few piles as possible, most participants sort them into 4 piles (not three!)
when do the 3 dimensions of color lose their independence?
when the color becomes very bright or very dark
when will a binocular cell respond most vigorously?
when the image of an object falls on both of the cell's receptive fields
when is there crossed disparity?
when the object is closer than fixation
when do oculomotor cues stop working?
when the object is more than 2 meters away
when does perceptual interpolation occur?
when the visual system perceptually completes an occluded or otherwise obscured edge or surface
when is a color impure
when there are multiple wavelengths
when do anomolous trichromacies occur
when there is a genetic mutation to the genes either encoding the L or M cone
when is a color pure
when there is a single wavelength
how does meaningfulness play into border ownership?
when there is meaningfulness, it is easier for you to assign the border
when is scotopic vision present
when there is no light
why do dichromatic deficiencies arise?
when there is one cone missing
when are objects non-corresponding?
when they are not on the horopter
when are objects corresponding?
when they are on the horopter
the similarity of color gestalt principle says...
when things are the same color, they tend to be grouped togther
what is the zero point
when we cannot psychologically detect a stimulus
when is the photopic visual system present
when you are in a reasonable amount of light
when do monocular cues work?
when you have at least one eye open
how does subtractive color mixture work?
when you mix two pigments together, the hue that is reflected is the hue that is not absorbed by either pigment
when is the method of adjustment best used?
when you need a quick estimate
the landmark test is the "_____" task
where
what is the role of the choroid?
where the blood vessels are to supply nutrients and carry away waste away from the eye
what is the optic disk
where the information leaves the eye a blind spot!
the light that reflects off of an object depends on the object, as well as...
which wavelengths are absorbed and reflected, and the SPD function
what is achromatic light also known as?
white light
what is trichromatic theory unable to explain?
why we see certain after colr image pairs
how do you maximally excite a +ML neuron?
yellow
do retinal ganglion cells carry information about color?
yes!
does each type of cone have a distinct spectral power distribution?
yes!
will cones still respond to wavelengths, even if it isn't their maximum sensitivity wavelength?
yes!
when do binocular cues work
you must have both eyes open
