Studied by 4 peopleSteps in color perception in the correct order?
detection (sensing light)
discrimination (differentiate wavelengths)
appearance (assignment of perceived colors to objects + assumption that colors are constant/stable (even in different lighting))
When looking at a blue sky during the day, ___________ photoreceptors are most active, while looking at a red sky during sunset photoreceptors are most active
short cones (blue) ; long cones (red)
Color vision is best during what type of lighting condition?
Phototopic, brighter light
The principle of univariance refers to the fact that:
There is one response to all color inputs/processing
Inputs from the rods and cones are combined to create one output
You’re taking several inputs and integrating them to get one output
What type of color-blindness results in a univariance problem?
Cone monochromat
Rod monochromat
True color blindness (complete and severe achromatopsia)
According to the Young-Helmholtz Theory, color vision can be understood best as:
any light perception in human vision is dictated by combining 3 variables: S, M, L
Mixing colors along these 3 responses can give us the rest of the spectrum, but not always perfectly; sometimes metamers (eg: yellow is over lap of red and green)
Trichromacy
RGB televisions and computer monitors have red, green, and blue pixels. Why don’t they have yellow pixels?
Trichromatic RGB model
Use red & green combo to form yellow
Mixing paints to create new colors is an example of color mixing, while shining lights to create new colors is an example of color mixing.
subtractive ; additive
In HSB (hue, saturation, brightness) color space, how does red differ from pink?
Saturation
Evidence for color opponency?
4 unique hue, color cancelling, cone opponent cells, afterimages
We have 4 unique hues that can’t be described using other colors
“Cant have yellow-ish blue or green-ish red”
Color canceling (once you mix enough yellow to blue they perfectly cancel out to make green, instead of making a mix)
We have cone opponent cells in the lvl of V1 and LGN that code for red vs green or blue vs yellow
Afterimages (opposite color)
In the hue cancellation experiments described in the textbook, if the starting color were too reddish, you would add to cancel that redness.
green
A single opponent cell in the LGN is shown to have a [color 1]+ center and a [color 2]- surround. What would the wavelength codes be for the center and for the surround?
(colors can be red, green, or blue)
Red is L, Green is M, Blue is S
Red+ center and a green- surround, the wavelength codes would be L+ center and M- surround
Green+ center and a red- surround, the wavelength codes would be M+ center and a L- surround
Blue+ center and a Red/green- surround, the wavelength codes would be S+ center and a L/M- surround
Red/green+ center and a blue- surround, the wavelength codes would be L/M+ center and a S- surround
Imagine you travel to a foreign country that has labels that differentiate two very specific shades of orange. If someone from that country were given a color discrimination task involving shades of orange that either did or did not cross that label boundary, what would you predict their performance would look like?
Increased performance from that country for orange shade differentiation (faster)
A(n) is an individual who suffers from color blindness that is due to the absence of L-cones.
protanopia (red)
Color Assimilation occurs when:
colors bleed into each other and combine (each taking on some of the chromatic quality of the other)
What piece of evidence suggests that color opponency processing occurs
unique hue, color cancelling, cone opponent cells, afterimages
We have 4 unique hues that can’t be described using other colors
“Cant have yellow-ish blue or green-ish red”
Color canceling (once you mix enough yellow to blue they perfectly cancel out to make green, instead of making a mix)
We have cone opponent cells in the lvl of V1 and LGN that code for red vs green or blue vs yellow
Afterimages (opposite color)
What is one potential explanation for why some people on the internet perceived “The Dress” as blue and black, while others perceived it as white and gold?
Different mental reference used
Color Constancy with the light source. If the light source is more blue the brain infers the color is white, if the light source is yellow your brain assumes the dress is blue.
Which of the following shows evidence that color vision can impact other senses as well?
Synthesia
When one stimulus evokes the experience of another stimulus that is not present.
Often tied to color
Example: letters appearing to have colors (grapheme-color synesthesia), colors having sounds, or sounds having tastes
What wavelength of light could would produce no response from an S cone, a moderate response from an M cone, and a large response from an L cone?
~625 nm
This heuristic results in both color constancy effects and the perception of depth.
shadows
Used the direction of the casted shadow to determine distance away
Determine that shadows in different grey originate from different colored object use luminance knowledge from shadows to make sense
In humans, evolution may have favored two eyes facing forward because it statistically increases the chance of detecting a stimulus. The combination of signals from the two eyes that enhances performance on many tasks is called
binocular summation
Monocular cues
SLAM FORTH
shadow, linear perspective, aerial perspective, motion parallax, familiar size, occlusion, relative size, texture gradients, height
Shadow
Linear Perspective: lines that are parallel in the 3D world will appear to converge as they extend away from your perspective (lines will meet at the vanishing point)
Aerial Perspective: more distant objects’ reflections will be more scattered by the time they reach us (hazier, less distinct)
Motion Parallax: objects closer to you will pass by more quickly than objects further away
Familiar Size: we use our knowledge on the sizes of objects to make assumptions about depth (ex. The lady’s different hand sizes in the slides)
Occlusion (you know what something is despite not seeing its full form, like going to the woods and knowing that on the floor you’re looking at a leaf, even though the leaf may be covered by dirt or branches)
Relative Size: the smaller an object is, the farther you assume it is from you, the bigger an object is, the closer you assume it is to you
Texture gradients: at further distances, textures become smaller, tighter and their spatial frequency increases (aka becomes harder to see)
Height: The greater the distance an object is from the foreground of the image, the farther away you assume it is from you, the shorter the distance it is to the foreground, the closer you assume it is to you
Binocular cues
TBD
Triangulation: figuring out the relative distance of an item by knowing the distance between your eyes and the angles at which the item is to those 2 points
Dichoptic inputs
Binocular Disparity
This depth cue does NOT require using size information in the perception of depth.
TO SLAM
texture gradients, occlusion, shadow, linear perspective, aerial perspective, motion parallax
Suppose you are looking at a road that recedes into the distance. Which depth cue describes the way the edges of the road seem to converge in the retinal image?
linear perspective
is an important depth cue that comes into play during head movements or while moving through an environment.
motion parallax
When looking through a telescope, you can judge the distance of an object based on the lens setting that causes the object to appear in focus. This lens adjustment is an example of what visual depth cue?
Accommodation?
Triangulation??
relative size/height?
Terms for the surface of zero disparity, or the location of objects whose images lie on corresponding points in the two eyes.
horopter, panum’s fusion area
As discussed in light/dark adaptation, wearing an eye-patch allowed pirates to have one light adapted eye, and one dark adapted eye. However, what depth cue(s) are they now unable to use?
binocular cues, triangulation, dichoptic inputs
What factors does the brain already KNOW that allows it to triangulate distance?
Eye position, distance between eyes, lens accommodation, angles, ocular vergence
You can figure out the relative distance of an item by knowing the distance between 2 points (your eyes) and the angles at which the item is to those 2 points
Panum’s Fusion Area
stereopsis, place of single vision from 2 inputs. involved in depth perception and visual comfort
This area/ the horopter circle in within an area with the similar property
This area has zero bin\ocular disparity = Horopter
Single vision, stereopsis
Moves with fixation
Diplopia: disparity past the Panum’s Fusion area creates
The difference between crossed disparity and uncrossed disparity is that crossed disparity involves objects that are _______ the plane of fixation, while uncrossed disparity involves objects that are _______ the plane of fixation.
closer than; farther than
In this figure, a person is fixating on a specific point, labeled FP. How would they see the point labeled and why?
A:
Double vision or diplopia is present
It is a uncrossed disparity type (further = uncross)
Slightly to the left in the left eye, slightly to the right in the right eye
Orange in the diagram of the persons view (reversed from retina)
B:
Fixation point
0 Disperity
Correspondence between the 2 retinas
Appear as a single stereo optic image
C:
In the panum’s fusion area
Allows some level of fusion
Less disparity between the two eyes (close to being a single stereo optic image)
D:
Double vision or diplopia is present
It is a crossed disparity type (closer = cross)
Slightly to the right in the left eye, slightly to the left in the right eye
Blue in the diagram of the persons view (reversed from retina)
What involves a dichoptic viewing manipulation?
Dichoptic = different information to each eye
Old school 3D movie glasses, VR, stereoscopes, viewmasters, Eye doctor test (where you put on glasses and specific things appear 3D)
What is used to solve the correspondence problem?
decreased spatial frequency, fewer objects being shown at once, uniqueness, and continuity
Lots of assumptions are made by your brain in result to the correspondence issue
Spatial frequency
Lower spatial frequency info is generally easier to achieve correspondence
Uniqueness
Any given feature should be represented only 1 time in each retinal image
Continuity
Neighboring points should be at similar distances unless at an edge
Binocular rivalry happens as eyes compete for visual dominance
If you are staring at this scene head on and are fixating on the [I will pick an object], the Square will appear to the _____ of it in your right eye, and to the ______ of it in you left eye.
If the square is in front of the shapes being fixated on (closer = cross)
slightly to the left in the right eye
Slightly to the right in the left eye
Blue in the diagram of the persons view (reversed from retina)
If the square is behind the shape being fixated on (further = uncross)
slightly to the right in the right eye
Slightly to the left in the left eye
Orange in the diagram of the persons view (reversed from retina)
What is the pattern of activity in neurons that code for retinal disparity?
do NOT fire when images from each eye match
Fire when there is disparity
Some V1 cells code for binocular disparity, binocular neurons in striate cortex
Exist across the brain (more along dorsal pathway)
Only fire in response to binocular disparity
Cells that can calculate the distance or the degree of difference between the two eyes in different fashions
Different cells fire for different types of disparity
What region of the brain is NOT sensitive to disparity?
LGN
Everything pasted V1 does
What is the Ponzo Illusion?
2 things of the same size seem to be different size due to the effect of perspective on linear track convergence
Which depth cue(s) allow you to recognize that Point A and Point B are at different distances in the below image [Point A and Point B aren’t labeled in the study guide, but you should be able to pick which cue(s) differentiate a set of 2 points in the figure below]:
Relative size/height
Smaller items further away
Objects touching the ground, higher object is further
Texture Gradients
At further distances textures become smaller, tighter and their spatial frequency increases
Aerial perspective
More distant objects reflections will be more scattered by the time they reach us: hazier, less distinct
is a type of strabismus where the affected eye deviates .
esotropia ; in (s…sit in)
exotropia ; out (x …. Exit out)
This depth cue is also important for solving the correspondence problem in motion:
Cells that code for disparity (Binocular disparity)
The is the period of time between the onset of one stimulus and the onset of another.
stimulus onset asynchrony
would be an example of a sustained attention task.
Vigilance
Continuously monitoring some stimulus over time
If you do not give any external signs that you are paying attention, what kind of attention are you using?
covert
In a Posner Cuing Paradigm, a cue is given to the left side of the array. If the object then shows up in the side, this would mean the cue is a cue.
left ; valid
right ; invalid
The Posner Cuing Paradigm suggests that covert attention is spatial. How does the data from this task demonstrate this?
Valid cues -> quicker RT
Invalid cue -> longer RT than if there was no cue
inhibition of return - If attention is cued to a location but then leaves that location, often even slower to return to it than if there had never been a cue
You’re searching your bedroom for your lucky neon pink shirt, which is the only neon pink thing you own. Which of the following predictions could you make about your ability to find that shirt amongst your other clothes?
it is easier to find than if you had more neon pink clothing, popout effect
pre-attentive feature integration
Less distractors
Feature search
On a given trial of the Posner Cuing Paradigm, a participant is given a valid cue. However, this does not result in a benefit in performance. What is one possible explanation of why a valid cue might not benefit performance?
spatial brain damage or hemineglect
inhibition of return (too many previous invalid cues)
took too long after showing the cue
If you are searching for your car keys and you restrict your attention to horizontal surfaces near the front door, you are using
guided search
Binding problem in visual attention?
Necessity of binding/unbinding features or traits to complete a target search, often switches between brain regions
A person falsely remembering a blue circle from an array that only had red circles, but had other blue objects
Binding problem:
Need to bind/unbind features to complete target search
Often these features are process by different brain regions/cells
You’re shown a sea of blue and red o’s, you may rebind those and perceived something that was a combo of the 2 instead of those as 2 distinct figures
The is the difficulty in perceiving and responding to the second of two target stimuli amid a rapid stream of stimuli if the observer has responded to the first target stimulus within 200 to 500 ms before the second stimulus is presented.
attention blink
Ways that the responses of a cell could be changed by attention?
enhancement
sharper tuning
altered tuning
Attention can alter orientation selectivity
Suppose you are looking at an image of a face superimposed on a house. What would we expect to happen in terms of neural activity if you are attending to the house, relative to baseline passive viewing?
higher activity in the PPA (parahippocampal place area)
According to feature integration theory, feature search is , while conjunction search is .
preattentive ; selectively attentive
parrellel ; serial
by one feature ; by multiple feature/co-occurance
Individual features are processed automatically, in parallel, and with little effort – the pop-out effect
Pre-attentive
Objects (which are a conjunction of features) are processed slowly, serially, and require effortful attention
Selective Attention
Suppose you lose your keys. You look everywhere and can’t find them until you notice them on the table right in front of you, clearly within view the whole time. What phenomenon have you just experienced?
Inattentional Blindness
Guided Search
Use information about the context/location to guide visual search as well.
limit the scope of your search
Some of this is based on objects themselves and their distinct features (relative to others)
What is the difference between the Spotlight model and the Zoom Lens model of attention?
Spotlight – attention restricted to space, movement from spot to spot requires time
Zoom lens – region of attention can shrink or grow
Both - possible explanations as to why if you are attending somewhere else, takes longer to move attention to real target
A researcher runs an experiment where participants fixate on the center of the screen while letters flash in each of the four corners. The research says the neural data showed him participants were covertly attending to the top left and top right quadrants while doing the task. What data would support this claim?
fMRI or eye movement charts with greater activity in the top quadrants
Hemineglect has been shown to be a deficit of conscious attention, not of overall visual perception. What data make it clear that participants are indeed perceiving the neglected side of space, even if they cannot attend to it?
When show a pic of 2 houses: 1 on fire, 1 not
Report they see no different
But if asked which one they want to live in will pick the one not on fire
A researcher is recording from a V1 cell that maximally fires for lines in a 90 degree orientation, fires moderately for 45 and 135 degree orientations, and doesn’t fire at all for 0 and 180 degree orientations. However, when the participant is attending to a task where they have to find 90 degree lines, the cell same stops firing at all to 45 and 135 degree orientations, without changing its maximum firing rate to 90 degree lines. How has attention altered this cells sensitivity?
Sharper tuning (horizontal bell curve shrinking)
What is the correct order of Posner Cuing Paradigm conditions, from slowest to fastest.
invalid, neutral, valid
More Specific:
Invalid short SOA
No-cue short SOA
No-cue long SOA = invalid long SOA
Neutral short SOA
Valid short SOA
Neutral long SOA
Valid long SOA
Ingrid is running a cuing paradigm where participants are attending to 4 possible locations, labeled A, B, C, and D. A and B are very close to each other, C and D are close to each other, but A and B are relatively far from C and D. When Ingrid provides an invalid cue for Point A, she finds that the response time cost is less when the target appears at Point C than at Point B. What is one possible reason for this finding?
Inhibition of return
If attention is cued to a location but then leaves that location, often even slower to return to it than if there had never been a cue
split attention between the two point groupings
A and C are part of the same object
A patient with ________ attentional disorder is initially shown the Figure Labeled Time 1. Then, while they watch the figure is rotated 180 degrees, shown in Time 2. In both figures, the + represents their fixation point and is not actually shown. What do you predict this patient will perceive at Time 1 and Time 2?
Hemineglect – left see pentagram whole time, square time one, right see triangle only
Balint/simultansgnosia – see pentagram & triangle OR square only the entire time
In an RSVP task where participants must detect and A vs. B followed by an X vs. a Y, a researcher finds that for one condition, participants are over 80% accurate. What lag condition must the researcher have used?
a long lag condition (time between stimuli and response) generally lead to higher accuracies
According to the selective vs. nonselective pathways model of attention, how can the nonselective pathway help deal with the attentional bottleneck?
nonselective pathway considers less information using the overall gist to scan for unique features
Non-selective pathway:
Picks up on gist and overall broad scene features, relatively automatic
Attentional bottleneck
In some cases, your attention doesn’t have time to finish processing one item before another appears
where more information is available than can pass through attention
Getting the gist allow you to move on to the next piece of information faster
What type of task would test for evidence of global attentional resources?
one that uses multiple senses at the same time (call & drive)
That a strong motion aftereffect is obtained when one eye is adapted and the other is tested suggests
interocular transfer with an opponent processing system - can adapt one eye and still get after image
The illusion of motion in a stationary object after prolonged exposure (adaptation) to movement
In simple terms: when you’re looking at something after it’s moved for a while, there’s an illusion of it slightly moving the moment it becomes stationary.
Which brain region is most specialized for motion processing?
Medial Temporal (hMT)
V5
Motion adaptation is similar to color adaptation in what way(s)?
Both Color vision and motion adaptation have opponent process systems
When you see an object moving in one direction (for example from left), when it abruptly stops moving, for a moment you think it’s moving to the opposite direction slightly (eg right)
When you stare at those flipped color illusions for a while, and then switch to the actual image in correct color, it becomes
The marquee outside of a theater has lights that blink on and off in rapid succession, leading to the impression that the lights are moving around the marquee. This is an example of which type of motion?
apparent motion: an image flickering on and off at 2 locations (not actual motion)
is motion of an object that is defined by changes in contrast or texture, but not by luminance.
2nd order motion
_______ describes the changing angular positions of points in a perspective image that we experience as we move through the world.
optic flow
This type of motion has been shown to activate not only the visual system, but also the motor system related to the motion.
Biological motion
What is the aperature problem?
correspondence, see too little to understand overall motion
V1 can only sample a small portion of the visual field
When you (your retinal cells) can only see a small window (aperture) of the world, it can become hard to know how objects are moving
In the first image it looked like those circles were moving up and down, but in the next image it appears that the left 3 circles are interchanging with 3 right circles.
A field of globally moving dots can make stationary targets in the periphery seem to disappear in a phenomenon known as
Motion induced blindness
How are the Aperture Problem and Binocular Disparity related?
both cause by having pieces of the picture, both can be solved with additional information
Looking through an aperture (or small window) and not knowing the true motion of the object (aperture problem) is like looking through only one eye and not knowing the true depth of an object (binocular disparity)
When you watch a bicyclist ride down the street, what term best describes the kind of eye movement are you using?
smooth pursuit
What region of the brain is important for initiating and guiding eye movements?
superior colliculus (midbrain)
Local motion is likely processed in while global motion is likely processed in _______.
V1 ; hMT or V5
A patient goes to the doctor’s office complaining that they cannot detect fast movements from large objects. Which region(s) of the brain might be damaged in this patient?
Magnocellular LGN
How is Tau related to Gestalt shape processing?
Tau: Basically, a heuristic estimate of whether an object is rapidly expanding and taking up a lot of retinal image
They are both using heuristics (top-down processing), which helps individuals perceive and predict the continuation of motion or change in a visual scene.
Processing whole object rather than separate parts
??
When we make a voluntary eye movement, the motor cortex sends a motor signal to the eye, and a signal to the visual system.
efference copy
Nirav is watching a soccer game. For a while, he is fixated on the goalie who is just standing in front of the goal. Nirav then quickly moves his eyes to midfield to watch the action, but realizes he didn’t notice the ball move while he shifted his eyes. This is due to .
saccadic suppression
The amplitude of a sound is the
loudness, intensity (magnitude of displacement of a sound pressure wave)
__________ is the psychological aspect of sound related mainly to the fundamental frequency.
Pitch
The purpose of the ear canal is to conduct sound vibrations to the tympanic membrane and .
3 ossicles
What happens if the ear canal is blocked, as when wearing earplugs?
Then sound cannot travel through the ear canal to reach the tympanic membrane, and so it can’t be transduced to the brain
Prevents normal pressure changes
Reduce ability to hear sounds
Particularly at high frequencies
High frequencies dont travel as far as low frequencies, and so you wouldn’t be able to detect high frequencies
Roles of the ossicles are?
amplifying, transmitting, and condensing sound to the inner ear
The ossicles transfer sound vibrations between the and .
tymphanic membrane ; oval window
What would happen if you did not have the stapedius and tensor tympani muscles?
inner ear/hearing damage from loud noises
Their function: Prevent loud sounds from causing too much vibration
How is the harmonic spectrum of sound analogous to the color spectrum of light?
Both are the ranges we can sense/detect for those given senses
Humans cannot perceive the entirety of either spectrum
The harmonic spectrum is a spectrum that contains multiple frequencies (the limits to what we can hear in terms of pitch), while the color spectrum of light is a spectrum that contains all the wavelengths we can see.
In what way(s) is transduction by hair cells similar to transduction by photoreceptors?
both take physical (sensory) stimuli to graded potential electrochemical signals
Opposite of photoreceptors, both graded potentials but photo get hyperpolarized and hearing get depolarized
Cause changes in firing rate
both aggregate info and pass it on to the brain with a signal type change to electrochemical
From the base of the cochlea to the apex of the cochlea, sound transduction is organized by .
frequency, frequency thresholds (lower frequencies travel further)
How do outer hair cells impact auditory processing in the cochlea?
refine sensitivity
amplify signals
physically adjust tension and stiffness of the membrane
The shapes of each function depicted in this figure determines the of each the four sounds
timbre
This graph illustrates the phenomenon of
Phase Locking
(when the neuron will fire more when a particular point on a frequency is reached)
Label the structure
Why would inflammation of the middle ear result in hearing loss?
Blocks vibration carrying, ossicles cannot move properly
Sound would not be able to reach the cochlea, and thus cannot be transduced to the brain
Vision is organized retinotopically, while sound is organized .
tonotopically (by frequency)
![<p><span>If you are staring at this scene head on and are fixating on the [I will pick an object], the Square will appear to the _____ of it in your right eye, and to the ______ of it in you left eye.</span></p>](https://knowt-user-attachments.s3.amazonaws.com/68be56e5-f14b-4848-85fa-beba0fd638b2.jpeg)
![<p><span>Which depth cue(s) allow you to recognize that Point A and Point B are at different distances in the below image [Point A and Point B aren’t labeled in the study guide, but you should be able to pick which cue(s) differentiate a set of 2 points in the figure below]: </span></p>](https://knowt-user-attachments.s3.amazonaws.com/696e2318-a646-4915-ac63-851fb3a812b8.jpeg)
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