SPA In-text questions / ISLE questions

What is object agnosia? What areas of the brain likely cause it, and what are its symptoms?

Neurological disorder characterized by the inability to recognize objects despite having intact vision. likely the result of damage to the inferotemporal cortex. symptoms include an inability to recognize familiar objects even with normal sight, and difficulty matching, copying, or naming objects.

Define object perception. What are some of the obstacles programmers must overcome to design a computer system with object perception?

complex process through which the brain interprets and assigns meaning to visual information to identify objects in the world. obstacles to overcome- limited data, occlusion and distortion, and the inverse projection problem

What is the difference between top-down and bottom-up processing?

top-down processing relies on prior knowledge and context to interpret incoming stimuli, moving from the general to the specific.

Bottom-up processing focuses on the physical stimulus itself to build understanding from specific sensory details to a broader whole.

What is meant by perceptual organization? What is the difference between grouping and segregation?

perceptual organization is the brains innate ability to structure and interpret sensory information, grouping elements into meaningful patterns and objects, rather than perceiving them as disjointed parts. this consists of two main interdependent processes: grouping and segregation.

grouping involves combining visual elements into perceptual wholes, such as seeing a group of dots as a circle

segregation involves parsing these wholes into distinct objects, like separating the wall from the flowers and tree in a garden scene 

Who were the gestalt psychologists? How did they contribute to our understanding of figure–ground perception?

Max Wertheimer, Wolfgang Kohler, and Kurt Koffka. contributed to figure-ground perception by developing the Gestalt principles of perceptual organization, which explain how the brain organizes sensory input into meaningful wholes rather than separate part

What is edge completion? How does it account for illusory contours?

perception of a physically absent but inferred edge, allowing us too complete the perception of a partially hidden object. it accounts for illusory contours because it uses information from surrounding elements to “fill in “ these gaps and create a complete contour.

What is object agnosia? How is object agnosia different from blindsight?

Object agnosia is the inability to recognize familiar objects visually, despite having intact senses, memory, and intelligence.

blindsight is a type of cortical blindness where a person cannot consciously perceive objects in a portion of their visual field due to damage to the primary visual cortex, but can still react to stimuli like motion and track objects without conscious awareness.

The key difference is that object agnosia affects object recognition and identification, whereas blindsight is a deficit in conscious vision itself. 

What computational difficulties does the visual system face in recognizing objects? How are these difficulties related to the difficulty in building self-driving cars?

The primary computational difficulty in visual object recognition stems from the infinite variation in object appearance (due to changes in position, lighting, pose, and size) and the resulting need for sophisticated, real-time processing to handle complex and unpredictable real-world environments

These challenges directly impact self-driving cars, which rely on this technology to perceive their surroundings, but struggle with adverse weather conditions, occlusions, distinguishing similar objects, real-time decision-making, and processing complex urban scenes.  

What processes are necessary in order to be able to remember an object that you saw earlier?

encoding, the initial learning or perception of the object; storage, the maintenance of that information over time; and retrieval, the ability to access the stored information when you need to remember it

What is figure–ground symmetry? Why is it important in visual perception?

figure-ground organization is a key Gestalt principle where symmetrical objects are perceived as figures (the main focus) against a less defined background.

It is important in visual perception because it helps the brain segment visual scenes, organize information into meaningful patterns, and focus attention by distinguishing the object from the surrounding ground

What are the laws of perceptual grouping? What do they account for?

perceptual grouping are principles describing how the brain naturally organizes visual stimuli into coherent, organized patterns and objects, such as the laws of proximity, similarity, continuity, closure, and common fate.

They account for the human tendency to perceive simple, orderly, and meaningful wholes from complex or fragmented visual information, ensuring that we can make sense of the world by forming unified structures from disparate parts

What are geons, and why are they considered the building blocks of object perception?

geons (short for "geometric ions") are basic, three-dimensional shapes such as cylinders, cones, and bricks that are proposed to be the fundamental building blocks of object recognition

What is prosopagnosia? Is it a form of object agnosia or something different?

a selective deficit in recognizing faces. it is a neurological condition in which face recognition is impaired, but other forms of visual object recognition are relatively intact.

While it is a type of agnosia—a general inability to process sensory information—it is distinct from general object agnosia, which involves difficulty recognizing non-face objects.

Your cat is sitting by the coffee table. You cannot see the cat’s stomach because of the coffee table leg; however, you are certain that the cat head and cat tail you are witnessing belong to one cat. This is an example of _____.

grouping

Even though the cat is tan and the table leg is tan, you can see these are two distinct objects because of the process of _____.

segregation

Which of the following features does not contribute to your ability to differentiate figure from ground?

color constancy

The gestalt laws were principally developed by

Wertheimer

Identify the gestalt law demonstrated below:

465 987 184 614

law of proximity

When we group objects together by size, color, orientation, or even motion, we are following the:

law of symmetry

What makes the Necker Cube illustrated in 5.5 ambiguous?

there are two potential 3-D interpretations of the illustration

Like other visual illusions, the Necker Cube is important because

it illustrates top-down processing in perception

When a Necker cube is made by using illusory contours, we find that

two 3-D interpretations are still apparent even when the cube is made using illusory contors

Illusory contours exist because of the process of

edge completion

__________ represent the basic units of objects and consist of simple shapes, such as cylinders and pyramids.

Geons

The recognition-by-components view is a theory that strongly represents which view of perception?

bottom-up processing

An advantage of the recognition-by-components view is that

any object is a combination of a few basic geons, and its position relative to the observer should not matter

How do the colors of the rainbow map onto wavelength as measured in nanometers?

Red = 620-750 nm. Orange = 590-620 nm. Yellow= 570-590 nm. Green = 495-570 nm. Blue = 450-495 nm. Violet (380-450 nm.

This order is determined by how each wavelength refracts (bends) at a different angle when passing through raindrops, causing them to separate into the visible spectrum

Describe the difference between monochromatic and heterochromatic lights.

Monochromatic light consists of a single wavelength, representing one color, while heterochromatic light is composed of multiple wavelengths, encompassing several colors

How is hue related to wavelength?

hue is the quality of color. hue is the base quality of a color, directly related to the physical property of wavelength

Describe the difference between brightness and intensity.

Brightness is a subjective human perception of how much light is seen, while intensity is an objective, physical measurement of light power per unit area

Define a metamer, and describe how color-matching experiments contribute to this concept.

a metamer refers to two color stimuli with different spectral power distribution that appear as identical color to the human eye under specific viewing condition. 

color matching experiments- directly demonstrate the concept of metamers and established the trichromatic theory of color vision.

Contrast additive and subtractive color mixing.

Additive color mixing involves adding different colors of light to create new colors, resulting in brighter colors as more light is added

Subtractive color mixing involves using pigments, dyes, or inks that absorb (or subtract) certain wavelengths of light from white light to produce color, leading to darker results as more colors are combined

Diagram the differences between the different cones that we have.

. S-cones (Short-wavelength sensitive)

• Peak sensitivity: ~420 nm

• Respond best to blue light

• Least numerous (about 5–10% of cones)

• Concentrated slightly outside the fovea center

2. M-cones (Medium-wavelength sensitive)

• Peak sensitivity: ~530 nm

• Respond best to green light

• Moderate in number

• Important for distinguishing greens from reds

• 3. L-cones (Long-wavelength sensitive)

• Peak sensitivity: ~560 nm

• Respond best to red/yellow light

• Most numerous cone type

• Crucial for high-resolution and daylight color vision

Why are three cones necessary to see the colors we do? What evidence is there that some people have a four-cone system?

Three cone types (sensitive to red, green, and blue wavelengths) are necessary for human color vision because they allow the brain to process and distinguish different colors by comparing the relative stimulation of each cone type. Evidence for a four-cone system, or tetrachromacy, exists in some women who carry two different X-chromosome-linked color genes, resulting in four types of cones that can perceive more subtle color distinctions than the average human

Explain how the fact that we have three cones is related to the three primaries of the trichromatic color system.’

The three cone cells in the human retina are sensitive to different wavelengths of light, corresponding to short (blue), medium (green), and long (red) wavelengths, which directly explains why the trichromatic color system uses three primary colors (red, green, and blue). 

If having three cones is necessary for having three primaries, how many primaries would be needed to match colors in a person with two cones?

A person with two cones would need only two primaries to match colors, as they would be a dichromat. This is because the number of functioning cone types directly corresponds to the number of primary colors required to represent their visible spectrum

Survey the evidence in support of opponent-process color theory.

Evidence for the opponent-process theory of color vision includes the perception of negative afterimages, the inability to perceive certain combined colors (like reddish-green), and the discovery of color-opponent cells in the retina and lateral geniculate nucleus that respond to opposing color pairs. These phenomena, which the rival trichromatic theory cannot fully explain, show how the visual system processes colors in opposing pairs of red/green, blue/yellow, and black/white

What are afterimages? Why do they support opponent-process color theory?

Afterimages are the persistent perception of an image with opposite colors after prolonged exposure to a visual stimulus, and they support the opponent-process theory because they demonstrate how the visual system processes color in opposing pairs

Describe how the process of habituation is used to determine if infants have color vision.

Researchers use the habituation method to test infant color vision by first repeatedly showing an infant a single color until their looking time decreases. If, during the test phase, the infant shows renewed interest in a new color compared to the original one (dishabituation), it indicates they can perceive the difference. If the infant continues to show little interest in the new color, it suggests they perceive it as similar to the original color

Diagram how the loss of transparency to short wavelengths causes yellow–blue confusion in older adults.

Yellow-blue confusion in older adults is caused by the aging of the eye's lens, which naturally thickens and yellows over time. This change acts like a built-in filter, blocking and scattering short-wavelength light (blue and violet) and reducing the eye's ability to perceive blue tones

Diagram the different types of color deficiencies

Types are grouped in to red-green, blue-yellow, and monochromatism (total color blindness). Red green most common

What is the difference between a rod monochromat and a cone monochromat? What differences are there in their vision?

A rod monochromat (a type of complete achromatopsia) has no functional cones, relying solely on rods for all vision, resulting in a lack of color vision, very poor visual acuity, and extreme light sensitivity. A cone monochromat (blue cone monochromatism) has functional but non-typical cone function, retaining only blue (S) cones, leading to a limited form of color vision, better but still poor visual acuity, and moderate light sensitivity. 

Why is it important to have color constancy in the real world? What function does it serve?

Color constancy is important because it allows us to perceive objects as having stable, consistent colors under varying lighting conditions, rather than seeing their appearance change drastically with each change in illumination.

What is the difference between color constancy and lightness constancy?

Color constancy is the brain's ability to maintain a consistent hue (e.g., "red") of an object under different lighting conditions, while lightness constancy is the brain's ability to perceive an object's consistent brightness or lightness (e.g., "white") despite varying illumination levels

What is the range in nanometers of the human visible spectrum? What is the difference between heterochromatic light and monochromatic light?

400-700 nm. Monochromatic light is composed of a single wavelength of light, producing a pure, saturated hue, whereas heterochromatic light (like white light) contains many different wavelengths mixed together

What is meant by the terms hue, saturation, and brightness? What does each contribute to our perception of color? Give an example of two colors that differ with respect to saturation.

Hue refers to the color quality of the light and corresponds to the color names that we use. Saturation refers to the purity of light. Brightness is related to the amount of light present and is our experience of the intensity of this light. IDK THE EXAMPLES

What are additive color mixing and subtractive color mixing? How do the two processes differ? When would you use each one?

 Additive color mixing is the creation of a new color by a process that adds one set of wavelengths to another set of wavelengths (remember spatial summation.  Subtractive color mixing is the creation of a new color by the removal of wavelengths from a light with a broad spectrum of wavelengths.

The key difference is that additive starts with darkness and adds light, while subtractive starts with white light and removes it.

What are the three cone systems? What kind of monochromatic light is each cone sensitive to? Why do the cone systems support the trichromatic view of color vision?

short-wavelength (s) cones, medium-wavelength(M) cones, and long-wavelength (L) cones

which are sensitive to short-wavelength (blue), medium-wavelength (green), and long-wavelength (red) light

The cone systems support the trichromatic view of color vision because the relative activity of these three distinct cone types to different wavelengths of light allows the brain to perceive a broad spectrum of colors

What is the problem of univariance? How does it relate to metameric matching? How does it relate to color blindness under scotopic conditions?

a single type of photoreceptor, unable to distinguish wavelength from intensity, gives an ambiguous response to different combinations of light

This problem is central to metameric matching, where different spectral distributions of light are perceived as the same color because they produce identical responses in the eye's three cone types, a phenomenon that arises from the univariance of each cone system

Under scotopic (low-light) conditions, only rods are active; because rods also obey the principle of univariance (all rods use the same pigment and have uniform wavelength sensitivity), the world appears monochromatic (drained of color) as there is no comparison across different photoreceptor types to extract color information. 

What is the opponent-process theory of color vision? Describe three perceptual phenomena that demonstrate the reality of opponent processing.

The opponent-process theory of color vision posits that color perception is based on three pairs of opposing colors: red-green, blue-yellow, and black-white.

negative afterimages, inability to perceive “impossible colors”, color constancy

What is the difference between cone-opponent cells and color-opponent cells? Where do you find each kind of cell? Describe the visual field of a double-opponent cell.

Cone-opponent cells combine signals from different types of cones in an antagonistic (opponent) manner, while color-opponent cells are a more general term for any neuron that responds to color in an opponent fashion, which includes single- and double-opponent cells found in the primary visual cortex (V1).

found early in the visual system in the retina

visual field is characterized by having two opposing color-senstive regions within its receptive field.

What is meant by the term color deficiency? What is the difference between a rod monochromat and a cone monochromat? What are the three types of dichromats? Describe the physiological issue and the perceptual consequences for each kind of dichromat.

A color deficiency is the reduced ability to distinguish between certain shades or colors.

What is the difference between a rod monochromat and a cone monochromat?

rod monochromats (achromatopsia) have no cone cells and see in shades of gray, while cone monochromats (like blue cone monochromatism) have functioning rod cells and only one type of cone cell, allowing them to see limited color, typically blue and some shades of yellow.

What are the three types of dichromats? Describe the physiological issue and the perceptual consequences for each kind of dichromat.

protanopes, deuteranopes, and tritanopes

Protanopes-(physiological) lack the l-cones in their eyes. (perceptual)unable to percieve any red light. world appears dominated by blues and yellows

deutranopes- (physiological) lack m-cones. (perceptual) also have a red green deficiency

tritanopia-(physciological) lack s-cones. blue-yellow deficiency

What is meant by the term constancy?

the ability of our visual system to perceive an object as stable and unchanging, even when the sensory information it provides changes

What are lightness constancy and color constancy? How do we infer the nature of the illuminant in each case?

Lightness constancy is the perception of an object's brightness as stable across different illumination levels, while color constancy is the perception of an object's color as stable under varying light sources.

What is the difference between violet and purple? What is the physiological explanation for why purple looks like a mix of red and blue?

Violet is a specific, short wavelength at the end of the visible spectrum, while purple is a composite color, a mix of red and blue light, which does not have its own wavelength.

Physiologically, purple appears because our eyes' cone cells detect both red and blue wavelengths, and the brain interprets this combination as a single color, even though red and blue aren't adjacent in the light spectrum

The hue of an object is most closely associated with the _____________ of the reflected light.

wavelength

A _____________ is an example of a natural prism.

rainbow

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

The short system of cones is optimally sensitive to ___________ wavelengths of light.

420 nm

The color orange (565 nm) activates

M-cones and L-cones

What color is generated when M-cones and L-cones are equally activated?

yellow

At least _______ cone type(s) are required for color vision.

two

The problem of ______________ explains why we do not see colors in the dark.

univariance

Aftereffects lead to the appearance of ____________ colors.

complementary 

The existence of aftereffects support the ___________ theory of color vision.

opponent 

If you focus on a red circle for 30 seconds, then the circle disappears, you will perceive a __________

afterimage

cyan

Dichromats are usually _______ because genes controlling color vision are located on the _____ chromosome(s).

male, X

Individuals lacking long-wavelength cones are called __________ and have difficulty seeing __________.

protanope, red 

Individuals lacking short-wavelength cones are called __________ and have difficulty seeing __________.

tritanope, blue

Color constancy refers to the observation that we see the same _______ despite changes in the composition of the ____________ of light that is striking that object.

color, wavelengths

The properties of an object (i.e. color, shape, etc.) seldom change when the source of ____________ is altered.

illumination

Which is the example of the failure of color constancy?

when an object looks to be a different color when it is illuminated by late evening light

The illustration of Behnam's Top demonstrates the illusion known as __________.

Fechner color effect 

The phenomenon of Fechner colors is based upon center-surround receptive fields. T or F 

False 

When a Benham top is spinning, suddenly changing the direction of the spinning will

not affect the perception of illusory colors 

___________________ refers to the observation that we continue to see an object in terms of the proportion of light it reflects rather than the total amount of light it reflects.

lightness constancy

The eyes of Adanson’s jumping spider have _____ photosensitive layers. A _____ image is focused on the first layer.

4; sharp

To compute depth, Adanson’s jumping spider compares an image across an eye’s retinal layers. The human depth cue of _____ compares one eye’s retinal image to the retinal image in the other eye.

binocular disparity

In Adanson’s jumping spider, the difference in an image’s blurriness across retinal layers is greatest for _____ objects, making the depth cue most useful for _____ objects.

near; far

The process whereby the eye’s lens adjusts to focus near and far objects on the retina is called:

accomodation

All the light rays reflected by an object gather at a single location called:

the focal point

Frankie brings her ring finger closer to her face as she inspects a splinter. As she does so, her ciliary muscles _____, causing her lens to _____.

contract; bulge

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

The maximum distance for which vergence is a reliable depth cue is:

2m 

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 depth cues include each of the following EXCEPT:

vergence

In the _____ depth cue called _____, parallel lines appear to converge with distance.

monocular; linear perspective

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

A change in position is called:

parallax

Which of the following is a motion depth cue?

vergence, occlusion, stereopsis, accretion 

accretion

Objects appear to change in size as we move toward or away from them. This is a motion depth cue called:

optic flow

The impression of depth is greater in 2D movies than in still pictures because 2D movies allow the viewer to use:

motion cues

Patty is seeing the movie “Pixels” in 3D. When she puts on her 3D glasses, Patty allows the depth cue of _____ to enhance her perception of depth in the movie.

stereopsis

What color is cyan?

blue-green

Each eye receives a slightly different view of the world. The difference between these cues is the basis of a depth cue known as:

binocular disparity

Binocular disparity provides information concerning an object’s distance from a(n) _____. Binocular disparity is therefore a cue to _____ depth.

focal point; relative

When one fixates an object, one:

looks at it

The horopter is an imaginary line connecting points corresponding to _____ retinal image disparity.

zero