CLPS 0020- Lectures - Vision

Question 1

How does the visual system resolve ambiguities?

Answer 1

makes assumptiosn about the way the world usually looks: perception is a constructive process based on these assumptions

Question 2

What do caricatures say about visual perception?

Answer 2

Do not need all features to be accurate to perceive something: certain features stand out more prominently

Question 3

What are neurons’ receptive fields?

Answer 3

the specific stimuli that the neuron fires to: the pattern in light that causes the cell to fire

Question 4

Wht happened in Hubel and Wiesel’s one-neuron electrode experiment?

Answer 4

neurons’ responses can be graded: not just all-or-nothing: depending on the pattern, neurons fired a lot or even just partially if the stimuli required that

Question 5

How fast is the search time for a popout task, in general terms?

Answer 5

Very fast: easy to identify which is different

Question 6

Why does it tak longer to identify a red t in a field of blue ts and read ls?

Answer 6

You need to itnegrate the double processing of color and shape

Question 7

When identifying boundary lines, which makes the boundary more salient, change in angle or change in letter?

Answer 7

Change in angle

Question 8

What is an illusory conjunction?

Answer 8

when you perceive and report both features, but pair them incorrectly: example: mismatching colors to letters in the five letter-color experiment

Question 9

During the early parsing of visual info, is the info mediated by separate properties, or by combinations, such as color and shape?

Answer 9

Separate properties: that’s why it takes longer to identfy a red t in a field of blue ts and red ls

Question 10

What are features?

Answer 10

basic units, building blocks present ina ll cognition

Question 11

What happened in the Takana neuron tiger experiment?

Answer 11

there is no tiger cell, but cells that fire in response to a tiger image may be part of a larger population of cells that can detect tigers in the end, and this one cell contributes to the interpretation of the tiger as a whole

Question 12

What researcher performed the tiger neuron experiment?

Answer 12

Takana

Question 13

Is the simple feature approach enough to perceive and process images?

Answer 13

Nope: also depends on context, hence the top-down approach as well

Question 14

What information is used in priming?

Answer 14

influence of prior or later information

Question 15

What is the object-constancy problem?

Answer 15

How do we perceive the same object despite variability in viewing conditions?

Question 16

What is the object-centered view?

Answer 16

objects are defined by invariant features that remain stable across variability, such as Biederman’s geons: color, shape, etc.; very economical

Question 17

What is the viewpoint-centered view?

Answer 17

object define by viewer’s experience: multiple viewpoints stored in memory, many to one mapping onto a known object

Question 18

What are some advantages to the object-centered view?

Answer 18

economical, efficient coding because object broken into elemental parts, Occam’s Razor (simplest solution is probably the most correct)

Question 19

What are some disadvantages to the object-centered view?

Answer 19

neglects the level of detail we see objects at, not all the world is geometric, more than shape contributes to object recognition, we store more tha visual info when recognizing objects

Question 20

What are some advantages to the viewer-centered view?

Answer 20

world perceived in terms of experience with it; canonical shape recognized faster than not: “most common viewpoint”; many to one mapping for same objects: Shepard and Metzler’s mental rotation exercise

Question 21

Shepard and Metzler

Answer 21

object rotation exercise

Question 22

What are some disadvantages to the viewer-centered viewpoint?

Answer 22

not economical: and how do multiple viewpoints map onto a single representation?

Question 23

What does Moshe Bar propose about time difference in identifying “house” vs “upside-down house?”

Answer 23

For upside-down house, still maps onto house representation, but through a different pathway: partial activation of neurons, graded reactions/response time

Question 24

What is the visual “what” system?

Answer 24

temporal lobe stream: ventral

Question 25

What is the visual “where” ssystem?

Answer 25

parietal lobe stream: dorsal

Question 26

Temporal lobe stream

Answer 26

What: enduring object characteristics, long-term perceptual representations, represents our knowledge base of the world, object-based: constancies of size, shape, color, etc.

Question 27

Parietal lobe stream

Answer 27

Where: moment to moment info about the location and disposition of an object with respect to the effector

Question 28

What happens to monkeys in object discrimination tasks with ventral lesions?

Answer 28

Can’t find the food under the new object: temporal lobe stream disrupted; what system

Question 29

What happens to monkey in object location tasks with dorsal legions?

Answer 29

Can’t find the food near the landmarl: parietal lobe stream system disrupted: where system

Question 30

What happens to carbon monoxide poisoning victims with damage to the occipital-temporal lobes?

Answer 30

“What” system damaged: can’t recognize faces, differentiate geometric figures, recognize names of objects from shape/form, name/match slot orientation; can recognize voices and objects placed in hand: visual (but NOT representational disorder)

Question 31

In patients with carbon monoxide poisoning and damage to the occipital/temporal lobes, is it a visual or a representational disorder?

Answer 31

Visual: can still identify voices and objects placed in hands

Question 32

Which visual processing stream is focused more on perceptions vs action?

Answer 32

Perception for what (temporal) and action for where (parietal)

Question 33

Which visual processing stream supports long-term vs online/temporary representations?

Answer 33

Long-term is temporal (what) and online/temporary is parietal (where)

Question 34

Does the dorsal stream care about the object or just the orientation?

Answer 34

orientation: parietal “where”

Question 35

Does the ventral stream care about the object, or just the orientation?

Answer 35

object: temporal “what”

Question 36

What is neglect syndrome due to?

Answer 36

damage to the right parietal lobe: ignores input from left side of space: eats food from only one side of plate, fails to locate objects on neglected face, reads pigpen as pen

Question 37

What happens during neglect syndrome?

Answer 37

ignores input from left side of space of the object (but if given two flowers, will draw right halves of both, not just the flower on the right)

Question 38

Do people with right parietal damage (neglect syndrome for left visual field) see the whole image, or are they really blind to the left side?

Answer 38

See the whole image: still show priming when stimulus is presented to either damaged or whole visual field-hemisphere combo

Question 39

What is the binding problem?

Answer 39

how to connect the what and the where of vision: temporal and parietal

Question 40

What does Roskies say about the binding problem?

Answer 40

Temporal solution? What and where are bound because they are perceived at the same time

Question 41

What did Kosslyn’s fictional maps experiment show?

Answer 41

That mental images are similar to pictures in how they represent positions and distances: takes longer to “arrive” at a further destination on a mental map

Question 42

What did Kosslyn’s neuroimaging study show about visual imagery and visual perception?

Answer 42

Similar neural areas activated: can extend that to other areas, so supposed similar activation between sensory imagery and sensory perception: like coma patientes with motor area activation when imagining running

Question 43

What is prosopagnosia?

Answer 43

selective deficit in visuallt recognizing faces

Question 44

Why is prosopagnosia considered only a visual deficit rather than a naming deficit?

Answer 44

Can still identify faces based on touch and verbal descriptions

Question 45

What is the difference in perception of houses and faces?

Answer 45

Faces: whole > parts; fewer errors upright, but more errors inverted than houses; Houses: parts > whole, more errors upright, fewer errors inverted than faces

Question 46

Would prosopagnosia patients show the inversion effect for inverted faces? (ie. not recognize as accurately)

Answer 46

Nope: treat faces, inverted or no, as objects; TDs treat faces differently, inverted or no

Question 47

What does the processing of faces by infants as they develop suggest?

Answer 47

prefer faces to objects, can discriminate upright faces from the same face inverted at 16-18 weeks, but not at 22 weeks; developmental trajectory towards seeing faces holistically instead of as separate objects

Question 48

Based on Greebles, is the face module really just for faces?

Answer 48

Not really: used in tiny identifying discriminations, being experts at identifying

Question 49

What does the Other Race Effect suggest about face identification?

Answer 49

That it’s also based off of experience

Question 50

What is suggested by the fact that infants can discriminate small differences in both human and monkey faces, but adults cannot discriminate between novel/familiar monkeys?

Answer 50

If you don’t use it, you lose it.