module 4 part 2 - textbook stuff

Question 1

primary visual cortex

Answer 1

the first part of the visual cortex - v1
- contains neurons that respond to simple patterns consisting of oriented edges of particular sizes

damage leads to conscious vision loss

Question 2

visual hierarchy

Answer 2

as we travel ‘higher up’ in the visual system, away from the original sensory input, the properties that neurons respond to become more complex and specific

Question 3

visual agnosias

Answer 3

cases in which a person has difficulty recognizing or perceiving one kind of visual stimulus while maintaining the ability to process other kinds of stimuli - the existence of various types of visual agnosias suggests that different areas of the brain may be important for different visual abilities- functional localization???

Question 4

prosopagnosia

Answer 4

marked difficulty in recognizing individual faces - damage to fusiform face area

Question 5

semantic agnosia

Answer 5

difficulty in recognizing everyday objects

Question 6

fusiform face area

Answer 6

area of the temporal cortex that shows greater activity when people engage in a facial recognition task - or…ability to discriminate between visually similar stimuli (greebles study)

Question 7

lateral occipital cortex

Answer 7

part of the brain that is selectively activated when people do an object recognition task

Question 8

dorsal stream of visual input

Answer 8

projects upward from the visual cortex and ends in the parietal lobe - action - ‘where’

Question 9

ventral stream of visual input

Answer 9

projects downward from the visual cortex and ends in the temporal lobe - perception - ‘what’

Question 10

image segmentation

Answer 10

how the brain divides up the retinal image into different objects and regions - depends on a combination of bottom up and top down processes

Question 11

depth perception

Answer 11

the ability of the brain to determine where objects are in three dimensions (in space)

• does so based on cues - objects that occlude (block) other objects , motion parallax, and binocular disparity

all depth cues are bottom up

Question 12

motion parallax

Answer 12

objects farther away from you will change their position more slowly on your retina as you move

Question 13

binocular disparity

Answer 13

because our two eyes are on slightly different positions on our head, they see slightly different images

the amount of disparity of the images changes as a function of how far away in depth an object is from the point you are fixating on - more disparity = further away in depth

Question 14

stereopsis

Answer 14

ability of the brain to use differences in binocular disparity to determine the depth of an object

Question 15

object recognition

Answer 15

ability of the brain the recognize what objects are - potentially the final step of perception

depends on matching some incoming stimulus to a stored representation in memory

Question 16

gestalt laws

Answer 16

similarity: tendency to group together features of an image that have similar properties

proximity: tendency to group features of an image that are close together

good continuation: tendency to group together features that form a smooth, continuous path rather than those with a sharp discontinuity

Question 17

template model of recognition

Answer 17

matching an object to an image stored in memory point by point - keeping an exact photographic representation of the object in memory

Question 18

identification

Answer 18

ability to identify the same object or person across variations - challenge to the template model of recognition

Question 19

classification

Answer 19

recognizing something as a member of a specific category even if we have never encountered that specific example before

Question 20

feature based recognition

Answer 20

using features of objects that remain common across different views and examples in order to overcome variability in order to recognize objects

Question 21

structural model to recognition

Answer 21

model that suggests that our brain extracts three dimensional features from the objects it encounters and it uses these features to determine what an object will look like under different conditions so that it can match a given example to the stored representation

Question 22

geon theory

Answer 22

example of a structural model - suggests that we recognize geons (volumentric 3d primitives that can be recovered from 2d images) and compose them into objects

Question 23

view based models

Answer 23

we use two dimensional images of objects in order to identify them- in order to overcome variability we store multiple views of the object that we encounter over time - an object has to be close enough to one of the learned examples in order to recognize it

Question 24

viewpoint dependency

Answer 24

prediction that we should be best at recognizing objects from the specific viewpoint from which you have seen it versus other viewpoints

Question 25

scene schema

Answer 25

people learn which objects tend to appear in particular contests

Question 26

phonemic restoration effect

Answer 26

the brain fills in details of missing sounds from a speech signal based on expectation

Question 27

blindsight

Answer 27

patients have no conscious awareness of visual objects in their damaged visual field but can implicitly respond to questions about objects presented in the damaged visual field - suggests that we can ‘see’ unconsciously - processing division between conscious and non conscious perception

Question 28

visual imagery and blindsight

Answer 28

blindsight patients have less brain activity when perceiving images compared to control participants but similar activity when it comes to imagining images

Question 29

akinetopsia

Answer 29

inability to perceive motion

Question 30

optic ataxia

Answer 30

inability to reach for objects - but can name them

damage to dorsal pathway

suggests that there might be action specificity in this pathway because selective damage leads to problems with certain types of movement

Question 31

against functional specialization for faces

Answer 31

greebles - fusiform face area active when study participants learn to discriminate between greebles (computer generated creatures) - suggests that ffa might be more for distinguishing between visually similar objects

Question 32

in support of functional specialization for faces

Answer 32

sheep farmer with prosopagnosia who could still recognize and distinguish his sheep

Question 33

apperceptive agnosia

Answer 33

problems perceiving objects - faces for prosopagnosia would look contorted

cannot group visual features to form perceptions that can be interpreted as meaningful - single visual feature perception is intact

• can draw from memory but not copy

Question 34

associative agnosia

Answer 34

problems assigning meaning or labelling objects - can’t recognize familiar famous faces for prosopagnosia

can’t access information from memory - can’t draw from memory. can’t name objects, can’t determine if a visual object is possible or impossible, can’t indicate functions

Question 35

principle of experience

Answer 35

experience and knowledge drives perception - we are more likely to notice things that are familiar to us

Question 36

direct models

Answer 36

perception involves using information directly from our environment, without transforming it in our minds

there are enough cues in the real world to guide our perception and action that we don’t need prior knowledge/top down processes

Question 37

examples of environmental cues in direct models

Answer 37

texture gradients : density of a texture provides information about distance - near objects tend to be farther apart and far objects are closer together

topological breakages: discontinuity created by the intersection of two textures tells us about the edges of objects and aids in object identification

Question 38

types of object recognition models

Answer 38

pattern recognition: identifying a pattern in visual input and matching the pattern to existing patterns stored in memory

feature detection: visual input is broken down into individual parts and processed separately - then brought back together for pattern recognition

Question 39

examples of pattern recognition models

Answer 39

template matching theory: every object has a template in long term memory - can’t explain identification or classification

prototype theory:
every object has an average representation in memory - recognition is based on resemblance - more flexible

Question 40

examples of feature detection

Answer 40

recognition by components: all objects are reducible to basic geometric shapes (geons) - recognition = mentally separating a visual object into geons and matching the arrangement to memory representations

geons can be perceived from any angle which accounts for how we can recognize objects with shifts in perspective

Question 41

recognition in context

Answer 41

scene consistency effect - we are better at recognizing things when they appear in the contexts we expect them to be in