object recognition and sound localisation

Question 1

What does perceptual organisation mean?

Answer 1

the way information is received from our sense

Question 2

What is the organisation like in retinal images?

Answer 2

they are not organised

Question 3

What is necessary for object recognition?

Answer 3

perceptual organisation

Question 4

What are the 2 aims of perceptual organisation?

Answer 4

perceptual segregation
figure background segregation

Question 5

What does perceptual segregation mean?

Answer 5

the ability to distinguish which elements belong together and form separate objects

Question 6

What does figure-background segregation mean?

Answer 6

where the visual system separates an image into figure and background by identifying one object as a figure so rest forms the ground

Question 7

What type of driven is the bottom-up approach?

Answer 7

stimulus driven

Question 8

What type of driven is a top-down process?

Answer 8

cognitive driven

Question 9

What are the 6 laws of perceptual organisation?

Answer 9

law of…
similarity
pragnanz
continuity
closure
proximity
common region

Question 10

What is law of similarity?

Answer 10

similar elements are grouped together perceptually

Question 11

What is law of pragnanz (or good figure)?

Answer 11

group elements so that the resulting shape is the simplest

Question 12

What is law of continuity?

Answer 12

where smooth curves are grouped together

Question 13

What is law of closure?

Answer 13

group elements in a single, recognisable pattern

Question 14

What is the law of proximity?

Answer 14

elements close together to one another grouped together

Question 15

What is the law of common region?

Answer 15

elements within a boundary are grouped together

Question 16

What is a criticism of the laws of perceptual organisation?

Answer 16

it’s provides a description not an explanation!!!
focus is on the cues the brain looks for not how an image is processed

Question 17

What provides information for perceptual organisation?

Answer 17

natural scene statistics

Question 18

What are physical regularities?

Answer 18

physical properties that commonly occur in the environment we live in

Question 19

Marr’s theory of object recognition (Structuralist)

Answer 19

object recognition as a computational problem

Question 20

What are generalised cones?

Answer 20

elementary units which objects are decomposed into

Question 21

Biderman’s extended theory from Marr’s

Answer 21

the visual system extracts simple, non-accidental features
these features are invariant
used to infer which geons are present in image

Question 22

What is a geon?

Answer 22

a simple 2D or 3D geometric shape
used to represent parts of an object

Question 23

What do structuralist theories like Marr’s and Biderman assume?

Answer 23

assume viewpoint independence
but recognition also depends on viewpoint

Question 24

What does modularity mean?

Answer 24

refers to how damage in a specific area impairs a specific function

Question 25

What does Agnosia mean? (Lissauer, 1890)

Answer 25

not knowing
causes problems not recognising object (visual agnosia)

Question 26

What are the 2 types of Agnosia?

Answer 26

apperceptive agnosia
associative agnosia

Question 27

What is apperceptive agnosia?

Answer 27

impaired ability to consciously perceive and discriminate stimuli
in posterior right hemisphere

Question 28

What is associative agnosia?

Answer 28

preserved ability to perceive stimuli but inability to interpret what was seen
e.g couldn’t say what an object it but can draw it

Question 29

Gathier and Tarr: recognition

Answer 29

recognition at an individual level is more common for faces than objets
more experience with faces than other objects

Question 30

What is prosopagnosia?

Answer 30

when face perception is selectively comprised after brain damage

Question 31

What areas of the brain does face perception activate?

Answer 31

fusiform gyrus

Question 32

What is visual imagery?

Answer 32

seeing with the mind’s eye
occurs when visual representation is present in STM but stimulus is not viewed

Question 33

The retina is spatiotopic, what does spatiotopic mean?

Answer 33

means the retina corresponds to positions in space

Question 34

The Cochlea is tonotopic, what does tonotopic mean?

Answer 34

means it corresponds to frequencies

Question 35

What does interaural time difference mean (ITD)?

Answer 35

means the difference in the arrival time of a sound to two ears

Question 36

What does interaural level difference mean (ILD)?

Answer 36

means the difference in the intensity of a sound between two ears

Question 37

Why does sound reach 2 ears at different levels?

Answer 37

due to acoustic shadow

Question 38

What are binaural cues?

Answer 38

auditory cues that help humans locate sound using both ears

Question 39

Lord Rayleigh: Duplex theory

Answer 39

states that low frequency sounds (below 800Hz) are localised using ITD
whereas high frequency sounds (above 1600Hz) are localised using ILD

Question 40

Are most sounds in the environment low or high frequency?

Answer 40

low frequency
so Interaural time difference is dominant cue

Question 41

What is used to localise low frequency sounds?

Answer 41

interaural time difference (ITD)

Question 42

What is used to localise high frequency sounds?

Answer 42

Interaural level difference (ILD)

Question 43

What does cone of confusion refer to?

Answer 43

how all points on a surface provide same binaural cue

Question 44

What are spectral cues?

Answer 44

a physical cue that helps us locate source of sound
but depends on frequency of sound

Question 45

What is head-related transfer functions?

Answer 45

a description of how sound waves are modified by the head, ears and other parts of the body as they travel to the ear

Question 46

What are 2 ways you measure sound localisation?

Answer 46

using an anechoic chamber
spectral cue manipualtion