lecture 14 - making sense of the visual world

Question 1

1st stage of visual processing

Answer 1

retinal information processing sensation (eye)

Question 2

2nd stage of visual processing

Answer 2

feature discrimination. early perception (optic cortex)

Question 3

3rd stage of visual processing

Answer 3

higher-order feature analyses. late perception (cerebral cortex)

Question 4

4th stage of visual processing

Answer 4

object (world) knowledge. cogntion and thought (cerebral cortex)

Question 5

5th stage of visual processing

Answer 5

action (eye movement)

Question 6

low-level processing

Answer 6

basic analysis of shapes, forms, colours, contours, contrasts and movements. these “primitives” are first processed in the eye and the electrical signals are then transmitted to the thalamus and the early visual cortex

Question 7

low-level vision

Answer 7

luminance colour, spatial frequency, temporal frequency, local motion -> low-level encoding

Question 8

mid-level processing

Answer 8

primitve information is organised into fundamental forms, as these are the basis for higher-order processing

Question 9

mid-level vision

Answer 9

textures, surfaces, lighting, global motion, depth -> mid-level encoding

Question 10

higher-level processing

Answer 10

fundamental forms are given meaning through connection/associations with our previous knowledge/experience of the world. this stage also directs our attention to specific parts of the visual scene, to areas of salient features or of particular interest. the brain can sometimes “supplement” information

Question 11

high-level vision

Answer 11

objects, characters, actions, intensions -> high-level encoding

Question 12

low-level and mid-level vision are bottom-up processing

Answer 12

visual experience is driven by piecing together information that is available

Question 13

high-level functioning is top-down processing

Answer 13

as your visual experience is driven by higher cognitive functions (e.g. attention, memory)

Question 14

ensemble of visual features

Answer 14

we achieve an understanding of what we see based on the ensemble of visual features, and it is this ensemble integrated together that generates the illusion of form

Question 15

4 key principles of Gestalt

Answer 15

emergence, reification, multistability and invariance

Question 16

emergence - Gestalt principle

Answer 16

process by which the visual system first recognises the whole, and then only after this stage are the individual features recognised

Question 17

reification - Gestalt principle

Answer 17

objects are perceived to contain more spatial information than what is actually present. our knowledge and expectations fill in the gaps of what we think we should see

Question 18

multistability - Gestalt principle

Answer 18

the phenomenon that describes ambiguous perceptual experiences that switch back and forth between alternative interpretations

Question 19

invariance - Gestalt principle

Answer 19

simple objects are recognised, independent of the lighting conditions, their rotation, the translation and their scale

Question 20

Prägnanz

Answer 20

tendency to interpret ambiguous and complex stimuli as the simplest forms possible. our experiences are ordered in a manner that is regular, orderly, symmetric and simple. the law of simplicity and good figure

Question 21

Gestalt laws

Answer 21

additional laws that help describe how the perceptual system organsises information

Question 22

what are the Gestalt laws

Answer 22

closure, proximity, similarity, continuity, symmetry and common fate

Question 23

closure - Gestalt law

Answer 23

any missinh information is fulled in to generate a complete figure

Question 24

similarity - Gestalt law

Answer 24

elements that are similar in low level features are grouped

Question 25

proximity - Gestalt law

Answer 25

spatially or temporally proximate elements will be grouped

Question 26

continuity - Gestalt law

Answer 26

lines are percieved as being continuous

Question 27

symmetry - Gestalt law

Answer 27

symmetrical features grouped together = harmony and balance

Question 28

common fate - Gestalt law

Answer 28

features that undergo similar changes = grouped

Question 29

Navon 1977

Answer 29

Subjects were presented with large characters made out of small ones, and they had to recognize either just the large characters or just the small ones.

Question 30

Navon - congruent

Answer 30

the letter E made up of multiple E's

Question 31

Navon - incongruent

Answer 31

the letter H made up of multiple E's

Question 32

Navon 1977 findings

Answer 32

Whereas the identity of the small characters had no effect on recognition of the large ones, global cues which conflicted with the local ones did inhibit the responses to the local level.

Question 33

Ariely 2001

Answer 33

showed that observers know a set's mean quite accurately but know little about the individual items, except their range. Taken together, these results suggest that the visual system represents the overall statistical, and not individual, properties of sets