lecture 5 Flashcards

1
Q

what is the importance of form and oragnisation?

A

environment contains hundreds of overlapping objects yet perceptual experience is:

  • structured
  • made of coherent objects that we can recognise, use and usually name
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how does the distal image differ from the proximal image?

A

the image is inverted, tiny and flat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

why is the proximal stimulus inverted, distorted, tiny and flat?

A

to compensate for eye movement, body movement and object movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

features of the retina that must be taken into consideration

A

the retina is curved

it is constantly moving

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how often does the retina move

A

up to 50 times a second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is marr’s approach concerned with?

A

representation of edged, contours and other areas of contrast chang e

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

is marr’s approach bottom up or top down? how so?

A

bottom up
starts off with retinal input into perceptual system in form of retinal image and describes in stages of processing this image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what type of model is marrs approach?

A

computational model

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what do you need to consider in computational theory?

A

what is the model trying to do? what are the processes for? what is the goal?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what needs to be considered on the algorithmic level of a computational model ?

A

what algorithm is needed? what process?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what needs to be considered on the mechanism level of computational model?

A

what mechanism is needed to implement the algorithm? eg. neural/ biological system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

importance of computational models?

A

algorithmic system is more likely to be understood by understanding the problem than explaining the mechanism in which it is embedded
(trying to understand perception by studying neurons is like trying to understand a bird in flight by studying only feathers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

5 stages of retinal image analysis (Marr’s approach)

A

1) retinal image
2) grey level description
3) primal sketch
4) 2 1/2 D sketch
5) 3D representation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

grey level description

A

measuring the intensity of light at each point in the image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

primal sketch

A

-representation of contrast change over a range of spatial frequencies (blobs, edges, bars..)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

2 1/2 D sketch

A

representation of orientation, depth and colour relative to the observer
primal sketch combined with depth cues, colour, motion
not 3D because it is observer oriented

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

3D representation

A

representation of objects independent of the observer
2 1/2 D sketch analysed for 3D volume primitives

produces a 3D representation that is independent from the observer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what stage of Marr’s approach is teh conscious experience of vision

A

3D representation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the Gestalt approach concerned with

A

rules of perceptual organisation

that we dont see in lines and figures but in forms and shapes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what did Gestalt believe?

A

the whole is greater (different) than the sum of its parts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are Gestalt psychologists interested in?

A

how we group parts of a stimulus together and the way we separate figure from ground (segregation and grouping)

22
Q

is the Gestalt approach top down or bottom up?

23
Q

what is insight learning?

A

sudden realisation of the solution to a problem

in the absence of trial and error-minimising teh gap between current state and goal

24
Q

what is important in insight learning?

A

you have to see the problem as a whole

25
what is special about insight learning?
it is thought to be a uniquely human trait/ skill
26
argument supporting the Gestalt approach
ambiguity does not arise in the real world, we see a stable and organised world. therefore we must have perceptual organisation argument: we see objects according to all their elements taken together as a whole
27
what are principles of perception?
seemingly innate laws that determine the ways in which objects are perceived
28
what did gestalt psychologist seek to do?
isolate the principles of perception
29
what are the gestalt laws of perceptual organisation?
1) similarity 2) good continuation 3) proximity 4) connectedness 5) closure 6) common fate 7) familiarity 8) invariance 9) pragnanz: good figure
30
similarity
things that appear to be grouped together
31
what can similarity occur due to?
shape, lightness, hue, orientation, size
32
good continuation
points that, when connected, result in a straight or smoothly curved lines are seen as belonging together lines tend to be seen in a way as to follow the smoothest path
33
proximity
things that are near one another appear to be grouped together
34
connectedness
things that are physically connected are seen as a unit
35
closure
of several geometrically possible perceptual organisations, a closed figure will be preferred to an open figure
36
why do we tend to complete a broken figure?
because of the strong closure cue for organising what we see
37
common fate
things that are moving in the same direction are grouped together objects with the same orientation are grouped together
38
familiarity
things are more likely to form groups if the group feels more familiar or meaningful
39
invariance
simple geometrical shapes are recognisable independent of rotation, translation and scale
40
captcha test? what does it rely on?
completely automated public Turing test to tell humans apart from computers relies on humans ability to perceptually organise images by invariance, and a computers lack of ability to do so
41
what is the central law of gestalt psychology?
pragnanz
42
pragnanz
of several geometrically possible organisations, one will occur that possesses the best, simplest and most stable shape
43
properties that affect whether the area is seen as figure or ground
``` symmetry convexity area orientation meaning/ importance ```
44
symmetry in figure-ground segregation
symmetrical areas are usually figures
45
convexity figure-ground segregation
convex shapes usually figures
46
area in figure-ground segregation
stimuli with comparatively smaller area usually the figure
47
orientation in figure-ground segregation
vertical and horizontal orientations are usually figures
48
meaning/ importance in figure-ground segregation? importance?
meaningful objects more likely to be seen as figures | infers top down process
49
problems with the Gestalt approach?
1) underplays parallel processing and unconscious processing that the brain does 2) explanation of how some of their laws worked was wrong 3) laws provide a description rather than an explanation 4) laws ill defined (e.g. what is the simplest and most stable shape?) 5) stating the obvious?
50
positives of the Gestalt approach
their laws appear to pe generally correct 1) percepts can be analysed into basic elements 2) the whole is greater than the sum of its parts 3) context and experience influence perception
51
David Marr dates
1945- 1980 | published 1982
52
Wolfgang Kohler
1887-1967 series of experiments in Kohler and Koffka by Wertheimer together they developed the Gestalt school series of influential publications (1920s)