The Visual-Spatial System:

Transcription

1 The Visual-Spatial System: Cognition & Perception DR. JAMES L. MOHLER ( 马健思博士 ) COMPUTER GRAPHICS TECHNOLOGY PURDUE UNIVERSITY

2 The Visual-Spatial System Visual Perception Cognitive processes that receive input from eyes and interpret/construct what we are seeing; the meaning making activity; visual intelligence Physiology (Physical Mechanisms) Eyes (as a mechanism) Retina (color & value input) Optic Nerve ( hardwire ) Brain (input receipt) Spatial Cognition (Brain Only) Spatial Ability Mental Visualization Mental Relations Mental Orientation

3 Examples of Visual-Spatial Thinking Visual-spatial l thinking sometimes requires: Visual recognition or identification Pattern matching (2D or 3D) Thinking and manipulating information (2D or 3D) Mental representations Rotations or transformations Orienting (or reorienting) yourself

4 Spatial Cognition

5 Why is Spatial Ability Important Spatial ability has been shown to be a critical skill in many different fields: At/d Art/design when we imagine i composition/layouts t Music when we hear in our mind Engineering when we create drawings Chemistry understanding chemical compositions Biology visualizing structures Science envisioning processes Geology mineral compositions Medicine understanding anatomical systems And the list goes on

6 Spatial Ability is Important! Spatial functioning i is critical to almost every professional field Some have advocated d that t it is as important t as mathematics/logic and language While seen as important, there is still much we don t understand (and much that researchers don t agree upon) However, researchers have generally agreed on the three primary factors that comprise spatial ability

7 Primary Spatial Ability Factors SPATIAL ORIENTATION SPATIAL RELATIONS V ISUALIZATION

8 Spatial Orientation (Lohman, 1979) Ability to imagine i how a stimulus array will appear from another perspective; there is often a left-right discrimination Ability to comprehend the nature of the arrangement of elements within a visual stimulus pattern primarily il with respect to the examinee s body as a frame of reference

9 Spatial Orientation Examples Wayfinding, map reading Driving a car Piloting an aircraft Brochure design (folding/facing pages)

10 Spatial Relations (Lohman, 1979) Ability to solve such problems (typically mental rotations) quickly, by whatever means. Speed in manipulating relatively simple visual patterns by whatever means (rotation, transformation, or otherwise).

11 Spatial Relations Examples Image an object in your mind. Sketch an example of what the top of the object would look like. Which of the following two objects match the stimulus object?

12 Spatial Visualization (Lohman, 1979) Ability to solve complex spatial-figural l content t Ability in manipulating visual patterns, as indicated by level of difficulty and complexity in visual stimulus material that can be handled successful, without regard to the speed of task solution.

13 Minor Spatial Ability Factors CLOSURE FLEXIBILITY OF CL OSURE DYNAMIC SPATIAL ABILITY

14 Minor Factors (Lohman, 1979) Closure Speed Speed in apprehending and identifying a visual pattern without knowing in advance what the pattern is, when the pattern is disguised or obscured in some way. Flexibility of Closure Speed in finding, apprehending, and identifying a visual pattern, knowing in advance what is to be apprehended, when the pattern is disguised or obscured in some way. Dynamic spatial ability the ability to deal with moving elements and relative motion (arrival and intercept)

15 History of Spatial Ability Research PIONEERING ERA ( ) DEFINING ERA ( ) PAPER AND PENCIL ERA ( ) TECHNOLOGY ERA (1989 -)

16 Pioneering Era Spatial ability and its role in intelligence Thorndike (1921) Abstract, t mechanical and social intelligence Kelly (1928) Crossroads in the mind of man El Kloussy (1935) Found evidence for the existence of a factor K Thurstone (1938) Defined a space factor that represented the ability to operate mentally on spatial or visual images.

17 Defining Era Thurstone (1950) S1, recognize an object if viewed from different orientations or angles (rotations/relations) S2, recognize the parts of an object if they were moving or are displaced from their original position (visualization) S3, which is the ability to use one s body orientation to relate to questions regarding spatial orientation (orientation) Descriptive terms added later

18 Paper and Pencil Era Focus on subfactors Gender Environmental Biological Cultural Social Educational Age Hemisphere specialization Speed and efficiency

19 Technology Era Focus on the use of computer technology and its impact on spatial ability Examples: 2D and 3D environments Animation i VR technologies Computer games

20 Future? Refocusing on intelligence A return to spatial ability s impact and contribution to intelligence Greater use of technology Use of emerging technologies (VR, real-time media, et. cetera) How do these new technologies help or hinder spatial ability training

21 Types of SA Research

22 Types of SA Research Psychometric Differential Developmental Information Processing

23 Break

24 What is Visual Perception? IT IS WHAT (AND HOW) WE CONSTRUCT

25 Do we really construct everything we see?

26 Is This Possible?

27 Possible?

28 Possible?

29 Difficult to focus?

30 Visual Intelligence Our visual system functions upon a set of rules that t are independent of gender, culture, race, or any other variable that differentiates human beings. These rules apply to form, color and motion

31 Constructing Form

32 What you see is what you construct We know this image is flat, but most people perceive 3D why? And Where is cube B when you are seeing cube A? Where is cube A when you are seeing cube B?

33 Necker and Kopfermann Fundamental problem of seeing depth. Image at the eye is 2D; therefore it has countless interpretations in 3D. You construct visual worlds from ambiguous images in conformance to visual rules.

34 Symmetry y Symmetry often leads one to see a 2D representation ti but the rule of generic views can override this. Do you see a 2D or 3D object? The answer reveals which is dominant for you.

35 Proximity Proximity it can play a role in our interpretation t ti of imagery Rule 4: interpret elements nearby in an image as Rule 4: interpret elements nearby in an image as nearby in 3D

36 Constructing Shape

37 Contrasting Values? K i bj ti t i l th t t i l Kanizsa ssubjective triangles; the center triangle appears whiter than the surrounding area.

38 Contrasting Values? Eh t i di k th t di k hit Ehrenstein s disks; the center disk appears whiter or blacker than the surrounding area.

39 Cusps Ab t h i l ( ) t Abrupt changes in slope (cusps) cause us to see subjective figures

40 Nonaccidental Relations On the left, do you see black stripes on a white background? O h i h d hi i bl k On the right, do you see white stripes on a black background?

41 Nonaccidental Relations If three or more curves intersect at a common point in an image, interpret them as intersecting at a common point in space.

42 Constructing Color

43 Color Context The context of a color greatly impacts your perception of it Note that color 1 and 2 are the same hues Adjacent color impacts perceptionp

44 Simultaneous Contrast Your vision i system constructs t values based upon surrounding values (it does the same with hue). Viewed in context, the right gray disk looks darker But is it?

45 Simultaneous Contrast Are the gray bars the same value? Are you sure?

46 Corrugated Mondrian A th th? (Y b bl Are the gray squares the same gray? (You probably will not say what you see )

47 Corrugated Mondrian A th th? (Y b bl Are the gray squares the same gray? (You probably will not say what you see )

48 Construction is NOT in Isolation Surface colors and grays are not constructed t in isolation. Colors and grays are constructed in the context of a mutually consistent coordinated construction of surface shapes, surface colors, light sources and transparent filters in as simple a manner as possible.

49 Transparent Filters Ted Adelson The argyle Diamond on left looks lighter; example of a filter Separate the diamonds reduces the effect

50 Why do we use these rules? We are cognitive misers we must process quickly and we want to do so efficiently Four markers of different subprocesses that synergize to construct the most specific and cognitively ii cheapest h image possible. Light source Luminance (comparative to surroundings) Filters Image shape

51 Constructing Motion

52 Rules of Motion You construct t motion, just like you do everything else you see At 200/50/200 / milliseconds motion is perceived The delay speed affects what you construct

53 Rules of Motion This delay is called the interstimulus interval (ISI) and the ISI controls what you construct. Slower => Dot moves Faster => Two dots flash Speed required depends on spacing and size

54 Rules of Motion If l th d f th fl hi d t till If we slow the speed of the flashing dots, you still see movement (200/400/200)

55 Rules of Motion If i th d f th fl hi d t If we increase the speed of the flashing dots, you see two flashing dots (10/0/10)

56 Rules of Motion If the speed is correct and a curve is added d (each one flashing in sequence), you perceive the movement of the dot as an arced path (130/130/130/130).

57 Rules of Motion Similarly, il l the addition of an obstruction ti causes you to see the dot around the obstruction (130/130/130/130)

58 Ternus Configuration With this configuration, your visual system causes the center dot to remain stationary, while the outer dot is seen as moving around it (130/130/130/130).

59 Ternus Group With thi fi ti b th d t (th i d With this configuration, both dots (the inner and outer) appear to be rotating on elliptical paths.

60 Von Schiller Motion Your visual system makes two subjective dots jump back and forth together, sometimes side to side and sometimes up and down.

61 Von Schiller Cont. d Your visual system makes two subjective dots jump back and forth together, sometimes side to side and sometimes up and down. Notice that all the pairs switch together.

62 Rotary Cross Your vision i system will also create rotary movement. Here you can see the cross go either clockwise, or counterclockwise

63 Rotary Cross When we add an extra frame to the animation, you see the cross with inertia and only clockwise ii f i lii d Your vision system focuses on simplicity and consistency.

64 Rotational Paths Brown and Voth showed that t ISIs affect how you perceive paths. h h S i l i h bj When the ISI is slower, you perceive the object moving from corner to corner.

65 Rotational Paths Cont. d Wh th ISI i f t i th bj t When the ISI is faster, you perceive the object moving in a circular pattern.

66 Rotational Paths Cont. d Given these two things, we can create an animation of something that is not there. What do you see in this animation? i

67 Rotational Paths Cont. d Given these two things, we can create an animation of something that is not there. What do you see in this animation? i And in this one?

68 Rigid Motion If possible, and if other rules permit, interpret t image motions as projections of rigid motions in three dimensions.

69 Rigid Motion What is the image on the left? What is the image in the middle? What is the image on the right?

70 The Visual-Spatial System: Cognition & Perception DR. JAMES L. MOHLER ( 马健思博士 ) COMPUTER GRAPHICS TECHNOLOGY PURDUE UNIVERSITY