2. Visual Distinctness What is easy to find How to represent quantitity Lessons from low-level vision Applications in Highlighting Icon (symbol) design - Nominal Glyph design – representing quantity

3. Spotfire product

4. Visual symbols

5. Architecture for visual thinking

6. Primitives of Perception (the graphemes). The whole visual field is processed in parallel This machinery tells us what kinds of information are easily distinguished Popout effects (general attention) Segmentation effects (dividing up the visual field)

8. Channel theory

9. Segmentation by Primitive Features

10. Orientation and Size (Gabor primitives)

11. Image segmentation based on texture

12. Textures for Maps

13. What is easy to find? A priori salience Top down salience Knowledge

14. Pre-Attentive Processing

15. Color is Pre-Attentive (Pops out)

16. Generic Pre-Attentive Experiment Number of irrelevant items varies Pre-attentive 10 msec per item or better. Triesman, A., and Gormican, S. Feature analysis in early vision: Evidence from search asymmetries. Psychological Review, 95(1) 15-48.

17. Color

19. Orientation

21. Motion

23. Size

25. Simple shading

27. Conjunction (does not pop out)

28. Semantic Depth of Field

30. Compound features (do not pop out)

32. Surrounded colors do not pop out

35. Laws of pre attentive display Must stand out on some simple dimension color, simple shape = orientation, size motion, depth Lessons for highlighting – one of each

36. Asymmetries

37. Blinking momentarily attracts attention Lessons: Highlighting how to make information available to attention A flying box leads attention Using color Using underlining Blinking momentarily attracts attention Motion elicits an orienting response

38. More on Conjunction (no pop)

39. Redundant coding

40. Pre-attentive conjunction

41. Conjunctions of motion and shape do pop out. (color also?) McLeod, P., Driver, J. and Crisp, J. (1988) Visual search for a conjunction of movement and form is parallel. Nature 332, 154-155. Driver, J., MacLeod, P. and Dienes, Z. (1992) Motion coherence and conjunction search: Implications for guided search theory. Perception and Psychophysics. 51, 1, 79-85.

43. MEGraph: Experimental system Allows for various topological range highlighting methods Goal from 30 to 2000 nodes MEGraph

44. Pre-Attentive Channels Form (orientation/size) Color Simple motion/blinking Addition/numerosity (up to 3) Spatial, stereo depth, shading, position

45. Pre-Attentive Conjunctions Stereo and color Color and motion Color and position Shape and position In general: spatial location and some aspect of form

46. Pre-Attentive Lessons Rapid visual search (10 msec/item) Easy to attend to Makes symbols distinct Based on simple visual attributes Faces, etc are not pre-attentive

47. Designing symbols

48. Perceptual Channels Color (3) Shape (size, orient) Motion (2?) Texture (2++) Position (x,y)

49. Spatial Channels Like interferes with like

50. Distortions: Size contrast effect

51. Orient contrast

52. Size contrast effects can cause errors in information display

53. Chris Weigle: orientation channels for info display

54. Mapping data to display variables Data glyphs Position (2) Orientation (1) Size (spatial frequency) Motion (2)++ Blinking? Color (3) Note we have the problem of heterogeneity – There is no good solution Star glyph Method

55. Starplot glyph

56. Spotfire product

59. Integral and Separable dimension (Garner) Can we read display attributes Independently Holistically Speeded classification task. Sort into two piles on one dimension or another

60. Separable Integral Motion Color red-greenyellow-blue black-whitered-green x-size y-size Color orientation

61. Lessons for Information Display Orthogonality - use a different channel for a different type of information If you need this use separable challenge If you need to highlight by two properties use separable dimensions.

63. The programmable filter We can only look for patterns of simple features Conjunctions of shape, color cannot be programmed for parallel search of field Conjunctions of depth/motion and color/shape can be Integral dimensions tend to be seen holistically cannot be separated Separable dimensions tend to be seen separately

64. Searchlight Model of Attention

65. Searchlight Properties Size varies with data density Size varies with stress level Attention operators work within the searchlight beam Attention is a tunable filter Eye movements 3/sec – A series of saccades