Diagram Narratives

1. Diagram Narratives Barbara Tversky Stanford University

2. Gratitude due: • Office of Naval Research • Julie Heiser, Julie Morrison, Marie-Paule Daniele, Mireille Betrancourt, Jeff Zacks, Gowri Iyer, Sandra Lozano, Sonny Kugelmass, Atalia Winter, Paul Lee, and many others

3. Mechanical Systems (Mayer & Gallini, 1990) (Hegarty, 1993)

4. Experiment 1: Describing diagrams • Participants given one diagram • either car brake, pulley, or bicycle pump • either arrows or no arrows

5. Experiment 1: Descriptions from Diagrams Mean number of units No Arrows Arrows

6. Experiment 2: Diagrams from Descriptions How did participants depict the descriptions? Structural Functional Description Description

7. Experiment 2: Diagrams from Descriptions No Arrows Arrows No Arrows Arrows Structural description Functional description

8. Learning complex systems • Diagrams with/without arrows • Structural/function text • Structural questions • Functional questions • Hi/lo mechanical ability

9. Results • Hi-ability: learn structural & functional from either diagram • Lo-ability: learn structural from diagrams, learn functional from text

10. Diagram narrative: linked graphics • Temporal • Causal/Logical • Whole to part/part to whole • Structure to function • Variations/types

24. Animation • Review: Animated graphics no better than equivalent static for instruction (Tversky, Morrison, & Betrancourt, 2001)

26. Animation • Review: Animated graphics no better than equivalent static • Animations: hard to perceive • Too fast, too complex • Disappear • Animations: hard to conceive • Conceive of events as sequence of discrete steps (Zacks, Tversky, and Iyer, 2001)

27. Cognitive Design Principles • Principle of Apprehension: structure & content of graphic should be readily & accurately perceived & comprehended • Principle of Congruity: structure & content of graphic should match structure & content of desired mental representation

28. Route maps & directions • Generalize turn angle to ~ 90 • Generalize curves in roads • Diminish long straight distances • Enlarge short tricky turns

29. Linedrive map at mapblast.com

30. How to make effective animations • Distort time and space to match desired mental representation • Study demonstrations for clues: How does demonstrating differ from doing? (Lozano and Tversky)

31. Assemble TV cart from photo Heiser & Tversky

32. Introduce

33. Segment actions into steps Step Initiation Step Completion

34. Preview steps

35. Exhibit large parts

36. Point to small parts

37. Make actions visible Reassembler Demonstrator

38. Model structure

39. Model action

40. Conclude

42. Creating effective spaces for thought • Survey examples for devices that work • Discover desired mental representations of space and time • Discover graphic devices that convey them • Test • Repeat….

45. External representations of thought • Cognitive tools to augment mind • Increase memory • Facilitate information processing • Uniquely human

46. Some ways graphics augment cognition • Record information • Convey information • Promote inferences • Enable new ideas • Facilitate collaboration

47. Animations tell stories • Links are temporal

48. Two kinds of graphics • Visualizations of inherently visual • Maps • Ancient • Visualizations of metaphorically visual • Graphs, charts, diagrams • Modern

49. Babylonian clay map

50. Eskimo coastal map