Diagram Narratives Barbara Tversky Stanford University.
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Transcript of Diagram Narratives Barbara Tversky Stanford University.
Diagram Narratives
Barbara Tversky
Stanford University
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
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(Hegarty, 1993)
(Mayer & Gallini, 1990)
Mechanical Systems
Experiment 1: Describing diagrams
• Participants given one diagram
• either car brake, pulley, or bicycle pump• either arrows or no arrows
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0
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Structural Functional Structural Functional
No Arrows Arrows
Experiment 1: Descriptions from Diagrams M
ean
nu
mb
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of
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its
Experiment 2: Diagrams from Descriptions
How did participants depict the descriptions?
Structural Functional Description Description
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Number of Participants
Structural description Functional description
No Arrows Arrows No Arrows Arrows
Experiment 2: Diagrams from Descriptions
Learning complex systems
• Diagrams with/without arrows
• Structural/function text
• Structural questions
• Functional questions
• Hi/lo mechanical ability
Results
• Hi-ability: learn structural & functional from either diagram
• Lo-ability: learn structural from diagrams, learn functional from text
Diagram narrative: linked graphics
• Temporal
• Causal/Logical
• Whole to part/part to whole
• Structure to function
• Variations/types
Animation
• Review: Animated graphics no better than equivalent static for instruction
(Tversky, Morrison, & Betrancourt, 2001)
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)
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
Route maps & directions
• Generalize turn angle to ~ 90
• Generalize curves in roads
• Diminish long straight distances
• Enlarge short tricky turns
Linedrive map at mapblast.com
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)
Assemble TV cart from photo
Heiser & Tversky
Introduce
Segment actions into steps
Step Initiation Step Completion
Preview steps
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Exhibit large parts
Point to small parts
Make actions visible
Reassembler Demonstrator
Model structure
Model action
Conclude
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….
External representations of thought
• Cognitive tools to augment mind• Increase memory• Facilitate information processing
• Uniquely human
Some ways graphics augment cognition
• Record information
• Convey information
• Promote inferences
• Enable new ideas
• Facilitate collaboration
Animations tell stories
• Links are temporal
Two kinds of graphics
• Visualizations of inherently visual• Maps• Ancient
• Visualizations of metaphorically visual• Graphs, charts, diagrams• Modern
Babylonian clay map
Eskimo coastal map
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South Sea Islanders’ map
18th c. Graph
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Good graphics schematize
• Not “realistic;” omit irrelevant
• Emphasize, simplify, distort relevant
Creating effective spaces for thought
• Survey ancient and spontaneous examples; these have undergone natural user-testing
• Discover underlying mental representations
• Discover graphic devices that convey them
• Test
• Repeat….
Graphics consist of
• Elements
• Spatial relations among them
• These can convey meaning directly
Spatial Relations
• Categorical: spacesbetweenwords, ( )
• Ordinal: lists, outlines, trees
• Interval: graphs
Producing “graphs”
• 3 language cultures: USA, Hebrew, Arabic
• K-College
• Space, time, quantity, preference Tversky, Kugelmass & Winter
Meaningful use of space
• Proximity in space signifies proximity on abstract dimension
• Directionality• Vertical loaded: up is more, better, stronger• Horizontal neutral• Parallels in language & gesture
Mixing spatial metaphors
Elements
• Iconic
Elements
• Iconic
• Metaphoric: Figures of depiction• Synecdoche: part for whole• Metonymy: associate for whole
Elements
• Iconic
• Metaphoric: Figures of depiction
• Schematic (meaningful abstract forms): lines, curves, crosses, blobs, bars, and arrows
Meaningful abstract forms
• Lines, crosses, arrows, blobs
• Like classifiers: stick, sheet, roll
• Context-specific meanings
• Meanings related to mathematical/Gestalt properties
Meaningful abstract forms
• Arrows in mechanical diagrams (Heiser)
• Bars and lines in graphs (Zacks)
• Curves, lines, crosses, & blobs in route maps (Lee)
Arrows
• Natural interpretation of directionality• Arrow heads• River beds
• Many uses, interpretations
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Arrows for Mechanical Systems
Arrows: temporal to causal reasoning
• No arrows: structural descriptions
• Arrows-->functional descriptions
• Structural descriptions: no arrows
• Functional descriptions-->arrows
Arrows
• Asymmetric--> symmetric <--> extent <-->• Connecting, pointing, labeling• Temporal: sequence• Causal• Movement: direction, manner• Change over time, increases/decreases• Forces
Producing Descriptions from Graphs
Please describe in a sentence what is shown in the graph above:
X
Y
A
B
•
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X
Y
B
A
Two Categories of Description
• Discrete• higher—lower
• greater—less
• more—fewer
• stronger—weaker
• Trend• rising—falling
• increasing—decreasing
• function
• relationship
• trend
Proportion of Trend Responses
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•
Female Male0
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50
60
Height (inches)
Female Male0
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20
30
40
50
60
Height (inches)
10-year-olds 12-year-olds0
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40
50
60
Height (inches)
•
•
10-year-olds 12-year-olds0
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20
30
40
50
60
Height (inches)
Discrete Domain
Bar Graph
Continuous Domain
Line Graph
Proportion of Trend Responses
•
•
Female Male0
10
20
30
40
50
60
Height (inches)
Female Male0
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50
60
Height (inches)
10-year-olds 12-year-olds0
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30
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50
60
Height (inches)
•
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10-year-olds 12-year-olds0
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Height (inches)
12%0%
61%7%
Discrete Domain
Bar Graph
Continuous Domain
Line Graph
Producing Graphs from Descriptions
Height for males is greater than for females.
Height for 12-year-olds is greater than for 10-year-olds.
Height increases from females to males.
Height increases from 10-year-olds to 12-year-olds.
Discrete Domain
Discrete Description
Continuous Domain
Trend Description
Proportion of Line Graphs
Height for males is greater than for females.
Height for 12-year-olds is greater than for 10-year-olds.
Height increases from females to males.
Height increases from 10-year-olds to 12-year-olds.
65%30%
100%56%
Discrete Domain
Discrete Description
Continuous Domain
Trend Description
Bars and Lines: Summary
• Constructing descriptions from depictions• Bars--> discrete comparisons • Lines--> trends
• Constructing depictions from descriptions• Discrete comparisons-->bars
• Trends-->lines
Route Maps & Route Directions
• Are the schematizations similar?
• Ask hungry students how to get to Taco Bell
Original Map 1
Original Map 2
Directions 1
• From Roble parking lot• R onto Santa Theresa• L onto Lagunita (the first stop sign)• L onto Mayfield• R onto Bowdoin• L onto Stanford Ave• R onto El Camino• go down a few miles. It’s on the right.
Directions 2
Go down street toward main campus (where most of the buildings are as opposed to where the fields are) make a right on the first real street (not an entrance to a dorm or anything else). Then make a left on the 2nd street you come to. There should be some buildings on your right (Flo Mo) and a parking lot on your left. the street will make a sharp right. Stay on it. That puts you on Mayfield Rd. The first intersection after the turn will be at Campus Dr. Turn left and stay until you get to El Camino. Turn right (south) and Taco Bell is a few miles down on the right.
Segmentation according to Denis
• Start point: “you leave the building”
• Reorientation: “you turn left”
• Path/progression: “you follow Main St.”
• End point: “until you get to the restaurant”
• Make, take, turn
• Go down
Semantics of depictions & descriptions
• Follow around
• Landmarks
• Direction
Graphic “Language”
• Semantics: schematic elements• Not iconic• Gestalt/geometric meanings• Categorical• Combinatoric
• Syntax: combine elements by rules
Gesture alone was best
• Gesturers received higher ratings
• Gesturers included more essential features
• Gesturers assembled faster/more accurately
Some ways diagrams augment cognition
• Record information
• Convey information
• Promote inferences• Structural, functional• Bars/lines; arrows
• Enable new ideas
• Facilitate collaboration
How to stop cholera epidemic Snow,
Where to reinforce bombers? Wald, WWII
Some ways diagrams augment cognition
• Record information
• Convey information
• Promote inferences
• Enable new ideas: ambiguity useful
• Facilitate collaboration
Suwa & Tversky
Some ways diagrams augment cognition
• Record information
• Convey information
• Promote inferences
• Enable new ideas
• Facilitate collaboration• Externalize common ground• Platform for inferences/plans/decisions
Heiser & Tversky
Why do graphics communicate effectively?
• Spatial inferences easy (e. g., proximity, distance, direction)
• Spatial metaphors available (e. g., time, value, strength)
• Elements interpretable (icons, figures of depiction, schematic abstract forms)
Spatial Thinking
• Began with world as we perceive it and interact with it
• Perception & action differ for different spaces, yielding different conceptions of spaces
• Unlike geometer’s view of space
• Unlike classic view of imagery
Multiple mental spaces
• Space around the body: biased retrieval
• Space of navigation: systematic errors
• Space of thought: meaning through metaphor
Conceptions of space have profound effects
• Augment memory, inference, discovery, collaboration
• Distort memory, bias information representation and retrieval
Onward and upward !