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The Roles of Knowledge and Display Characteristics in Interpretation of Weather Maps

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Meteorology as a Domain. Data/displays can be arbitrarily complex ... Novices had more domain knowledge but were not better at weather prediction ... – PowerPoint PPT presentation

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Title: The Roles of Knowledge and Display Characteristics in Interpretation of Weather Maps


1
The Roles of Knowledge and Display
Characteristics in Interpretation of Weather Maps
  • Mary Hegarty
  • University of California, Santa Barbara
  • Thanks To ONR,
  • Naomi Shimozawa, Matt Canham, Dustin Calvillo, N.
    Hari Narayanan, Joel Michaelsen, Ted Tsui

2
Model of Graph(ics) Comprehension (Pinker, 1990)
Conceptual Message
Early Visual Processes
Match
Encoding
Graph
Visual array
Visual Description
Inference
Graph Schema
Conceptual Questions
3
(No Transcript)
4
(Implicit) Assumptions about Knowledge and
Graphics Comprehension
  • More knowledge leads to better comprehension,
    particularly inferences
  • If you can encode information from a display and
    have the relevant knowledge to make an inference
    from that information, the inference will be made
  • Information encoded and inferred is propositional

5
Other Possibilities
  • Knowledge and correct interpretation may not be
    sufficient conditions for an inference to be
    made.
  • May not activate correct knowledge
  • Propositional knowledge vs. visual-spatial
    representation
  • Naïve theories may interfere with correct
    principles
  • Characteristics of the graphics (e.g. complexity)
    may affect inference process

6
Meteorology as a Domain
  • Data/displays can be arbitrarily complex
  • Visual displays are typically used to make
    inferences (predict weather)
  • People vary in their amound and source of their
    knowledge
  • Newspaper/weather channel
  • Direct experience of weather
  • Formal instruction
  • Forecasting experience of experts

7
Introduction to Our Weather Prediction Task
The weather at X is getting warmer. True or false?
X
8
How Can you Tell?
L
H
9
How Can you Tell?
L
H
Pressure Gradient Force (PGF) Air moves from
high to low pressure.
10
How Can you Tell?
L
H
(Northern Hemisphere)
Pressure Gradient Force (PGF) Air moves from
high to low pressure. Coriolis Effect Air
moves counterclockwise around low, clockwise
around high pressure.
11
How Can you Tell?
  • Step 1 Infer wind direction from pressure

Step 2 Infer temperature change from wind
direction
12
- Air will move counterclockwise inward -
Weather at X will get colder
13
Experiment 1
  • Participants
  • 16 novices (geography) students
  • 15 naïve (psychology) students
  • Tasks
  • Meteorology Questionnaire
  • Weather Prediction
  • Display
  • Separate temperature and pressure maps
  • Combined temperature and pressure map
  • Temperature, pressure and cloud cover map
  • Accuracy, RT, verbal protocols

14
Separate Maps
Will the weather get warmer or colder at X?
15
Integrated Map
Will the weather get warmer or colder at X?
16
Complex Maps
Will the weather get warmer or colder at X?
17
Questionnaire Data
18
Weather Prediction Accuracy(Proportion Correct)
Chance
19
Weather Prediction Reaction Time (seconds)
20
Heuristics Identified in Protocols
(1) Pressure differential (Air moves
from high pressure to low pressure.) (2) Coriolis
effect (Air moves counterclockwise
around low pressure,
clockwise around high pressure.) (3)
Temperature-Pressure Associations (Low
pressure is cold. High pressure is warm.) (4)
West-East flow of air (Air moves from
west to east.) Other Unable to classify.
21
Trials Principle mentioned
22
Trials Principle mentioned
23
Trials Principle mentioned
Students using heuristic consistently
24
Correct answer consistent with all 4
principles 83 accurate
25
Correct answer inconsistent with 3 principles 23
accuracy
26
Summary (Experiment 1)
  • Novices had more domain knowledge but were not
    better at weather prediction
  • Weather prediction performance close to chance
  • Performance faster and more accurate for
    integrated maps compared to separate and complex
    maps
  • Novices more likely to base answers on principles
    (not always correct principles)

27
Experiment 2a Experts
  • Is there a right answer?
  • 3 Meteorology Experts
  • NRL Monterey
  • Ph.D. in Meteorology
  • 15 years experience
  • 2/3 had experience as forecasters
  • 10 weather maps

28
The area is getting colder.
  • Draw arrows indicating how the wind will blow
    around the target area.
  • Is the statement True or False? (Please circle
    true or false.)
  • Explain why you think so. Please write your
    explanations as clearly as possible.

29
- Arrows counterclockwise inward - Agreed on
correct answer
30
Experiment 2b Naïve Individuals
  • Taught Naïve individuals the Pressure Gradient
    and Coriolis principles
  • 3 groups of 16 participants
  • Control
  • Learned Principles
  • Learned Principles and worked-out examples
  • Measured
  • Pretest posttest performance (10 problems)
  • Written explanations to 5 problems

31
Meteorology Knowledge
32
Weather Prediction
33
Use of PGF and Coriolis Principles in Explanations
34
Other Heuristics used by Naïve Participants.
  • Pressure Temperature association.
  • West to East movement of air.
  • Temperature area dominance.
  • Temperature proximity.

35
Conclusions
  • Knowledge of principles not sufficient for making
    correct inference.
  • Naïve heuristics still present after learning
    correct principles

36
Experiment 2c Novices
  • Why do Novices (Geography students) fail to make
    the correct inferences when they have the
    relevant knowledge?
  • Considered 2 possibilities
  • They fail to activate the relevant information
  • They are not able to make necessary chain of
    inferences, that is,
  • Infer wind direction from pressure
  • Infer temperature change from wind direction

37
Method
  • 17 students in an undergraduate meteorology class
  • 8 participants received a hint
  • 9 participants did not receive a hint
  • No guidance Does the area get warmer or colder?
  • Arrows first 1. Draw arrows
  • 2. Does the area get warmer or colder?
  • 3. Explain answer

38
Meteorology Knowledge
39
Weather Prediction
40
Arrows
Reminder What the Experts Drew
41
Examples of What Novices Drew
42
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43
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44
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45
Arrows Consistent with PGF and Coriolis Effect
94 of answers consistent with arrows
46
Conclusions Experiment 3c
  • Inference guidance lead to somewhat better
    performance
  • Novices performance was based on heuristics,
    however
  • Sometimes only partial knowledge (e.g., PGF but
    not Coriolis)
  • Sometimes misapplication of rules (e.g. reverse
    Coriolis)

47
Summary
  • Ability to read a graph and possession of
    knowledge are not sufficient conditions for
    making inferences.
  • Relevant knowledge not always activated
  • Naïve theories sometimes activated instead
  • Small significant effects of
  • Integrated displays
  • Inference guidance (arrow task)

48
Practical Implications
  • Trainees need to be taught explicitly to make
    inferences from graphical displays.
  • Instruction must confront naïve mental models.
  • Displays should integrate the relevant
    information and show no irrelevant information.
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