Empirical Investigation into the
Effect of Orientation on Text
Readability in Tabletop Displays
Daniel Wigdor
Ravin Balakrishnan
Presented at ECSCW, Paris, France
Tabletop Displays
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Text Orientation
• .
• Solutions:
1:
3:
2:
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Multiple Copies
Advantage:
• Spatial proximity for free
Disadvantages:
• More space used
• SDG shared interaction space lost
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Diff’ View for Each User
• Agrawala et al 1997
• Matsushita et al 2004
Advantages
• Conserves real-estate
• Optimal to all users
Disadvantages
• Loss of shared position of objects
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Algorithmic Rotation
• Many different techniques
(see Hancock et al Tabletop 2006)
Advantages:
• Only one copy of object
• Collaboration cues (CHI03)
Disadvantages
• Adds complexity to system
• Optimal orientation to only 1 viewer
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But, Why Reorient?
• Orientation used for other things:
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Preferred for drawing & design
Denotes ownership
Denotes intention to share
See Kruger et al CHI ’03
See Fitzmaurice et al CHI ‘99
• Users may prefer right-side up, but
what is performance penalty?
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Past Work
• Tinker 1972: Paragraphs
• Koriat & Norman 1985: Words
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Tinker (1972)
• Used Chapman SoRT (1923)
Orientation
Penalty
+/- 45o
52%
+/- 90o
205%
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Koriat & Norman (1985)
• Classify real/fake words
Orientation
+-60o
Penalty
Not significant
> 60o
> 120%
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Limited Applicability
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Head position constrained
Identification of non-conforming text
Does not allow for “natural” reading
Penalties may be exaggerated
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Our Experiments
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Study on tabletop
Free movement of the head
Task allows more natural reading
Apparatus:
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Experiment 1: Speed of Reading
• 3 types of text: phrase, word,
number
• Phrases:
• Coherent & Meaningful
• Mackenzie phrase set (Mackenzie 2003)
• Words: 5-6 letters
• Numbers: 6-digits
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Procedure
1. Location of string primed
2. Text appears & timer begins
3. User begins to type:
1.
• text disappears, timer stops
2.
3.
(printing error in proceedings)
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Design
3 treatments (single word, number, phrase) X
4 on-screen positions (each corner of tabletop) X
8 orientations (starting at 0o, in 45o increments) X
3 strings at each position/orientation X
15 participants
= 4320 strings entered in total.
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Hypotheses
• Orientation on SoR significant
• Not as dramatic as others showed
• Numbers would be most affected
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Results: Speed of Reading
• Orientation on SoR:
• single word (F7,10 = 28.0, p < .0001)
• short phrase (F7,10 = 64.28, p < .0001)
• numbers (F7,10 = 7.76, p < .0001)
• Position not significant on SoR
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Results: SoR Single Word
μ (seconds)
σ
% off 0o
-135o
1.19
0.67
64.70%
-90o
-45o
0.92
0.78
0.40
0.60
26.60%
7.98%
0o
45o
90o
0.72
0.77
0.91
0.22
0.22
0.37
5.93%
25.78%
135o
180o
1.35
1.11
1.00
0.57
86.42%
53.67%
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Results: SoR Short Phrase
μ (seconds)
σ
% off 0o
-135o
-90o
-45o
0o
3.82
2.66
2.07
1.84
1.52
1.07
1.02
0.86
107.13%
44.25%
12.62%
-
45o
90o
135o
1.97
3.09
3.90
0.70
1.30
1.97
7.19%
67.71%
112.82%
180o
3.69
1.89
100.27%
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Results: SoR Numbers
μ (seconds)
σ
% off 0o
-135o
2.85
1.06
17.48%
-90o
-45o
2.85
2.36
1.63
1.17
17.19%
-2.71%
0o
45o
90o
2.43
2.39
2.78
1.57
1.19
1.21
-1.65%
14.56%
135o
180o
3.01
3.03
1.24
1.16
24.26%
24.87%
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Design Implications
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Effects of orientation less dramatic
Longer text should be reoriented
Menus with can be shared
Numerical data can be shared
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Experiment 2
• Orientation may play role in spatial
memory
• “Correcting” orientation may hurt!
• Measured performance repeated
search
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Procedure
1. Told word to find
2. Presented with search field (static)
• User enters suffix (dynamic)
1.
2.
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Design
3 datasets:
no rotation
small rotation (-45o, 0o, 45o)
complete rotation (all 8 compass) X
24 strings per dataset (pos, orient random) X
3 searches per string (order random) X
9 participants
= 1944 searches in total.
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Hypotheses
• Harder to search rotated field at first
• Learning faster for rotated fields
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Results
• Significant effect of orientation on
search time (F2,215 = 9.80, p < .0001)
• No effect of orientation on learning
• But, penalty not as much as expected:
Condition
No rotation
Some rotation
All rotations
Expected
Penalty
5%
34%
Observed
Penalty
3%
15%
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Discussion
• Orientation hurts search less than
reading: not previously reported
• Measured only short-term learning
• Effect may assert itself long-term
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Thanks!
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Jonathan Deber
John Hancock
Members of the DGP Lab
Mitsubishi Electric Research Labs
Experimental participants
ECSCW reviewers
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Questions?
1.
2.
1.
3.
2.
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Results: Errors
• Error: user submits wrong text
• Orientation on error: not significant
• Type on error: F2,26 = 34.04, p < .0001
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