Empirical Investigation into the Effect of Orientation on Text Readability in Tabletop Displays Daniel Wigdor Ravin Balakrishnan Presented at ECSCW, Paris, France

2 Tabletop Displays

3 Text Orientation. Solutions: 1:3: 2:

4 Multiple Copies Advantage: Spatial proximity for free Disadvantages: More space used SDG shared interaction space lost

5 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

6 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

7 But, Why Reorient? Orientation used for other things: 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?

8 Past Work Tinker 1972: Paragraphs Koriat & Norman 1985: Words

9 Used Chapman SoRT (1923) Tinker (1972) OrientationPenalty +/- 45 o 52% +/- 90 o 205%

10 Koriat & Norman (1985) Classify real/fake words OrientationPenalty +-60 o Not significant > 60 o > 120%

11 Limited Applicability Head position constrained Identification of non-conforming text Does not allow for “natural” reading Penalties may be exaggerated

12 Our Experiments Study on tabletop Free movement of the head Task allows more natural reading Apparatus:

13 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

14 Procedure 1.Location of string primed 2.Text appears & timer begins 3.User begins to type: text disappears, timer stops (printing error in proceedings)

15 Design 3 treatments (single word, number, phrase) X 4 on-screen positions (each corner of tabletop) X 8 orientations (starting at 0 o, in 45 o increments) X 3 strings at each position/orientation X 15 participants = 4320 strings entered in total.

16 Hypotheses Orientation on SoR significant Not as dramatic as others showed Numbers would be most affected

17 Results: Speed of Reading Orientation on SoR: single word (F 7,10 = 28.0, p <.0001) short phrase (F 7,10 = 64.28, p <.0001) numbers (F 7,10 = 7.76, p <.0001) Position not significant on SoR

18 Results: SoR Single Word μ (seconds)σ% off 0 o -135 o % -90 o % -45 o % 0o0o o % 90 o % 135 o % 180 o %

19 Results: SoR Short Phrase μ (seconds)σ% off 0 o -135 o % -90 o % -45 o % 0o0o o % 90 o % 135 o % 180 o %

20 Results: SoR Numbers μ (seconds)σ% off 0 o -135 o % -90 o % -45 o % 0o0o o % 90 o % 135 o % 180 o %

21 Design Implications Effects of orientation less dramatic Longer text should be reoriented Menus with can be shared Numerical data can be shared

22 Experiment 2 Orientation may play role in spatial memory “Correcting” orientation may hurt! Measured performance repeated search

23 Procedure 1.Told word to find 2.Presented with search field (static) User enters suffix (dynamic) 1.2.

24 Design 3 datasets: no rotation small rotation (-45 o, 0 o, 45 o ) 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.

25 Hypotheses Harder to search rotated field at first Learning faster for rotated fields

26 Results Significant effect of orientation on search time (F 2,215 = 9.80, p <.0001) No effect of orientation on learning But, penalty not as much as expected: ConditionExpected Penalty Observed Penalty No rotation-- Some rotation5%3% All rotations34%15%

27 Discussion Orientation hurts search less than reading: not previously reported Measured only short-term learning Effect may assert itself long-term

28 Thanks! Jonathan Deber John Hancock Members of the DGP Lab Mitsubishi Electric Research Labs Experimental participants ECSCW reviewers

29 Questions?

30 Results: Errors Error: user submits wrong text Orientation on error: not significant Type on error: F 2,26 = 34.04, p <.0001