earPod : Efficient, Hierarchical, Eyes-free Menu Selection

1. earPod: Efficient, Hierarchical, Eyes-free Menu Selection Shengdong Zhao Department of Computer Science University of Toronto July 9, 2008

2. Outline Research problem Previous research Research questions Research strategy and focus Prototype Empirical studies Contributions Future work

3. Research problems and objectives • Motivating problem • How can users interact with information devices in mobile environments when their visual attention is taken up by other tasks (e.g navigation through the environment) • Objective • To develop interactive techniques that support user control and feedback without relying on the visual modality • Scope • This research focuses on menu selection because this is an elemental task(Foley et al. ‘84)

4. Previous research • Visual menus • Linear menus (e.g., Sear and Schneiderman ’94; Cockburn and Gin ‘06, etc.) • Radial menus (e.g., Callahan et al. ‘88; Kurtenbach ’93, etc.) • Auditory applications • Accessibility for the blind (e.g., Edwards ‘89; Mynatt and Weber ‘94, etc.) • Mobile auditory interfaces (e.g., Roy and Schmandt ‘96; Pirhonen et al. ’02, etc.) • Auditory menus • Interactive Voice Response (IVR) systems (e.g., Marics and Engelbeck 1997; Resnick and Virzi ’92, etc.) • Head gesture auditory pie menu (Brewster et al. ‘03)

5. Research questions • How to design usable eyes-free menus? • Designing interfaces with reasonable levels of efficiency and ease of use • Facilitating a smooth novice to expert transition • How to work around the problems with serial and temporal audio feedback? • Facilitating scan and compare of menu items • Providing users with a sense of control and responsiveness

6. Research strategy Define research problem Review literature Define general design concept Perform iteratively design and pilot studies for prototype Conduct empirical studies to explore prototype properties Derive design recommendations based on empirical results

7. Selected input and output modalities • Touch input • Combines relative and absolute pointing (Hinckley ‘01) • Can be robustly operated in motion (Buxton et al. ‘85) • Can be combined with other input devices (Hinckley and Sinclair ‘99; Rekimoto et al. ‘03) • Auditory feedback • The other primary remote sense (Gaver ‘97) • The only other sense with a natural language*

8. earPod prototype A touch-sensitive device with software to perform eyes-free, hierarchical menu selection earPod prototype used commercial touchpad augmented with custom-built plastic cover, with cable to computer for voice output Built in University of Toronto in 2006 with Pierre Dragicevic

9. earPod Prototype

10. earPod interaction Novice Intermediate Intermediate Expert

11. Video - browsing

12. Video - fast browsing

13. Video - very fast browsing

14. Video - expert use

15. Prototype design • Efficiency • By-pass audio • Use interruptible audio feedback • Use non-speech audio • Sense of control • Synchronous communication (reactive audio feedback) • Simplicity and power • Gliding and tapping • Easy to learn • Use spatial audio to reinforce mental model • Self-discoverable transition

16. Empirical studies Motivating questions: • How does earPod compare with a popular visual menu selection technique used by iPod? • How does earPod compare with a number of competitor techniques with different modalities and menu styles? • What are learning behaviors for earPod and the related techniques? • How does earPod and the related techniques perform with a visually demanding primary task?

17. Evaluation issues • Modality • Visual • Audio • Dual • Menu style • Linear • Radial

18. 4 empirical studies 4 empirical studies were conducted at UofT in 2006-08 Experiment 1:earPod vs. iPod (audio radial vs. visual linear) Experiment 2: 3 x 2 study (3 modalities x 2 menu styles) Experiment 3: 2 x 2 longitudinal study (audio linear, visual linear, audio radial, visual radial) Experiment 4: 3 x 2 dual-task study (3 modalities x 2 menu styles)

19. Experimental 1 design • Goal: compare earPod with iPod-like linear menu • 60-90 minute session, within-subject, counter-balanced • Setup: 12 participants x 2 techniques (audio and visual) x (40+80) items for the 2 menu configurations (8 and 8x8) x 4 blocks = 11,520 menu selections in total.

20. Results: response time Block number Block number

21. Results: response time Block number Block number

22. Results: response time Block number Block number

23. Experiment 1 - results and discussion earPod has comparable performance with iPod-like linear menu earPod user performance improves more rapidly than that of iPod-like linear menu With practice, earPod can outperform iPod-like linear menu

24. Experiment 2 design • Goal: systematic investigation of modality of feedback and menu style • 60-minute, within subject, counter-balanced • Setup 12 participants x 6 techniques x 8 menu items x 13 blocks (12 blocks + 1 practice block) = 7488 menu selections in total

25. Response time Visual radial Audio visual radial Audio visual linear Visual linear Audio radial Audio linear

26. Experiment 2 - results and discussion • Accuracy • Comparable performance among all techniques • Speed • visual radial ~ dual radial < audio radial ~ visual linear ~ dual linear < audio linear • Modality • Visual ~ dual < audio • Menu style • Radial < linear

27. Experiment 3: longitudinal study Goal: learning of earPod and related techniques 5 one-hour sessions in a week, between-subject Setup: 2 participants (per technique) x 4 techniques x 64 items for 1 menu configuration (8 x 8) x 7 blocks per day x 5 days = 17920 menu selections in total

28. Accuracy Day

29. Response time Day

30. Gliding to tapping transition Items explored Tapping percentage Day Day

31. Experiment 3 - results and discussion Novice performance is determined by modality, expert performance is determined by menu style Rapid learning is observed for earPod Users can perform tapping for 70-80% of the 64 menu items from day 3 onwards Audio linear has comparable performance with visual linear from day 3 onwards

32. Experiment 4: dual-task study Goal: Investigate the properties of using earPod and the related techniques as a secondary task in a dual-task setting and their impact on the visually demanding primary task

33. Experiment 4: dual-task study • Dual-task • Primary task: simulated driving • Secondary task: menu selection • External validity: similar settings have been successfully used by Salvucci et al. ‘01, ‘02, ‘05

34. Experiment 4 design • Conditions • Desktop • 12 participants X 6 techniques X 8 items of 1 menu configurations X (3 + 1) blocks = 2304 menu selections • Driving • 12 participants X 6 techniques X 8 items of 1 menu configurations X (1 + 1) blocks = 1152 menu selections • Measures • Desktop • Speed & accuracy of menu selection • Driving • Speed & accuracy of menu selection (secondary task) • Driving performance (primary task)

35. Experiment 4 setup

36. Response time: modality Audio Visual Dual

37. Response time: menu style Radial Linear P

38. Lateral velocity

39. Following distance

40. Experiment 4 - results and discussion • Audio techniques work better with a visually demanding primary task • Comparable performance with visual techniques, less impact on primary tasks • Although dual-channel techniques have similar performance with audio techniques, users prefer single channel audio feedback

41. Summary of empirical studies earPod has comparable performance with visual linear menus Transition from novice to expert for earPod is fast Audio techniques work better with a visually demanding primary task Users only pay attention to the appropriate channel when are presented with both channels of feedback

42. Contributions Developed a novel interaction technique called earPod Conducted empirical evaluations on earPod and related techniques Derived design recommendation for incorporating earPod and related techniques to mobile devices

43. Future work Explore eyes-free menu techniques for long and dynamic lists Investigate the role of compression and dichotic listening Extend earPod to other mobile scenarios (e.g., walking, running, etc.) Develop eyes-free interaction techniques for other tasks and applications (e.g., drag & drop, text entry, etc.)

44. Questions

45. The End