Touch typing using thumbs: understanding the effect of mobility and hand posture

ABSTRACT

Mobile touch devices have become increasingly popular, yet typing on virtual keyboards whilst walking is still an overwhelming task. In this paper we analyze; firstly, the negative effect of walking on text-input performance, particularly the users' main difficulties and error patterns. We focused our research on thumb typing, since this is a commonly used technique to interact with touch interfaces. Secondly, we analyze how these effects can be compensated by two-hand interaction and increasing target size. We asked 22 participants to input text under three mobility conditions (seated, slow walking, and normal walking) and three hand conditions (one-hand/portrait, two-hand/portrait, and two-hand/landscape). Results show that independently of hand condition, mobility significantly decreased input quality, leading to specific error patterns. Moreover, it was shown that target size can compensate the negative effect of walking, while two-hand interaction does not provide additional stability or input accuracy. We finish with implications for future designs.

References

1. Barnard, L., Yi, J., Jacko, J., Sears, A. An empirical comparison of use-in-motion evaluation scenarios for mobile computing devices. In Int. Journal of Human-Computer Studies, 2005, 62(4), 487--520.
2. Bergstrom-Lehtovirta, J., Oulasvirta, A., Brewster, S. The Effects of Walking Speed on Target Acquisition on a Touchscreen Interface. In Proc. MHCI11, 2011, 143--146.
3. Hoggan, E. and Brewster, S. A. and Johnston, J. Investigating the effectiveness of tactile feedback for mobile touchscreens. In Proc. CHI08, 2008, 1573--1582.
4. Kane, S., Wobbrock, J., Smith, I. Getting off the treadmill: evaluating walking user interfaces for mobile devices in public spaces. In Proc. MHCI08, 2008, 109--118.
5. Lin, M., Goldman, R., Price, K., Sears, A., Jacko, J. How do people tap when walking? An empirical investigation of nomadic data entry. In Int. J. of Human-Computer Studies, 2007, 65(9),759--769.
6. Mizobuchi, S., Chignell, M., Newton, D. Mobile text entry: relationship between walking speed and text input task difficulty. In Proc. MHCI05, 2005, 122--128.
7. Parhi, P., Karlson, A., Bederson, B. Target size study for one-handed thumb use on small touchscreen devices. In Proc. MHCI06, 2006, 203--210.
8. Schildbach, B., Rukzio, E. Investigating selection and reading performance on a mobile phone while walking. In Proc. MHCI10, 2010, 92--102.

Index Terms

• Human-centered computing

  • Human computer interaction (HCI)