Movement model, hits distribution and learning in virtual keyboarding

ABSTRACT

In a ten-session experiment, six participants practiced typing with an expanding rehearsal method on an optimized virtual keyboard. Based on a large amount of in-situ performance data, this paper reports the following findings. First, the Fitts-digraph movement efficiency model of virtual keyboards is revised. The format and parameters of Fitts' law used previously in virtual keyboards research were incorrect. Second, performance limit predictions of various layouts are calculated with the new model. Third, learning with expanding rehearsal intervals for maximum memory benefits is effective, but many improvements of the training algorithm used can be made in the future. Finally, increased visual load when typing previously practiced text did not significantly change users' performance at this stage of learning, but typing unpracticed text did have a performance effect, suggesting a certain degree of text specific learning when typing on virtual keyboards

REFERENCES

• 1: Baddeley, Human Memory - Theory and Practice. Revised Edition ed. 1998, Boston: Allyn and Bacon.
• 2: Cooper, W.E., ed. Cognitive aspects of skilled typewriting. 1983, Springer-Verlag: New York.
• 3: Dvorak, A., N.L. Merrick, W.L. Dealey, and G.C. Ford, Typewriting Behavior. 1936, New York: American Book Company.
• 4: Fitts, P.M., The information capacity of the human motor system in controlling the amplitude of movement. Journal of Experimental Psychology, 1954. 47: p. 381--391.
• 5: Getschow, C.O., M.J. Rosen, and Goodenough-Trepagnier. A systematic approach to design a minimum distance alphabetical keyboard. in Proceedings of RESNA (Rehabilitation Engineering Society of North America) 9th Annual Conference. 1986. Minneapolis, Minnesota. p. 396--398.
• 6: Landauer, T.K. and R.A. Bjork, Optimum rehearsal patterns and name learning, in practical aspects of memory, P.E.M. M.M. Gruneberg, & R.N. Sykes, Editor. 1978, Academic Press: London. p. 625--632.
• 7: Lewis, J.R., P.J. Kennedy, and M.J. LaLomia. Development of a Digram-Based Typing Key Layout for Single-Finger/Stylus Input. in Proceedings of The Human Factors and Ergonomics Society 43rd Annual Meeting. 1999.
• 8: MacKenzie, I.S., Fitts' law as a research and design tool in human computer interaction. Human Computer Interaction, 1992. 7: p. 91--139.
• 9: I. Scott MacKenzie , Abigail Sellen , William A. S. Buxton, A comparison of input devices in element pointing and dragging tasks, Proceedings of the SIGCHI conference on Human factors in computing systems: Reaching through technology, p.161-166, April 27-May 02, 1991, New Orleans, Louisiana, United States [doi>10.1145/108844.108868]
• 10: I. Scott MacKenzie , Shawn X. Zhang, The design and evaluation of a high-performance soft keyboard, Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit, p.25-31, May 15-20, 1999, Pittsburgh, Pennsylvania, United States [doi>10.1145/302979.302983]
• 11: Neisser, U., Memory: What are the important questions?, in Practical aspects of memory, M.M. Gruneberg, P.G. Morris, and R.N. Sykes, Editors. 1978, Academic Press: London.
• 12: Sears, A., J.A. Jacko, J. Chu, and F. Moro, The role of visual search in the design of effective soft keyboards. Behaviour and Information Technology, 2001. 20(3): p. 159--166.
• 13: Smith, B.A. and S. Zhai. Optimised Virtual Keyboards with and without Alphabetical Ordering - A Novice User Study. in Proceedings of INTERACT'2001 - IFIP International Conference on Human-Computer Interaction. 2001. Tokyo, Japan: IFIP. p. 92--99.
• 14: Soukoreff, W. and I.S. MacKenzie, Theoretical upper and lower bounds on typing speeds using a stylus and keyboard,. Behaviour & Information Technology, 1995. 14: p. 379--379.
• 15: Yamada, H., A historical study of typewriters and typing methods: from the position of planning Japanese parallels. Journal of Information Processing, 1980. 2(4): p. 175--202.
• 16: Shumin Zhai , Michael Hunter , Barton A. Smith, The metropolis keyboard - an exploration of quantitative techniques for virtual keyboard design, Proceedings of the 13th annual ACM symposium on User interface software and technology, p.119-128, November 06-08, 2000, San Diego, California, United States [doi>10.1145/354401.354424]
• 17: Zhai, S., B.A. Smith, and M. Hunter, Performance Optimization of Virtual Keyboards. Human-Computer Interaction, 2001. in press.

INDEX TERMS

Primary Classification:
  I. Computing Methodologies
  I.3 COMPUTER GRAPHICS
      I.3.4 Graphics Utilities
          Subjects: Virtual device interfaces

Additional Classification:
  D. Software
  D.2 SOFTWARE ENGINEERING
      D.2.2 Design Tools and Techniques
          Subjects: User interfaces

  H. Information Systems
  H.1 MODELS AND PRINCIPLES
      H.1.2 User/Machine Systems
          Subjects: Human factors

  I. Computing Methodologies
  I.3 COMPUTER GRAPHICS
      I.3.7 Three-Dimensional Graphics and Realism
          Subjects: Virtual reality

General Terms:
Design, Human Factors, Performance, Theory

Keywords:
Fitts' law, expanding rehearsal, graphical keyboard, learning, memory, mobile computing, on screen keyboard, skill acquisition, soft keyboard, text entry, text input, virtual keyboard