How does Fitts' law fit pointing and dragging?

ABSTRACT

Two experiments examined selecting text using a movement sequence of pointing and dragging. Experiment 1 showed that, in the Point-Drag sequence, the pointing time was related to the pointing distance but not to the width of the text to be selected; in contrast, pointing time was related to both the pointing distance and the width of the text in the Point-Click sequence. Experiment 2 demonstrated that both the pointing and dragging times for the Point-Drag sequence were sensitive to the height of the text that was selected. The discussion of the results centers around the application of Fitts' Law to pointing and dragging in a point-drag sequence, proposing that the target for pointing is the leftmost edge of the text to be selected, and the target for dragging is the rightmost edge of the text.

REFERENCES

• 1: Card, S. K., English, W. K., and Burr, B. J. (1978). Evaluation of the mouse, rate-controlled isometric joystick, step keys, and text keys for text selection on a CRT. Ergonomics, 21,601-613.
• 2: Stuart K. Card , Allen Newell , Thomas P. Moran, The Psychology of Human-Computer Interaction, Lawrence Erlbaum Associates, Inc., Mahwah, NJ, 1983
• 3: Fitts, P. M. (1954). The information capacity of the human motor system in controlling the amplitude of movement. Journal of Experimental Psychology, 47, 381-391.
• 4: Gillan, D.J., Holden, K., Adam, S., Rudisill, M., and Mage~, L. An analysis of pointing and dragging in text editing. In preparation.
• 5: Hollan, J. D., Hutchins, E. L., and Norman, D. A. (1986). Direct manipulation interfaces. In D. A. Norman and W. S. Draper (Eds.), User-Centered System Design: New Perspectives in Human- Machine Interaction. Hillsdale, NJ: L. Erlbaum.
• 6: Nowell, A., and Card, S. K. (1985). The prospects for psychological science in human-computer interaction. Human-Computer Interaction, 1, 20% 242.
• 7: Welford, A. T. (1968). The f~ndamentals of skill. London: Methuen.

INDEX TERMS

Primary Classification:
  I. Computing Methodologies
  I.3 COMPUTER GRAPHICS
      I.3.1 Hardware architecture
          Subjects: Input devices

Additional Classification:
  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.3.6 Methodology and Techniques
          Subjects: Interaction techniques

General Terms:
Experimentation, Human Factors, Performance