Investigating the Difficulty of One Degree of Freedom Positioning: Associating Movement Phases with Regions

Abstract

Positioning an object within specified bounds is a common daily computer task, for example making selections using a touch screen or positioning icons relative to each other. This experiment measured times for participants (n = 145) to position rectangular cursors with various widths, p, within rectangular targets with various tolerances, t, in one dimension. The analysis divides the total movement time into three parts, the time for the cursor to touch the target, the time to enter the target after touching, and the centering time, the remaining time for participants to indicate that the cursor is completely within the target by clicking on the mouse button. The time to touch the target was modeled well by the initial cursor-target separation, r ²/sup> = 0.95. The entering time was modeled well by log₂(p/t + 1), r ²/sup> = 0.99, and the centering time was modeled well by r ²/sup> = 0.94

Get full access to this article

View all access options for this article.

References

Accot

Zhai

(2003) Refining Fitts' law models for bivariate pointing. Proc. of CHI 92 Conf. on Human Factors in Com. Sys., 219–223.

Fitts

P. M.

(1954) The Information Capacity of the Human Motor System in Controlling the Amplitude of Movement, Quarterly Journal of Psychology, 47, 381–391

Hoffmann

E. R.

(1995) Effective target tolerance in an inverted Fitts task, Ergonomics, 38(4), 828–836

Hoffmann

E. R.

Tsang

K. K.

(1995) Data-entry keyboard geometry and keying movement times, Ergonomics, 38, 940–950.

Hoffmann

E. R.

(1991) Capture of moving targets: A modification of Fitts' Law, Ergonomics 34, 211–220

Keppel

(1991) Design and analysis: A researcher's handbook. Englewood Cliffs, NJ, Prentice Hall.

Langoff

G.D.

Chaffin

D.B.

Foulke

(1976) An investigation of Fitts' law using a winde range of movement amplitudes, Journal of Motor Behavior 8, 113–128

MacKenzie

S. I.

Buxton

(1992) Extending Fitts' law to two-dimensional tasks, In Extending Fitts' Law to Two-dimensional Tasks, Proc. of CHI 92 Conf. on Human Factors in Com. Sys., 219–223

Pastel

, (2008) The Difficulty of Centering Circular Discs, In Proc. of the Human Factors and Ergonomics Society, 1312–1316

10.

Pastel

Himes

Harper

Helton

(2007) Gravity Mouse Design and Evaluation: Effects of Distracters and Target Size, In Proc. of the Human Factors and Ergonomics Society, 444–448.

11.

Srinivasan

Martin

(2008) Object and Target Size Interactions in Placement Tasks, In Proc. of the Human Factors and Ergonomics Society, 940–944.

12.

Wiker

S. F.

Langolf

G. D.

Caffin

D. B.

(1989) Arm posture and human movement capability, Human Factors, 31, 421–441