Acquisition Speed with Targets on the Edge of the Screen: An Application of Fitts' Law to Commonly Used Web Browser Controls

Abstract

According to Fitts' law, the time to acquire a target can be reduced by either reducing the target's distance or increasing its size. Tognazzini (1999) proposed that the time to acquire a target on graphical user interfaces could be reduced further by moving targets to the edge of the screen (i.e., edge targets). Two studies tested these predictions with a web browser interface's back-button (Experiment 1) and scroll bar (Experiment 2). Results support the aforementioned hypotheses. Edge targets were always faster to acquire than targets placed one pixel from the edge of the screen. However, within the constraints of the current studies, this speed advantage is maximal at approximately 393 ms for target heights ≥ 2.00 cm and target distances ≥ 11.75 cm. Design recommendations and a cost/benefit analysis are given.

Get full access to this article

View all access options for this article.

References

Tognazzini

(1999). Ask Tog. A quiz designed to give you Fitts. http://www.asktog.com/columns/022DesignedToGiveFitts.html [available 20 February, 2000].

Card

S.K.

English

W.K.

Burr

B.J.

(1978). Evaluation of mouse, rate-controlled isometric joystick, step keys and text keys for text selection on a CRT Ergonomics, 21, 601–613.

Epps

B.W.

(1986). Comparison of six cursor control devices based on Fitts' Law models. Proceedings of the 30th Annual Meeting of the Human Factors Society, 327–331.

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.

MacKenzie

I. S.

(1992). Movement time prediction in human-computer interfaces. Graphics Interface 1992, 483–493.