Citation

Hoffmann ER. Int. J. Ind. Ergonomics 1994; 14(3): 251-261.

Copyright

(Copyright © 1994, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Two tasks in which subjects aim at an array of devices were considered: moving to one knob within an array and moving the finger on a numeric keypad. It was shown by a mathematical model based on Fitts' law, that when the array density is specified for the array of knobs or keys, there is an optimum control size for minimum movement time. The theoritical result was obtained by considering a two-element model of the movement, the first being a reach to the general location of the control and the second describing the insertion of the fingers into the space between adjacent controls. As the first element has a movement time that decreases with increase of control size and the second a time increasing with control size, there is an optimum controlsize where the movement time is a minimum.