Fitts' Law as an Explicit Time/Error Trade-Off

Yves Guiard (1) , Halla H. Olafsdottir (1) , Simon T. Perrault (1)

1 LTCI - Laboratoire Traitement et Communication de l'Information

The widely-held view that Fitts' law expresses a speed-accuracy trade-off is certainly correct but vague. We outline a simple trade-off theory of Fitts' law in which movement time and error trade for each other. The theory accounts quite accurately for the data of Fitts' (1954) seminal study, as well as some fresh data of our own. Although our experimental protocol differed from Fitts' and we, unlike Fitts, focused on the best performance of our best performers, we found evidence in both data sets that the time/error trade-off obeys a power law. Fitts' data suggest that the time/error trade-off might boil down to a square root function with a single adjustable constant. Our data, which we could analyze more thoroughly than Fitts', are consistent with this view. We suggest that a combination of trade-off and information theory should improve the account of Fitts' law.

Mots clés: Fitts' law; trade-off function; speed-accuracy trade-off.; speed-accuracy trade-off

Domaines: Interface homme-machine [cs.HC]; Psychologie

Yves Guiard, Halla H. Olafsdottir, Simon T. Perrault. Fitts' Law as an Explicit Time/Error Trade-Off. Proceedings of CHI 2011, ACM Conference on Human Factors in Computing Systems, 2011, pp.1-10. ⟨hal-00547247⟩