Authors:
Coline Fons
1
;
2
;
Sylvain Huet
2
;
Denis Pellerin
2
and
Christian Graff
1
Affiliations:
1
Univ. Grenoble Alpes, Univ. Savoie Mont-Blanc, CNRS, LPNC, 38000 Grenoble, France
;
2
Univ. Grenoble Alpes, CNRS, Grenoble INP, GIPSA-lab, 38000 Grenoble, France
Keyword(s):
Spatial Interaction, Fitts’ Law, Sound Guidance, Sonification, Visual Impairment, User Performance Evaluation.
Abstract:
Visually impaired people often face challenges in spatial interaction tasks. Sensory Substitution Devices assist them in reaching targets by conveying spatial deviations to the target through sound. Typically, sound guidance systems are evaluated by target reaching times. However, reaching times are influenced by target size and user-target distance, which varies across studies. We propose to explore the potential of Fitts’ law for evaluating such systems. In a preliminary experiment, visually impaired and sighted participants used non-spatialized sonification to reach 3D virtual targets. Movement times were correlated with the Index of Difficulty, confirming that Fitts’ law is a valuable model to evaluate target-reaching in 3D non-visual interfaces, even with non-spatialized sonification as feedback. In a second experiment, we compared two non-spatialized sonifi-cations, one dissociating the height and azimuthal direction of the target, and the other combining them into a single 3D
angle. Fitts law did allow the comparison of performance in favor of the first sonification. The potential of using Fitts’ law to compare performances across studies using different experimental settings deserves exploration in future research. We encourage researchers to provide the full linear regression equations obtained when using Fitts’ law, to facilitate standardized performance comparisons across studies.
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