Measuring the spatial Acuity of vibrotactile Stimuli: A new Approach to determine universal and individual Thresholds

TL;DR

This study introduces automated vibrotactile discrimination tasks to measure spatial acuity, revealing differences between static and vibratory stimuli perception, and aims to inform tactile display design.

Contribution

Developed and validated a new automated method for measuring tactile spatial acuity, providing both universal and individual thresholds for vibrotactile stimuli.

Findings

Static stimuli have finer spatial acuity than vibrotactile stimuli from 15 mm separation.

The new method successfully measures individual differences in vibrotactile perception.

Results support the need for tailored tactile display design guidelines.

Abstract

Tactile perception is an increasingly popular gateway in human-machine interaction, yet universal design guidelines for tactile displays are still lacking, largely due to the absence of methods to measure sensibility across skin areas. In this study, we address this gap by developing and evaluating two fully automated vibrotactile tasks that require subjects to discriminate the position of vibrotactile stimuli using a two-interval forced-choice procedure (2IFC). Of the two methodologies, one was initially validated through a preliminary study involving 13 participants. Subsequently, we applied the validated and improved vibrotactile testing procedure to a larger sample of 23 participants, enabling a direct and valid comparison with static perception. Our findings reveal a significantly finer spatial acuity for static stimuli perception compared to vibrotactile stimuli perception from a stimulus separation of 15 mm onwards. This study introduces a novel method for generating both universal thresholds and individual person-specific data for vibratory perception, marking a critical step towards the development of functional vibrotactile displays. The results underline the need for further research in this area and provide a foundation for the development of universal design guidelines for tactile displays.