Thermal Illusion for Wearables: Effects of Vibrotactile Parameters and Placement on Thermal Masking and Comfort

Abstract

Within the increasing capability of computing and battery of handheld and wearable electronics, device heating has become a critical issue of user comfort and hardware usability. From Gate Control Theory, haptic stimulation may mitigate the thermal discomfort. Through two within-subjects experiments, we examined whether vibrotactile stimulation can attenuate contact-heat unpleasantness and whether placement on the upper limb provides the most actionable design guidance. Experiment 1 screened vibrotactile parameters using 7-point ratings and found an efficacy-tolerability trade-off: amplitude and duty cycle dominated perceived outcomes, whereas frequency had comparatively small effects. We therefore fixed frequency at 150 Hz and selected three candidate codes (221/231/232) spanning strong-effect to balanced profiles. Experiment 2 evaluated these candidates during individualized ramped heating (baseline vs. vibration) using window-locked metrics within 35–48 °C. Vibration generally reduced unpleasantness relative to baseline. Placement effects were most reliable in the mid-to-high window (L2; Friedman χ2 = 7.87, p = 0.0195), driven by robust forearm attenuation (Wilcoxon p = 0.0054, dz ≈ −0.73). Vib-code differences were not stable at the group level, although some codes showed within-window reductions. Late-window results were treated as exploratory due to sparse sampling under conservative stop criteria.

Keywords: Thermo-tactile Interaction, Vibrotactile Stimulation, Thermal Masking, Haptics, Hardware Usability

DOI: 10.54941/ahfe1007450