Comparing Electrical and Vibrotactile Stimulation for Thermal Referral on the Forearm

Abstract

Thermal feedback has been widely used in HCI, particularly in applications such as VR and gaming, but thermal stimulation alone faces practical limitations in producing spatially refined sensations. To address this, prior work has combined thermal stimulation with tactile cues such as vibration, leveraging thermal referral and masking phenomena. In contrast, the interaction between thermal perception and transcutaneous electrical nerve stimulation (TENS) remains underexplored. In this study, we applied a thermal actuator together with either TENS or vibrotactile stimulation and compared thermal referral characteristics across tactile modalities. Participants (n=16) completed experiments under four temperature conditions (-8(circle)C, -4(circle)C, +4(circle)C, and +8(circle)C) on the dorsal and ventral sides of the forearm. Across both tactile modalities, thermal referral and masking responses were observed. We further defined a mid-dominant perceptual state to capture trials in which thermal sensation was predominantly perceived in the intermediate region between the thermal and tactile actuators.