Effect of remote masking on tactile perception of electrovibration

Abstract

In this study, we investigated whether it is possible to change the absolute detection threshold and intensity difference threshold of electrovibration at fingertip of index finger via remote masking, i.e. by applying a (mechanical) vibrotactile stimulus on the proximal phalanx of the same finger. The masking stimuli were generated by a voice coil (Haptuator). For 16 participants, we first measured the detection thresholds for electrovibration at the fingertip and for vibrotactile stimuli at the proximal phalanx. Then, the vibrations on the skin were measured at four different locations on the index finger of subjects to investigate how the mechanical masking stimulus propagated as the masking level was varied. Later, masked absolute thresholds of 8 participants were measured. Finally, for another group of 8 participants, intensity difference thresholds were measured in the presence/absence of vibrotactile masking stimuli. We proposed two models based on hypothetical neural signals for prediction of masking effect on intensity difference threshold for electrovibration: amplitude and energy models. The energy model was able to predict the effect of masking more accurately, especially at high intensity masking levels.