Mapping of Vibrotactile Stimuli into a Perceptual Space

To transmit tactile information with a discrete set of symbols, the alphabet of the code has to pack as many stimuli as can be reliably discriminated. Here we introduce a notion of perceptual space to construct such a code, defined in terms of the probabilities that pairs of neighboring stimuli are perceived as equal. We perform discrimination experiments exhibiting the well-known effects described by Weber's law, and identify the physical properties of vibrotactile stimuli that most efficiently modulate perceptual discriminability. We conclude that widely used libraries of vibration profiles contain stimuli that are far from homogeneously discriminable. We present our preliminary results as a starting point for the construction of optimal codes.