Morphing in periodic tactile signals

Humans naturally use both categorical and continuous structures when classifying perceptual experiences. However, design of haptic information displays is eased by the availability of design parameters that can be smoothly modulated along a continuous dimension. Taking guidance from visual and auditory media design, we identified and validated a perceptually successful ldquomorphrdquo function that modulates a tactile vibration between two disparate endpoints (a square and a triangle or sine wave), by varying the magnitude of the vertical (highest frequency content) component of the waveform. This finding suggests a specific psychonomic function related to frequency perception, points towards a practical utility in haptic information design, and supports reflections on further possibilities for haptic morphing.