The Multi-Dimensional Nature of Encoding Tactile and Haptic Interactions: From Psychophysics to Design Guidelines

Designers are very well aware of the multi-dimensionality of visual stimuli and extensively use dimensions such as color, form and contrast to encode information. An analogous multi-dimensionality applies to haptic and tactile stimuli. Based on the fact that the human visual system only has two receptor types (cones and rods) while the sense of touch has closer to ten, one might argue that the design space is even larger for tactile and haptic interactions than for visual. The approach taken in this paper is to take the different sensory systems and their (perceptual) characteristics as a starting point. Bridging the gap between the neurophysiological and psychophysical data and the design guidelines can give this field a head start. For example, data on just noticeable differences of frequency, amplitude, force, and indentation can be an important driver in choosing the encoding dimension in the multidimensional haptic/tactile design space.