An understanding of coding granularity requires some funda-mental knowledge about the receptive haptic system. Haptic per-ception includes tactile as well as proprioceptive perception. The former derives its information from direct cutaneous contact, the latter from body position, movement and applied forces when contacting objects [37], [11]. In perceiving a surface texture, such as granularity, tactile stimulation plays an especially important role. Tactile sensations are detected by receptors sensitive to me-chanical stimulation, such as pressure, indentation depth, move-ment, and vibration [11], [30]. Each receptor type codes different events (see table 1): Merkel discs are activated by tissue strain, pressure, form, and texture, the Ruffini endings are sensitive to lateral movement, skin stretch, and slip detection [55], [30], [3], [19], [34], [33]. The Meissner and Pacinian corpuscles provide in-formation about vibration [55], [3], [19], [33]. The former are sen-sitive to movement, responsible for grip control, detect “micro-scopic surface features and low-frequency vibration” ([30], p. 452), but respond only to “the transient phase of indentation” ([34], p. 310). Moreover, the Meissner corpuscles show less tac-tile acuity than the Merkel discs [34], [33]. The Pacinian corpus-cles are sensitive to “nanometer-level skin motion” ([42], p. 452) and high-frequency vibrations [55], [3], [19].