The vibrations of texture

Abstract

The Pacinian channel has been implicated in the perception of fine textures (Hollins et al., Somatosens Mot Res 18: 253-262, 2001a). In the present study, we investigate candidate codes for Pacinian-mediated roughness perception. We use a Hall effect transducer to record the vibrations elicited in the skin when a set of textured surfaces is passively presented to the index finger. The peak frequency of the vibrations is found to decrease systematically as spatial period increases. The power of the vibrations--weighted according to the spectral sensitivity of the Pacinian system--increases with spatial period for all but the coarsest surfaces. By varying the scanning velocity, we manipulate the temporal and intensive characteristics of the texture-induced vibrations and assess the effect of the manipulation on perceived roughness. We find that doubling the scanning velocity does not result in the substantial decrease in roughness predicted by a frequency theory of vibrotactile roughness perception. On the other hand, the effects of speed on roughness match those of speed on power. We propose that the roughness of a fine surface (spatial period<200 microm) is a function of the Pacinian-weighted power of the vibrations it elicits.

Factors affecting the haptic filled-space illusion for dynamic touch

“…On the other hand, studies on tactile roughness perception show that discrimination performance is remarkably independent of scanning speed (Bensmaïa and Hollins 2003;Lamb 1983;Lederman 1974;Lederman 1983;Meftah et al 2000;Smith et al 2002;Vega-Bermudez et al 1991). Thus, textures are generally perceived as equally rough, no matter how fast observers move their hands over the texture.…”

Finger pad friction and its role in grip and touch

“…He argued that coarse textures involve spatial coding as a result of the response of the low-threshold cutaneous mechanoreceptors in the finger pad while fine texture perception relies on a temporal coding, which has been termed vibrotaction. Essentially, the movement of the finger pad over such surfaces causes vibrations that have been measured directly by proximity sensing [15]. A similar mechanism applies to indirect touch in which a probe is moved across a surface causing vibrations to be propagated along the probe to the fingers [16,17].…”

“…As in the case of the normal force during tactile exploration, it might be expected that the velocity is a variable that is controlled by a subject at an intermediate range of values; the factors involved would include comfort and an optimization of the time to make a tactile assessment. Bensmaïa & Hollins [15] investigated the influence of the sliding velocity on vibrotaction particularly in the context of measuring the intensity and frequency of the induced vibrations in tactile perception. However, there have been only a few systematic studies of the effect of this variable on the friction of the finger pad [111].…”

Roughness perception in haptic virtual reality for sighted and blind people

“…Roughness perception has been postulated to increase in the vibratory process and to decrease in the spatial process. Many researchers have indeed found decreasing psychophysical functions for larger interelement spacing (Bensmaïa & Hollins, 2003;Blake, Hsiao, & Johnson, 1997;Hollins, Faldowski, Rao, & Young, 1993;Hollins & Risner, 2000;Klatzky, Lederman, Hamilton, Grindley, & Swendsen, 2003;Yoshioka, Gibb, Dorsch, Hsiao, & Johnson, 2001). …”