Effects of spatial factors on tactile roughness perception : A study based on signal detection theory(Summary of Awarded Presentation at the 31st Annual Meeting)

Abstract

Our previous studies demonstrated that spatial factors, such as finger position (hand posture) and distance from the stimulated finger to the head modulate tactile roughness perception. Herein we investigate whether spatial factors influence the sensitivity or response bias of tactile roughness discrimination using signal detection techniques. Participants were asked to discriminate the roughness of two-sided stimuli between two fingers in a variety of postures. When the stimuli were presented close to the head, the discrimination sensitivity for the finger located on the back surface of the stimuli was lower than that for the finger on the front surface. Furthermore, judgments by the finger on the back-side were biased toward the same direction as the roughness of the front surface regardless of the distance of the hand from the head. These results indicate that spatial factors differently modulate the sensitivity and the response bias of roughness discrimination.