Identification of tactile mechanisms for the evaluation of object sizes during texture perception

Perception of sour, sweet, bitter, and salty taste can be related to specialized sensors (taste buds), however, this is not possible for texture perception. Although different types of oral mechanoreceptors are known, it remains unclear how texture perception relates to these structures. The aim of this work is to better understand textural attributes such as grittiness. As a first step to this end, an experimental determination of size resolution capability was carried out. Small discs of varying diameter, thickness, and materials were evaluated by subjects for differences in diameter and thickness between tongue and palate (oral system) and also between finger and palm (manual system). Diameter determination was found to be very accurate. Thickness evaluation was more complex and appeared to rely on two mechanisms. Differences between the manual and oral evaluation were found and could be explained in terms of mechanical models as well as anatomical data. The hypothesis of two different mechanisms was experimentally verified.