Kinaesthetic and Cutaneous Contributions to the Perception of Compressibility

364

254

This paper reviews studies on the tactile dimensionality of physical properties of materials in order to determine a common structure for these dimensions. Based on the commonality found in a number of studies and known mechanisms for the perception of physical properties of textures, we conclude that tactile textures are composed of three prominent psychophysical dimensions that are perceived as roughness/smoothness, hardness/softness, and coldness/warmness. The roughness dimension may be divided into two dimensions: macro and fine roughness. Furthermore, it is reasonable to consider that a friction dimension that is related to the perception of moistness/dryness and stickiness/slipperiness exists. Thus, the five potential dimensions of tactile perception are macro and fine roughness, warmness/coldness, hardness/softness, and friction (moistness/dryness, stickiness/slipperiness). We also summarize methods such as psychological experiments and mathematical approaches for structuring tactile dimensions and their limitations.

Section: Hardness/softnessmentioning

confidence: 99%

Psychophysical Dimensions of Tactile Perception of Textures

Okamoto

Nagano

Yamada

2013

364

254

“…Thus, for the "sandwich," the Young's modulus is the same as for the "thick" stimulus made of the same material, but the stiffness is different. A more detailed description of the fabrication procedure can be found in [15].…”

Section: Stimulimentioning

confidence: 99%

Cues for Haptic Perception of Compliance

Tiest

Kappers

2009

196

115

Abstract-For the perception of the hardness of compliant materials, several cues are available. In this paper, the relative roles of force/displacement and surface deformation cues are investigated. We have measured discrimination thresholds with silicone rubber stimuli of differing thickness and compliance. Also, the influence of the finger span is assessed. When compliance is expressed as the Young's modulus, the thresholds in the different conditions follow Weber's law with a Weber fraction of 15 percent. When the surface deformation cue was removed, thresholds more than trebled. Under the assumption of optimal cue combination, this suggests that a large fraction of the information comes from the surface deformation cue. Using a matching experiment, we found that differences in object thickness are correctly taken into account. When cues appear to contradict each other, the conflict is resolved by means of a compromise.

“…A recent study showed that people are able to perceive the hardness of rubber specimens (specified by Young's modulus) directly based on surface deformation, without having to calculate the ratio of force/displacement changes [28]. An earlier study by the same authors suggested that the kinesthetic channel contributes just one quarter of the information used to assess stiffness, with cutaneous cues providing the rest [29]. Indeed, with deformable surfaces, tactile information alone is sufficient for discrimination, while for rigid surfaces, both tactile and kinesthetic information are required ( [30]; see also [31] for an integrated haptic system that uses a fingertip contact area display to enhance softness discrimination).…”

Section: Discussionmentioning

confidence: 99%

A Comparative Study of Haptic Stiffness Identification by Veterinarians and Students

Forrest

Baillie

Kalita

et al. 2011

Abstract-Palpation is an important clinical skill in both veterinary and medical health professions. The present study compares the ability of practicing veterinarians and veterinary students to identify the stiffness of virtual surfaces through palpation. An absolute identification paradigm was used where a force-feedback haptic device rendered virtual surfaces with five levels of stiffness within a "clinically relevant" range (0.2-0.5 N/mm). The mean information transfer was 0.97 bits (almost two perfectly identifiable stiffness levels) for 12 veterinarians and 0.58 bits (one correctly identified level) for 14 veterinary students. Although the difference between the two groups was significant (p < 0:001), neither group was able to reliably identify more than two levels of stiffness, indicating that the success of veterinarians in clinical practice probably relies on additional properties such as size, shape, and texture. Analyses of force versus time and displacement versus time recordings suggest that the superior performance of the veterinarians may be partially attributable to motor strategy. Specifically, veterinarians used a greater mean maximum force (2.0 N) compared to students (1.6 N) (p < 0:05). However, further studies are required to investigate motor strategy in more detail. The implications of our findings for veterinary education and quantitative skill assessment are discussed.