Effects of contact method and acclimation on temperature and humidity in touch perception

Abstract

Physical stimuli from contacted objects are recorded by skin receptors and are transmitted to neural signals to the cerebrum to generate touch perceptions. Despite numerous studies having been conducted on the link between the physical properties of contacted objects and psychological sensations, factors besides the stimuli themselves have seldom been investigated. The contact method and acclimation to environmental factors, such as temperature and humidity, could affect the functions of responsible receptors, which, in consequence, might affect the touch perception. This study is designed around a series of experiments involving 226 human subjects adapted to the climate environments of six East-Asia cities. The results revealed that the contact method affected the responses of smoothness sensation but not the stimuli discriminations. This agrees with the hypothesis that both the slowly adapting type I (SA1) fiber and the Pacinian afferent (PC) fiber are responsible for smoothness sensation. SA1 fibers can function through passive touch because of a superficial location in the dermis, while PC fibers, which are located deeper in the dermis, are triggered during active touching. The effect of contact method on softness sensation is not significant because the responsible receptor is the SA1 fiber. The effects of acclimation to temperature and relative humidity were also investigated. Positive relationships were found with smoothness perception and negative relationships were found with warmth perception. This suggests that acclimation to temperature and relative humidity can affect the receptor thresholds and, in consequence, affect the touch sensation.

A comprehensive approach for human hand evaluation of split or large set of fabrics

“…31 Smoothness refers to a surface free from projections, irregularities or inequalities. 32 The opposite property of smoothness is roughness which is described by the indentations and ridges on the fabric surface. 33 Softness relates to the ability of the fabric to bend as fabrics that can easily bend are described as soft and the opposite property is stiff or hard.…”

“…These three attributes are often used to explain the judgements made on fabric handle 9,30 and also included in ASTM D123 standards on terminology used to describe hand. 31 Smoothness refers to a surface free from projections, irregularities or inequalities 32 . The opposite property of smoothness is roughness which is described by the indentations and ridges on the fabric surface 33 .…”

Representations of fabric hand attributes in the cerebral cortices based on the Automated Anatomical Labeling atlas

“…In particular, at the starting point of the ''touching task'' block, one piece of fabric (10 cm  10 cm) was put into the interspace between the thumb and index finger of the subject's right hand, and the subject was required to perform the task of touching the fabric for 30 seconds. Because the touch sensations can be affected by the contact method, 31 the subjects were required to touch the fabric in a specified way. Before the formal experiment, a piece of light cotton fabric was used to train all the subjects touching the fabric in the same way as follows: the subjects were required to gently hold (or pinch) the fabric with small pressure just using the thumbs and index fingers of their right hands, and then repeatedly rotate and rub the thumbs on the fabric surface in the anti-clockwise direction, at the frequency of about 1 Hz for 30 seconds, to consciously feel the touch feeling of the fabric.…”

“…Related studies 30 have shown that the method of active touch is able to generate more physical stimuli than passive touch, as it involves the exertive manipulating of objects. 31 Therefore, subjects in this study were required to touch fabrics in active methods, rather than receiving fabric touch passively.…”

Indexing surface smoothness and fiber softness by sound frequency analysis for textile clustering and classification

“…Liao et al. 2 and Simões-Franklin et al. 5 evaluated fabric texture using two methods of contact on the arm and forearm, namely passive touch and active touch.…”