Psychophysical Relations between Interacted Fabric Thermal-Tactile Properties and Psychological Touch Perceptions

Touch sensation perception includes three processes - physical, neurophysiological and psychological. Psychophysical relationships that bridge physical and psychological results have varied. Meanwhile, interactive effects of thermal-tactile physical features have seldom been investigated. Therefore, this study aims to compare various hypothesized psychophysical relations, including monomode relations between single stimuli and single sensations, as well as multimode relations between multistimuli and sensory dimensions. Potential simultaneous effects from thermal-tactile factors and their interactions are also explored. This study uses physical data, obtained from a simultaneous measurement instrument Fabric Touch Tester, and psychological data collected from over 200 subjects. The results imply that a universal psychophysical function relation can hardly be achieved. Different neural stimulation mechanisms seem to be better presented by dissimilar function relations. It is also found that thermal and tactile physical information can simultaneously affect all defined sensory dimensions - including smoothness, softness and warmth. Interaction effects from multistimuli are also concluded to be important predictors. Practical Applications: Study of the relationship between psychological touch sensations and fabric physical properties has always been an attractive field in textile sensory research. Along with the increased demands on the touch comfort of clothing, precise quantitative characterization methods are eagerly needed in industry. A number of approaches have been proposed during past studies, including psychophysical laws and stepwise-box-linear regression. However, these resolutions focused on tactile properties and mechanical sensations only. Although the latest neurophysiological findings have enlarged the scope of thermal-tactile properties, there is still a lack of investigation into interactive effects of both thermal and tactile properties. This work provides comparison studies on different types of psychophysical relations and particularly explores the interactive effects of multiple physical aspects. Proposed psychophysical relations are concluded with satisfied correlation coefficients to the subjective sensations. Such interactive multimode psychophysical relations could be used to advance current prediction models with stronger connections to neurophysiological perception mechanisms.