Anne Klöcker
Institute of Neuroscience, Universitå catholique de Louvain, Belgium
Massimo Penta
Institute of Neuroscience, Universitå catholique de Louvain, Belgium
Vincent Hayward
Institut des Systèmes Intelligents et de Robotique, UPMC Universitå de Paris, France
Jean-Louis Thonnard
Institute of Neuroscience, Universitå catholique de Louvain, Belgium/Cliniques Universitaires Saint-Luc, Physical and Rehabilitation Medicine Department,Universitå catholique de Louvain, Belgium
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Published in: KEER2014. Proceedings of the 5th Kanesi Engineering and Emotion Research; International Conference; Linköping; Sweden; June 11-13
Linköping Electronic Conference Proceedings 100:88, p. 1041-1066
Published: 2014-06-11
ISBN: 978-91-7519-276-5
ISSN: 1650-3686 (print), 1650-3740 (online)
Humans constantly explore surfaces with their fingertips; providing information regarding the surfaces’ physical attributes and their (un)pleasantness level. It is therefore of interest to investigate whether the perception of pleasantness is related to surfaces’ physical attributes. Pleasant touch perception is generally measured indirectly and generates ordinal scores; lacking fundamental psychometric properties which are essential for objective and quantitative measurement. Consequently; probabilistic measurement models have been established to allow transformations of ordinal scores into linear measures.
Accordingly; we first elaborated a solid basis for future investigations in the domain of pleasantness sensation resulting from active surface explorations with index fingertips. The Rasch model was used to develop a unidimensional; linear and invariant Pleasant Touch Scale; which classifies 37 different everyday life materials according to their pleasantness levels. The latter seemed to be influenced by the respective surfaces’ topographies and by the frictional forces resulting from the tactile surface exploration. These evidences were confirmed in our second study. Indeed; the net values of friction forces; recorded during active fingertip explorations of various material samples of the Pleasant Touch Scale could reliably be correlated with their respective pleasantness measures. A further correlation was found between the fluctuations of friction forces and the surfaces’ pleasantness measures. Our third study was conducted to determine whether (i) these findings hold true for passive fingertip stimulations and (ii) temperature variations of stimuli impact their pleasantness levels. Frictional forces and surfaces’ topographies of stimuli played a crucial role in passive touch pleasantness perception.
