The arousing power of everyday materials: an analysis of the physiological and behavioral responses to visually and tactually presented textures.

Previous research has shown that during multisensory perception, vision frequently dominates over the other sensory modalities. However, it is still unclear whether sensory dominance also implies the generation of a greater state of arousal. Here, we assess the psycho-physiological reactions to different materials when presented tactually (Group 1) or visually (Group 2). In Group 1, the participants' forearm was stroked with different textures (satin, tinfoil, leather, sandpaper and abrasive sponge), by either a male or a female experimenter. The speed of stimulation was set to elicit a vigorous response of C-tactile afferents, involved in the perception of the more pleasant aspects of touch. The participants were asked to rate the pleasantness of the stimulation. In Group 2, the same textures were presented only visually, and the participants were asked to rate the imagined pleasantness of being touched by those stimuli. Skin conductance responses were recorded in both groups. The results revealed that the tactile presentation of the stimuli led to higher skin conductance responses than the visual presentation; this difference was higher for women than for men. Smooth materials were perceived as more pleasant than rough materials, but no differences in terms of skin conductance responses were found among them. Moreover, the textures were rated as less pleasant when presented visually than when presented tactually. These findings are relevant to understand how physiological arousal is modulated by different senses and to elucidate the mechanisms involved in hedonic tactile perception.