Sensory and Emotional Perception of Wooden Surfaces through Fingertip Touch

You can touch this! Brain correlates of aesthetic processing of active fingertip exploration of material surfaces

The haptic exploration and aesthetic processing of all kinds of materials' surfaces are part of everyday life. In the present study, functional near-infrared spectroscopy (fNIRS) was used to investigate the brain correlates of active fingertip exploration of material surfaces and subsequent aesthetic judgments of their pleasantness (feels good or bad?). In absence of other sensory modalities, individuals (n = 21) performed lateral movements on a total of 48 textile and wood surfaces varying in terms of their roughness. Behavioral results confirmed the influence of the stimuli's roughness on aesthetic judgments, with smoother textures being rated as feeling better than rough textures. At the neural level, fNIRS activation results revealed an overall increased engagement of the contralateral sensorimotor areas as well as left prefrontal areas. Moreover, the perceived pleasantness modulated specific activations of left prefrontal areas with increasing pleasantness showing greater activations of these regions. Interestingly, this positive relationship between the individual aesthetic judgments and brain activity was most pronounced for smooth woods. These results demonstrate that positively valenced touch by actively exploring material surfaces is linked to left prefrontal activity and extend previous findings of affective touch underlying passive movements on hairy skin. We suggest that fNIRS can be a valuable tool to provide new insights in the field of experimental aesthetics.

Materials aesthetics: A replication and extension study of the conceptual structure

Natural occurrences and the choice of specific materials have a major impact on the experience of the physical environment. The results of a recent study using a free listing task involving only adjectives suggested that the conceptual structure of the aesthetics of materials is structured by sensorial, neutrally valenced, descriptive terms, while showing no primacy of beauty. The present article examined the conceptual structure underlying the aesthetic experience of various materials using a different methodological approach. Applying a technique based upon semantic differentials, individuals in the present study (n = 272) were asked to judge the applicability of the most frequently listed terms in the previous study to the aesthetics of different materials. Overall, the results of multiple analyses yielded a converging picture for the two studies. Additionally, as materials constitute the basis of complete entities, the role of products in the conceptual representation of the aesthetics of materials was investigated with an exploratory approach. No support was found for the hypothesis that products play such a role. Finally, limitations regarding the outcome of the present study are discussed. All things considered, the results of this study highlight the uniqueness of the aesthetics of materials and its distinctness from the conceptual representations underlying most other aesthetic domains.

Physiological Effects of Touching Coated Wood

This study examined the physiological effects of touching wood with various coating with the palm of the hand on brain activity and autonomic nervous activity. Participants were 18 female university students (mean age, 21.7 ± 1.6 years). As an indicator of brain activity, oxyhemoglobin concentrations were measured in the left and right prefrontal cortices using near-infrared time-resolved spectroscopy. Heart rate variability (HRV) and heart rate were used as indicators of autonomic nervous activity. The high-frequency (HF) component of HRV, which reflects parasympathetic nervous activity, and the low-frequency (LF)/HF ratio, which reflects sympathetic nervous activity, were measured. Plates of uncoated, oil-finished, vitreous-finished, urethane-finished, and mirror-finished white oak wood were used as tactile stimuli. After sitting at rest with their eyes closed for 60 s, participants touched the stimuli with their palm for 90 s each. The results indicated that tactile stimulation with uncoated wood calmed prefrontal cortex activity (vs. urethane finish and mirror finish), increased parasympathetic nervous activity (vs. vitreous finish, urethane finish, and mirror finish), and decreased heart rate (vs. mirror finish), demonstrating a physiological relaxation effect. Further, tactile stimulation with oil- and vitreous-finished wood calmed left prefrontal cortex activity and decreased heart rate relative to mirror-finished wood.