1,721,012 research outputs found
The arousing power of everyday materials: an analysis of the physiological and behavioral responses to visually and tactually presented textures
No full textPrevious 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
An olfactory display to study the integration of vision and olfaction in a Virtual Reality environment
No full textStroking and tapping the skin: behavioral and electrodermal effects
No full textBeing caressed represents one of the most typical expressions of affection conveyed by touch. Converging evidence suggests that the pleasant perception of gentle and slow stroking delivered to the hairy skin is mediated by C-Tactile afferents (CTs). While behavioral and neural responses to CT-optimal touch have been moderately explored so far, less is known about the autonomic reaction to different kinds of touch (both CT-optimal and not). Here, we investigated whether physiological arousal varies as a function of the specific tactile stimulation provided. Stroking (slow: 3 cm/s ‘CT-optimal’; or fast: 30 cm/s) and tapping (random or fixed spatial order) stimulations were delivered to the participants’ forearm with a brush, for durations of 9 or 60 s. Participants’ skin conductance response (SCR) and level (SCL), as well as subjective evaluations, were recorded. The results revealed that being stroked (at both the velocities) induced higher SCR and SCL than being tapped. Moreover, while higher SCR was elicited by CT-suboptimal stroking compared to CT-optimal stroking, SCL was not affected differently by CT-optimal touch. No differences were found between the effects of 9 and 60 s stimulations. Slow stroking was evaluated as the most pleasant, relaxing and ‘social’ type of touch compared to the other tactile stimulations. Taken together, these findings shed light on the psychophysiological responses to stroking (including CT-optimal touch) and tapping, and contribute to elucidate the mechanisms underlying hedonic tactile perception
An Exploratory Study on the Effect of Virtual Environments on Cognitive Performances and Psychophysiological Responses
No full textResearch shows that reduced exposure to natural contexts is associated with an increase in psychophysical disorders. Recent evidence suggests that even a brief experience in natural scenarios can positively affect people's health and well-being. However, natural contexts are not always easily accessible. This study investigates the effects of natural and indoor virtual environments (VREs) on psychophysiological and cognitive responses. Following a within-subject design, 34 healthy participants were exposed to two VREs (i.e., a forest and a living room) in a counterbalanced order through a head-mounted display (Oculus Rift). Participants were asked to explore the scenarios and execute a modified version of the Paced Auditory Serial Addition Test. Physiological parameters (heart rate, skin conductance level [SCL], and respiration rate) were recorded during the whole session. After the exposure to VREs, participants filled a set of visual analog scales to rate their subjective experience of presence, relaxation, and stress. Participants reported a higher perceived sense of relaxation in the virtual forest. Moreover, their SCLs were significantly higher in this environment, showing that the forest elicited higher physiological arousal than the living room. Furthermore, their SCLs were significantly higher during the attentional task in the virtual living room. The results suggest that a natural virtual environment can make people feel more relaxed and physiologically engaged than an indoor scenario. The latter instead can be linked to a performing venue, as reported for real contexts. However, these changes were not related to modulations of attentional performance
Textures that we like to touch: An experimental study of aesthetic preferences for tactile stimuli.
Full text linkWe report two experiments designed to investigate the nature of aesthetic preferences for tactile textures in humans. In Experiment 1, the participants rated their preference for a range of actively and passively explored textures presented on their hands and on their cheeks. The results revealed that those textures that were subjectively-rated as smoother were preferred over those that were rated as rougher. Moreover, certain textures were disliked more during active than during passive stimulation. In Experiment 2, the speed of tactile stimulation was controlled in order to elicit vigorous responses from C-tactile fibers (present only in hairy skin), which are thought to play a central role in pleasant aspects of touch. The results revealed that textures were preferred when presented on the hairy skin of the forearm than on the glabrous palm of the hand. These results provide preliminary evidence regarding people's preferences for different attributes of tactile surface
When sandpaper is 'kiki' and satin is 'bouba': An exploration of the associations between words, emotional states, and the tactile attributes of everyday materials
No full textOver the last decade, scientists working on the topic of multisensory integration, as well as designers and marketers involved in trying to understand consumer behavior, have become increasingly interested in the non-arbitrary associations (e.g., sound symbolism) between different sensorial attributes of the stimuli they work with. Nevertheless, to date, little research in this area has investigated the presence of these crossmodal correspondences in the tactile evaluation of everyday materials. Here, we explore the presence and nature of the associations between tactile sensations, the sound of non-words, and people's emotional states. Samples of cotton, satin, tinfoil, sandpaper, and abrasive sponge, were stroked along the participants' forearm at the speed of 5 cm/s. Participants evaluated the materials along several dimensions, comprising scales anchored by pairs of non-words (e.g., Kiki/Bouba) and adjectives (e.g., ugly/beautiful). The results revealed that smoother textures were associated with non-words made up of round-shaped sounds (e.g., Maluma), whereas rougher textures were more strongly associated with sharp-transient sounds (e.g., Takete). The results also revealed the presence of a number of correspondences between tactile surfaces and adjectives related to visual and auditory attributes. For example, smooth textures were associated with features evoked by words such as 'bright' and 'quiet'; by contrast, the rougher textures were associated with adjectives such as 'dim' and 'loud'. The textures were also found to be associated with a number of emotional labels. Taken together, these results further our understanding of crossmodal correspondences involving the tactile modality and provide interesting insights in the applied field of design and marketing
Spatial sensorimotor mismatch between the motor command and somatosensory feedback decreases motor cortical excitability. A transcranial magnetic stimulation‐virtual reality study
No full textEffective control of movement predominantly depends on the exchange and integration between sensory feedback received by our body and motor command. However, the precise mechanisms governing the adaptation of the motor system's response to altered somatosensory signals (i.e., discrepancies between an action performed and feedback received) following movement execution remain largely unclear. In order to address these questions, we developed a unique paradigm using virtual reality (VR) technology. This paradigm can induce spatial incongruence between the motor commands executed by a body district (i.e., moving the right hand) and the resulting somatosensory feedback received (i.e., feeling touch on the left ankle). We measured functional sensorimotor plasticity in 17 participants by assessing the effector's motor cortical excitability (right hand) before and after a 10-min VR task. The results revealed a decrease in motor cortical excitability of the movement effector following exposure to a 10-min conflict between the motor output and the somatosensory input, in comparison to the control condition where spatial congruence between the moved body part and the area of the body that received the feedback was maintained. This finding provides valuable insights into the functional plasticity resulting from spatial sensorimotor conflict arising from the discrepancy between the anticipated and received somatosensory feedback following movement execution. The cortical reorganization observed can be attributed to functional plasticity mechanisms within the sensorimotor cortex that are related to establishing a new connection between somatosensory input and motor output, guided by temporal binding and the Hebbian plasticity rule
Promoting eco-driving behavior through multisensory stimulation: a preliminary study on the use of visual and haptic feedback in a virtual reality driving simulator
Full text linkThis paper describes the design and preliminary test of a virtual reality driving simulator capable of conveying haptic and visual messages to promote eco-sustainable driving behavior. The driving simulator was implemented through the Unity game engine; a large street environment, including high-speed and urban sections, was created to examine different driving behaviors. The hardware setup included a gaming driving seat, equipped with a steering wheel and pedals; the virtual scenarios were displayed through an Oculus Rift headset to guarantee an immersive experience. Haptic stimulation (i.e., vibrations) was delivered to the driver through the accelerator pedal, while visual stimuli (i.e., icons and colors) were shown on a virtual head-up display. The sensory feedbacks were presented both alone and in combination, providing information about excessive acceleration and speed. Four different virtual scenarios, each one including a distracting element (i.e., navigator, rain, call, and traffic), were also created. Ten participants tested the simulator. Fuel consumption was evaluated by calculating a mean power index (MPI) in reference to the sensory feedback presentation; physiological reactions and responses to a usability survey were also collected. The results revealed that the haptic and visuo-haptic feedback were responsible for an MPI reduction, respectively, for 14% and 11% compared with a condition of no feedback presentation; while visual feedback alone resulted in an MPI increase of 11%. The efficacy of haptic feedback was also accompanied by a more relaxing physiological state of the users, compared with the visual stimulation. The system’s usability was adequate, although haptic stimuli were rated slightly more intrusive than the visual ones. Overall, these preliminary results highlight how promising the use of the haptic channel can be in communicating and guiding the driver toward a more eco-sustainable behavior
The effect of visual and auditory information on the perception of pleasantness and roughness of virtual surfaces
No full textDespite the large number of studies on the multisensory aspects of tactile perception, very little is known regarding the effects of visual and auditory sensory modalities on the tactile hedonic evaluations of textures, especially when the presentation of the stimuli is mediated by a haptic device. In this study, different haptic virtual surfaces were rendered by varying the static and dynamic frictional coefficients of a Geomagic® Touch device. In Experiment 1, the haptic surfaces were paired with pictures representing everyday materials (glass, plastic, rubber and steel); in Experiment 2, the haptic surfaces were paired with sounds resulting from the haptic exploration of paper or sandpaper. In both the experiments, participants were required to rate the pleasantness and the roughness of the virtual surfaces explored. Exploration times were also recorded. Both pleasantness and roughness judgments, as well as the durations of exploration, varied as a function of the combinations of the visuo-tactile and the audio-tactile stimuli presented. Taken together, these results suggest that vision and audition modulate haptic perception and hedonic preferences when tactile sensations are provided through a haptic device. Importantly, these results offer interesting suggestions for designing more pleasant, and even more realistic, multisensory virtual surfaces
Multisensory Experiences in eXtended Reality
No full textSince the beginning, virtual reality (VR) has been envisioned as a technology that engages multiple senses. Examples include Morton Heilig’s Sensorama simulator and Ivan E. Sutherland’s notion of the Ultimate Display described in the 1960s. In more than 60 years, technological development and scientific knowledge have predominantly focused virtual and extended reality (VR and XR) applications on the sense of sight and hearing. Despite their importance in everyday interaction, the other senses remain on the margins of VR and XR applications. The potential to include additional senses has been acknowledged and extensively explored in the literature. Those who deal with this topic encounter challenges in understanding the functioning mechanism of the human sensorial and perceptive components and creating interfaces capable of communicating through these senses. Last but not least, it is important to design case studies capable of exploiting the potential of this technology and encouraging investors to believe in its development and end users to adopt it once it is ready. These challenges drive the research activities included in this special issue
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