Sairam Saikumar - Quantifying the Role of Fingertip Friction in Tactile Pleasantness Perception
The act of ‘touch’ can have an affective dimension, such as a sensation of ‘pleasantness’. We have explored the relationship between the perceived tactile pleasantness and the measured fingertip friction of Aluminum surfaces that varied in roughness. Preliminary results from two pilot studies strongly indicate that friction is anti-correlated with pleasantness votes. Interestingly, the ‘polished’ surface with the lowest roughness, despite its high friction, received more votes than anticipated, suggesting that there might be predictors for pleasant sensations other than friction. When the polished sample is excluded, the percentage of pleasantness votes for low-friction surfaces increases in the psychometric analysis. Understanding the role of friction and roughness in affective tactile experiences can guide us in altering the perceived pleasantness of any material.
Bora Celebi - Time flies by when you are happy: Both happy and sad mood accelerates the perceived time of vibrotactile events
Affect changes the speed of subjective time such as accelerating it when stressed. Previous research mainly focused on the time perception of emotional events themselves. Only a few studies tested the effect of mood on the time perception of neutral events. Here, we investigated the effect of happy and sad mood on the time perception of neutral vibrotactile events. We conducted an experiment in that we used classical music pieces to induce happy, sad, and neutral mood in different participant groups. Before the mood induction, participants were trained to discriminate the two anchor durations of 800 (short) and 2000 (long) ms. Participants, then performed a temporal bisection task on vibrotactile stimuli on the torso. Results showed shortened time perception in both happy and sad mood conditions compared to neutral mood. We conclude that transient changes in mood influence subjective time perception of neutral events on the human torso.
Sophia Faresse - Characterization of touch perception on the torso
Much research has been carried out into touch on the hands and haptic interactions. However, the skin over the body contributes to our sense of self and interactions we have with the world. We aim to investigate somatosensory perception on the human torso, focusing on the breast, and comparing this to the forearm and glabrous hand skin. The goal is to better understand the fundamental mechanisms in somatosensory perception, to apply the insights to reproduce realistic sensations in breast prosthetics, after mastectomy. We investigate affective touch (pleasantness) and discriminative touch (force detection), as well as thermal perception thresholds, over these skin sites. We present here the context of the study, the methodology and some results. We aim to relate these findings to the underlying neurophysiology of the skin and identify how somatosensation can be dependent on the body area stimulated, requiring a consideration of this throughout prosthetic and haptic devices.
Maria Rosa Bufo - Physiological and Perceptual Responses to Objects Presented in Visual and Tactile Modalities
We use our senses to interact with objects in our environment. When the skin of our hands is in contact with an external object, tactile information is obtained, including discriminative and affective/emotional elements. We appreciate these characteristics via other senses, such as visually seeing the object. We study the physiological responses associated with the touch of objects, particularly unpleasant objects, which we will compare with pleasant and neutral objects. Unpleasant touch, which has been little studied, does not evoke pain, but provokes a response that is emotionally negative and often highly pertinent, in contrast to neutral or positive emotional (e.g. pleasant affective touch) interactions. We will study bodily physiological responses from simply seeing, or touching, or using both senses, to assess objects, linking this with tactile perception. Our results should show differences between modalities and affective objects, where we predict seeing greater responses in the tactile and negative affective conditions.
Sarah Bonnet - Development of a Novel, Low-Cost Accelerometer System for Recording Vibration Propagation over the Skin
We present a novel accelerometer system, that aims to quantify skin vibration propagation through a cost-effective, scalable, flexible solution. The system's innovative design allows for the modular inclusion of multiple accelerometers to suit specific research needs, making it highly adaptable for various experimental setups and recording from anatomical locations over the body. This means that it can capture tactile interactions at different skin sites, including inter-personal touch and the vibrations elicited when touching objects. The core of our system comprises of a networked array of low-cost microcontrollers, each connected to up to 8 accelerometers. We aim to incorporate wireless capabilities into our system to further extend its applicability across a wider spectrum of fields, thus opening up further opportunities especially in haptic and affective touch. By enhancing the system's versatility and user-friendliness, our work sets a new standard in the study of haptics, with implications in capturing tactile interactions.
Laura Pehkonen - Exploring the Central and Peripheral Mechanisms of Affective Touch through Apparent Motion
Although the general outlines of pleasant touch perception and CT-afferents have been sketched out, the current extent of knowledge still lags behind our understanding of other neural pathways and somatosensory modalities.This project explored the peripheral and central mechanisms in affective touch, through comparing gentle stroking with apparent motion – an illusory perception of movement produced by successively presented stimuli. We examined whether previously established velocity tuning of true lateral motion is also observed in apparent motion. If similar patterns were observed, then central modulation may govern the velocity dependence of the perception of pleasant touch. To investigate this relationship, pleasantness-ratings were collected across an array of velocities (1-300 mm/s). For both brushing-like and apparent motion, significant negative quadratic terms were observed (p<0.001). No significant linear terms were observed on the group level. These findings suggest that the velocity-tuning of pleasantness in apparent motion cannot be attributed to velocity-tuning of individual CT-afferents.