Modeling and Simulation of Thermal Grill Illusion Using Neurophysiological Theory

The Thermal Grill Illusion (TGI) is a temperature-based perceptual illusion in which innocuous warm and cold stimuli evoke pain when applied simultaneously in a juxtaposed pattern. Based on neurophysiological and psychological findings, several theories have been proposed to explain the mechanisms behind TGI. However, the significance of an analytical model for TGI is not addressed in the literature. This study focuses on developing an analytical model based on the 'disinhibition theory' to predict the intensity of TGI pain. A psychophysical experiment on perceived TGI pain was first conducted, and then an analytical model was developed. The model's objective is to predict the neuronal activity of pain-sensitive HPC (Heat-Pinch-Cold) nerve fibers by leveraging the existing popular models of warm and cold receptors. An experimental thermal grill setup was used to provide five temperature differences between warm and cold grills (each repeated three times). Participants rated the perceived TGI pain sensation on a Likert scale of one to ten. Both the experimental results and the simulation showed a monotonically increasing relationship between temperature differences and the perceived TGI intensity. The proposed model bridges the gap between neurophysiological and psychophysical knowledge of TGI, potentially aiding thermal display designs

MindTouch: Effect of Mindfulness Meditation on Mid-Air Tactile Perception

As we constantly seek to improve and expand upon the capabilities of technology, we frequently wonder whether we use technology to its fullest extent. Studies indicate that increasing our awareness and mindfulness of our senses may lead to a journey of unexplored experiences. In this paper, we focus on the perception of mid-air haptics stimuli and whether it can be improved through mindfulness meditation. We have conducted an experiment with 22 participants given the task to recognize digits 0 to 9 drawn on their palms using a mid-air haptic device under two conditions - with and without prior mindfulness meditation. Results show that for frequencies targeting both Meissner (40 Hz) and Pacinian (200 Hz) receptors, meditation significantly improves performance of the participants, as well as increases their confidence. This suggests that including a short meditation step in haptic user interfaces could lead to improved system performance and user satisfaction

Multi-point STM: Effects of Drawing Speed and Number of Focal Points on Users’ Responses using Ultrasonic Mid-Air Haptics

Spatiotemporal modulation (STM) is used to render tactile patterns with ultrasound arrays. Previous research only explored the effects of single-point STM parameters, such as drawing speed (Vd). Here we explore the effects of multi-point STM on both perceptual (intensity) and emotional (valence/arousal) responses. This introduces a new control parameter for STM - the number of focal points (Nfp) – on top of conventional STM parameter (Vd). Our results from a study with 30 participants showed a negative effect of Nfp on perceived intensity and arousal, but no significant effects on valence. We also found the effects of Vd still aligned with prior results for single-point, even when different Nfp were used, suggesting that effects observed from single-point also apply to multi-point STM. We finally derive recommendations, such as using single-point STM to produce stimuli with higher intensity and/or arousal, or using multi-point STM for milder and more relaxing (less arousing) experience

Responsible Innovation of Touchless Haptics: A Prospective Design Exploration in Social Interaction

The rapid development of touchless systems has introduced many innovations in social interaction scenarios in recent years. People now can interact with touchless systems in social applications that are aimed to be used in everyday situations in the future. This accelerated development makes us ask, what will the next generation of touchless systems be like? How can we responsibly develop new touchless technologies in the future? To answer the first question, we brought together 20 experts to ideate, speculate, and evaluate possible touchless applications for social interactions. A total of 48 ideas were generated from two consecutive workshops. Then, to answer the second question, we critically analyzed those ideas through a thematic analysis using a responsible innovation (RI) framework, and identified key ethical considerations to guide developers, practitioners when designing future touchless systems. We argue that the social scenarios described, and the RI framework proposed in this paper are a useful starting point for responsibly designing the next generation of touchless systems