Many illusion and interaction techniques in Virtual Reality (VR) rely on Hand Redirection (HR), which has proved to be effective as long as the introduced offsets between the position of the real and virtual hand do not noticeably disturb the user experience. Yet calibrating HR offsets is a tedious and time-consuming process involving psychophysical experimentation, and the resulting thresholds are known to be affected by many variables---limiting HR's practical utility. As a result, there is a clear need for alternative methods that allow tailoring HR to the perceptual boundaries of individual users. We conducted an experiment with 18 participants combining movement, eye gaze and EEG data to detect HR offsets Below, At, and Above individuals' detection thresholds. Our results suggest that we can distinguish HR At and Above from no HR. Our exploration provides a promising new direction with potentially strong implications for the broad field of VR illusions.
https://doi.org/10.1145/3654777.3676425
This paper explores the impact of vibrotactile haptic feedback on heart activity when the feedback is provided at four different body locations (chest, wrist, neck, and ankle) and with two feedback rates (50 bpm and 110 bpm). A user study found that the neck placement resulted in higher heart rates and lower heart rate variability, and higher frequencies correlated with increased heart rates and decreased heart rate variability. The chest was preferred in self-reported metrics, and neck placement was perceived as less satisfying, harmonious, and immersive. This research contributes to understanding the interplay between psychological experiences and physiological responses when using haptic biofeedback resembling real body signals.
https://doi.org/10.1145/3654777.3676435
We propose, engineer, and study a novel method to augment the feeling of breathing—enabling interactive applications to let users feel like they are inhaling more/less air (perceived nasal airflow). We achieve this effect by cooling or heating the nose in sync with the user’s inhalation. Our illusion builds on the physiology of breathing: we perceive our breath predominantly through the cooling of our nasal cavities during inhalation. This is why breathing in a “fresh” cold environment feels easier than in a “stuffy” hot environment, even when the inhaled volume is the same. Our psychophysical study confirmed that our in-nose temperature stimulation significantly influenced breathing perception in both directions: making it feel harder & easier to breathe. Further, we found that ~90% of the trials were described as a change in perceived airflow/breathing, while only ~8% as temperature. Following, we engineered a compact device worn across the septum that uses Peltier elements. We illustrate the potential of this augmented breathing in interactive contexts, such as for virtual reality (e.g., rendering ease of breathing crisp air or difficulty breathing with a deteriorated gas mask) and everyday interactions (e.g., in combination with a relaxation application or to alleviate the perceived breathing resistance when wearing a mask).
https://doi.org/10.1145/3654777.3676438
This study presents a novel method for creating moving thermal sensations by integrating the thermal referral illusion with tactile motion. Conducted through three experiments on human forearms, the first experiment examined the impact of temperature and thermal actuator placement on perceived thermal motion, finding the clearest perception with a centrally positioned actuator under both hot and cold conditions. The second experiment identified the speed thresholds of perceived thermal motion, revealing a wider detectable range in hot conditions (1.8 cm/s to 9.5cm/s) compared to cold conditions (2.4cm/s to 5.0cm/s). Finally, we integrated our approach into virtual reality (VR) to assess its feasibility through two interaction scenarios. Our results shed light on the comprehension of thermal perception and its integration with tactile cues, promising significant advancements in incorporating thermal motion into diverse thermal interfaces for immersive VR experiences.
https://doi.org/10.1145/3654777.3676460