Detailed hand motions play an important role in face-to-face communication to emphasize points, describe objects, clarify concepts, or replace words altogether. While shared virtual reality (VR) spaces are becoming more popular, these spaces do not, in most cases, capture and display accurate hand motions. In this article, we investigate the consequences of such errors in hand and finger motions on comprehension, character perception, social presence, and user comfort. We conduct three perceptual experiments where participants guess words and movie titles based on motion captured movements. We introduce errors and alterations to the hand movements and apply techniques to synthesize or correct hand motions. We collect data from more than 1000 Amazon Mechanical Turk participants in two large experiments, and conduct a third experiment in VR. As results might differ depending on the virtual character used, we investigate all effects on two virtual characters of different levels of realism. We furthermore investigate the effects of clip length in our experiments. Amongst other results, we show that the absence of finger motion significantly reduces comprehension and negatively affects people’s perception of a virtual character and their social presence. Adding some hand motions, even random ones, does attenuate some of these effects when it comes to the perception of the virtual character or social presence, but it does not necessarily improve comprehension. Slightly inaccurate or erroneous hand motions are sufficient to achieve the same level of comprehension as with accurate hand motions. They might however still affect the viewers’ impression of a character. Finally, jittering hand motions should be avoided as they significantly decrease user comfort.

We present an empirical evaluation of immersion and self-avatars as compared to desktop viewing in Virtual Reality (VR) for learning computer programming and computational thinking in middle school education using an educational VR simulation. Students were asked to programmatically choreograph dance performances for virtual characters within an educational desktop application we built earlier called Virtual Environment Interactions (VEnvI). As part of a middle school science class, 90 students from the 6th and 7th grades participated in our study. All students first visually programmed dance choreography for a virtual character they created in VEnvI on a laptop. Then, they viewed and interacted with the resulting dance performance in a between-subjects design in one of the three conditions. We compared and contrasted the benefits of embodied immersive virtual reality (EVR) viewing utilizing a head-mounted display with a body-scaled and gender-matched self-avatar, immersive virtual reality only (IVR) viewing, and desktop VR (NVR) viewing with VEnvI on pedagogical outcomes, programming performance, presence, and attitudes towards STEM and computational thinking. Results from a cognition questionnaire showed that, in the learning dimensions of Knowledge and Understanding (Bloom's taxonomy) as well as Multistructural (SOLO taxonomy), participants in EVR and IVR scored significantly higher than NVR. Also, participants in EVR scored significantly higher than IVR. We also discovered similar results in objective programming performance and presence scores in VEnvI. Furthermore, students' attitudes towards computer science, programming confidence, and impressions significantly improved to be the highest in EVR and then IVR as compared to NVR condition. Our work suggests that educators and developers of educational VR simulations, who want to enhance knowledge and understanding as well as simultaneous acquisition of multiple abstract concepts, can do so by employing immersion and self-avatars in VR learning experiences.

A primary goal of the Virtual Reality ( VR ) community is to build fully immersive and presence-inducing environments with seamless and natural interactions. To reach this goal, researchers are investigating how to best directly use our hands to interact with a virtual environment using hand tracking. Most studies in this field require participants to perform repetitive tasks. In this article, we investigate if results of such studies translate into a real application and game-like experience. We designed a virtual escape room in which participants interact with various objects to gather clues and complete puzzles. In a between-subjects study, we examine the effects of two input modalities (controllers vs. hand tracking) and two grasping visualizations (continuously tracked hands vs. virtual hands that disappear when grasping) on ownership, realism, efficiency, enjoyment, and presence. Our results show that ownership, realism, enjoyment, and presence increased when using hand tracking compared to controllers. Visualizing the tracked hands during grasps leads to higher ratings in one of our ownership questions and one of our enjoyment questions compared to having the virtual hands disappear during grasps as is common in many applications. We also confirm some of the main results of two studies that have a repetitive design in a more realistic gaming scenario that might be closer to a typical user experience.

Most commercial virtual reality applications with self avatars provide users with a “one-size fits all” avatar. While the height of this body may be scaled to the user's height, other body proportions, such as limb length and hand size, are rarely customized to fit an individual user. Prior research has shown that mismatches between users' avatars and their actual bodies can affect size perception and feelings of body ownership. In this paper, we consider how concepts related to the virtual hand illusion, user experience, and task efficiency are influenced by variations between the size of a user's actual hand and their avatar's hand. We also consider how using a tracked controller or tracked gestures affect these concepts. We conducted a 2×3 within-subjects study (n=20), with two levels of input modality: using tracked finger motion vs. a hand-held controller (Glove vs. Controller), and three levels of hand scaling (Small, Fit, and Large). Participants completed 2 block-assembly trials for each condition (for a total of 12 trials). Time, mistakes, and a user experience survey were recorded for each trial. Participants experienced stronger feelings of ownership and realism in the Glove condition. Efficiency was higher in the Controller condition and supported by play data of more time spent, blocks grabbed, and blocks dropped in the Glove condition. We did not find enough evidence for a change in agency and the intensity of the virtual hand illusion depending on hand size. Over half of the participants indicated preferring the Glove condition over the Controller condition, mentioning fun and efficiency as factors in their choices. Preferences on hand scaling were mixed but often attributed to efficiency. Participants liked the appearance of their virtual hand more while using the Fit instead of Large hands. Several interaction effects were observed between input modality and hand scaling, for example, for smaller hands, tracked hands evoked stronger feelings of ownership compared to using a controller. Our results show that the virtual hand illusion is stronger when participants are able to control a hand directly rather than with a hand-held device, and that the virtual reality task must first be considered to determine which modality and hand size are the most applicable.

Hand tracking and haptics are gaining more importance as key technologies of virtual reality (VR) systems. For designing such systems, it is fundamental to understand how the appearance of the virtual hands influences user experience and how the human brain integrates vision and haptics. However, it is currently unknown whether multi-sensory integration of visual and haptic feedback can be influenced by the appearance of virtual hands in VR. We performed a user study in VR to gain insight into the effect of hand appearance on how the brain combines visual and haptic signals using a cue-conflict paradigm. In this paper, we show that the detection of surface irregularities (bumps and holes) sensed by eyes and hands is affected by the rendering of avatar hands. However, sensitivity changes do not correlate with the degree of perceived limb ownership. Qualitative feedback provides insights into potentially distracting cues in visual-haptic integration.

The ability to select or customize characters in educational applications and games has been shown to influence factors related to learning effects such as transfer, self-efficacy, and motivation. Most previous conclusions on the perception of virtual characters and the effect of character assignment in interactive applications have been reached through short, one-task experiments. To investigate more long-term effects of assigning versus customizing characters as well as explore perceptions of personal character appearance, we conduct a study in which sixth and seventh grade students are introduced to programming concepts with the software VEnvI (Virtual Environment Interactions) in seven one-hour sessions over two weeks. In VEnvI, students create performances for virtual characters by assembling blocks. With a between-subjects design, in which some of the students can alter their character and others are not given that possibility, we examine the influence of the presence or absence of character choice options on learning.

How does the appearance of a virtual hand affect own-body perception? Previous studies have compared either two or three hand models at a time, with their appearances limited to realistic hands and abstract or simple objects. To investigate the effects of different realisms, render styles, and sensitivities to pain on the virtual hand illusion (VHI), we conduct two studies in which participants take on controllable hand models with six distinct appearances. We collect questionnaire data and comments regarding responses to impacts and threats to assess differences in the strength of the VHI.

The virtual hand illusion is a body ownership illusion that occurs in a virtual environment. Previous studies reached different conclusions on the effect of realism of the controllable virtual hand model on the intensity of the perceived illusion. In our experiments, we compare participants' responses to virtual impacts and threats when using hand models with different levels of realism. Our findings indicate that an illusion can be created for any model but that the effect is perceived weakest for a non-anthropomorphic block model and strongest for a realistic human hand model in direct comparison. We furthermore find that the reactions to our experiments highly vary between participants.

Virtual reality has reached the consumer market and exhibited the potential to become a large social and commercial platform for mainstream markets. New, low-cost devices for virtual reality or mixed reality such as the Oculus Rift, Sony's Project Morpheus, or Microsoft's HoloLens are already available or have been announced and might even outperform previous high-cost systems [Young et al. 2014]. Techniques to measure hand motions are in the making with the goal of being able to control virtual hands using one's own hand movements as well as interact with objects in virtual reality applications. Prototypes such as the combination of the Leap Motion Controller and the Oculus Rift are already available. Applications for these devices will certainly follow.