Avatars are important for games and immersive social media applications. Although avatars are still not complete digital copies of the user, they often aim to represent a user in terms of appearance (color and shape) and motion. Previous studies have shown that humans can recognize their own motions in point-light displays. Here, we investigated whether recognition of self-motion is dependent on the avatar's fidelity and the congruency of the avatar's sex with that of the participants. Participants performed different actions that were captured and subsequently remapped onto three different body representations: a point-light figure, a male, and a female virtual avatar. In the experiment, participants viewed the motions displayed on the three body representations and responded to whether the motion was their own. Our results show that there was no influence of body representation on self-motion recognition performance, participants were equally sensitive to recognize their own motion on the point-light figure and the virtual characters. In line with previous research, recognition performance was dependent on the action. Sensitivity was highest for uncommon actions, such as dancing and playing ping-pong, and was around chance level for running, suggesting that the degree of individuality of performing certain actions affects self-motion recognition performance. Our results show that people were able to recognize their own motions even when individual body shape cues were completely eliminated and when the avatar's sex differed from own. This suggests that people might rely more on kinematic information rather than shape and sex cues for recognizing own motion. This finding has important implications for avatar design in game and immersive social media applications.

Chronic stress is one of the major problems in our current fast paced society. The body reacts to environmental stress with physiological changes (e.g. accelerated heart rate), increasing the activity of the sympathetic nervous system. Normally the parasympathetic nervous system should bring us back to a more balanced state after the stressful event is over. However, nowadays we are often under constant pressure, with a multitude of stressful events per day, which can result in us constantly being out of balance. This highlights the importance of effective stress management techniques that are readily accessible to a wide audience. In this paper we present an exploratory study investigating the potential use of immersive virtual reality for relaxation with the purpose of guiding further design decisions, especially about the visual content as well as the interactivity of virtual content. Specifically, we developed an underwater world for head-mounted display virtual reality. We performed an experiment to evaluate the effectiveness of the underwater world environment for relaxation, as well as to evaluate if the underwater world in combination with breathing techniques for relaxation was preferred to standard breathing techniques for stress management. The underwater world was rated as more fun and more likely to be used at home than a traditional breathing technique, while providing a similar degree of relaxation.

Many have experienced vastness, the feeling when the visual space seems to extend without limits away from you, making you feel like a small element within the space. For over 200 years, people have been writing about this experience, for example stating that vastness is important to the experience of awe [Mikulak 2015]. Yet vastness has received little attention in empirical research. Specifically, it is unknown which aspects of the visual stimulus contribute to perceived vastness. This may be due to the inherent difficulties in presenting a variety of vast stimuli while varying only specific visual cues. Using virtual reality addresses these difficulties, as this technology provides precise control over the presented visual stimuli. Here we investigate whether the feeling of vastness can be evoked using virtual reality and explore potential objective measures to assess vastness. We used three different measures during this experiment: 1) An avatar height adjustment task where participants had to adjust an avatar to be equivalent to their own height as viewed from a distance, 2) a distance estimation task and 3) a subjective vastness rating task. These tasks were performed in four environments: a plain (used in all subsequent environments for the ground and sky surfaces), a forest, a mountain and the mountain and forest environments combined. Our results indicate that the feeling of vastness can indeed be experienced to various degrees in virtual environments, demonstrating the potential of VR as a tool for exploring the perception of vastness. Yet the results combined suggest that the percept of vastness is a rather complex construct.

The International Air Transport Association forecasts that there will be at least a 30% increase in passenger demand for flights over the next five years. In these circumstances the aircraft industry is looking for new ways to keep passengers occupied, entertained and healthy, and one of the methods under consideration is immersive virtual reality. It is therefore becoming important to understand how motion sickness and presence in virtual reality are influenced by physical motion. We were specifically interested in the use of head-mounted displays (HMD) while experiencing in-flight motions such as turbulence. 50 people were tested in different virtual environments varying in their context (virtual airplane versus magic carpet ride over tropical islands) and the way the physical motion was incorporated into the virtual world (matching visual and auditory stimuli versus no incorporation). Participants were subjected to three brief periods of turbulent motions realized with a motion simulator. Physiological signals (postural stability, heart rate and skin conductance) as well as subjective experiences (sickness and presence questionnaires) were measured. None of our participants experienced severe motion sickness during the experiment and although there were only small differences between conditions we found indications that it is beneficial for both wellbeing and presence to choose a virtual environment in which turbulent motions could be plausible and perceived as part of the scenario. Therefore we can conclude that brief exposure to turbulent motions does not get participants sick.

Virtual reality technology can be considered a multipurpose tool for diverse applications in various domains, for example, training, prototyping, design, entertainment, and research investigating human perception. However, for many of these applications, it is necessary that the designed and computer-generated virtual environments are perceived as a replica of the real world. Many research studies have shown that this is not necessarily the case. Specifically, egocentric distances are underestimated compared to real-world estimates regardless of whether the virtual environment is displayed in a head-mounted display or on an immersive large-screen display. While the main reason for this observed distance underestimation is still unknown, we investigate a potential approach to reduce or even eliminate this distance underestimation. Building up on the angle of declination below the horizon relationship for perceiving egocentric distances, we describe how eye height manipulations in virtual reality should affect perceived distances. In addition, we describe how this relationship could be exploited to reduce distance underestimation for individual users. In a first experiment, we investigate the influence of a manipulated eye height on an action-based measure of egocentric distance perception. We found that eye height manipulations have similar predictable effects on an action-based measure of egocentric distance as we previously observed for a cognitive measure. This might make this approach more useful than other proposed solutions across different scenarios in various domains, for example, for collaborative tasks. In three additional experiments, we investigate the influence of an individualized manipulation of eye height to reduce distance underestimation in a sparse-cue and a rich-cue environment. In these experiments, we demonstrate that a simple eye height manipulation can be used to selectively alter perceived distances on an individual basis, which could be helpful to enable every user to have an experience close to what was intended by the content designer.

Our vision is that regardless of future variations in the interior of airplane cabins, we can utilize ever-advancing state-of-the-art virtual and mixed reality technologies with the latest research in neuroscience and psychology to achieve high levels of comfort for passengers. Current surveys on passenger's experience during air travel reveal that they are least satisfied with the amount and effectiveness of their personal space, and their ability to work, sleep or rest. Moreover, considering current trends it is likely that the amount of available space is likely to decrease and therefore the passenger's physical comfort during a flight is likely to worsen significantly. Therefore, the main challenge is to enable the passengers to maintain a high level of comfort and satisfaction while being placed in a restricted physical space.

Most of the time point-light figures are used for motion-recognition, which present motions by only displaying the moving joints of the actor. In this study we were interested in whether self-recognition of motion changes with different representations. First, we captured participants' motions and remapped them on a point-light figure and a male and female virtual avatar. In the second part the same participants were asked to recognize their own motions on all three representations. We found that the recognition rate for own motions is high across all representations and different actions. The recognition rate was better on the point-light figure, despite being perceived as most difficult from the participants. The gender of the visual avatar did not matter in self-recognition.