Daniel Hepperle

In the broader field of human behavior studies, there are several trade-offs for on-site experiments. To be tied to a specific location can limit both the availability and diversity of participants. However, current and future technological advances make it possible to replicate real-world scenarios in a virtual environment up to a certain level of detail. How these differences add up and affect the cross-media validity of findings remains a topic of debate. How a virtual world is accessed, through a computer screen or a head-mounted display, may have a significant impact. Not surprisingly, the literature has presented various comparisons. However, while previous research has compared the different devices for a specific research question, a systematic review is lacking. To fill this gap, we conducted this review. We identified 1083 articles in accordance with the PRISMA guidelines. Following screening, 56 articles remained and were compared for a qualitative synthesis to provide the reader a summary of current research on the differences between head-mounted displays (HMDs), computer screens, and the real world. Overall, the data show that virtual worlds presented in an HMD are more similar to real-world situations than to computer screens. This supports the thesis that HMDs are more suitable than computer screens for conducting experiments in the field of human behavioral studies.

The visual representation of human-like entities in virtual worlds is becoming a very important aspect as virtual reality becomes more and more “social”. The visual representation of a character’s resemblance to a real person and the emotional response to it, as well as the expectations raised, have been a topic of discussion for several decades and have been debated by scientists from different disciplines. But as with any new technology, the findings may need to be reevaluated and adapted to new modalities. In this context, we make two contributions which may have implications for how avatars should be represented in social virtual reality applications. First, we determine how default and customized characters of current social virtual reality platforms appear in terms of human likeness, eeriness, and likability, and whether there is a clear resemblance to a given person. It can be concluded that the investigated platforms vary strongly in their representation of avatars. Common to all is that a clear resemblance does not exist. Second, we show that the uncanny valley effect is also present in head-mounted displays, but—compared to 2D monitors—even more pronounced.

In virtual reality different demands on the user interface have to be addressed than on classic screen applications. That's why established strategies from other digital media cannot be transferred unreflected and at least adaptation is required. So one of the leading questions is: which form of interface is preferable for virtual reality? Are 2D interfaces-that are mostly used in combination with mouse or touch interactions- the means of choice, although they do not use the medium's full capabilities? What about 3D interfaces that can be naturally integrated into the virtual space? And last but not least: are speech interfaces, the fastest and most natural form of human interaction/communication, which have recently established themselves in other areas (e.g. digital assistants), ready to conquer the world of virtual reality? To answer these question this work compares these three approaches based on a quantitative user study and highlights advantages and disadvantages of the respective interfaces for virtual reality applications.