Human sensory processing is sensitive to the proximity of stimuli to the body. It is therefore plausible that these perceptual mechanisms also modulate the detectability of content in VR, depending on its location. We evaluate this in a user study and further explore the impact of the user's representation during interaction. We also analyze how embodiment and motor performance are influenced by these factors. In a dual-task paradigm, participants executed a motor task, either through virtual hands, virtual controllers, or a keyboard. Simultaneously, they detected visual stimuli appearing in different locations. We found that, while actively performing a motor task in the virtual environment, performance in detecting additional visual stimuli is higher when presented near the user's body. This effect is independent of how the user is represented and only occurs when the user is also engaged in a secondary task. We further found improved motor performance and increased embodiment when interacting through virtual tools and hands in VR, compared to interacting with a keyboard. This article contributes to better understanding the detectability of visual content in VR, depending on its location in the virtual environment, as well as the impact of different user representations on information processing, embodiment, and motor performance.

Cursors, avatars, virtual hands or tools, and other rendered graphical objects, enable users to interact with computers such as PCs, game consoles or virtual reality systems. We analyze the role of these various objects from a user perspective under the unifying concept of “User Representations”. These representations are virtual objects that artificially extend the users’ physical bodies, enabling them to manipulate the virtual environment by performing motor actions that are continuously mapped to their User Representations. In this paper, we identify a set of concepts that are relevant for different User Representations, and provide a multidisciplinary review of the multisensory and cognitive factors underlying the control and subjective experience of User Representations. These concepts include visual appearance, multimodal feedback, sense of agency, input methods, peripersonal space, visual perspective, and body ownership. We further suggest a research agenda for these concepts, which can lead the human-computer interaction community towards a wider perspective of how users perceive and interact through their User Representations.

Mid-air haptic interfaces have several advantages - the haptic information is delivered directly to the user, in a manner that is unobtrusive to the immediate environment. They operate at a distance, thus easier to discover; they are more hygienic and allow interaction in 3D. We validate, for the first time, in a preliminary study with sighted and a user study with blind participants, the use of mid-air haptics for conveying Braille. We tested three haptic stimulation methods, where the haptic feedback was either: a) aligned temporally, with haptic stimulation points presented simultaneously (Constant); b) not aligned temporally, presenting each point independently (Point-By-Point); or c) a combination of the previous methodologies, where feedback was presented Row-by-Row. The results show that mid-air haptics is a viable technology for presenting Braille characters, and the highest average accuracy (94% in the preliminary and 88% in the user study) was achieved with the Point-by-Point method.