Augmented Reality (AR) embeds virtual content in physical spaces, including virtual agents that are known to exert a social presence on users. Existing design guidelines for AR rarely consider the social implications of an agent's personal space (PS) and that it can impact user behavior and arousal. We report an experiment (N=54) where participants interacted with agents in an AR art gallery scenario. When participants approached six virtual agents (i.e., two males, two females, a humanoid robot, and a pillar) to ask for directions, we found that participants respected the agents' PS and modulated interpersonal distances according to the human-like agents' perceived gender. When participants were instructed to walk through the agents, we observed heightened skin-conductance levels that indicate physiological arousal. These results are discussed in terms of proxemic theory that result in design recommendations for implementing pervasive AR experiences with virtual agents.
Research on intelligent virtual agents (IVAs) often concerns the implementation of human-like behavior by integrating artificial intelligence algorithms. Thus far, few studies focused on mimicry of cognitive imperfections inherent to humans in IVAs. Neglecting to implement such imperfect behavior in IVAs might result in less believable or engaging human-agent interactions.
In this paper, we simulate human imprecision in conversational IVAs' temporal statements. We conducted a survey to identify temporal statement patterns, transferred them to a conversational IVA, and conducted a user study evaluating the effects of time precision on perceived anthropomorphism and usefulness. Statistical analyses reveal significant interaction between time precision and agents' use of memory aids, indicating that (i) imprecise agents are perceived as more human-like than precise agents when responding immediately, and (ii) unnaturally high levels of temporal precision can be compensated for by memory aid use. Further findings underscore the value of continued inquiry into cultural variations.
Behaviour in virtual environments might be informed by our experiences in physical environments, but virtual environments are not constrained by the same physical, perceptual, or social cues. Instead of replicating the properties of physical spaces, one can create virtual experiences that diverge from reality by dynamically manipulating environmental, aural, and social properties. This paper explores digital proxemics, which describe how we use space in virtual environments and how the presence of others influences our behaviours, interactions, and movements. First, we frame the open challenges of digital proxemics in terms of activity, social signals, audio design, and environment. We explore a subset of these challenges through an evaluation that compares two audio designs and two displays with different social signal affordances: head-mounted display (HMD) versus desktop PC. We use quantitative methods using instrumented tracking to analyse behaviour, demonstrating how personal space, proximity, and attention compare between desktop PC and HMDs.
Virtual humans can be used to deliver persuasive arguments; yet, those with synthetic text-to-speech (TTS) have been perceived less favorably than those with recorded human speech. In this paper, we investigate standard concatenative TTS and more advanced neural TTS. We conducted a 3x2 between-subjects experiment (n=79) to evaluate the effect of a virtual human’s speech fidelity at three levels (Standard TTS, Neural TTS, and Human speech) and the listener’s gender (male or female) on perceptions and persuasion. We found that the virtual human was perceived as significantly less trustworthy by both genders, if they used neural TTS compared to human speech, while male listeners (but not females) also perceived standard TTS as less trustworthy than human speech. Our findings indicate that neural TTS may not be an effective choice for persuasive virtual humans and that gender of the listener plays a role in how virtual humans are perceived.
Visualizing biosignals can be important for social Virtual Reality (VR), where avatar non-verbal cues are missing. While several biosignal representations exist, designing effective visualizations and understanding user perceptions within social VR entertainment remains unclear. We adopt a mixed-methods approach to design biosignals for social VR entertainment. Using survey (N=54), context-mapping (N=6), and co-design (N=6) methods, we derive four visualizations. We then ran a within-subjects study (N=32) in a virtual jazz-bar to investigate how heart rate (HR) and breathing rate (BR) visualizations, and signal rate, influence perceived avatar arousal, user distraction, and preferences. Findings show that skeuomorphic visualizations for both biosignals allow differentiable arousal inference; skeuomorphic and particles were least distracting for HR, whereas all were similarly distracting for BR; biosignal perceptions often depend on avatar relations, entertainment type, and emotion inference of avatars versus spaces. We contribute HR and BR visualizations, and considerations for designing social VR entertainment biosignal visualizations.