Am I the Odd One? Exploring (In)Congruencies in the Realism of Avatars and Virtual Others in Virtual Reality

TL;DR

This study investigates how realism and (in)congruence in a group of co-located virtual humans, plus the realism of the participant’s self-avatar, shape users’ VR experience. Using a 2x3 mixed design across three VR exposures, the authors manipulate self-avatar realism (realistic vs stylized) and the group realism (realistic, stylized, mixed) and measure plausibility, co-presence, affective appraisal, embodiment, and spatial presence. Key findings show that groups with higher realism elevate co-presence, impression of interaction possibilities, and humanness, while a realistic self-avatar enhances virtual body ownership and self-identification; incongruence, especially for stylized self-avatars with realistic others, can diminish self-location and self-identification. These results support CaP-based notions of plausibility and congruence in XR and offer actionable guidance for designing SVEs with virtual crowds and personal avatars to optimize social experience and embodiment.

Abstract

Virtual humans play a pivotal role in social virtual environments, shaping users' VR experiences. The diversity in available options and users' preferences can result in a heterogeneous mix of appearances among a group of virtual humans. The resulting variety in higher-order anthropomorphic and realistic cues introduces multiple (in)congruencies, eventually impacting the plausibility of the experience. In this work, we consider the impact of (in)congruencies in the realism of a group of virtual humans, including co-located others and one's self-avatar. In a 2 x 3 mixed design, participants embodied either (1) a personalized realistic or (2) a customized stylized self-avatar across three consecutive VR exposures in which they were accompanied by a group of virtual others being either (1) all realistic, (2) all stylized, or (3) mixed. Our results indicate groups of virtual others of higher realism, i.e., potentially more congruent with participants' real-world experiences and expectations, were considered more human-like, increasing the feeling of co-presence and the impression of interaction possibilities. (In)congruencies concerning the homogeneity of the group did not cause considerable effects. Furthermore, our results indicate that a self-avatar's congruence with the participant's real-world experiences concerning their own physical body yielded notable benefits for virtual body ownership and self-identification for realistic personalized avatars. Notably, the incongruence between a stylized self-avatar and a group of realistic virtual others resulted in diminished ratings of self-location and self-identification. We conclude on the implications of our findings and discuss our results within current theories of VR experiences, considering (in)congruent visual cues and their impact on the perception of virtual others, self-representation, and spatial presence.

Figures (5)

• Figure 1: A participant embodying a realistic self-avatar (front) while solving a logic task in a group of virtual others (back). The group features a configuration of mixed styles consisting of three realistic virtual humans and three stylized virtual humans.
• Figure 2: The scan process for personalization of realistic avatars (A), the GUI for customization of stylized avatars (B), an immersed person (C), Captury Live's tracking view (D), and the first- and third-person perspective of an embodied realistic (E) and a stylized (F) avatar in the mirror.
• Figure 3: Overview of the experimental procedure (left) and the repeated VR exposures (right). All participants underwent the same procedure regardless of their randomly assigned test condition. The icons on the right side of the steps indicate whether the participants used a workstation or were immersed in VR. The icons on the left side of the steps indicate the amount of repetition of the respective step. The VR exposure was repeated for each group configuration, i.e., the within-subject factor. All logic tasks are defined in \ref{['subssec:logictask']}. The overall procedure is described in detail in \ref{['subsec:procedure']}.
• Figure 4: The interaction plots show the type of self-avatar (x-axis) and the contrast between realistic, mixed, and stylized virtual others for the evaluation of the perception of virtual others. Error bars represent 95 % confidence intervals estimated using bootstrapped standard deviations.
• Figure 5: Interaction plots show the type of self-avatar (x-axis) and the contrast between realistic, mixed, and stylized virtual others for the evaluation of spatial presence and the perception of the self-representation. Error bars represent 95 % confidence intervals estimated using bootstrapped standard deviations.