  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.
