Almost the same: experiential and behavioral effects in talking with virtual humans

In this paper, we present a study assessing experiential and behavioral responses in real and virtual dyadic interactions. Fifty participants have been involved in a within-subject study consisting of rehearsing an oral literature assessment. Three experimental conditions were tested: rehearsal with a human teacher, rehearsal with a virtual human in an immersive virtual reality (VR) setting, and rehearsal alone as a control. Experiential and behavioral measures have been collected through self-assessments and automatically extracted behavioral features, respectively. The results provide evidence that, for the task at hand, interacting with virtual humans is similar to interacting with a real person in some respects, while in others, it may be considered closer to the all alone experience. Specifically, participants were engaged in a similar way in both interactive conditions, and no statistically significant differences were found in perceived effort, task accuracy, and perceived usefulness. However, a higher level of stress is evident in the virtual human condition than in the human teacher condition, both subjectively and from behavioral responses. Furthermore, the attitude of the participant toward the virtual human is crucial in determining the experience: participants who regarded the virtual human more as an agent than a tool reported a higher engagement and an increased perception of usefulness in the virtual interaction. They also performed better in the virtual oral assessment. The evidence collected with this study, albeit in several respects still preliminary, can be a valuable asset to guide further research in the field of interaction in VR environments.