Emotional Response-Based Approach for Assessing the Sense of Presence of Subjects in Virtual Building Evacuation Studies

Using the latest advances in virtual reality (VR) technologies, it is possible to create immersive virtual environments (IVEs) that can be used for behavioral experiments in controlled setups to examine individual evacuee behaviors. As a first step to achieving sufficient ecological validity, this study proposes an approach for assessing the sense of presence of the subjects performing virtual evacuation tasks, and this assessment can serve as an indirect indicator of the overall validity of the experiments. The proposed approach integrates a set of subjective and objective measures to assess the subjects' emotional responses, including emotional valence and emotional arousal, which are highly reflective of their sense of presence in the IVEs. Three IVEs are developed, presenting an apartment under normal or fire emergency situations with different levels of realism. The subjects were asked to perform an evacuation task in all IVEs, and their emotional responses were monitored and analyzed throughout the experiments. The results show that the proposed approach can not only detect changes in subjects' emotions triggered by the IVEs but can differentiate subjects' emotions when they were immersed in IVEs with different levels of realism. These findings suggest that it is feasible to use the proposed approach to assess the sense of presence experienced by subjects conducting virtual evacuation tasks and ultimately the level of ecological validity of IVE-based evacuation studies. (C) 2017 American Society of Civil Engineers.