Contribution of Stereopsis and Motion Parallax to Fear Responses in the Pit Room Environment

Virtual reality, in contrast to visual stimulation on computer screens, is characterized by the illusion of presence. Stereopsis and motion parallax are two of the main perceptual factors provided by head mounted displays to create a sense of depth in virtual environments. However, the relative contribution of stereopsis and motion parallax to create the sense of presence is not clear and existing results are somewhat controversial. Here, we study the contribution of stereopsis and motion parallax using the classic pit room paradigm. Participants are required to cross a deep abyss between two platforms on a narrow plank under three experimental conditions. Participants responded to a presence questionnaire after each condition and their electrodermal activity (EDA) was recorded as a measure of stress and anxiety in a threatening situation. The EDA results demonstrated the importance of motion parallax over stereopsis, however, the questionnaire scores were not different among three conditions.