Physical body orientation impacts virtual navigation experience and performance.

Most human navigation studies in MRI rely on virtual navigation. However, the necessary supine position in MRI makes it fundamentally different from daily ecological navigation. Nonetheless, until now, no study has assessed whether differences in physical body orientation (BO) affect participants' experienced BO during virtual navigation. Here, combining an immersive virtual reality (VR) navigation task with subjective BO measures and implicit behavioral measures, we demonstrate that physical BO (either standing or supine) modulates experienced BO. Also, we show that standing upright BO is preferred during spatial navigation: participants were more likely to experience a standing BO and were better at spatial navigation when standing upright. Importantly, we report that showing a supine virtual agent reduces the conflict between the preferred BO and physical supine BO. Our study provides critical, but missing, information regarding experienced BO during virtual navigation, which should be considered cautiously when designing navigation studies, especially in MRI. Significance Statement While virtual navigation studies in MRI have greatly contributed to our understanding of human spatial navigation systems, they have relied on a highly untypical navigation body orientation (BO) and experience: navigating while in a supine position. Whether such navigation BO and related experience influence navigation behavior is currently unknown. Investigating participants' subjective reports and implicit navigational measures in supine and standing BO, we show that real-world BO influences BO experienced in VR, and it causes a conflict with preferred navigation BO (i.e., standing) when physically supine. Our results underline the importance of carefully considering the body and its orientation when designing virtual navigation studies.