Distance Perception and the Visual Horizon in Head-Mounted Displays

Can distance perception be studied using virtual reality (VR) if distances are systematically underestimated in VR head-mounted displays (HMDs)? In an experiment in which a real environment was observed through an HMD, via live video, distances, as measured by visually directed walking, were underestimated even when the perceived environment was known to be real and present. However, the underestimation was linear, which means that higher-order space perception effects might be preserved in VR. This is illustrated in a second experiment, in which the visual horizon was artificially manipulated in a simulated outdoor field presented in immersive VR. As predicted by the claim that angle of declination from the horizon may serve as a strong cue to distance, lowering the horizon line produced “expansiv ” judgments of distance (power function exponents greater than one) both in verbal and in motor estimates.