Illusory scene distortion occurs during perceived self-rotation in roll

We report a novel illusory distortion of the visual scene, which became apparent during both: (i) observer rotation inside a furnishedstationary room; and (ii) room rotation about the stationary observer. While this distortion had several manifestations, the most commonexperience was that scenery near Wxation appeared to sometimes lead and other times lag more peripheral scenery. Across a series ofexperiments, we eliminated explanations based on eye-movements, distance misperception, peripheral aliasing, diVerential motion sensitivityand adaptation. We found that these illusory scene distortions occurred only when the observer perceived (real or illusory) changesin self-tilt and maintained a stable Wxation.