In both conditions, a scene rotating at 60
/sec around the vertical
axis was shown in an HMD. The scene was recorded on videotape by rotating a
camera on a tripod in the counter-clockwise direction as viewed from above
in a plaza on the University of Washington campus. The IVB condition A provides a real background visible through the half-silvered mirror of
the HMD which is consistent with the lack of inertial self-motion cues. The
IVB was rated by participants as being less visible than the HMD scene. The
non-IVB condition B placed an occlusion behind the half-silvered
mirror such that only the rotating scene was visible.