Abstract
Research has shown that visual illusions of self-motion (vection) can be improved by adding consistent stereoscopic information to inducing displays. However here we examined the effect of placing this stereoscopic information into direct conflict with monocular motion signals (by swapping left and right eye views to reverse disparity). We compared the vection in depth induced by stereo-consistent, stereo-reversed and flat-stereo displays. We also manipulated the amount of monocular self-motion information in these inducing displays (by providing explicit changing-size cues in half of the trials). As expected, we found that stereo-consistent conditions improved the vection induced by both changing-size and same-size patterns of optic flow (relative to their equivalent flat-stereo conditions). However, stereo-reversed conditions were also found to improve the vection induced by same-size patterns of optic flow. Additional evidence from our experiments suggested that all of these stereoscopic advantages for vection were due to the effects on perceived motion-in-depth (not perceived scene depth). These findings demonstrate that stereoscopic information does not need to be consistent with monocular motion signals in order to improve vection in depth. Rather they suggest that stereoscopic information only needs to be dynamic (as opposed to static) in order to enhance the experiences of vection induced by optic flow.