Orientation-defined visual rotation significantly affects observer's perceived self-motion.

It is believed that visual self-motion perception (vection) can be effectively induced only in the case where the inducer's motion is defined by luminance modulation. In this study, psychophysical experiments examining the potential effects of visual motion defined by features other than luminance on visual self-motion perception (vection) were conducted, employing orientation-defined rotation (so-called fractal rotation) as a visual inducer. The experiments clearly indicate that orientation-defined visual rotation can strongly induce an observer's perceived self-rotation (roll vection), although it was significantly weaker than that induced by luminance-defined rotation. In the case where the orientation and luminance rotations were combined and presented simultaneously, perceived self-rotation was mainly determined by the luminance rotation when both factors were set to rotate in consistent or inconsistent directions. These results suggest that feature-defined visual motion containing no luminance modulation has the potential to contribute to visual self-motion perception.