Static visual components without depth modulation alter the strength of vection

We conducted a series of psychophysical experiments to investigate the effects of static visual components on visually-induced self-motion perception ('vection'). Static gratings with various spatial frequencies were added to a moving vertical grating, presented either orthogonally or parallel to the motion of the grating. Adding a static component orthogonal to a motion component was found to facilitate vection, whereas adding a static component parallel to a motion component inhibited vection. No anisotropy was found between low and high spatial frequencies of static stimuli in the facilitation/inhibition of vection. We discuss these findings in terms of perceived motion of the visual pattern and the number of visual features in the stimulus.