Purpose: The role of motion contrast and motion capture in the 'Ouchi'
effect was investigated in a simplified stimulus. Methods: Sinewave g
ratings were rapidly oscillated vertically within two concentric stati
onary 'apertures', an inner disc surrounded by an annulus. Results: A
strong illusion of relative motion between the disc and annulus is obs
erved in the horizontal direction for 8 and 12 cycles/deg given small
orientation differences between the two gratings. Conclusion: These pa
rameters coincide with those of the 'Ouchi' effect, suggesting a shari
ng of the same causal mechanism.