Motion in depth induced by brightness changes in the background.
A disc of  unvarying brightness and position is presented against a background whose brightness is continuously changing up and down. This change is perceived as a pendular movement to and from the subject and, in its turn, clearly induces an analogous but contrary movement in the disc.
D000328:Adult; D003867:Depth Perception; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D009039:Motion Perception