Local form-motion interactions influence global form perception

Object motion perception depends on the integration of form and motion information into a unified neural representation. Historically, form and motion perception are thought to be independent processes; however, research has demonstrated that these processes interact in numerous and complex ways. For example, an object's orientation relative to its direction of motion will influence its perceived speed (Georges, Seriès, Frégnac, & Lorenceau, Vision Research 42:2757-2772, 2002). Here, we investigated whether this local form-motion interaction influences global form processing. In Experiment 1, we replicated the effect of orientation-dependent modulation of speed. In Experiment 2, we investigated whether the perceived speed of local elements could influence the perceived shape of a global object constructed from grouping of those elements. The results indicated that the orientation of local elements indeed influenced the perceived shape of a global object. We propose that inputs from local form-motion processes are one of perhaps many neural mechanisms underlying global form integration.