Abstract
Introduction. Rapidly rotating objects that stimulate retinal locations at high temporal frequencies (e.g., a fan blade) may appear as a stationary region (e.g., a blurred disk). Despite the inability of observers to consciously perceive the motion of such objects, information about this motion may impact perception. Mattler & Fendrich (2010) reported an instance where this occurred. Observers viewed a ring of 16 points (the inducing ring), which was rotated at angular velocities as high as 2250 deg/s so that observers saw only an unbroken outline circle. When the inducing ring was replaced by a stationary ring of 16 points this stationary ring appeared to visibly spin to a halt, primarily in the same direction as the inducing ring rotation. This illusion was labeled the Motion Bridging Effect (MBE). In the 2010 study the start and end positions of the inducing ring points and the position of the points in the stationary ring were identical. Here we investigated the effect of misaligning these positions. Methods. Displays were presented on an oscilloscope with a customized fast-phosphor CRT. The start and end positions of the points of the inducing ring were shifted relative to the fixed positions of the stationary ring by advancing those positions across the 22.5 deg angular gap that separated the successive points of the ring. Twelve steps of misalignment were investigated. Results and Conclusion. The MBE was replicated when start and end positions of inducing and stationary ring were identical. When start and end positions were misaligned, however, the MBE decreased with increasing misalignment and completely reversed when the start and end position of the points of the inducing ring were located midway between the position of the points of the stationary ring. These findings provide new constraints on the mechanisms of the MBE.
Meeting abstract presented at VSS 2018