Abstract
Moving frames strongly affect dot organization (Johansson) and motion direction (the Duncker illusion). In both cases, the direction of motion is altered. Here we report that a moving frame also shifts the perceived positions of dots flashed within it. Specifically, when participants are asked to judge the absolute locations of flashed dots, they tend to report the relative dot locations within the frame, as if the frame were almost stationary. For example, while a frame is moving up and down vertically, one dot is flashed near the upper edge of the frame when it is at its lowest end of travel and a second dot flashed near the bottom edge of the frame at the upper end of the travel. Even though these two dots are physically located at the same position they appear separated by almost 70% of the frame’s travel. These effects are also seen with a moving “frame” consisting of just one or two dots. These frame-induced position effects suggest a link to visual constancy where we see a steady world despite massive displacements during saccades. In this case, object locations are experienced relative to their positions in the overall scene, ignoring its motion, rather than to their ever-changing retinal locations within the visual field.