Abstract
Motion looks faster when it moves along a short compared with a long path (Ryan & Zanker 2001), but little is understood about why this occurs. We examined possible causes of this effect, including scaling effects, landmarks, edge transients, nonlinear judgments of time and space, and temporal frequency judgments (J.F. Brown 1931). We used a random-dot pattern that translated horizontally over a sixteenfold range of speeds, ranging from 0.34 to 5.5°/s; it seemed to move 50% faster when viewed through a shorter (0.5°) rather than a longer (4.5°) aperture in the form of a horizontal slot, and twice as fast when viewed through a vertical compared with a horizontal slot (regardless of its actual speed). We also found that transparent, superimposed orthogonal motions could undergo separate speed illusions dependent upon slot shape. Nearby stationary landmarks did not affect perceived speed. We varied rectangular aperture lengths over a tenfold range; manipulated the size, shape, orientation of the apertures, and used limited-lifetime dots and transparent dot fields moving in different directions.
Meeting abstract presented at VSS 2017