Abstract
Brief visutal stimuli presented in rapid sequience, one to the left and one to the right, appear to occur left first, then right, regardless of the actual order of presentation. This illutsion persists under conditions of forced-choice testing and does not vary with presemitation to the same or opposite retinal hemifields, A series of experiments suggests that this illutsion may be the product of an internal mechanism that scans visual inputs in a left-to-right order.