A series of experiments will investigate a new motion illusion in which dots passing through one another appear to pause momentarily upon coincidence. Three classes of models (inference, vector integration, and configuration) will be examined using both qualitative and quantitative measurement procedures. Interference models hold that the perception of pausing is a result of cognitive inference (zero velocity inferred to result from the perception of bouncing) and are distinguished from models specifying early, automatic, sensory processes. Vector integration models hold that pausing results from the integration of equal but opposite motion vectors. Two forms of integration (vector addition and vector averaging) will be examined. Configuration models specify global units for integration (local vectors are integrated to correspond to a detected global unit). These models are contrasted with models specifying integration on only local units occupying the same spatial location. Each model makes different predictions on a series of motion displays as to the degree and nature of pausing that should be seen. Finally, to find the processing locus of the illusion (central or peripheral), displays containing cognitive (subjective and phantom) contours will be examined. If these contours pause it would suggest a central locus for the illusion.