Good continuation with kinetic edges

Abstract

We examined the perceptual formation of extended contours from second-order kinetic-edges created by motion discontinuities. Paths were formed by spatially separate kinetic-edge elements, aligned along smooth paths, and embedded in randomly oriented noise elements. Path detection was severely degraded when the sign of motion contrast alternated along the path compared to when the same sign was used, or if random motion direction was assigned to each edge element, or if alternating opposite motion directions was used along the paths. Performance increased monotonically with the length of the path. Irrespectively of path curvature a fast temporal summation occurs within the first 200-400 ms and then levels off. Hence, the kinetic-edge grouping is relatively fast and a pure second-order process that senses whether the motion is globally in the same phase and direction along extended contours. © 2004 Elsevier Ltd. All rights reserved.