Local-level and global-level form characteristics in apparent-motion correspondence

This study addressed the "correspondence" problem of apparent-motion (AM) perception in which parts of a scene must be matched with counterparts separated in time and space. Given evidence that AM correspondence can be mediated by two distinct processes--one based on a low-level motion-detection mechanism (the Reichardt process), the other involving the tracking of objects by visual attention (the attention-based process)--the present study explored how these processes interact in the perception of apparent motion between hierarchically structured figures. In three experiments, hierarchical figures were presented in a competition motion display so that, across frames, figures were identical at either the local or the global level. In experiment 1 it was shown that AM occurred between locally identical figures. Furthermore, with the Reichardt AM component eliminated in experiments 3 and 4, no preference was obtained for either level. While evidence from previous studies that form extraction for hierarchically structured figures proceeds from the global to the local levels, the present results indicate the irrelevance of such a global precedence in AM correspondence. In addition, it is suggested that Reichardt AM correspondence between local elements constrains attention-based AM correspondence between global figures so that both components move in the same direction. It is argued that this constraining process represents an elegant means of achieving AM correspondence between objects undergoing complex transformation.