Coherence of visual representations: attention and integration of contour shape information

Change blindness demonstrations illustrate the limited detail of visual representations. These demonstrations typically require disruption to the visual input when the change occurs or changes that occur very slowly. With sustained viewing or faster changes to the scenes, changes are more easily detected because attention can be effectively allocated to the part of the scene that is changing. Here, we investigate the interaction of visual attention and memory in the domain of 2-D contour shapes. We show, using a novel combination of established change blindness paradigms, that changes can go unnoticed even when they occur on isolated 2-D contour shapes. The effect appears to be due to involuntary updating of stored shape information. This involuntary updating process, however, is constrained so that previously attended shape information is updated only when attention is reallocated to qualitatively similar shape information.