Abstract
How is object correspondence established across dynamic changes in the world so that objects are treated as continuous entities? Correspondence could be established by spatiotemporal continuity or by surface feature continuity. We examined the relative contributions of surface feature and spatiotemporal information to object correspondence, within the context of object-based inhibition of return (IOR). In contrast to previous paradigms that depended on conscious report to assess object correspondence, object-based IOR assesses correspondence implicitly by measuring the efficiency of orienting to a previously attended object. In the present experiments, one of two colored array objects was cued, the objects moved to new locations, and participants executed a saccade to either the previously attended or unattended object. We systematically manipulated the objects' surface feature and spatiotemporal properties to measure the relative contributions of both sources of information to object correspondence. In Experiments 1 and 2, we kept spatiotemporal information consistent but either changed the objects' colors to new values (Experiment 1) or swapped the objects' colors (Experiment 2) during the change in spatial position. Object-based IOR was observed despite a color change in Experiment 1 but was eliminated in Experiment 2 when the objects switched surface features, demonstrating that surface feature continuity contributes to object correspondence in IOR. In Experiment 3, we kept surface feature information consistent but eliminated spatiotemporal continuity by removing the linking motion between the original and updated locations. Surface feature continuity was not sufficient to support object-based IOR in the presence of this type of salient spatiotemporal discontinuity. These data indicate that, contrary to the classic view that only spatiotemporal information drives correspondence operations, object persistence in dynamic displays is also computed on the basis of surface feature continuity. However, spatiotemporal features may be weighted more heavily than surface features in this paradigm.