The Influence of a Moving Object's Location on Object Identity Judgments

People integrate "what" and "where" information to recognize objects. Even when irrelevant or uninformative, location information can influence object identity judgments. When two sequential stationary objects occupy the same location, people are faster and more accurate to respond (sensitivity effects) and are more likely to judge the objects as identical (spatial congruency bias [SCB]). Other paradigms using moving objects highlight spatiotemporal contiguity's role in object processing. To bridge these gaps, we conducted two preregistered experiments asking how moving objects' locations (trajectories) affect identity judgments, both at fixation and across eye movements. In Experiment 1, subjects fixated a constant location and judged whether two sequentially presented moving stimuli were the same or different object identities. The first stimulus moved linearly from behind one occluder to another. The second stimulus reappeared (still moving) continuing along the same spatiotemporal trajectory (Predictable trajectory), or from the same initial location (Same Exact trajectory), or a different location (Different trajectory). We found the strongest sensitivity and SCB for Same Exact trajectory, with a smaller but significant SCB for Predictable trajectory. In Experiment 2, subjects performed a saccade during occlusion, revealing a robust SCB for Same Exact trajectory in retinotopic coordinates, with a smaller SCB for Predictable trajectory in both retinotopic and spatiotopic coordinates. Our findings strengthen prior reports that object-location binding is primarily retinotopic after both object and eye movements, but the presence of concurrent weak SCB effects along predictable and spatiotopic trajectories suggests more ecologically relevant information may also be incorporated when objects are moving more continuously.