The influence of a moving object’s location on object identity judgments

People have the ability to combine both ‘what’ and ‘where’ information to recognize objects. Prior studies have revealed several ways location information can influence object identity judgments, even when location is irrelevant or uninformative. Specifically, in tasks determining whether two sequentially shown objects are the same or different, two types of location effects have been reported: facilitation (through reaction time priming and/or enhanced sensitivity) and “spatial congruency bias” (where people are more likely to judge objects as identical) when objects are in the same location. However, previous studies mainly focused on stationary instead of moving objects, with minimal exploration into how object movement affects object identity judgment and the underlying reference frames for such effects. To address these gaps, we conducted two pre-registered experiments using moving stimuli. In Experiment 1, subjects were required to fixate at one fixation location and judge whether two sequentially presented moving stimuli were the same or different object identities. The first stimulus emerged from an occluder and moved along a linear trajectory to pass behind another occluder. The second stimulus then emerged (still moving) from either the predictable location along the occluded spatiotemporal trajectory (predictable trajectory), from the same initial location (same exact trajectory), or from a different location (different trajectory). We found the most pronounced sensitivity and spatial congruency bias for stimuli on the same exact trajectory, with a smaller but significant bias effect for the predictable trajectory. In Experiment 2, subjects were required to perform a saccade during the occlusion period, further revealing that the spatial congruency bias on the same exact trajectory relies on retinotopic coordinates, while the (smaller) bias on the predictable trajectory is based on both retinotopic and spatiotopic coordinates across the eye movement. Our findings suggest that object-location binding for moving objects is still strongly retinotopic, but may also reflect more ecologically relevant predictable and spatiotopic information.