Abstract
As we move about the world, and objects in the world move relative to us, objects constantly move in and out of view as they are occluded by other objects. How does the visual system maintain attention on objects of interest, given such disruptions? To explore the spatiotemporal cues used to link the pre- and post-occlusion views of objects, we asked observers to track a set of moving objects that frequently passed behind static vertical occluders, as we manipulated each object's exit position.
Experiment 1 tested whether linking the two views relies on memory for the object's location. When objects exited occluders higher or lower than expected, tracking performance dropped, suggesting that linking the two object views relies on a location ‘marker’ at the site of disappearance. In Experiment 2, performance was better when objects exited closer to the initial entry location, rather than their expected extrapolated location, suggesting that the marker is not placed at the extrapolated position. In Experiment 3, tracking performance improved when objects reappeared from occluder centers, compared to at edges, again suggesting that the marker is placed close to the initial point of occlusion.
Together, these results suggest that when an object is occluded, the occlusion location is a critical factor in linking pre- and post-occlusion views, but not the extrapolated exit point, or even rudimentary elements of scene structure like the edges of the occluder. This simple trick could underlie much of our perception of persisting objecthood when an object disappears from view.
SLF was supported by a Killam Postdoctoral Fellowship, ZWP by NIMH Grant 1R01-MH60924, and BJS by NSF #0132444