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Nicole L. Jardine, Adriane E. Seiffert; Shape influences target recovery after a blank in multiple object tracking. Journal of Vision 2009;9(8):243. doi: 10.1167/9.8.243.
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© ARVO (1962-2015); The Authors (2016-present)
People can keep track of target objects moving among identical distractors. If all objects momentarily disappear during tracking, observers have more difficulty recovering targets that move during the blank than objects that do not, suggesting observers tend to track without motion prediction (Keane & Pylyshyn, 2006). Is tracking always non-predictive or can object features assist observers' predictions of object positions? Here we test whether an object's shape can assist target recovery when its orientation corresponds to the object's direction of motion. Observers tracked 3 of 10 isosceles triangles whose orientation was either aligned or misaligned with their trajectories. All triangles moved in linear, predictable paths inside a square box and bounced off the walls of the box. All triangles moved for 4.2 sec before disappearing for 400 ms and then reappearing and continuing to move for 1 sec. During this blank, all triangles either paused or continued to move. Triangles reappeared in the same orientation that they had before disappearing. Results replicated previous work showing better target recovery when objects paused relative to when they moved during the blank. When triangles paused during the blank, tracking accuracy was significantly higher for aligned orientations (85±2%) relative to misaligned orientations (83±2%; t(24) = 2.12, p F(2,48) = 3.357, p t(24) = 3.357, p [[lt]].001). Target reacquisition after a disappearance improved when triangles were oriented toward their directions of motion. This suggests that, while object tracking primarily recruits position-tracking mechanisms, tracking can be predictive when an object's shape indicates its direction.
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