Abstract
We are studying how people track objects, and how eye-movements and attention contribute to this ability. We extend Keane and Pylyshyn (2006) and Aks, Pylyshyn, Haladjian et al. (2010), research on multiple object tracking (MOT) during disrupted viewing to learn whether the visual system encodes the position of tracked objects. Observers blinked their eyes when a brief tone was presented midway into each trial where they were tracking 4 of 8 identical items. Eye-blinks triggered item disappearance and the onset of a mask that blocked the display of items (for up to 1 second). During their disappearance, objects either continued moving, or halted until their reappearance. Better tracking occurred when items halted (or were displaced further back along their quasi-random motion trajectory) suggesting that the visual system refers back to past position samples to guide where tracked items are likely to reappear. In the current study, we explore the role of eye-movements in MOT. Our gaze-to-item analysis, described in Aks et al., VSS 2011, shows parallels between eye-movements and MOT performance. Gaze tends to remain near targets that were tracked just before the blink when objects disappeared. This gaze- to-item linkage was reliable across “halt” trials, highly idiosyncratic on “move” trials, and intermittent during the uninterrupted part of the tracking task. Switching gaze across targets, accounting for the intermittency, was surprisingly common and often spontaneous (see Elfanagely et al., VSS 2011). These results suggest that different eye-movement strategies can be used to maintain mental links to tracked objects.