Abstract
We extend earlier Multiple Object Tracking (MOT) work assessing how position-coding mediates our ability to track objects. Past studies of interrupted tracking, where items disappear briefly from view, show MOT is better when objects halt during their disappearance than when they move (Keane & Pylyshyn; 2006), and that this halt-move difference occurs even when the abruptness of item-offset is controlled (Aks et al, VSS, 2009). Here we examine further the effect of masking, cuing item interrupts, and disappearance times on MOT. Method. We compare mask vs. no-mask, and cued vs. no-cued interruptions in a standard MOT task. Eye-blinks trigger items to disappear for different durations (50 to 900ms), and changes to item movement (e.g., halt vs. move). Eye-blinks and mask control abruptness of item offset and visible persistence. In cued-MOT, subjects blink their eyes when they hear a sound probe. In no-cued MOT, subjects spontaneously blink their eyes. Results. MOT is impaired in mask and cued trials, and when items move during their disappearance. The greater the distance between the disappearance and reappearance sites (measured along a linear motion extrapolation) the greater the impairment in tracking. We report several other interactions of this distance effect such as the finding that performance drops when the disappearance time increases, but only for the Move and not the Halt condition. One unexpected result is that MOT improved with disappearance time when eye-blinks and item disappearance were not cued. Conclusions. Our results provide further support for location-coding in MOT with the main effects of distance and whether objects halt or continue moving while invisible. The unexpected improvement in no-cue trials, when eye-blinks and item-disappearance occur spontaneously, suggests an additional influence on MOT.
Meeting abstract presented at VSS 2014