Attentional processing in a modified multiple object-tracking paradigm.

Previous research examining dynamic visual search showed that pop-out effects can be observed for color targets, though it is unclear whether these effects are attributable to the same pre-attentive mechanisms driving pop-out in static displays (Fu et al., Attention, Perception, & Psychophysics, 82, 3329-3339, 2020). Other research examining multiple-object tracking (MOT) demonstrated that people can track three to five objects simultaneously, with some uncertainty about the flexibility of attentional allocation during tracking (Meyerhoff et al., Attention, Perception, & Psychophysics, 79, 1255-1274, 2017). In three experiments, the present study combined a dynamic pop-out display with the MOT task. Participants saw moving objects with colors changing continuously and responded when a uniquely shaded target popped out among identical items. Experiment 1 examined the mechanisms driving dynamic visual search efficiency and dual task interference on both tracking and searching performance. Experiment 2 explored the effect of processing orientations (i.e., global/local). Experiment 3 incorporated an abrupt color change to examine performance. Results showed that search for a unique target in dynamic contexts required attention, with an interference effect observed for both searching and tracking in the dual task. Making the color change more abrupt improved performance but remained less efficient than static pop-out. Moreover, there is some evidence suggesting that adopting a global processing orientation may be more advantageous for task performance than a local processing orientation. Taken together, the current findings suggest that search for a unique target in dynamic contexts requires focal attention and that tracking and searching appear to involve similar processing mechanism that likely compete to draw from a shared pool of resources.