Unequal attention allocation during multiple object tracking: Evidence from an eye-tracking study

In many situations, such as driving and playing team sports, we are required to allocate our attention unevenly across multiple moving targets that have different levels of relevance or importance (priority) to us. While previous studies have demonstrated an apparent ability to allocate attention in an uneven way to objects/regions in multiple object tracking (MOT), how such differential prioritisation comes about is still an open question. In this study, we investigated the role of eye movements in an MOT task where two targets varied in their likelihood of being queried for a motion direction estimate. As the priority of a target increased, participants fixated on or near the object more frequently and longer, and their direction estimates were more accurate. We explored the role of different tracking strategies (centroid vs. target-switching), investigating how these are differentially employed depending on target priority. Our findings support the flexible deployment of attention in a graded manner and demonstrate that differential prioritisation primarily involves differential looking between targets.