Disentangling vision and attention in multiple-object tracking: How crowding and collisions affect gaze anchoring and dual-task performance

Abstract

Previous studies of multiple-object tracking have shown that gaze behavior is affected by target collisions and target-distractor crowding. Therefore, in order to experimentally disentangle this collision-crowding confound, we examined events of target collisions with the bordering frame and crowding with distractors. We hypothesized that collisions are particularly demanding for covert attentional processing, whereas crowding particularly challenges peripheral vision. Results show that gaze is located closer to targets when they are crowded, as would be expected to reduce negative crowding effects by utilizing the higher spatial acuity of foveal vision. However, saccades, which interrupt visual information processing, were instead initiated as a function of target collisions with the bordering frame. Consequently, in a dual-task condition that required the detection of target changes, participants more frequently missed changes if they occurred in time intervals around a collision. Based on these results, superior performance should be expected if foveal gaze is optimally anchored among crowded targets and if potential target changes are monitored with peripheral vision. In addition to the implications for further laboratory research of multiple-object tracking, these findings are relevant to a multitude tasks that require the monitoring of several targets and the simultaneous detection of certain events in the visual periphery, as it is commonly the case, for instance, in sports.

Selection enables enhancement: An integrated model of object tracking

“…Although IMOT explains why tracking becomes difficult when targets are close to each other, it does not explain the related finding that tracking becomes difficult when targets are close to distractors (Shim et al, 2008;Vater et al, 2017). There are at least two possible ways that nearby distractors may disrupt tracking.…”

“…This effect is most obvious when an eye tracker is used to measure overt attention shifts. Participants fixate on threatened targets, that is, targets that have moved near distractors and are at risk of being lost (Vater et al, 2017;Zelinsky & Todor, 2010). Shifting gaze to a threatened target minimizes visual crowding, making it easier to distinguish the target from its surroundings (Whitney & Levi, 2011).…”

“…By exploring the conditions where tracking fails, researchers can determine when it is or is not possible to attend to moving objects. Holcombe, Chen, & Howe, 2014;Shim, Alvarez, & Jiang, 2008;Vater et al, 2017). These findings have given rise to a spatial interference account, which claims that neighboring targets interfere with each other during tracking (Franconeri et al, 2010).…”

Multiple-target tracking in human and machine vision

“…In addition, they tend to locate their gaze close to the targets that are in a crowd. This way, the crowd is projected to the fovea and can be handled easier because of the fovea's higher spatial resolution [80]. In general, this spatial limit in MTT is distinct from the attention-capacity limit [81].…”

Examining the functionality of peripheral vision: From fundamental understandings to applied sport science

“…Directing attention to relevant locations thus seems to facilitate task performance and "boost" the capabilities of peripheral vision. Hence, to identify how visual and attentional demands affect gaze behavior and performance in dual-task situations, these two demands were selectively manipulated in a third MOT study, conducted by Vater, Kredel, and Hossner (2017b). For the visual manipulation, a so-called crowding effect, which is "one of the most characteristic traits of peripheral vision" (Strasburger, Rentschler, & Jüttner, 2011, p. 29), was created by temporarily bringing certain targets and distractors into close proximity.…”