Fig. 1.

Timeline for a dual-task trial involving the Gabor- and dot-tracking tasks. During the pretracking phase (8,000 ms), participants were shown a white dot overlaid over a colored Gabor. A cue appeared (3,000 ms), indicating whether the task would involve dot tracking, Gabor tracking, or both. The cue was onscreen for 2,000 ms, and then, a further 2,000 ms after it had disappeared, the distractor stimuli appeared (a second dot and second Gabor). The Gabors alternated every screen refresh for 1,000 ms, allowing both to be visible. The dots and Gabors then changed in featural values over an 8,000-ms tracking interval. Participants had to follow the identity of the target(s) stimuli and indicate whether or not a single probe was the target (equally likely). In dual-tracking trials, the probed task (Gabor or dot task) was selected at random