Mallory E. Terry¹, Lana M. Trick¹; ¹University of Guelph

Many everyday tasks such as driving a car or playing team sports require keeping track of the positions of several independently moving items among others. This ability to select and keep track of the locations of multiple targets among identical non-targets (distractors) is called multiple-object tracking (MOT) and is thought to provide critical location information for performing actions toward the tracked targets (e.g., Pylyshyn, 2001). In support of this, our lab found reduced MOT performance when participants had to touch targets in MOT while tracking as compared to touching distractors. Though the theoretical framework supporting MOT is debated, several studies have found support for attentional enhancement of target locations during MOT. In the present study, we sought to investigate the impact of touch on the attentional enhancement of MOT targets by modulating what item was touched (target, distractor in MOT) and when the touch occurred in the trial (early, late, or both early and late). We hypothesized that if the attentional enhancement of targets decreased over time and was impacted by touch, touches that occurred later in the trial would have a more considerable impact on tracking performance relative to those that occurred earlier in the trial. In support of this, error rates were significantly lower for targets that were touched later in the trial compared to earlier. Interestingly, the impact of touch timing differed based on the item in MOT that was touched. For touched distractors, error rates did not differ based on when the distractor was touched, but instead RTs to decide if the touched distractor was a target were slower when it was touched later in the trial. Taken together, these findings provide evidence of a shared mechanism employed in MOT and visually guided touch that may be differentially impacted the item touched and the timing.