Figure 1
Schematic illustration of the two hypothesized effects when adding knowledge and visual information as two sources of predictability. The left half shows additive effects, meaning that participants do not only lower the tracking error on repeated vs. random segments, but improve further when visual information is added. The right half shows the alternative option of visual information winning the race for resources and determining actions based on a feedforward control strategy.
Figure 2
Small portions of the tracking path as displayed during the experiment. We tested the effect of displaying 400ms of the tracking path ahead (b) vs. just the target (a). Participants followed the red square and its path as accurately as possible by controlling the white cross.
Figure 3
Experimental schedule over three testing days. The Familiarization and Practice blocks had 20 trials while the Test and Retention Blocks had 40 trials with a break. The 20 single- and 20 dual-task trials in the Test and Retention Block were counterbalanced across the sample. Half of the sample started with single-task trials and the other half started with dual-task trials. The third column of each block indicates whether predictive visual information was given (x = 400 ms), the fourth column indicates the presence of a repeating segment (middle = repeating segment in the middle, left or right = repeating segment that was trained in the middle was placed on the left or right, random = the repeating segment from the training blocks was replaced with a random segment).
Figure 4
Test Block. Left: RMSE data showing dual-task tracking performance for the two groups. The combination of Predictive visual information and a Repeated segment (light grey bars) significantly improved tracking performance (additive effect). Right: Reaction Times for the two groups. There were no differences in RT, neither between random and repeated segments, nor for the two predictive visual information conditions. Error bars represent the standard error of the mean.
Figure 5
Retention Block. Left: RMSE data showing dual-task tracking performance for the two groups. The combination of Predictive visual information and a Repeated segment (light grey bars) significantly improved tracking performance (additive effect). Right: Reaction Times for the two groups. There were no differences in RT, neither between random and repeated segments, nor for the two predictive visual information conditions. Error bars represent the standard error of the mean.
Figure 6
Additive effects of prior knowledge (Segment) and predictive visual information during dual tasking, showing that both sources of predictability aid dual tasking and that knowledge is not abandoned in favor of a feedforward control strategy.