Figure 1.
Participants observed a rapid serial visual presentation (RSVP) of letters with two targets (a white letter, and an “X”). In the single-task condition, participants observed a blank screen for 3 s before the next trial. For the dual task condition, participants answered two questions at the end of each trial; they were asked to identify the white letter and whether the “X” appeared before or after the white letter. Attentional load was manipulated by varying the inter-stimulus-interval across trials: 500 ms for the low attentional load, 300 ms for the intermediate attentional load, and 100 ms for the high attentional load. All trials were approximately 5.5 s long. Participants vocalized the/a/sound during the letter stream in both conditions, while listening to their auditory feedback, which was perturbed downward 50 cents for 200 ms either 250–1000 ms before target 1, or 100–1000 ms after target 1.
Figure 2.
Mean response accuracy for white letter identification during low, intermediate, and high attentional load.
Error bars represent standard error.
Figure 3.
Mean “X”-placement accuracy during low, intermediate, and high attentional load.
“X”-placement refers to whether the second target (“X”) in the RSVP was presented before or after the white letter. Error bars represent standard error.
Figure 4.
Averaged F0 traces for each attentional load condition.
Time zero represents the onset of the feedback perturbation.
Figure 5.
Block-order specific F0 traces for each attentional load condition.
Left: single-task first block-order; averaged F0 traces for the single-task, and dual-task low, intermediate, and high attentional load conditions. Right: dual-task first block-order; averaged F0 traces for the single-task, and dual-task low, intermediate, and high attentional load conditions. Time zero on both graphs represents the onset of the feedback perturbation.
Figure 6.
ERP waveforms averaged across all electrode sites for each attentional load condition.
The six averaged electrode sites are: F3, C3, Fz, Cz, F4 and C4. Time zero represents the onset of the feedback perturbation.
Figure 7.
Mean N1 amplitudes for the each electrode site.
The left electrode site is the average of the F3 and C3 electrodes; the medial electrode site is the average of the Fz and Cz electrodes; and right electrode site is the average of the F4 and C4 electrodes. Error bars represent standard error.