Experimental task designs and behavioral results. (A) Experiment 1 task design, which included single-task auditory-vocal (AV) trials; single-task visual-manual (VM) trials; and Dual-Task (DT) trials. (B) Reaction time (RT) results for Experiment 1. (C) Task design for Experiments 2 and 3. For both experiments, Task 1 consisted of an array of one or four letters to be encoded for later recall at the end of the trial. In Experiment 3 only, the encoding array was followed at an SOA of 250 or 1,850 ms by Task 2, a sound requiring a speeded online response. (D) RT results for Experiment 3.