On the way to an interpreter advantage in coordination

We hypothesize that there may be an interpreter advantage associated with the bottleneck switching component of the coordination skill. If an advantage in coordination was to be found in the present study, the advantageous group of interpreting students would outperform in dual-task costs (the difference between dual-task and single-task conditions, with smaller costs suggesting better coordination), and the better performance would be restricted to Task 2 (suggesting bottleneck switching component of coordination). The advantage may probably be found at the intermediate stage of interpreting training (Experiment 1) but not at the beginning stage (Experiment 2).
Data obtained from the dual-task experiment included accuracy (ACC) and response time (RT) for Task 1 and Task 2. The four types of data were analyzed separately following the same procedure. Specifically, the dual-task costs were subjected to an ANCOVA analysis with a between-group variable of Group (Interpreting, Control for Experiment 1; Interpreting-less and Control for Experiment 2a; Interpreting-more and Control for Experiment 2b), a within-group variable of Condition (dual-task_100, dual-task_150, dual-task_450, with 100, 150, 450 referring to the three SOA conditions). The covariate for Experiment 1 (the intermediate stage of interpreting training) was mother’s education level, and that for Experiment 2a (the beginning stage, with relatively less interpreting training) was L2 proficiency and frequency of L2 use, but there was no covariate for Experiment 2b.
The results showed that, in Experiment 1, the Interpreter group exhibited smaller dual-task costs only in Task 2 than the Control group, suggesting an interpreter advantage in coordination, especially in the bottleneck switching component at the intermediate stage of interpreting training. In Experiment 2a and 2b, no significant group differences were obtained, suggesting no evidence for an interpreter advantage in coordination.