Executive processes are required to coordinate the processing stages in dual-task situations. It is often assumed that executive processes schedule potentially interfering processing stages sequentially. As a result of the sequential scheduling, dual-task costs (e.g., an increase in processing time and/or errors during the simultaneous processing of two tasks compared to the processing of the single component tasks) can be observed.

Some recent results indicate that dual-task costs may disappear after prolonged dual-task practice. Our general goal in the proposed project is to specify the nature of the learning processes leading to the disappearance of dual-task costs. What exactly is it that is learned during repeated dual-task performance? That is, which kind of executive knowledge enables participants to perform two tasks without any dual-task costs?

Our previous findings are suggestive of two different learning mechanisms. First, participants might acquire executive knowledge that allows them to better coordinate two tasks. Second, participants might improve their processing of the individual component tasks. Our previous findings suggest that the combined influence of the two mechanisms allows dual-task costs to disappear and enables so-called perfect time sharing.

Our first specific goal in the proposed project is to specify further the two learning mechanisms and their interplay when performance in interfering dual-task situations needs to be optimized. Our second goal is to examine whether or not the disappearance of dual-task costs that occurs with prolonged task practice is accompanied by a re-organization of the involved neural structures. For that purpose, functional magnetic resonance imaging techniques will be used to investigate the neural implementation of dual-task processing at the beginning and at the end of a prolonged period of task practice.Executive processes are required to coordinate the processing stages in dual-task situations. It is often assumed that executive processes schedule potentially interfering processing stages sequentially. As a result of the sequential scheduling, dual-task costs (e.g., an increase in processing time and/or errors during the simultaneous processing of two tasks compared to the processing of the single component tasks) can be observed.