Cognitive and neural practice-related changes
in the ability to coordinate two tasks

Executive processes are required to coordinate the processing stages in dual tasks. It has often assumed that executive processes control the temporal scheduling of potentially interfering processing stages. As a result of this scheduling, dual-task costs, e.g., an increase in processing time or errors during the simultaneous processing of two tasks compared to the processing of single tasks, can be observed. However, some recent results indicate that dual-task costs may disappear after prolonged dual-task practice. One main goal of the current project is to specify the nature of the learning processes leading to the disappearance of dual-task costs in the PRP paradigm. What exactly is it that is learned during repeated dual-task performance? That is, which kind of executive knowledge enables participants to perform the tasks without any dual-task costs? Two alternative hypotheses have been proposed that are addressed experimentally in the proposed project. According to the first hypothesis, participants acquire general executive knowledge on how to perfectly schedule (i.e., without any costs) the processing stages of two tasks that are performed simultaneously. According to the second hypothesis, participants acquire direct associations between the stimuli and responses that have been experienced. The direct links allow for automatic processing and enable the system to perfectly coordinate performances on two different tasks. Our second main goal in the context of the present research project 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 will be applied to localize dual-task related brain areas at the beginning and at the end of a prolonged period of task practice.

Department of Psychology
Humboldt-University Berlin
Wolfgang Köhler-Haus
Rudower Chaussee 18
D-12489 Berlin