The dual-task practice advantage: Empirical evidence and cognitive mechanisms

Practice of two simultaneous component tasks in dual-task situations leads to an improvement in dual-task performance. The present paper reviews empirical evidence for this practice-related improvement and discusses its underlying cognitive mechanisms. In particular, the robustness of the phenomenon of dual-task practice advantage (DTPA) is evaluated. This phenomenon is described as an advantage in dual-task performance at the end of dual-task practice (i.e., simultaneous task practice) in comparison to the dual-task performance after single-task practice (i.e., separate task practice). The review investigates the existence of empirical evidence of the DTPA phenomenon and specifications of its mechanisms in the context of the allocation and scheduling hypothesis and the integration hypothesis. Evidence for the existence of the DTPA phenomenon and the allocation and scheduling hypothesis was demonstrated in dual tasks with (1) combinations of two sensorimotor tasks, (2) combinations of one continuous task and one sensorimotor task, (3) combinations of two working-memory tasks, and (4) combinations of one motor task and one cognitive task. In contrast, the findings demonstrate that the DTPA phenomenon in dual tasks with (5) combinations of two long-term memory retrieval tasks can instead be explained by the integration hypothesis. The relevance of these findings is discussed in relation to real-world problems.