Practice-related optimization of dual-task performance: Efficient task instantiation during overlapping task processing.

We compared the effects of extended dual-task practice in a task situation of the psychological refractory period (PRP) type with the effects of single-task practice. The experiments tested the assumption that performance of Task 2 in the PRP task improves more rapidly with dual-task practice than with single-task practice, which points to a preponed instantiation of Task 2 during dual-task processing in working memory and to the acquisition of dual-task coordination skills. Experiments 1 and 2 showed that such dual-task coordination skills can be acquired under conditions of less-complex tasks with no more than four stimulus-response mappings in Task 2, independently on the compatibility of the mappings. Experiment 3 showed no evidence for the acquisition of dual-task coordination skills under condition of eight stimulus-response mappings in Task 2. This indicates that the working memory load exposed by the number of stimulus-response mappings is a critical parameter limiting the degree to which participants can prepone the conjoint instantiation of two task sets during dual-task processing. The findings specify a model assuming the conjoint and efficient initiation of task sets in working memory as a result of extended dual-task practice. (PsycINFO Database Record (c) 2018 APA, all rights reserved).