Two related accounts of dual-task costs—multiple resource competition and crosstalk—explain why costs can be reduced when there is less overlap between the two tasks. However, distinguishing between competition for limited resources and crosstalk between concurrently performed operations has proven difficult. In the present study, we compared these two accounts with a dual-task paradigm in which participants were required to coordinate visual-manual and auditory-manual tasks with experimentally induced action effects. Critically, stimulus and response modalities were constant across conditions; what differed was the conceptual relationship between stimuli and action effects such that conceptual overlap was present either within or between tasks. We observed larger dual-task costs when related conceptual codes were present between tasks. We conclude that these results are best supported by the crosstalk account and that postresponse action effects are integrated into task representations engaged by central operations during response selection.

双任务成本的两个相关解释——多资源竞争和串扰——解释了为什么当两个任务之间的重叠较少时可以降低成本。然而，已证明难以区分对有限资源的竞争和同时执行的操作之间的串扰。在本研究中，我们将这两个帐户与双任务范式进行了比较，其中要求参与者将视觉-手动和听觉-手动任务与实验诱导的动作效果进行协调。至关重要的是，刺激和反应方式在各种条件下都是不变的。不同之处在于刺激和动作效果之间的概念关系，因此在任务内部或任务之间存在概念重叠。当任务之间存在相关的概念代码时，我们观察到更大的双任务成本。